944T headgasket
- Thread starter rcsalmons
- Start date
Diver944
Active member
If the gasket fails spectacularly when the car is very hot and being used very hard then there is the possibility that the head could warp. If it just starts to gradually leak then you will notice oil in the water or vice versa and poor running symptoms but generally it is only the gasket itself that needs changing.
We had a spate of HG failures several years ago when people started to up the boost but I think that was due to incorrect fuelling and running dangerously lean which causes the HG to burn away. I haven't heard of any for a while now and I believe it is because the current range of remapped chips have addressed that issue and also use a 3 bar Fuel Pressure Regulator and maybe uprated injectors o ensure enough fuel can get to the cylinders.
I think it's important to regard the HG as a consumable safety valve, it's much easier to replace than melted pistons. If there is no record of the gasket being changed and the car is north of 100k miles then it may be prudent to change it before upping the boost and subjecting the original one to a bit more strain.
We had a spate of HG failures several years ago when people started to up the boost but I think that was due to incorrect fuelling and running dangerously lean which causes the HG to burn away. I haven't heard of any for a while now and I believe it is because the current range of remapped chips have addressed that issue and also use a 3 bar Fuel Pressure Regulator and maybe uprated injectors o ensure enough fuel can get to the cylinders.
I think it's important to regard the HG as a consumable safety valve, it's much easier to replace than melted pistons. If there is no record of the gasket being changed and the car is north of 100k miles then it may be prudent to change it before upping the boost and subjecting the original one to a bit more strain.
sawood12
New member
My car is 117k miles young and as far as I can tell from the cars maintenance history is still on it's original head gasket. I am a big fan of preventive maintenance and plan to replace the gasket pro-actively - just a question of when. Although in theory you can run the car till it goes and alot of people do with no problems at all, however I don't like the idea of running any part of my car to failure.
The only time i've heard of it being dangerous is if you have a small leak that fills the cylinders with water if the car is left standing for long enough. My specialist has seen two cases of when the owners come to start their cars it actually breaks a con rod - these cars have very powerful startermotors. A very rare failure indeed but as I said my specialist has seen it twice. They have seen a hell of alot of broken starter motors due to cylinders filling with water. In fact this happened to a work collegue - he took his starter motor in as it was broken, the specialist took one look at it and said "head gasket", and sure enough he was right.
Another issue i've heard about that makes me worry is that some people have reported to have pitting and corrosion once they come to remove their gasket. This is because the soft material in between the metal rings can literally disintegrate over time and exposes the top of the block and underside of the head to the engine coolant. If your coolant doesn't have enough antifreeze in it then corrosion can occur. You might very well have made sure your coolant is at the right concentration, but what about previous owners?
As Paul has said the thing that breaks gaskets is not necessarily boost pressure but poor fueling that results in higher combustion temps, so if you are planning upgrades be sure to concentrate as much on the fuelling side of your mods as the turbo side. First mod = wideband AFR gauge.
The only time i've heard of it being dangerous is if you have a small leak that fills the cylinders with water if the car is left standing for long enough. My specialist has seen two cases of when the owners come to start their cars it actually breaks a con rod - these cars have very powerful startermotors. A very rare failure indeed but as I said my specialist has seen it twice. They have seen a hell of alot of broken starter motors due to cylinders filling with water. In fact this happened to a work collegue - he took his starter motor in as it was broken, the specialist took one look at it and said "head gasket", and sure enough he was right.
Another issue i've heard about that makes me worry is that some people have reported to have pitting and corrosion once they come to remove their gasket. This is because the soft material in between the metal rings can literally disintegrate over time and exposes the top of the block and underside of the head to the engine coolant. If your coolant doesn't have enough antifreeze in it then corrosion can occur. You might very well have made sure your coolant is at the right concentration, but what about previous owners?
As Paul has said the thing that breaks gaskets is not necessarily boost pressure but poor fueling that results in higher combustion temps, so if you are planning upgrades be sure to concentrate as much on the fuelling side of your mods as the turbo side. First mod = wideband AFR gauge.
sawood12
New member
I'm plumping for an Innovate one that has an in-dash gauge and the ability to datalog (link below). Seems like a good price considering the current US/GBP exchange rate.
http://www.lindseyracing.com/mm5/merchant.mvc?Screen=PROD&Store_Code=LR&Product_Code=IM-3781&Category_Code=
http://www.lindseyracing.com/mm5/merchant.mvc?Screen=PROD&Store_Code=LR&Product_Code=IM-3781&Category_Code=
George Elliott
New member
You need a bit of thought ref preventative HG replacement. Mine popped last year on Cyl 4 just where most seem to go. It was a Victor Reinz gasket, and had corroded badly.
(I now believe the Lindsay Racing vent theory, and will fit it next time the head's off given the cost is peanuts.)
I would do a compression test to make sure you have (i'd say 140psi, but other better informed folk here may advise a different psi value). If it is below 130psi then it needs rings. You may as well give it new big end bearings while your there, then reassemble with a cometic Head gasket.
Also fit a water pump, Thermostats, Cam /Balance belts and rollers, HT leads, Dizzy Cap, Plugs, Idle Valve maybe while the inlet manifolds off, (I changed mine with it fitted but its awkward), PAS Belt, Alternator Belt.
That will leave you with all the "stuff" done for 100k miles with just routine service required IMO.
I got all the bits plus some advice from Promax and did it DIY as there are no local specialists - and I enjoy some spannering.
The labour for all this will be £X but if you do it one at a time it will be £X times 6.
EG I know my compression is about 130, and I need to fit new rings, - but my new Head gasket (plus time & the other gaskets in the set) will all be scrapped when I do the rings.
The advantage of your planned approach is it is more efficient if planned properly.
happy planning and good luck
George
944T
(I now believe the Lindsay Racing vent theory, and will fit it next time the head's off given the cost is peanuts.)
I would do a compression test to make sure you have (i'd say 140psi, but other better informed folk here may advise a different psi value). If it is below 130psi then it needs rings. You may as well give it new big end bearings while your there, then reassemble with a cometic Head gasket.
Also fit a water pump, Thermostats, Cam /Balance belts and rollers, HT leads, Dizzy Cap, Plugs, Idle Valve maybe while the inlet manifolds off, (I changed mine with it fitted but its awkward), PAS Belt, Alternator Belt.
That will leave you with all the "stuff" done for 100k miles with just routine service required IMO.
I got all the bits plus some advice from Promax and did it DIY as there are no local specialists - and I enjoy some spannering.
The labour for all this will be £X but if you do it one at a time it will be £X times 6.
EG I know my compression is about 130, and I need to fit new rings, - but my new Head gasket (plus time & the other gaskets in the set) will all be scrapped when I do the rings.
The advantage of your planned approach is it is more efficient if planned properly.
happy planning and good luck
George
944T
sawood12
New member
Good advice George. I'd also go for the venturi delete and vapour purge delete while I was in there. Both systems are not needed and all that extra tubing and piping in the bay just makes it look busy and provides more potential boost leaks.
Warning about the Cometic HG - there are alot of guys in the US running them and some have reported leaks after fitting. Although there is some compliance in the Cometic gasket there isn't much and not as much as a conventional gasket. This means your head and the top of your block really need to be very flat for the gasket to seal properly. If not then your head and block might need skimming.
I had previously made my mind up about going for the Cometic but since have decided against it. With what i've got planned for my engine I don't think a Cometic would really benefit me and with the extra risks and potential complications I've decided against it. I think i'll go with stock. My current stock one has lasted 20yrs and 117k miles so far and the 1 - 1.2 bar boost pressure i've got planned is not really pushing things too much as long as I make sure i've got good fuelling.
You can also get Widefire gaskets, but they have had mixed responses from people that have used them and so the jury is still out on whether or not they are any better than stock.
Warning about the Cometic HG - there are alot of guys in the US running them and some have reported leaks after fitting. Although there is some compliance in the Cometic gasket there isn't much and not as much as a conventional gasket. This means your head and the top of your block really need to be very flat for the gasket to seal properly. If not then your head and block might need skimming.
I had previously made my mind up about going for the Cometic but since have decided against it. With what i've got planned for my engine I don't think a Cometic would really benefit me and with the extra risks and potential complications I've decided against it. I think i'll go with stock. My current stock one has lasted 20yrs and 117k miles so far and the 1 - 1.2 bar boost pressure i've got planned is not really pushing things too much as long as I make sure i've got good fuelling.
You can also get Widefire gaskets, but they have had mixed responses from people that have used them and so the jury is still out on whether or not they are any better than stock.
George Elliott
New member
Scott,
agreed, thanks for reminding me, I forgot those points.
May I suggest that when you see your Std Gasket you will go cometic. It will be rotten to bits, some of them in the waterpump probably - really.
Your fear of component flatness is unfounded, - make sure the fastners are free running, and the torque wrench is accurate with a good operator.
Many heads are skimmed to be less flat than they were before skimming IMO.
The wide Fire Gasket replaced the standard one many years back I understand. I'd offer you the one from my gasket set only I binned it.
George
944T
agreed, thanks for reminding me, I forgot those points.
May I suggest that when you see your Std Gasket you will go cometic. It will be rotten to bits, some of them in the waterpump probably - really.
Your fear of component flatness is unfounded, - make sure the fastners are free running, and the torque wrench is accurate with a good operator.
Many heads are skimmed to be less flat than they were before skimming IMO.
The wide Fire Gasket replaced the standard one many years back I understand. I'd offer you the one from my gasket set only I binned it.
George
944T
Peter Empson
PCGB Member
I've been looking at these too. There's an eBay seller with good feedback who does them delivered for £250, so I think it should work out cheaper than getting them from Lindsey. I'm planning on getting one within the next 2-3 weeks, so I might be up for combining an order if anyone else is tempted as it might save a bit of postage.
http://stores.ebay.co.uk/PowerTuning
sawood12
New member
I've just missed the boat Peter. I ordered mine from Lindsay this afternoon. He did say it was $350 even though his website say's $400 so i'll have to see what he actually charged me. I have a work collegue who lives in Dallas so I got it shipped to him and he'll either hand carry it over for me next time he comes to the UK or he'll post it on to me minus any invoices or paperwork that might attract the attention of the customs people.
Peter Empson
PCGB Member
Hi Scott, no worries, it should work out at a good price if you can skip the duty - good one [
]
I've not decided for definate yet, but my manifold/downpipe is on its last legs - it has a little hole in it and looks well past it. Even before the SC project started I was planning on having a custom equal length replacement made as many US 968 owners have seen worthwile improvements with aftermarket ones, but I didn't fancy importing one so will try to get a specialist to work on something for me. This'll also give me the freedom to munt the sensor whichever way is best.
Best regards,
Peter
]I've not decided for definate yet, but my manifold/downpipe is on its last legs - it has a little hole in it and looks well past it. Even before the SC project started I was planning on having a custom equal length replacement made as many US 968 owners have seen worthwile improvements with aftermarket ones, but I didn't fancy importing one so will try to get a specialist to work on something for me. This'll also give me the freedom to munt the sensor whichever way is best.
Best regards,
Peter
rcsalmons
New member
ORIGINAL: Peter Empson
Hi Scott, no worries, it should work out at a good price if you can skip the duty - good one [
I've not decided for definate yet, but my manifold/downpipe is on its last legs - it has a little hole in it and looks well past it. Even before the SC project started I was planning on having a custom equal length replacement made as many US 968 owners have seen worthwile improvements with aftermarket ones, but I didn't fancy importing one so will try to get a specialist to work on something for me. This'll also give me the freedom to munt the sensor whichever way is best.
Best regards,
Peter
Peter
I have a standard S2 manifold you can have if you need it.
Rich
Peter Empson
PCGB Member
Thanks Rich, I'm definately interested as it would tide me over and help me spread the costs a bit.
Best regards,
Peter
Best regards,
Peter
Peter Empson
PCGB Member
Thanks Rich, that's really appreciated, I owe you a burger/beer []
]
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