which cylinder head gasket?

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Al2O3

Al2O3

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I've got a recon turbo ready to put on this Saturday, weather permitting.
I suspect I have a head gasket issue too, so I've been doing a quick read up on LZ.
How do I find out if I need a 0, 1, 2, 3 hole gasket? :confused: I've read about possible codes on the engine somewhere??? I've also read about measuring how far above TDC each piston goes. What on earth do you measure that with?
 
Look at the cylinder head to block mating join just forward of the Number 4 cylinder area, you should see a tab sticking out which is part of the head gasket....it will be punched with the number of holes (or none for a zero hole - thickest - gasket)....

To measure, use a straight edge on the piston and feeler gauges stacked up and added together to measure the protrusion under the straight edge.....our use a depth gauge on a set of verniers (Very-Nears!!)

Or a Dial Indicator mounted on the block with the probe set to zero on the block then measure the piston as it protrudes.
 
Al2O3 said:
I've got a recon turbo ready to put on this Saturday, weather permitting.
I suspect I have a head gasket issue too, so I've been doing a quick read up on LZ.
How do I find out if I need a 0, 1, 2, 3 hole gasket? :confused: I've read about possible codes on the engine somewhere??? I've also read about measuring how far above TDC each piston goes. What on earth do you measure that with?
Click to expand...
the gasket thats on must be giving the required thickness for clearance otherwise youd notice valves hitting the piston , if you look between 3 and 4th injector there is a tap of gasket poking out with the holes in,,piston height is measured using a dti you zero on the block face then twist it over the bore turning the crank and so rising piston to and past tdc will give height above block face,valves also make a difference in the depth they are compared to head face (valve stand down)if you skim head you reduce stand down and so thicker gasket maybe neeeded, valve seats can be cut to restore valve stand down
 
Saint.V8 said:
Look at the cylinder head to block mating join just forward of the Number 4 cylinder area, you should see a tab sticking out which is part of the head gasket....it will be punched with the number of holes (or none for a zero hole - thickest - gasket)....

To measure, use a straight edge on the piston and feeler gauges stacked up and added together to measure the protrusion under the straight edge.....our use a depth gauge on a set of verniers (Very-Nears!!)

Or a Dial Indicator mounted on the block with the probe set to zero on the block then measure the piston as it protrudes.
Click to expand...


I always thought the higher the number the thicker the head gasket?
 
jamesmartin said:
the gasket thats on must be giving the required thickness for clearance otherwise youd notice valves hitting the piston , if you look between 3 and 4th injector there is a tap of gasket poking out with the holes in,,piston height is measured using a dti you zero on the block face then twist it over the bore turning the crank and so rising piston to and past tdc will give height above block face,valves also make a difference in the depth they are compared to head face (valve stand down)if you skim head you reduce stand down and so thicker gasket maybe neeeded, valve seats can be cut to restore valve stand down
Click to expand...
James I have often seen that procedure described, but why not get a short length of flat steel (prefrably bright drawn) about 8 to 10 mm thick, make sure it is smooth with no burrs and put it on the top of the block spanning the cylinder bore, set the dti onto the top of the steel and zero it. Then slowly turn the crank shaft until the piston gets to TDC at this point the dti will read the amount that the steel has been lifted by the piston I.e. The piston protrusion. It would avoid any error due to shifting the position of the dti.
 
Gentlemen, I greatly appreciate all of your replies. I have learned a great deal, including that I'm not prepared enough for this weekends potential work.
Recon turbo arrived mid week as did the compression tester. I don't think it's just the turbo though. I've no experience of this, but I suspect that the head gasket must have gone too. Investigations will start tomorrow morning. In the rain by the look of it :( I'll have to get the old gazebo out of the shed, so hopefully it's not too windy :eek::)
Because my mind is working over time on this, I wonder if you can shed any light on this thought. The engine has done 180k. I'm hoping, if the gasket has gone, that it has just worn through with natural wear and tear and that the head hasn't warped or cracked. The coolant level is still fine and so it hasn't over heated. What sort of proportion of head gasket failures are natural wear and tear (just new gasket needed) or warped heads,cracks etc? Just my mind working over time and staring at the dark side:rolleyes:
Thanks again, gents.
 
First.....Don't be overly concerned with taking the head off - it is dead simple - I did a How To when I did the 200Tdi (link here: https://www.landyzone.co.uk/land-ro...hange-and-cylinder-head-refurb-how-to.282598/ ) Process is very similar on the 300Tdi....just nuts and bolts is all it is.

Second.....Stop over thinking things.....

Third......HG can 'just go' through age. This is coupled with the heat cycle the poor little blighters go through, as they expand and contract, they can go hard and brittle and the constant need to hold back the combustion pressures means that after a while they just go....

Now, if the last person who put the HG on didn't clean the mating faces well enough, they can go quicker due to stress fractures where the gasket is being made to 'mold' to the contours of a bit of dirt or a fragment of old gasket not cleaned away properly. Whilst people do talk of cracked/warped heads, this is in the extreme cases (remember 70% of posts on here are because someone has an issue or fault) so don't begin to think that all you read on here is warped heads and cracked exhaust ports etc.....if you have not suffered an overheat or other such extreme situation, than your head is probably fine.

Forth......Take your time. Take Photos before you take things off so you can refer to them again when re-assembling. Take a break regularly to keep yourself fresh - better than rushing it, trust me.

And finally.....

Fifth......if you get stuck, post on here, there may be others who can help and assist you and offer opine and advice.

Oh, PS. Soak your exhaust manifold nuts and bolts overnight in penetrating oil/fluid or if none available - liberal dowsing of WD40. Use copper grease on them when you refit - you'll be glad you did in the future!
 
Saint.V8 said:
First.....Don't be overly concerned with taking the head off - it is dead simple - I did a How To when I did the 200Tdi (link here: https://www.landyzone.co.uk/land-ro...hange-and-cylinder-head-refurb-how-to.282598/ ) Process is very similar on the 300Tdi....just nuts and bolts is all it is.

Second.....Stop over thinking things.....

Third......HG can 'just go' through age. This is coupled with the heat cycle the poor little blighters go through, as they expand and contract, they can go hard and brittle and the constant need to hold back the combustion pressures means that after a while they just go....

Now, if the last person who put the HG on didn't clean the mating faces well enough, they can go quicker due to stress fractures where the gasket is being made to 'mold' to the contours of a bit of dirt or a fragment of old gasket not cleaned away properly. Whilst people do talk of cracked/warped heads, this is in the extreme cases (remember 70% of posts on here are because someone has an issue or fault) so don't begin to think that all you read on here is warped heads and cracked exhaust ports etc.....if you have not suffered an overheat or other such extreme situation, than your head is probably fine.

Forth......Take your time. Take Photos before you take things off so you can refer to them again when re-assembling. Take a break regularly to keep yourself fresh - better than rushing it, trust me.

And finally.....

Fifth......if you get stuck, post on here, there may be others who can help and assist you and offer opine and advice.

Oh, PS. Soak your exhaust manifold nuts and bolts overnight in penetrating oil/fluid or if none available - liberal dowsing of WD40. Use copper grease on them when you refit - you'll be glad you did in the future!
Click to expand...
Cheers, mate. I was hoping that it would just be natural wear and tear due to, as you say, the extreme conditions it's operating in. Now that it's Friday night I've had time to think, what if the heads warped? OTT, I know. So, what you have said is very reassuring and I appreciate you taking the time. It's stopped me over thinking it. :)
Unless I get sickened in the rain, tomorrow will be compression testing and then making the decision about removing the head. If need be, the head will come off and I can inspect the bores etc. Buy the right gasket before next weekend and get it all back together then. Could be a few postings on here in between ;)
This'll be run of the mill stuff for a lot of folk on here, but it's about 35 yrs since I've taken the top off an engine. Exciting though :)
Thanks again for your help.
 
Depends on the amount of warp.....up to a certain amount (don't know what that is sorry!) they can be skimmed flat and the valves re-seated to take into account the amount removed. But that is extreme.

There is a 'flatness' tolerance of how much 'warp' there is allowed to be before machining is required, but again I don't know what that is - it may be in RAVE, I'll take a look-see.

If it is approaching the upper limit of 'flatness' tolerance, you can fit the Zero hole thickest gasket as this will mask the minor discrepency - but it won't solve a head that has gone beyond the upper limit of 'flatness', in this instance it would need to be machined back to tolerance.

Or you could purchase a replacement head at around £300 iirc.

Take on step at a time, do the compression check and report back....fingers crossed it doesn't reveal an issue, but if you have had experience of taking a head off before (even 35 years ago) it will all seem simples in the end and you'll sit back with a cup of coffee afterwards thinking 'wtf was I worried for?'
 
Saint.V8 said:
Depends on the amount of warp.....up to a certain amount (don't know what that is sorry!) they can be skimmed flat and the valves re-seated to take into account the amount removed. But that is extreme.

There is a 'flatness' tolerance of how much 'warp' there is allowed to be before machining is required, but again I don't know what that is - it may be in RAVE, I'll take a look-see.

If it is approaching the upper limit of 'flatness' tolerance, you can fit the Zero hole thickest gasket as this will mask the minor discrepency - but it won't solve a head that has gone beyond the upper limit of 'flatness', in this instance it would need to be machined back to tolerance.

Or you could purchase a replacement head at around £300 iirc.

Take on step at a time, do the compression check and report back....fingers crossed it doesn't reveal an issue, but if you have had experience of taking a head off before (even 35 years ago) it will all seem simples in the end and you'll sit back with a cup of coffee afterwards thinking 'wtf was I worried for?'
Click to expand...

I'd be about 17 or 18 when I took the head off my Mini 1275 GT. The PO had had the engine reconditioned, but they mustn't have put the gudgeon pins in properly cos two of them moved milling perfect slots up the side of the cylinders! :eek:
I'm half thinking it might be worth taking it off for peace of mind. That's a decision for after compression testing and seeing if any oil gets thrown out of a cylinder.

jamesmartin said:
allways undo the brass block drain on lhs block before undoing any head bolts
Click to expand...
Cheers, JM. I presume that's drains any residual water in the head to block water ways?
 
Al2O3 said:
I'd be about 17 or 18 when I took the head off my Mini 1275 GT. The PO had had the engine reconditioned, but they mustn't have put the gudgeon pins in properly cos two of them moved milling perfect slots up the side of the cylinders! :eek:
I'm half thinking it might be worth taking it off for peace of mind. That's a decision for after compression testing and seeing if any oil gets thrown out of a cylinder.


Cheers, JM. I presume that's drains any residual water in the head to block water ways?
Click to expand...
yes, its the only way you can fully
 
Al2O3 said:
Cheers, James. Excellent info.
Any other seals etc worth changing in the head if I have to take it off?
Click to expand...
stem seals if theyve been on awhile,worth buying a couple of head dowels they are often broken etc8352, when tightening bolts a felt tip to mark head and knowing one flat of the bolt head is 60 degrees helps
 
Depends on how far you want to go....

If it were me, then I'd do the valve stem seals while its off (if you have a valve spring compressor that is).

It is always worth looking at the P Gasket on the 300Tdi, it is pretty much the main weakness on the cooling system (aside from the design fault of the expansion tank height compared with the water pump height!). It is relatively simple to do, just need to remove the alternator (2 bolts), the belt tensioner (one nut) and the PAS pump (4 bolts holding the mounting plate on) don't have to remove the water pump, just the 3 bolts at the bottom of the pump is all. Then there is 3 fixings holding the assembly in place (a nut under the belt tensioner, a long bolt and nut at the bottom and a shorter bolt next to it).

Also, while the head is off, take a look at the cam followers brass slides and the rollers, they are fairly hardy and last a while, but there is no harm in looking at them. To get them out is a fiddle, you have to partially undo the slide guide bolt on the side of the block just sufficiently that you can reach down with a small hook or bent wire and pull the brass slide upwards, oftentimes the roller will come with it, if not, you'll have to hook that out too. Don't lift the Slide Guide out if you haven't taken the slide and roller out, else they will fall over and get stuck or worse, the roller will fall off the cam and that's a pig! Again, this is in my How To linked above!

Make sure all your valve stems have the little caps on, and you might aswell replace them while the heads off, they are pence each and can get worn through.
 
Ive done a few 200/300 head gaskets and never even checked the head for flatness never mind had them skimmed, remove head scrape clean and slap them back on, two sit outside my house and still running fine, great engines to work on.
I have always just slapped a 3 hole gasket on all the ones I have done, being speedy gonzallis I never checked to see what was fitted, never been any issues.
You can even get away with some pretty impressive cracks between the valve seats again with no issues.

Once fitted a 300 head gasket back to front, that was messy and a tad embarassing:rolleyes:
 
Just use the thickest gasket, the difference between the thinnest and the thickest gasket isn't that different, but the valves won't hit with the thickest gasket.
 
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