300TDi inspection results

Pictures!

http://www.ddol-las.fsnet.co.uk/temp/head1.jpg

general shot of the area between #2 and #3. the head between these two is
around 8 thou' from being flat, measured with a steel rule and feeler gauge,
so not all that accurate. Book says max 0.01mm distortion, which is about
4/10 thou, so that's obviously not much cop. Book *doesn't* say what, if
any, machining is allowed on the head - anyone know?

http://www.ddol-las.fsnet.co.uk/temp/head2.jpg
http://www.ddol-las.fsnet.co.uk/temp/head3.jpg

close ups of the middle two pots.

a) there are small cracks beside the hole where the glow plug is fitted.
Are these sufficient to condemn the head, or do they all do that, guvnor?

b) what are the odd burnt-looking patches about? all 4 pots show this
effect, all about the same.


turning to the block/pistons, the bores look pretty good - there's no
scoring or similar or heavy scuff marks. However. All 4 pistons show signs
of contact (not recent) with the inlet valves (only). The only way I can
see for that to happen is either one of 3 things: incorrect valve timing,
cambelt failure at speed (but I'd expect exhaust valve contact as well) or
*serious* over-revving. It had a 3-hole gasket fitted, so I doubt the
gasket being too thin.

how close do the inlet valves get to the pistons normally? the inlet valves
are only fully open during the inlet stroke, and obviously on the
compression stroke they're closed. I guess they probably start to open
before TDC on the exhaust stroke, before induction, but the books (including
the "real" shop manual, natch) don't divulge the valve timing data.

I guess the only way to be sure would be to do the cambelt at the same time,
and thus know the timing to be right.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Festina Lente" (Hasten slowly) Suetonius (c.70-c.140) Augustus, 25

Austin Shackles wrote:
> Pictures!
>
> http://www.ddol-las.fsnet.co.uk/temp/head1.jpg

General disclaimer - I haven't had one of these motors apart but I'm a
mechanic and I do a lot of diesel repair work.

> general shot of the area between #2 and #3. the head between these two is
> around 8 thou' from being flat, measured with a steel rule and feeler gauge,
> so not all that accurate. Book says max 0.01mm distortion, which is about
> 4/10 thou, so that's obviously not much cop. Book *doesn't* say what, if
> any, machining is allowed on the head - anyone know?

Well you've measured it the right way, and it's outside spec so
machining it is going to be necessary. If you lop .008" off then you're
going to want a gasket that's .008" thicker than the existing one. I'm
not sure if they're available but I'd go for a laminated steel gasket if
I could - reasons for this follow. The alloy head expands at a
different rate to the steel block and as a result frets on the gasket -
the laminated steel gaskets are much less prone to this, do not need
re-torquing and I have never seen one give trouble on a motor I have
fitted them to (mostly Toyota diesels).
>
> http://www.ddol-las.fsnet.co.uk/temp/head2.jpg
> http://www.ddol-las.fsnet.co.uk/temp/head3.jpg
>
> close ups of the middle two pots.
>
> a) there are small cracks beside the hole where the glow plug is fitted.
> Are these sufficient to condemn the head, or do they all do that, guvnor?

Dunno if they all do that, but if it pressure tests okay I wouldn't be
overly concerned about it - plenty of other alloy heads do this sort of
thing with no ill effects.
>
> b) what are the odd burnt-looking patches about? all 4 pots show this
> effect, all about the same.

They almost look like it might have been overfuelling at some time but
don't look serious - I'd ignore them.
>
> turning to the block/pistons, the bores look pretty good - there's no
> scoring or similar or heavy scuff marks. However. All 4 pistons show signs
> of contact (not recent) with the inlet valves (only). The only way I can
> see for that to happen is either one of 3 things: incorrect valve timing,
> cambelt failure at speed (but I'd expect exhaust valve contact as well) or
> *serious* over-revving. It had a 3-hole gasket fitted, so I doubt the
> gasket being too thin.

Carbon build up on the valves through lot's of slow running, that then
knocks itself off on the piston is a possibility - I see it all the time
on diesels. Is it just a "show" of touching or has it actually left an
impression in the crown of the piston?
>
> how close do the inlet valves get to the pistons normally?

Really close. That's why you'll need a thicker gasket if you remove any
material from the head.
>
> I guess the only way to be sure would be to do the cambelt at the same time,
> and thus know the timing to be right.

It's cheap insurance - I'd do it as a matter of course. I'd also pull
the valves, give them a quick reface (or lap depending on the gear
you've got) and reassemble with new stem seals.

ACR want GBP 261 for a remanufactured head (or 309 for a stage 1 flowed
one). Depending on what you'll end up paying for machining, crack &
pressure testing it may make sense to spring for one of these
(guaranteed, and you know exactly what you've got).

Good luck, if you need any more info email me and I'll do some asking
around - unmunge my address as per the signature.


--
EMB
change two to number to reply

Austin Shackles <[email protected]> wrote in
news:[email protected]:

> a) there are small cracks beside the hole where the glow
> plug is fitted. Are these sufficient to condemn the head,
> or do they all do that, guvnor?

I'd seriously suggest taking it to a specialist "just in case",
but that's based on my Pug experiences! As I recall, there are
some cracks in an ali head that can be welded -- if necessary.
In Inverness we have Auto-Head Recon. Excellent people and
always very busy. I'd give "the other place" a miss...

Derry

In article <[email protected]>, Austin Shackles
<[email protected]> writes


Hi Austin

Landrover say you cannot (should not) skim a Tdi head.

I skim every one that comes in and have never had a problem.

As a matter of coarse a three hole gasket is fitted. You will struggle
to find a main dealer that sells anything else.

If the valves have been hitting the pistons on a regular basis you would
of heard a strange popping noise from the air intake.

When you check the timing belt it is worth removing the camshaft
sprocket and making sure the locating pin on the cam has not broken
which would cause the valve timing to move.

It is unusual for a tdi head gasket to blow between cylinders 2 and 3
normally they blow from number 4 to a pushrod hole or straight out the
back of the block. blowing between 2 and 3 might point to it getting a
little hot before it blew.

Hope this helps
--
Marc Draper

Forsale

Landrover Defender 90 300tdi county hardtop 1996 72K
Landrover Discovery comercial 300tdi S reg 70k
Landrover Discovery Comercial 300tdi R reg 62k
Toyota Hilux surf 2.4 AW/AC/EW/SR

Super winch X9 + genuine Landrover fitting kits for 200 Disco.

On or around Wed, 28 Jul 2004 20:11:00 +0100, marc
<[email protected]> enlightened us thusly:

>In article <[email protected]>, Austin Shackles
><[email protected]> writes
>
>
>Hi Austin
>
>Landrover say you cannot (should not) skim a Tdi head.

hmmm.

>I skim every one that comes in and have never had a problem.
>
>As a matter of coarse a three hole gasket is fitted. You will struggle
>to find a main dealer that sells anything else.

I figured as much, same applies to the peugeot/citroen ones I've had
experience of.

>If the valves have been hitting the pistons on a regular basis you would
>of heard a strange popping noise from the air intake.

I don't think it's regular. each piston is marked, but not recently.

>When you check the timing belt it is worth removing the camshaft
>sprocket and making sure the locating pin on the cam has not broken
>which would cause the valve timing to move.

noted, ta.

>It is unusual for a tdi head gasket to blow between cylinders 2 and 3
>normally they blow from number 4 to a pushrod hole or straight out the
>back of the block. blowing between 2 and 3 might point to it getting a
>little hot before it blew.

from what I can deduce, it overheated terminally. I'm amazed it's not in
worse condition. Father has a habit of not watching gauges... It does look
as though it might have been blowing slightly from #4 as you describe, but
the main damage is in the middle, which could of course be warping due to
overheating. this engine has, for ages, been losing coolant *very* slowly,
such that you top it up about every month or 2. It's not, however, had a
habit of overheating, even with low coolant.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"You praise the firm restraint with which they write -_
I'm with you there, of course: They use the snaffle and the bit
alright, but where's the bloody horse? - Roy Campbell (1902-1957)

On or around Thu, 29 Jul 2004 09:30:39 +1200, EMB <[email protected]>
enlightened us thusly:

>ACR want GBP 261 for a remanufactured head (or 309 for a stage 1 flowed
>one). Depending on what you'll end up paying for machining, crack &
>pressure testing it may make sense to spring for one of these
>(guaranteed, and you know exactly what you've got).

that's worth knowing. By the time it gets tested properly, etc...

and since it's already got the 3-hole gasket, there are no thicker ones
(from stock, anyway) to be had.

Book say the tolerance for head flatness is 0.01mm which is pretty damned
fine.

provided the rings are OK (no way of telling without stripping it much more
than I want to at the moment) it looks to only need the head looking at.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Confidence: Before important work meetings, boost your confidence by
reading a few pages from "The Tibetan Book of the Dead"
from the Little Book of Complete B***ocks by Alistair Beaton.

On or around Wed, 28 Jul 2004 16:44:56 +0100, Austin Shackles
<[email protected]> enlightened us thusly:


and a picture of one of the pistons, showing valve marks...

http://www.ddol-las.fsnet.co.uk/temp/piston.jpg


--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Confidence: Before important work meetings, boost your confidence by
reading a few pages from "The Tibetan Book of the Dead"
from the Little Book of Complete B***ocks by Alistair Beaton.

In article <[email protected]>,
[email protected] (Austin Shackles) wrote:

> provided the rings are OK (no way of telling without stripping it much
> more
> than I want to at the moment) it looks to only need the head looking at.

Hargreaves in Carmarthen might be able to help. Though I don't always agree
with their opinions.

--
Niamh
4x4 Cymru
http://www.4x4cymru.co.uk

On or around Thu, 29 Jul 2004 09:30:39 +1200, EMB <[email protected]>
enlightened us thusly:

>ACR want GBP 261 for a remanufactured head (or 309 for a stage 1 flowed
>one). Depending on what you'll end up paying for machining, crack &
>pressure testing it may make sense to spring for one of these
>(guaranteed, and you know exactly what you've got).

been talking to 'em, they reckon a warped and cooked 300 head is most likely
to be scrap, and offered a brand new built-up one with new valves and
springs for 381 plus vat (the 261 is plus vat as well), so one is currently
on order, along with a few gaskets and such and a timing belt.

I've been meaning to check on the belt for a while, so now's a good
opportunity.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Blue: The sky is blue for a reason. Blue light is a source of strength
and harmony in the cosmos. Create a blue light in your life by
telephoning the police
from the Little Book of Complete B***ocks by Alistair Beaton.

On or around Thu, 29 Jul 2004 18:16 +0100 (BST),
[email protected] (Niamh Holding) enlightened us thusly:

>In article <[email protected]>,
>[email protected] (Austin Shackles) wrote:
>
>> provided the rings are OK (no way of telling without stripping it much
>> more
>> than I want to at the moment) it looks to only need the head looking at.
>
>Hargreaves in Carmarthen might be able to help. Though I don't always agree
>with their opinions.

following a chat with ACR's bloke, I've gone for a new one.

's not that silly, really, and is new and guaranteed. He reckons that after
you cook it, the head metal isn't ever the same again, and by the account I
had, this one was well cooked.

new head a bit more pricey, but still... should be OK for plenty more miles
afterwards.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Beyond the horizon of the place we lived when we were young / In a world
of magnets and miracles / Our thoughts strayed constantly and without
boundary / The ringing of the Division bell had begun. Pink Floyd (1994)

In article <[email protected]>,
[email protected] (Austin Shackles) wrote:

> following a chat with ACR's bloke, I've gone for a new one.

Well we the engine one of ours we'd do the same.

> new head a bit more pricey, but still... should be OK for plenty more
> miles
> afterwards.

One would hope so

--
Niamh
4x4 Cymru
http://www.4x4cymru.co.uk

Austin Shackles wrote:

> 's not that silly, really, and is new and guaranteed. He reckons that after
> you cook it, the head metal isn't ever the same again, and by the account I
> had, this one was well cooked.

And he's right - the ally was heat treated to harden it after casting,
and it's just been heat treated back to soft again - more than likely
it'll just move all over the place and blow another gasket (I missed the
original reference to how hot it had been). If you ever want to
re-use an alloy head that's been hot ask the machinist who skims it to
do a hardness test for you.

--
EMB
change two to number to reply

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Wed, 28 Jul 2004 16:44:56 +0100, Austin Shackles
> <[email protected]> enlightened us thusly:
>
>
> and a picture of one of the pistons, showing valve marks...
>
> http://www.ddol-las.fsnet.co.uk/temp/piston.jpg
>

Not much help to you, but this is a Td5 when the piston starts touching the
valves properly (collapsed big end bearing):

http://www.web-rover.co.uk/images/post/block_web.jpg

It's worn through the carbon and down to the metal. Was clattering nicely...

Just out of interest, does the Tdi piston actually have an offset piston
bowl, or is a trick of the camera?
--
Martin
1988 90 Td5 NAS Replica
www.web-rover.co.uk

On or around Thu, 29 Jul 2004 23:06:08 +0100, "Martin Lewis"
<[email protected]> enlightened us thusly:

>"Austin Shackles" <[email protected]> wrote in message
>news:[email protected]...
>> On or around Wed, 28 Jul 2004 16:44:56 +0100, Austin Shackles
>> <[email protected]> enlightened us thusly:
>>
>>
>> and a picture of one of the pistons, showing valve marks...
>>
>> http://www.ddol-las.fsnet.co.uk/temp/piston.jpg
>>
>
>Not much help to you, but this is a Td5 when the piston starts touching the
>valves properly (collapsed big end bearing):
>
>http://www.web-rover.co.uk/images/post/block_web.jpg
>
>It's worn through the carbon and down to the metal. Was clattering nicely...
>
>Just out of interest, does the Tdi piston actually have an offset piston
>bowl, or is a trick of the camera?

they are offset. I'll get the hoover on 'em to suck the dust out, I reckon,
before I reassemble it.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"I am tired and sick of war. Its glory is all moonshine... War is hell"
Gen. Sherman (1820-1891) Attr. words in Address at Michigan Military
Academy, 19 June 1879.

In article <[email protected]>,
[email protected] (Austin Shackles) wrote:

> provided the rings are OK (no way of telling without stripping it much
> more
> than I want to at the moment) it looks to only need the head looking at.

Hargreaves in Carmarthen might be able to help. Though I don't always agree
with their opinions.

--
Niamh
4x4 Cymru
http://www.4x4cymru.co.uk

In article <[email protected]>,
[email protected] (Austin Shackles) wrote:

> following a chat with ACR's bloke, I've gone for a new one.

Well we the engine one of ours we'd do the same.

> new head a bit more pricey, but still... should be OK for plenty more
> miles
> afterwards.

One would hope so

--
Niamh
4x4 Cymru
http://www.4x4cymru.co.uk

Austin Shackles wrote:

> 's not that silly, really, and is new and guaranteed. He reckons that after
> you cook it, the head metal isn't ever the same again, and by the account I
> had, this one was well cooked.

And he's right - the ally was heat treated to harden it after casting,
and it's just been heat treated back to soft again - more than likely
it'll just move all over the place and blow another gasket (I missed the
original reference to how hot it had been). If you ever want to
re-use an alloy head that's been hot ask the machinist who skims it to
do a hardness test for you.

--
EMB
change two to number to reply

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Wed, 28 Jul 2004 16:44:56 +0100, Austin Shackles
> <[email protected]> enlightened us thusly:
>
>
> and a picture of one of the pistons, showing valve marks...
>
> http://www.ddol-las.fsnet.co.uk/temp/piston.jpg
>

Not much help to you, but this is a Td5 when the piston starts touching the
valves properly (collapsed big end bearing):

http://www.web-rover.co.uk/images/post/block_web.jpg

It's worn through the carbon and down to the metal. Was clattering nicely...

Just out of interest, does the Tdi piston actually have an offset piston
bowl, or is a trick of the camera?
--
Martin
1988 90 Td5 NAS Replica
www.web-rover.co.uk