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Head Gasket Prob

M

maggotcorps

New member
Hi, i'm just about to start working on replacing my head gasket etc and i was just wondering while i'm doing this i might as well do some upgrades to the engine seeing as its apart already. The only thing is i haven't got a dam clue what upgrades i could do. So can you give me some ideas please.
 
Ah. Good spot.

In terms of what to do to an '87 Turbo with the head off I'd say just make sure the bores are not marked and put it back together again. You can use performance head fasteners and a fancy gasket if you like though the standard stuff is fine if you don't want to modify the car too far. Last rebuild I used a Cometic gasket and Raceware studs (both now in my garage and both reusable, scary as that sounds). Don't bother with a Widefire gasket as they are no better than standard.

While the head is off and you can get to the sides of the block it might be worth replacing the rubber hoses that live primarily under the inlet manifold - of course it goes without saying that you replace the belts and if they weren't done within the last 48k miles / 4 years the rollers, tensioners and water pump.

In terms of performance mods while you're in there you could go for a dual port wastegate (I'd recommend a TiAL) and a boost controller which would allow you to perform the "venturi delete" which is just a fancy way of saying take off the cycling valve and its associated plumbing. You're as close as you will get to the turbo now as well so if you want to change it now is a good time.

There isn't anything internal to replace - basically unless you have a scored bore or need to renew bearings there is no internal stuff to do unless you want to go 2.8 (which involves engine out, sump off, replace crank, pistons and rods). 3.0 or bigger is a completely new engine.

When I had my gasket done before the last rebuild I had a cylinder head overhaul. You could replace the valve guides and if necessary the valves (££££), or you might get away with just lapping them back in. I had 3 angle seats as I recall. You could also port match the head to the inlet and possibly the exhaust manifolds. It's possible to replace the cam, I think with one from a 2.5 NA engine, but I'm not sure if anyone on here has done it yet or what changes it makes. Of course you could get the head flowed or replace it with a big valve head.

It all depends how deep your pockets are and what you want to achieve from the work.
 
You could look to performing a venturi delete. You can get the kit for about $60 or make one up yourself from std rubber hoses. This isn't a performance mod as such but it does take out several joints in your vacuum line system and minimise the risk of vacuum leaks as 20yr old rubber hoses perish. As far as I can tell from the research i've done there are no adverse effects from removing the venturi so it seems it was one of those over-engineering things Porsche incorporated that have very little real benefit. I always feel it's best to remove things that don't have any effect.
 
cheers for the replies people. got a few things to think over there. However, i've checked my oil res/dip stick and my expansion tank and there is no residue at all. I've only been told by a couple of people that i have white smoke coming out of my exhaust, its not bad enough to see while driving and people have only noticed it when i've started my car from cold. Could it be anything else producing this white smoke or is it a common thing with 944's?
 
It is quite common for a 944 Turbo expecially to blow a head gasket. The reason is that they have gone brittle over the years and constant heat/cool cycles, usually they go after the owner starts to tweak the boost, but they can fail on a standard car as well.

When mine went it was pretty obvious as I had magically disappearing coolant and it started on 3 cylinders one morning, but once it was warm the gasket made a seal and you wouldn't have known there was a problem. It's quite possible you have a smaller leak that is only apparent when cold, but if you do I bet it's a bigger leak pretty soon.
 
ok, i thought you might say that. Just how bigga job is changing the head gasket on the turbo's. I've only really worked on vw's before whch are as easy to work on as working on a tonka toy, just a few bolts here and there. Is it a long job?
 
Dunno; I pay people to do that sort of thing [8D]

Jon will be able to tell you for sure and Tony is at least one member who did their own and can maybe help.
 
I've been looking into this as my car is on it's original head gasket so it's bound to fail sooner rather than later, especilly since i've tweaked to boost levels up (although it's not necessarily boost pressure that causes failures). The job is no more complicated than any other car - in fact it's probably easier due to Porsche over-engineering meaning everything comes apart and goes back together well, however it is a very labour intensive job due to all the gubbins you have to remove to get at the head - it takes an experienced specialist a good 10 to 12 mh to complete so a DIY mechanic doing the job for the first time should allow at least double that. I've decided to pay someone to do it like Fen when it does eventually let go.
 
At this time of year as the mornings get colder and if the car is outside then the exhaust will contain large qtys of water which will exit the exhaust as steam shortly after start up. If your coolant level is dropping then check the seal around the header tank. Also get a test for exhaust gases in the coolant. Changing the Head gasket is relatively straight forward, though involved, the workshop manuals are good - available free from http://www.cannell.co.uk/ and the guides on clarkes garage http://www.clarks-garage.com/ are usefull too.
The hardest part may be getting the correct tension the belts, I had a local specialist available to check mine before starting the engine.
Finally a few special tools are required, flywheel lock etc.
Tony
 
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