Head repair on an S14
Discussion
A few weeks ago I had a bit of an off in my E30 M3. Unfortunately the engine took the brunt of the force when the sump and crossmember struck a bloody great rock. The rad was also split in the impact and this meant an immediate loss of all oil and coolant. Once the engine was removed from the car it was clear the impact had also cracked the timing chain cover, which requires removal of the head in order to replace it and its gaskets.
Due to the engine having been run with no oil or coolant (admittedly only for a minute) and also because of the s14 head being aluminium on a steel block, the engine builder said the head should be skimmed. Obviously this would also mean re shimming the valves etc. They also said this was normal practice on an engine as specialised as the S14 but given both the cooling issue and the significant impact, it would be a false economy not to rebuild the head in this case.
Whilst I wholly agree with the planned rebuild and the reasons for doing so, the insurance engineer has said that he disagrees and that the head should just be re fitted as it was. I realise it is his job to keep a reign on costs but it seems crazy to go against both the engine builder and machine shops advice. Should I be insisting that the head be skimmed prior to rebuilding the engine or is the engineer correct in the assessment?
The engine builder and the machine shop are both refusing to warranty their work if they are forced to rebuild the engine without skimming the head.
So does skimming and rebuilding the head seem like common sense or not?
Due to the engine having been run with no oil or coolant (admittedly only for a minute) and also because of the s14 head being aluminium on a steel block, the engine builder said the head should be skimmed. Obviously this would also mean re shimming the valves etc. They also said this was normal practice on an engine as specialised as the S14 but given both the cooling issue and the significant impact, it would be a false economy not to rebuild the head in this case.
Whilst I wholly agree with the planned rebuild and the reasons for doing so, the insurance engineer has said that he disagrees and that the head should just be re fitted as it was. I realise it is his job to keep a reign on costs but it seems crazy to go against both the engine builder and machine shops advice. Should I be insisting that the head be skimmed prior to rebuilding the engine or is the engineer correct in the assessment?
The engine builder and the machine shop are both refusing to warranty their work if they are forced to rebuild the engine without skimming the head.
So does skimming and rebuilding the head seem like common sense or not?
Tricky situation. It would seem obvious to go with Joe's opinion on the head, especially in light of any guarantee scenario.
Could you sit tight and wait until the head is off and see whether it actually needs a skim or not once it's put on the table? At that point if it does then you have more ammunition to go back to the assessor? Presumably at that point he can't really refuse?
If however the head appears ok , and the assessor won't budge but the builders maintain the same stance with regard any warranty, then i would consider paying for that element of the build out of my own pocket just to tick all boxes so to speak?
Looks like that sump took a whack. When I first heard I was going to text you with the name of a contact who is an exceptionally talented welder but a big wing sump would be a great upgrade. Have you seen any, I've seen one but it wasn't what you might call a bargain !
Could you sit tight and wait until the head is off and see whether it actually needs a skim or not once it's put on the table? At that point if it does then you have more ammunition to go back to the assessor? Presumably at that point he can't really refuse?
If however the head appears ok , and the assessor won't budge but the builders maintain the same stance with regard any warranty, then i would consider paying for that element of the build out of my own pocket just to tick all boxes so to speak?
Looks like that sump took a whack. When I first heard I was going to text you with the name of a contact who is an exceptionally talented welder but a big wing sump would be a great upgrade. Have you seen any, I've seen one but it wasn't what you might call a bargain !
Head is going to be skimmed and rebuilt either way. I just won't risk it after the loss of the oil and coolant. There's also the issue with the timing chain cover, as I know how prone they can be to oil leaks if everything isn't spot on. I also don't want to find myself having issues down the line, with no warranty to fall back on and an £8k bill for the sake of saving 800!
Have gone with big wing sump and guard this time.
Have gone with big wing sump and guard this time.
Absolutely.
Have you seen this? Looks a lovely bit of kit.
http://www.m3motorsport.co.nz/#!/products/engine/g...
Have you seen this? Looks a lovely bit of kit.
http://www.m3motorsport.co.nz/#!/products/engine/g...
Firstly, there should be no reason to re-shim the valves when skimming the head. The head face is not related to the valvetrain stack height.
Secondly, a minuet of running without oil and water would have probably done more harm to the crank bearings than the head face. An engine builder can assume the head might need skimming, but the only way to know is to measure it for flatness.
But, if you can get the insurers to pay for an top end rebuild (recut valve seats, re-faced valves, new guides), then chance your arm.
Secondly, a minuet of running without oil and water would have probably done more harm to the crank bearings than the head face. An engine builder can assume the head might need skimming, but the only way to know is to measure it for flatness.
But, if you can get the insurers to pay for an top end rebuild (recut valve seats, re-faced valves, new guides), then chance your arm.
mark.c said:
Have you seen this? Looks a lovely bit of kit.
http://www.m3motorsport.co.nz/#!/products/engine/g...
That is rather nice. http://www.m3motorsport.co.nz/#!/products/engine/g...
stevesingo said:
Firstly, there should be no reason to re-shim the valves when skimming the head. The head face is not related to the valvetrain stack height.
Secondly, a minuet of running without oil and water would have probably done more harm to the crank bearings than the head face. An engine builder can assume the head might need skimming, but the only way to know is to measure it for flatness.
But, if you can get the insurers to pay for an top end rebuild (recut valve seats, re-faced valves, new guides), then chance your arm.
Do they not strip the head bare prior to skimming then? (I'm asking because I just assumed they would, not because I doubt you.) I'm doing the bottom end too, as it seemed daft not to with everything being apart. Secondly, a minuet of running without oil and water would have probably done more harm to the crank bearings than the head face. An engine builder can assume the head might need skimming, but the only way to know is to measure it for flatness.
But, if you can get the insurers to pay for an top end rebuild (recut valve seats, re-faced valves, new guides), then chance your arm.
They should strip it bare to prevent contamination from the swarf, but some places don't and rely on a good clean afterwards. If the valves spring, retainers etc go back in to the original location, there is no reason that the stack height should change.
In saying that, if you are changing cams, then it will need shimming anyway.
Like I say, if the insurance are picking up the bill, then you should do as much as you can.
In saying that, if you are changing cams, then it will need shimming anyway.
Like I say, if the insurance are picking up the bill, then you should do as much as you can.
Edited by stevesingo on Sunday 16th October 10:03
Ah, I understand. If honest, the whole shimming valves thing is new to me (although as I said earlier, I'm no mechanic) but in the past I have had heads give issues in 02's which is why I'm loathe to put things back together without being certain everything is right.
As an aside, is it a good idea to hone the bores whilst the engine is apart? I seem to recall using a 'glazebuster' on a Pinto I rebuilt many moons ago?
As an aside, is it a good idea to hone the bores whilst the engine is apart? I seem to recall using a 'glazebuster' on a Pinto I rebuilt many moons ago?
If your oil consumption prior to your off was acceptable, then I would be tempted to leave the bores alone. A glaze buster is a kind of sticking plaster job in that if the bores are excessively glazed and you wanted to re-ring the pistons, the easy way is to run a glaze buster up and down the bores to help the new rings bed in. But, if the bores are that worn there is all likelyhood that the bores are out of round and or tapered. In which case, a re-bore and a new set of pistons.
I would suggest your engine builder strips the engine and discovers enough damage through loss of oil pressure to justify a complete rebuild.
I would suggest your engine builder strips the engine and discovers enough damage through loss of oil pressure to justify a complete rebuild.
I don't get why they are both arguing about the head before it seems its even been removed and checked. From what you've said its being removed regardless so will be checked regardless. Even if its flat and undamaged and the builder wants to skim it regardless ( assuming this hasn't been done before and is able to ) , the cost is cheap ( £50 ) enough to not argue, no ?
If its warped and you can say this is a consequence of the engine being run with no coolant and oil, the insurance guy can hardly say it can't be skimmed.
If its warped and you can say this is a consequence of the engine being run with no coolant and oil, the insurance guy can hardly say it can't be skimmed.
Deptford Draylons said:
I don't get why they are both arguing about the head before it seems its even been removed and checked. From what you've said its being removed regardless so will be checked regardless. Even if its flat and undamaged and the builder wants to skim it regardless ( assuming this hasn't been done before and is able to ) , the cost is cheap ( £50 ) enough to not argue, no ?
If its warped and you can say this is a consequence of the engine being run with no coolant and oil, the insurance guy can hardly say it can't be skimmed.
It's not just the cost of the skimming. It's the cost of rebuilding afterwards he has baulked at. Unfortunately I am in the middle but I have written to the engineer and a) reminded him of the loss of oil / coolant and b) said that the engineering shop felt a skim was needed / justified. I will just have to wait for his response.If its warped and you can say this is a consequence of the engine being run with no coolant and oil, the insurance guy can hardly say it can't be skimmed.
e21Mark said:
Deptford Draylons said:
I don't get why they are both arguing about the head before it seems its even been removed and checked. From what you've said its being removed regardless so will be checked regardless. Even if its flat and undamaged and the builder wants to skim it regardless ( assuming this hasn't been done before and is able to ) , the cost is cheap ( £50 ) enough to not argue, no ?
If its warped and you can say this is a consequence of the engine being run with no coolant and oil, the insurance guy can hardly say it can't be skimmed.
It's not just the cost of the skimming. It's the cost of rebuilding afterwards he has baulked at. Unfortunately I am in the middle but I have written to the engineer and a) reminded him of the loss of oil / coolant and b) said that the engineering shop felt a skim was needed / justified. I will just have to wait for his response.If its warped and you can say this is a consequence of the engine being run with no coolant and oil, the insurance guy can hardly say it can't be skimmed.
Is there any flexibility with the builder to take the head away yourself and strip it yourself ? I was looking at my spare 215bhp head the other day, and there is scope for cleaning up both ports to match the later intake gaskets and exhaust better on a DIY basis, plus decoking the exhaust ports and checking the valve tilt and cleaning them if needed. If you did have a skim done, you could always CC the head and get it perfect and do minor mods yourself.
Anyway, insurance companies often need a bit of a push along, usually hoping customers wont make a fuss.
My understanding is that a) the head looks to have never been off before and b) they felt a skim was both justified and prudent due to the coolant/oil loss. Personally, I just assumed (wrongly as it turns out) that if you skim the head you strip it right down anyway and that would mean a full rebuild. Especially in something like the S14. Anyway, I let the insurance chap know my thoughts and have left he and the engineering company thrash it out between them.
As for the ports and my doing some DIY, I simply wouldn't trust myself. Added to which if I balls it up, finding a replacement head would prove much harder nowadays and wouldn't be cheap. So, whilst it will be getting some fettling it won't be by my fat fingers.
As for the ports and my doing some DIY, I simply wouldn't trust myself. Added to which if I balls it up, finding a replacement head would prove much harder nowadays and wouldn't be cheap. So, whilst it will be getting some fettling it won't be by my fat fingers.
If the head is not off yet and the engine only ran for a minute or two, I can't understand the definite need for a skim.
Once the head has been inspected then the decision should be made. If the gasket face is flat and unmarked there is no logical reason to skim it. Nor any reason not to put a warranty on their work.
However if the face is not flat due to age/running with the coolant drained or the gasket face is marked by the existing head gasket after 20+ years then it needs a skim.
If it were mine I'd strip the head, inspect and relapp the valves, then cc the combustion chambers and tidy up the ports to match your manifolds. If you're re-camming it, then you'll need it shimming to match.
If you've no oil usage and all the bores look/measure OK, you'll be OK to just leave the pistons in place. Replacing the shells would be sensible for little cost. But depending on budget (and what's available for the S14) now might be the time for an oversize bore/forged pistons, rods and higher quality bolts/studs etc.
I hope you get it all sorted nice and quickly.
Once the head has been inspected then the decision should be made. If the gasket face is flat and unmarked there is no logical reason to skim it. Nor any reason not to put a warranty on their work.
However if the face is not flat due to age/running with the coolant drained or the gasket face is marked by the existing head gasket after 20+ years then it needs a skim.
If it were mine I'd strip the head, inspect and relapp the valves, then cc the combustion chambers and tidy up the ports to match your manifolds. If you're re-camming it, then you'll need it shimming to match.
If you've no oil usage and all the bores look/measure OK, you'll be OK to just leave the pistons in place. Replacing the shells would be sensible for little cost. But depending on budget (and what's available for the S14) now might be the time for an oversize bore/forged pistons, rods and higher quality bolts/studs etc.
I hope you get it all sorted nice and quickly.
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