advice on cylinder head please!

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T

Tim Hobbs

Guest
Finally got around to removing the cylinder head today on the S2 (2.25
petrol, 3 bearing). A few oddities (Haynes has more head bolts than
my engine does!), but not too bad. Almost put my back out lifting the
bugger of course...

Anyway, the head gasket is actually in one piece - a few bits of
frayed metal but nothing that looks remotely like a breach. The
pistons and combustion chambers are very black though, and there is
some fairly thick coking on the pistons.

So, I'm not sure what is causing the poor compression. Having never
lifted the top off an engine before, I'm not sure what it is meant to
look like. I'm aware it shouldn't be black, but it's run like crap
for a fair while so not too surprising.

2 and 3 cylinder have a very noticeable step at TDC in the bores,
which are otherwise fairly smooth. Haven't measured it, but it's
enough to stop a fingernail. 1 and 4 aren't so bad.

Any suggestions on what I should do next? I'd expected to find a
totally shagged gasket, but I suspect that alone is not the cause of
my problems.

Tim
--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70
'06 Nissan Navara aka "The Truck"
 
On 2006-04-22, Tim Hobbs <[email protected]> wrote:

> I'm aware it shouldn't be black, but it's run like crap
> for a fair while so not too surprising.

I'm told that coking is pretty normal, I was surprised when I
dismantled an engine for the first time and found that three cylinders
were black with soot and coking while one was clean. As it turns out,
the clean one was the problem as its very cleanliness demonstrated,
washed by a coolant leak.

As for compression, if you've got a step in the bores then that
signifies wear, which if it's large enough it could cause exhaust
gasses to get into the crankcase (as it did in my case) but I'm not
sure if that's enough to lead to a drop in compression. The bores
becoming oval through wear might do I suppose. I used to get a lot of
oil in the air filter, it was coming up the crankcase breather hose
into the air system and being sucked as mist round to the filter, this
was happening due to the exhaust gasses blowing past the cylinder into
the crankcase. This was on a non-landy engine though.

Hopefully someone will tootle along later on and know your particular
model of landy engine well, all the above is just FYI.

--
Blast off and strike the evil Bydo empire!
 
Tim Hobbs wrote:
> Finally got around to removing the cylinder head today on the S2 (2.25
> petrol, 3 bearing). A few oddities (Haynes has more head bolts than
> my engine does!), but not too bad. Almost put my back out lifting the
> bugger of course...
>
> Anyway, the head gasket is actually in one piece - a few bits of
> frayed metal but nothing that looks remotely like a breach. The
> pistons and combustion chambers are very black though, and there is
> some fairly thick coking on the pistons.
>
> So, I'm not sure what is causing the poor compression. Having never
> lifted the top off an engine before, I'm not sure what it is meant to
> look like. I'm aware it shouldn't be black, but it's run like crap
> for a fair while so not too surprising.
>
> 2 and 3 cylinder have a very noticeable step at TDC in the bores,
> which are otherwise fairly smooth. Haven't measured it, but it's
> enough to stop a fingernail. 1 and 4 aren't so bad.
>
> Any suggestions on what I should do next? I'd expected to find a
> totally shagged gasket, but I suspect that alone is not the cause of
> my problems.
>
> Tim

Was this a general loss of compression on all cylinders or on one/two
cylinders only? Remember that there is not much compression on these
things, anyway. What was the reason for strating this investigation?

Whilst you've got the head off why not inspect/grind the valves? I've
had two cases of chunks out of exhaust valves. This whole area is
another potential compression loser.

I don't imagine that the wear in the bores is anything to worry about.
What you describe is fairly normal when a few miles have been
accumulated. As long as all cylinders are equally oily (preferably not
oily!) you can probably also rule out broken piston rings. Any other
symptoms like burning oil or high crankcase pressure?

Is the blackness oily?
 
On Sat, 22 Apr 2006 16:23:57 +0100, Dougal
<DougalAThiskennel.free-online.co.uk> wrote:

>Tim Hobbs wrote:
>> Finally got around to removing the cylinder head today on the S2 (2.25
>> petrol, 3 bearing). A few oddities (Haynes has more head bolts than
>> my engine does!), but not too bad. Almost put my back out lifting the
>> bugger of course...
>>
>> Anyway, the head gasket is actually in one piece - a few bits of
>> frayed metal but nothing that looks remotely like a breach. The
>> pistons and combustion chambers are very black though, and there is
>> some fairly thick coking on the pistons.
>>
>> So, I'm not sure what is causing the poor compression. Having never
>> lifted the top off an engine before, I'm not sure what it is meant to
>> look like. I'm aware it shouldn't be black, but it's run like crap
>> for a fair while so not too surprising.
>>
>> 2 and 3 cylinder have a very noticeable step at TDC in the bores,
>> which are otherwise fairly smooth. Haven't measured it, but it's
>> enough to stop a fingernail. 1 and 4 aren't so bad.
>>
>> Any suggestions on what I should do next? I'd expected to find a
>> totally shagged gasket, but I suspect that alone is not the cause of
>> my problems.
>>
>> Tim
>
>Was this a general loss of compression on all cylinders or on one/two
>cylinders only? Remember that there is not much compression on these
>things, anyway. What was the reason for strating this investigation?
>
>Whilst you've got the head off why not inspect/grind the valves? I've
>had two cases of chunks out of exhaust valves. This whole area is
>another potential compression loser.
>
>I don't imagine that the wear in the bores is anything to worry about.
>What you describe is fairly normal when a few miles have been
>accumulated. As long as all cylinders are equally oily (preferably not
>oily!) you can probably also rule out broken piston rings. Any other
>symptoms like burning oil or high crankcase pressure?
>
>Is the blackness oily?

The blackness is dry soot / carbon. It's rubbing off quite nicely
with a non-metallic pan scourer. The bores are clean without any
major scoring.

Last compression test was about 2002, just before it laid up for about
3 years. At the time the outer cylinders were about 7, the centre two
about 5. I suspected the gasket between the two centre bores. It ran
a bit rough, a bit smoky, but would still pull 60 mph+, so I didn't
fret about it. The more I ran it, the better it got.

Now back with an MoT, it ticks over OK but only if running quite rich.
It also produces bugger all power - only just enough to move itself in
low ratio. So I decided to lift the head and see how things looked,
expecting a buggered gasket. The gasket isn't great, but it is all in
one piece, just a few little splits and cracks, but nothing right
through.

I'll have a look at the Haynes and see if the valve grinding looks to
be within my skill set!! Now it's apart I want it to go back together
as good as it can be without spending money on it. If I'm going down
that route I can be trailered to Warren for a remanufactured engine.
My ethos on this truck is that I either botch it cheap at home or
really sort it properly.

Thanks for the advice - the valves, incidentally have a variety of
little dots on them. Some have 1, some 2 and one has 3. Does this
signify something?


--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70
'06 Nissan Navara aka "The Truck"
 
Tim Hobbs wrote:

> On Sat, 22 Apr 2006 16:23:57 +0100, Dougal
> <DougalAThiskennel.free-online.co.uk> wrote:
>
>
>>Tim Hobbs wrote:
>>
>>>Finally got around to removing the cylinder head today on the S2 (2.25
>>>petrol, 3 bearing). A few oddities (Haynes has more head bolts than
>>>my engine does!), but not too bad. Almost put my back out lifting the
>>>bugger of course...
>>>
>>>Anyway, the head gasket is actually in one piece - a few bits of
>>>frayed metal but nothing that looks remotely like a breach. The
>>>pistons and combustion chambers are very black though, and there is
>>>some fairly thick coking on the pistons.
>>>
>>>So, I'm not sure what is causing the poor compression. Having never
>>>lifted the top off an engine before, I'm not sure what it is meant to
>>>look like. I'm aware it shouldn't be black, but it's run like crap
>>>for a fair while so not too surprising.
>>>
>>>2 and 3 cylinder have a very noticeable step at TDC in the bores,
>>>which are otherwise fairly smooth. Haven't measured it, but it's
>>>enough to stop a fingernail. 1 and 4 aren't so bad.
>>>
>>>Any suggestions on what I should do next? I'd expected to find a
>>>totally shagged gasket, but I suspect that alone is not the cause of
>>>my problems.
>>>
>>>Tim
>>
>>Was this a general loss of compression on all cylinders or on one/two
>>cylinders only? Remember that there is not much compression on these
>>things, anyway. What was the reason for strating this investigation?
>>
>>Whilst you've got the head off why not inspect/grind the valves? I've
>>had two cases of chunks out of exhaust valves. This whole area is
>>another potential compression loser.
>>
>>I don't imagine that the wear in the bores is anything to worry about.
>>What you describe is fairly normal when a few miles have been
>>accumulated. As long as all cylinders are equally oily (preferably not
>>oily!) you can probably also rule out broken piston rings. Any other
>>symptoms like burning oil or high crankcase pressure?
>>
>>Is the blackness oily?
>
>
> The blackness is dry soot / carbon. It's rubbing off quite nicely
> with a non-metallic pan scourer. The bores are clean without any
> major scoring.
>
> Last compression test was about 2002, just before it laid up for about
> 3 years. At the time the outer cylinders were about 7, the centre two
> about 5. I suspected the gasket between the two centre bores. It ran
> a bit rough, a bit smoky, but would still pull 60 mph+, so I didn't
> fret about it. The more I ran it, the better it got.
>
> Now back with an MoT, it ticks over OK but only if running quite rich.
> It also produces bugger all power - only just enough to move itself in
> low ratio. So I decided to lift the head and see how things looked,
> expecting a buggered gasket. The gasket isn't great, but it is all in
> one piece, just a few little splits and cracks, but nothing right
> through.
>
> I'll have a look at the Haynes and see if the valve grinding looks to
> be within my skill set!! Now it's apart I want it to go back together
> as good as it can be without spending money on it. If I'm going down
> that route I can be trailered to Warren for a remanufactured engine.
> My ethos on this truck is that I either botch it cheap at home or
> really sort it properly.
>
> Thanks for the advice - the valves, incidentally have a variety of
> little dots on them. Some have 1, some 2 and one has 3. Does this
> signify something?

The cylinders/bores don't sound too horrible - probably not even
horrible at all - from your description.

I'd look at taking the valves out of the head, cleaning up the crud
which I suspect is partially blocking the airways (caused by cold
running, valve stem oil leaks etc.) and grinding the valves.

Dots on the valves - probably marks made by those who have had the
engine apart before to indicate from which cylinder each came.
 

"Tim Hobbs" wrote ...
>
> The blackness is dry soot / carbon. It's rubbing off quite nicely
> with a non-metallic pan scourer. The bores are clean without any
> major scoring.
>
> Last compression test was about 2002, just before it laid up for about
> 3 years. At the time the outer cylinders were about 7, the centre two
> about 5. I suspected the gasket between the two centre bores. It ran
> a bit rough, a bit smoky, but would still pull 60 mph+, so I didn't
> fret about it. The more I ran it, the better it got.
>
> Now back with an MoT, it ticks over OK but only if running quite rich.
> It also produces bugger all power - only just enough to move itself in
> low ratio. So I decided to lift the head and see how things looked,
> expecting a buggered gasket. The gasket isn't great, but it is all in
> one piece, just a few little splits and cracks, but nothing right
> through.
>
> I'll have a look at the Haynes and see if the valve grinding looks to
> be within my skill set!! Now it's apart I want it to go back together
> as good as it can be without spending money on it. If I'm going down
> that route I can be trailered to Warren for a remanufactured engine.
> My ethos on this truck is that I either botch it cheap at home or
> really sort it properly.
>
> Thanks for the advice - the valves, incidentally have a variety of
> little dots on them. Some have 1, some 2 and one has 3. Does this
> signify something?
>

Grinding the valves in is not a difficult job (getting the head off is much
worse) provided you have the necessary tools ,a "G" clamp with two prongs to
compress the valve spring so you can get the cotter pins out which will then
fly everywhere, and it's one job I would certainly do as a matter of course
if you have the head off.
It also allows you to check the valves for soundness, no chips or dents on
the rim etc which could be your problem, the springs for soundness, and to
replace the little rubber valve stem seals which will cause smoking if old
and knackered.

That said, if you are going to go down the road of a full professional
rebuild don't bother.

--
Regards
Bob Hobden
17mls W. of London.UK


 
On Sat, 22 Apr 2006 16:54:26 +0100, "Bob Hobden" <[email protected]>
wrote:

>
>"Tim Hobbs" wrote ...
>>
>> The blackness is dry soot / carbon. It's rubbing off quite nicely
>> with a non-metallic pan scourer. The bores are clean without any
>> major scoring.
>>
>> Last compression test was about 2002, just before it laid up for about
>> 3 years. At the time the outer cylinders were about 7, the centre two
>> about 5. I suspected the gasket between the two centre bores. It ran
>> a bit rough, a bit smoky, but would still pull 60 mph+, so I didn't
>> fret about it. The more I ran it, the better it got.
>>
>> Now back with an MoT, it ticks over OK but only if running quite rich.
>> It also produces bugger all power - only just enough to move itself in
>> low ratio. So I decided to lift the head and see how things looked,
>> expecting a buggered gasket. The gasket isn't great, but it is all in
>> one piece, just a few little splits and cracks, but nothing right
>> through.
>>
>> I'll have a look at the Haynes and see if the valve grinding looks to
>> be within my skill set!! Now it's apart I want it to go back together
>> as good as it can be without spending money on it. If I'm going down
>> that route I can be trailered to Warren for a remanufactured engine.
>> My ethos on this truck is that I either botch it cheap at home or
>> really sort it properly.
>>
>> Thanks for the advice - the valves, incidentally have a variety of
>> little dots on them. Some have 1, some 2 and one has 3. Does this
>> signify something?
>>
>
>Grinding the valves in is not a difficult job (getting the head off is much
>worse) provided you have the necessary tools ,a "G" clamp with two prongs to
>compress the valve spring so you can get the cotter pins out which will then
>fly everywhere, and it's one job I would certainly do as a matter of course
>if you have the head off.
>It also allows you to check the valves for soundness, no chips or dents on
>the rim etc which could be your problem, the springs for soundness, and to
>replace the little rubber valve stem seals which will cause smoking if old
>and knackered.
>
>That said, if you are going to go down the road of a full professional
>rebuild don't bother.

Thanks Bob - that's what I'm trying to avoid. I don't plan to do a
pro rebuild on this engine - if I can't get this one right then I'll
simply swap the lot for a new one. Getting this one right will be a
whole lot cheaper, and more rewarding!

--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70
'06 Nissan Navara aka "The Truck"
 

>The cylinders/bores don't sound too horrible - probably not even
>horrible at all - from your description.
>
>I'd look at taking the valves out of the head, cleaning up the crud
>which I suspect is partially blocking the airways (caused by cold
>running, valve stem oil leaks etc.) and grinding the valves.
>
>Dots on the valves - probably marks made by those who have had the
>engine apart before to indicate from which cylinder each came.

Right - quick dash to Halfords before closing to get a spring
compressor!

--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70
'06 Nissan Navara aka "The Truck"
 
>
>Now back with an MoT, it ticks over OK but only if running quite rich.
>It also produces bugger all power - only just enough to move itself in
>low ratio. So I decided to lift the head and see how things looked,
>expecting a buggered gasket. The gasket isn't great, but it is all in
>one piece, just a few little splits and cracks, but nothing right
>through.
>
>I'll have a look at the Haynes and see if the valve grinding looks to
>be within my skill set!! Now it's apart I want it to go back together
>as good as it can be without spending money on it. If I'm going down
>that route I can be trailered to Warren for a remanufactured engine.
>My ethos on this truck is that I either botch it cheap at home or
>really sort it properly.
>

It's certainly worth doing a full decoke, grinding the valves in,
checking the head for flatness - use a good, new steel rule and a
feeler gauge - and re-assembling with a new head gasket. The cost is
low and will eliminate gasket trouble, valve trouble and a warped
head. If it still isn't giving good compressions then you're looking
at a more expensive rebuild, possibly rebore etc etc, at this point
you should be seriously considering a professional rebuild or a recon
engine (unless you fancy doing it all yourself.....)

One point, if you can't get good compressions after doing the head,
take an oil can (one of those with the plunger) and pump 3 or 4
squirts of oil into the spark plug hole, refit the compression tester
and test the compression again. If the compression gets significantly
better then suspect worn rings/bores - rebore/recon time.

Alex
 
Tim Hobbs wrote:

> On Sat, 22 Apr 2006 16:54:26 +0100, "Bob Hobden" <[email protected]>
> wrote:
>
>>
>>"Tim Hobbs" wrote ...
>>>
>>> The blackness is dry soot / carbon. It's rubbing off quite nicely
>>> with a non-metallic pan scourer. The bores are clean without any
>>> major scoring.
>>>
>>> Last compression test was about 2002, just before it laid up for about
>>> 3 years. At the time the outer cylinders were about 7, the centre two
>>> about 5. I suspected the gasket between the two centre bores. It ran
>>> a bit rough, a bit smoky, but would still pull 60 mph+, so I didn't
>>> fret about it. The more I ran it, the better it got.
>>>
>>> Now back with an MoT, it ticks over OK but only if running quite rich.
>>> It also produces bugger all power - only just enough to move itself in
>>> low ratio. So I decided to lift the head and see how things looked,
>>> expecting a buggered gasket. The gasket isn't great, but it is all in
>>> one piece, just a few little splits and cracks, but nothing right
>>> through.
>>>
>>> I'll have a look at the Haynes and see if the valve grinding looks to
>>> be within my skill set!! Now it's apart I want it to go back together
>>> as good as it can be without spending money on it. If I'm going down
>>> that route I can be trailered to Warren for a remanufactured engine.
>>> My ethos on this truck is that I either botch it cheap at home or
>>> really sort it properly.
>>>
>>> Thanks for the advice - the valves, incidentally have a variety of
>>> little dots on them. Some have 1, some 2 and one has 3. Does this
>>> signify something?
>>>
>>
>>Grinding the valves in is not a difficult job (getting the head off is
>>much worse) provided you have the necessary tools ,a "G" clamp with two
>>prongs to compress the valve spring so you can get the cotter pins out
>>which will then fly everywhere, and it's one job I would certainly do as a
>>matter of course if you have the head off.
>>It also allows you to check the valves for soundness, no chips or dents on
>>the rim etc which could be your problem, the springs for soundness, and to
>>replace the little rubber valve stem seals which will cause smoking if old
>>and knackered.
>>
>>That said, if you are going to go down the road of a full professional
>>rebuild don't bother.
>
> Thanks Bob - that's what I'm trying to avoid. I don't plan to do a
> pro rebuild on this engine - if I can't get this one right then I'll
> simply swap the lot for a new one. Getting this one right will be a
> whole lot cheaper, and more rewarding!
>

Black is normal for the combustion chambers of this engine (or any other
I've had apart for that matter) and will have been made worse by the fact
it would only run rich - as long as it is the same on all cylinders and not
oily. Along with others I agree that you may have poor valve sealing - I
don't suppose you checked tappet clearances before taking it apart? With
valves reground and checked and cylinder head flatness checked and a new
gasket, the only remaining source of poor compression will be broken or
worn rings (or excessively worn/scored bores, which you appear not to have)
which usually show as crankcase pressure (oil leaking everywhere) before
engine performance gets as bad as you report. You may have had valves
sticking as well as poor seating. Once the valves are out it is possible
you may find it bad enough that you need new valves or even seat inserts
fitted (the last is not a home job!)
JD
 

"Tim Hobbs" wrote ...
"Bob Hobden" wrote>
>>
>>Grinding the valves in is not a difficult job (getting the head off is
>>much
>>worse) provided you have the necessary tools ,a "G" clamp with two prongs
>>to
>>compress the valve spring so you can get the cotter pins out which will
>>then
>>fly everywhere, and it's one job I would certainly do as a matter of
>>course
>>if you have the head off.
>>It also allows you to check the valves for soundness, no chips or dents on
>>the rim etc which could be your problem, the springs for soundness, and to
>>replace the little rubber valve stem seals which will cause smoking if old
>>and knackered.
>>
>>That said, if you are going to go down the road of a full professional
>>rebuild don't bother.
>
> Thanks Bob - that's what I'm trying to avoid. I don't plan to do a
> pro rebuild on this engine - if I can't get this one right then I'll
> simply swap the lot for a new one. Getting this one right will be a
> whole lot cheaper, and more rewarding!
>

Did I say Cotter pins !!! I must have had too much to drink.

--
Regards
Bob
"Never get so busy making a living
that you forget to make a life"


 

"Alex" wrote
>
> It's certainly worth doing a full decoke, grinding the valves in,
> checking the head for flatness - use a good, new steel rule and a
> feeler gauge - and re-assembling with a new head gasket. The cost is
> low and will eliminate gasket trouble, valve trouble and a warped
> head. If it still isn't giving good compressions then you're looking
> at a more expensive rebuild, possibly rebore etc etc, at this point
> you should be seriously considering a professional rebuild or a recon
> engine (unless you fancy doing it all yourself.....)
>
> One point, if you can't get good compressions after doing the head,
> take an oil can (one of those with the plunger) and pump 3 or 4
> squirts of oil into the spark plug hole, refit the compression tester
> and test the compression again. If the compression gets significantly
> better then suspect worn rings/bores - rebore/recon time.
>

Would it be worth his while replacing the rings anyway while he has the head
off? Provided Tim feels happy doing that. I say that as a friend had a
Diesel 2.5 NA that started to smoke a bit and he changed his whilst doing
the head and valve stem seals etc. Reckons it's made a noticeable difference
to the engine as some rings were well stuck in the pistons.

--
Regards
Bob
"Never get so busy making a living
that you forget to make a life"



 
Tim Hobbs wrote:
> Finally got around to removing the cylinder head today on the S2 (2.25
> petrol, 3 bearing). A few oddities (Haynes has more head bolts than
> my engine does!), but not too bad. Almost put my back out lifting the
> bugger of course...
>
> Anyway, the head gasket is actually in one piece - a few bits of
> frayed metal but nothing that looks remotely like a breach. The
> pistons and combustion chambers are very black though, and there is
> some fairly thick coking on the pistons.
>
> So, I'm not sure what is causing the poor compression. Having never
> lifted the top off an engine before, I'm not sure what it is meant to
> look like. I'm aware it shouldn't be black, but it's run like crap
> for a fair while so not too surprising.
>
> 2 and 3 cylinder have a very noticeable step at TDC in the bores,
> which are otherwise fairly smooth. Haven't measured it, but it's
> enough to stop a fingernail. 1 and 4 aren't so bad.
>
> Any suggestions on what I should do next? I'd expected to find a
> totally shagged gasket, but I suspect that alone is not the cause of
> my problems.
>
> Tim
First, do not use a chisel, screwdriver, knife or any other sharp tool
to get the gasket off. I've found that a Dremel-like tool works best.

Second, make sure that you take the head to a machine shop so it can be
milled. Anytime, cylinder heads are removed from the block they will
warp. Explain any damage the machine shop and why you removed the head
in the first place. More they know the better the job you get.

Third, use the highest quality head gasket available. I have always had
success with copper shim type gaskets. Those are generally found on high
compression, supercharged and turbocharged engines.

Fourth, run a straight edge (such as a machinists ruler) across the top
of the engine block. You're checking for any warping of the block
itself. You may [or may not] have to remove the block for the shop to
work on it.

I started off with the hairy stuff at first, Eh? You didn't mention what
the engine was, petrol or diesel. If petrol, any backfiring? If so,
fouled plugs, ignition wire gone bad, distributor/rotor needs replacing.
If diesel, a lost of compression through a fault in the head gasket, oil
blow by on the piston rings, timing belt/chain out-of-wack.

If you have a diesel and you're close to a seaport, such as I am here in
Norfolk [aka Hampton Roads] Virginia, a marine mechanic could be quite a
bit cheaper than your local Land Rover dealer.

Sorry, folks but the local dealer has tried to rape me when my wife
brought hers or I brought mine in. My son learned from my experiences.
Just my quid's worth of knowledge.

Cheers.
 
Jeffrey S Austin wrote:

> Tim Hobbs wrote:
>> Finally got around to removing the cylinder head today on the S2 (2.25
>> petrol, 3 bearing). A few oddities (Haynes has more head bolts than
>> my engine does!), but not too bad. Almost put my back out lifting the
>> bugger of course...
>>
>> Anyway, the head gasket is actually in one piece - a few bits of
>> frayed metal but nothing that looks remotely like a breach. The
>> pistons and combustion chambers are very black though, and there is
>> some fairly thick coking on the pistons.
>>
>> So, I'm not sure what is causing the poor compression. Having never
>> lifted the top off an engine before, I'm not sure what it is meant to
>> look like. I'm aware it shouldn't be black, but it's run like crap
>> for a fair while so not too surprising.
>>
>> 2 and 3 cylinder have a very noticeable step at TDC in the bores,
>> which are otherwise fairly smooth. Haven't measured it, but it's
>> enough to stop a fingernail. 1 and 4 aren't so bad.
>>
>> Any suggestions on what I should do next? I'd expected to find a
>> totally shagged gasket, but I suspect that alone is not the cause of
>> my problems.
>>
>> Tim
> First, do not use a chisel, screwdriver, knife or any other sharp tool
> to get the gasket off. I've found that a Dremel-like tool works best.
>
> Second, make sure that you take the head to a machine shop so it can be
> milled. Anytime, cylinder heads are removed from the block they will
> warp. Explain any damage the machine shop and why you removed the head
> in the first place. More they know the better the job you get.

With the 2.25 Landrover petrol engine the head will not be warped unless it
has been cooked, and there should be no need to have it machined. We are
talking about a very robustly built low compression engine here.

>
> Third, use the highest quality head gasket available. I have always had
> success with copper shim type gaskets. Those are generally found on high
> compression, supercharged and turbocharged engines.

This engine is neither high compression, supercharged nor turbocharged. Any
good quality gasket will be satisfactory provided the head is not warped
and the mating surfaces are clean and undamaged, and the head is tightened
down correctly and retensioned at around 1000km.

>
> Fourth, run a straight edge (such as a machinists ruler) across the top
> of the engine block. You're checking for any warping of the block
> itself. You may [or may not] have to remove the block for the shop to
> work on it.
>
> I started off with the hairy stuff at first, Eh? You didn't mention what
> the engine was, petrol or diesel. If petrol, any backfiring? If so,
> fouled plugs, ignition wire gone bad, distributor/rotor needs replacing.
> If diesel, a lost of compression through a fault in the head gasket, oil
> blow by on the piston rings, timing belt/chain out-of-wack.

He says clearly it is a 2.25 petrol engine.

>
(snip)
>
> Sorry, folks but the local dealer has tried to rape me when my wife
> brought hers or I brought mine in. My son learned from my experiences.
> Just my quid's worth of knowledge.
>
> Cheers.

JD

 
In message <[email protected]>
Tim Hobbs <[email protected]> wrote:

> Finally got around to removing the cylinder head today on the S2 (2.25
> petrol, 3 bearing). A few oddities (Haynes has more head bolts than
> my engine does!), but not too bad. Almost put my back out lifting the
> bugger of course...
>
> Anyway, the head gasket is actually in one piece - a few bits of
> frayed metal but nothing that looks remotely like a breach. The
> pistons and combustion chambers are very black though, and there is
> some fairly thick coking on the pistons.

That's not terribly inusual on engines of that age, indeed de-coking
used to a fairly routine operation - hence top-end sets are often
referred to as de-coke sets.

>
> So, I'm not sure what is causing the poor compression. Having never
> lifted the top off an engine before, I'm not sure what it is meant to
> look like. I'm aware it shouldn't be black, but it's run like crap
> for a fair while so not too surprising.
>
> 2 and 3 cylinder have a very noticeable step at TDC in the bores,
> which are otherwise fairly smooth. Haven't measured it, but it's
> enough to stop a fingernail. 1 and 4 aren't so bad.

The 2¼'s will take a fair bit of abuse, so a step is not the end
of the world - it does need to be measured though to check it
is in tolerance. Look of the sides of the bores for signs of
blow-by, i.e. gas passing the piston rings. Black/discoloured
"scorching" indicates ring/bore problems.

>
> Any suggestions on what I should do next? I'd expected to find a
> totally shagged gasket, but I suspect that alone is not the cause of
> my problems.
>

While you have the head off, strip it down and check the condition
of the valves and valve seats - there should be a nice shiney ring
round the valves and a corresponding one on the valve seat - any
"gaps" mean the valve is not closing properly which will give
low compression. Also check the valve guides for wear. The Haynes
manual gives the required info. Having got that far, you may as
well get the head skimmed. Also check the condition of the
rockers - particulary the bits that make contact with the push
rods - and check the push rods (roll them on a flat surface looking
for kinks). Also have a look at th valve springs - line them up on
a flat surface an see if they are all the same length. The springs
are not over-critical on a 2¼ pertol, by one school of thought
says replace them anyway having got that far (94p each).

Assuming all is well, and you intend running the engine again for
a while, you might consider having "unleaded" valave seats put
it while the head is away - not least as you get to avoid lapping
the valves yourself that way!

> Tim

Richard

--
www.beamends-lrspares.co.uk [email protected]
RISC-OS - Where have all the good guys gone?
Boycott the Yorkshire Dales - No Play, No Pay
 
Jeffrey S Austin wrote:
> Tim Hobbs wrote:
>> Finally got around to removing the cylinder head today on the S2 (2.25
>> petrol, 3 bearing). A few oddities (Haynes has more head bolts than
>> my engine does!), but not too bad. Almost put my back out lifting the
>> bugger of course...
>>
>> Anyway, the head gasket is actually in one piece - a few bits of
>> frayed metal but nothing that looks remotely like a breach. The
>> pistons and combustion chambers are very black though, and there is
>> some fairly thick coking on the pistons.
>>
>> So, I'm not sure what is causing the poor compression. Having never
>> lifted the top off an engine before, I'm not sure what it is meant to
>> look like. I'm aware it shouldn't be black, but it's run like crap
>> for a fair while so not too surprising.
>>
>> 2 and 3 cylinder have a very noticeable step at TDC in the bores,
>> which are otherwise fairly smooth. Haven't measured it, but it's
>> enough to stop a fingernail. 1 and 4 aren't so bad.
>>
>> Any suggestions on what I should do next? I'd expected to find a
>> totally shagged gasket, but I suspect that alone is not the cause of
>> my problems.
>>
>> Tim
> First, do not use a chisel, screwdriver, knife or any other sharp tool
> to get the gasket off. I've found that a Dremel-like tool works best.
>
> Second, make sure that you take the head to a machine shop so it can be
> milled. Anytime, cylinder heads are removed from the block they will
> warp. Explain any damage the machine shop and why you removed the head
> in the first place. More they know the better the job you get.

Explain to me how a cast iron head will warp off the engine? You may know more than me, but they sell
heads as a whole unit dont they?

>
> Third, use the highest quality head gasket available. I have always had
> success with copper shim type gaskets. Those are generally found on high
> compression, supercharged and turbocharged engines.

This is one of the most basic engies ever produced!!! It's never going to be revved above twice idle
spees in it's life! Why the hell would you put a head gasket for a Escort Cosworth on a 60hp LR engine!

>
> Fourth, run a straight edge (such as a machinists ruler) across the top
> of the engine block. You're checking for any warping of the block
> itself. You may [or may not] have to remove the block for the shop to
> work on it.
>
> I started off with the hairy stuff at first, Eh? You didn't mention what
> the engine was, petrol or diesel. If petrol, any backfiring? If so,
> fouled plugs, ignition wire gone bad, distributor/rotor needs replacing.
> If diesel, a lost of compression through a fault in the head gasket, oil
> blow by on the piston rings, timing belt/chain out-of-wack.
>
> If you have a diesel and you're close to a seaport, such as I am here in
> Norfolk [aka Hampton Roads] Virginia, a marine mechanic could be quite a
> bit cheaper than your local Land Rover dealer.
>
> Sorry, folks but the local dealer has tried to rape me when my wife
> brought hers or I brought mine in. My son learned from my experiences.
> Just my quid's worth of knowledge.

Did you call the Police?

>
> Cheers.

--

Subaru WRX
Range Rover 4.6 HSE (The Tank!)
110 Hi Cap (Ben)

'"Opinions are like arseholes, everyones got one"


 
Nige wrote:
> Jeffrey S Austin wrote:
>
>>Tim Hobbs wrote:
>>
>>>Finally got around to removing the cylinder head today on the S2 (2.25
>>>petrol, 3 bearing). A few oddities (Haynes has more head bolts than
>>>my engine does!), but not too bad. Almost put my back out lifting the
>>>bugger of course...
>>>
>>>Anyway, the head gasket is actually in one piece - a few bits of
>>>frayed metal but nothing that looks remotely like a breach. The
>>>pistons and combustion chambers are very black though, and there is
>>>some fairly thick coking on the pistons.
>>>
>>>So, I'm not sure what is causing the poor compression. Having never
>>>lifted the top off an engine before, I'm not sure what it is meant to
>>>look like. I'm aware it shouldn't be black, but it's run like crap
>>>for a fair while so not too surprising.
>>>
>>>2 and 3 cylinder have a very noticeable step at TDC in the bores,
>>>which are otherwise fairly smooth. Haven't measured it, but it's
>>>enough to stop a fingernail. 1 and 4 aren't so bad.
>>>
>>>Any suggestions on what I should do next? I'd expected to find a
>>>totally shagged gasket, but I suspect that alone is not the cause of
>>>my problems.
>>>
>>>Tim
>>
>>First, do not use a chisel, screwdriver, knife or any other sharp tool
>>to get the gasket off. I've found that a Dremel-like tool works best.
>>
>>Second, make sure that you take the head to a machine shop so it can be
>>milled. Anytime, cylinder heads are removed from the block they will
>>warp. Explain any damage the machine shop and why you removed the head
>>in the first place. More they know the better the job you get.
>
>
> Explain to me how a cast iron head will warp off the engine? You may know more than me, but they sell
> heads as a whole unit dont they?
>
>
Even cast iron heads will warp. It has to do with the metallurgy of the
material. New heads haven't been subjected to heating and cooling cycles
that previously installed ones have.

>>Third, use the highest quality head gasket available. I have always had
>>success with copper shim type gaskets. Those are generally found on high
>>compression, supercharged and turbocharged engines.
>
>
> This is one of the most basic engies ever produced!!! It's never going to be revved above twice idle
> spees in it's life! Why the hell would you put a head gasket for a Escort Cosworth on a 60hp LR engine!
>
>
My personal philosophy is to do it right the first time. Before you chew
my head off for the last statement, I'm an engineer by training and do
have a habit of over building.

>>Fourth, run a straight edge (such as a machinists ruler) across the top
>>of the engine block. You're checking for any warping of the block
>>itself. You may [or may not] have to remove the block for the shop to
>>work on it.
>>
>>I started off with the hairy stuff at first, Eh? You didn't mention what
>>the engine was, petrol or diesel. If petrol, any backfiring? If so,
>>fouled plugs, ignition wire gone bad, distributor/rotor needs replacing.
>>If diesel, a lost of compression through a fault in the head gasket, oil
>>blow by on the piston rings, timing belt/chain out-of-wack.
>>
>>If you have a diesel and you're close to a seaport, such as I am here in
>>Norfolk [aka Hampton Roads] Virginia, a marine mechanic could be quite a
>>bit cheaper than your local Land Rover dealer.
>>
>>Sorry, folks but the local dealer has tried to rape me when my wife
>>brought hers or I brought mine in. My son learned from my experiences.
>>Just my quid's worth of knowledge.
>
>
> Did you call the Police?

Rape as in price gouging. I did better, just spread the word.

>
>>Cheers.
>
>
> --�
>
> Subaru WRX
> Range Rover 4.6 HSE (The Tank!)
> 110 Hi Cap (Ben)
>
> '"Opinions are like arseholes, everyones got one"
>
>

 
>>>
>>>Second, make sure that you take the head to a machine shop so it can be
>>>milled. Anytime, cylinder heads are removed from the block they will
>>>warp. Explain any damage the machine shop and why you removed the head
>>>in the first place. More they know the better the job you get.
>>
>>
>> Explain to me how a cast iron head will warp off the engine? You may know more than me, but they sell
>> heads as a whole unit dont they?
>>
>>
>Even cast iron heads will warp. It has to do with the metallurgy of the
>material. New heads haven't been subjected to heating and cooling cycles
>that previously installed ones have.
>
>>>Third, use the highest quality head gasket available. I have always had
>>>success with copper shim type gaskets. Those are generally found on high
>>>compression, supercharged and turbocharged engines.
>>
>>
>> This is one of the most basic engies ever produced!!! It's never going to be revved above twice idle
>> spees in it's life! Why the hell would you put a head gasket for a Escort Cosworth on a 60hp LR engine!
>>
>>
>My personal philosophy is to do it right the first time. Before you chew
>my head off for the last statement, I'm an engineer by training and do
>have a habit of over building.
>

On of the professors when I did my eng degree had a favourite
mantra...

"Any fool can build a bridge that will stay up. It takes an engineer
to build one that only just stays up."

The gasket that came out is a copper one. I haven't even looked at
the new one in the Britpart kit, but it's a forty year old engine with
very low compression even when new. I don't think there is any
benefit to anything remotely exotic in this instance.

There is no sign that the head is warped, nor the block. I have,
however, done a Yell search and found a few workshops in reasonable
distance that can rebuild the head. So I'm quite confident pulling it
apart :)

My decision now is whether I should just have the head fully rebuilt
and be done with it. There doesn't seem much point, given that I can
buy an exchange one from Turners. It's not an original engine - the
car is a real 'bitsa', so there's no need to keep the original pieces.

If the block is worn, and I put the new head on it and still get crap
compression it won't be lost money, because I can then get Turners to
put the head onto a new block for me.

I can see where this is heading....





--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70
'06 Nissan Navara aka "The Truck"
 
On Sun, 23 Apr 2006 00:34:31 +0100, "Bob Hobden" <[email protected]>
wrote:

>
>"Alex" wrote
>>
>> It's certainly worth doing a full decoke, grinding the valves in,
>> checking the head for flatness - use a good, new steel rule and a
>> feeler gauge - and re-assembling with a new head gasket. The cost is
>> low and will eliminate gasket trouble, valve trouble and a warped
>> head. If it still isn't giving good compressions then you're looking
>> at a more expensive rebuild, possibly rebore etc etc, at this point
>> you should be seriously considering a professional rebuild or a recon
>> engine (unless you fancy doing it all yourself.....)
>>
>> One point, if you can't get good compressions after doing the head,
>> take an oil can (one of those with the plunger) and pump 3 or 4
>> squirts of oil into the spark plug hole, refit the compression tester
>> and test the compression again. If the compression gets significantly
>> better then suspect worn rings/bores - rebore/recon time.
>>
>
>Would it be worth his while replacing the rings anyway while he has the head
>off? Provided Tim feels happy doing that. I say that as a friend had a
>Diesel 2.5 NA that started to smoke a bit and he changed his whilst doing
>the head and valve stem seals etc. Reckons it's made a noticeable difference
>to the engine as some rings were well stuck in the pistons.

Changing rings is a rather more involved job, the only things you
don't take off the engine when doing rings is the front cover and
camshaft.

Personally, I'm very reluctant to change rings on thier own, if the
rings are worn then chances are the bores will be too. And for that
sort of stripdown you might as well be looking at doing everything, as
with the crank out you can inspect the mains, which on a 3-bearing
crank will probably need doing anyway.

Alex
 
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