White smoke and power loss *UPDATE*

[mushtykev]

Took my 86 944 turbo for a drive today. Started fine no smoke etc. About 6 miles into the journey, overtook a car everything was ok, went up to full boost held for a second then hesitated. Noticed after that the car was feeling sluggish as if turbo not boosting and the gauge seemed to confirm this by struggling to go past 1 bar even at full throttle!
Took it steady on a long stretch of road and let the car accelerate slowly, it made it past 1 bar...just, then i noticed a steady stream of white smoke coming out of the exhaust.
Nursed her home idling on the drive way and again a steady stream of white smoke, even more when blipping the throttle.

I guess a vacuum leak would cause the boosting problem but would it cause the white smoke too?

Any help would be appreciated.

Cheers

 

[T3rra]

Not what u want 2 hear, but my fears would be head gaskit.

 

[zcacogp]

I'd disagree with T3rra; my suspicions would be a head gasket. [] Although I don't think either scenario would be cheap. Sorry it's not good news. Oli.

 

[mushtykev]

Reading around i thought as much, but hoped it wasn't. I had just hoped that the lack of boost was down to a vacuum problem. I assume the lack of boost is down to the lack of exhaust gas spooling the turbo? Also can you recommend a good after market head gasket kit, bearing in mind i intend to track the car next year. I see Promax sell a cometic kit and a wildfire kit and didn't know if anyone here had ever used one of them? Cheers. kev

 

[944Turbo]

classic overboost symptoms (assuming standard chips) and steam from a cold exhaust on a cold day warming up - combined with more observation than normal! Check the coolant level to be sure and try it again now the ignition has been off/on Tony

 

[GPF]

Head gasket is the the obvious culprit. Do not try to start the engine until you know - water doesn't compress and you can do much more damage if one of the cylinders is now full of water. Check the coolant level and take the plugs out and check. No 4 ( the back one) is the usual one so start there. The other possibility is that the turbo bearings have broken and taken out the oil seal, in which case the high pressure feed will be dumping oil into the downpipe and will vaporise to give white smoke. This could also explain the lack of boost. Not good news either way, but maybe an opportunity for some mods......

 

[mushtykev]

Will check the state of the plugs tonight. An excuse for some mods is the same thought i had [] Car is totally standard atm Need to do cambelt, water pump and balance belts so will do it all at the same time..hopefully this easter weekend. Anyone have any opinion on the head gasket kits i mentioned that Promax sell? I guess they are both good for track days but didn't know if anyone on the forum has ever used one of the kits on a track car? Thanks for the advice btw! Kev Forgot to ask, if the turbo bearings have broken i assume this will be obvious with an inspection of the turbo still on the car, like excessive movement in the shaft and oil in the IC pipes?

 

[GPF]

ORIGINAL: mushtykev Will check the state of the plugs tonight.

The plugs may not show anything, you need to look down into the cylinder and see if there is water in there.

ORIGINAL: mushtykev Need to do cambelt, water pump and balance belts so will do it all at the same time..hopefully this easter weekend.

You could also do the oil seals on the front of the engine while you are in there [] While the head is off, you could also lap the valves, do the valve stem seals and maybe the steam vent mod.

ORIGINAL: mushtykev Anyone have any opinion on the head gasket kits i mentioned that Promax sell?

I had a widefire fitted at one point but that let go a couple of years ago on a very hot track day. (Number4 as usual) I replaced it with the cometic kit from ProMax. It's a good kit, and also includes a metal cam tower gasket which is great, but whether it's really necessary is difficult to tell. The original, or a widefire, may act as more of a safety valve according to some but others will disagree.

ORIGINAL: mushtykev Forgot to ask, if the turbo bearings have broken i assume this will be obvious with an inspection of the turbo still on the car, like excessive movement in the shaft and oil in the IC pipes?

You would think so.

 

[edh]

couple of other thoughts If it is the headgasket (which it does sound like), there will be traces of exhaust gases in the coolant - an MOT place will be able to detect them with the hydrocarbon test equipment. That's pretty conclusive (obviously Graham makes a good point about not trying anything until you confirm one of the cylinders isn't full of water) From my own experience, you don't always get oil & water mixing with a 944 headgasket failure, just coolant into the combustion chamber. I'd agree with Graham about the steam vent kit - seems daft not to if the head's off. Standard headgasket should be fine for trackdays - but of more importance is that your cooling systems are up to scratch - oil cooler, radiator and intercooler. Too much boost on a hot track day will see temps soaring.

 

[mushtykev]

I am probably going to order a new cambelt kit, balance shaft kit and water pump kit from Porsche Exeter today & collect this thursday afternoon. The dealership belongs to the same people who own the VW garage i work for so i can get cost price on parts...which is handy! I think their cambelt kit comes with all the front seals for the engine, but they are about to fax me a couple of pic's so i can pick out what i need to order. Their water pump kit includes both stats and gaskets too. Yer a steam vent kit sounds a good plan, just seen promax do them! Yeah lapping the valves also makes sense whilst the head is off, just such a tedious job lol

 

[mushtykev]

Just spoke to the lads at porsche. Their balance shaft kit comes with all the toothed belt pulleys and their cambelt kit comes without front engine seals. It seems a little excessive to replace the toothed belt pulleys, surely the tensioner's and belt rollers would be sufficient as the promax kit supplies? http://www.promaxmotorsport.co.uk/products/23-belts-rollers-kit-944-turbo-25-non-s-27-86-on.aspx Then order front engine seals seperate? Also porsche say to change the seals for the balance shafts, is this necessary? I guess any oil seal is worth changing on these engines whilst it's stripped haha

 

[peanut]

I agree it does sound like a head gasket but why you don't buy a £10 compression tester from a car accessory shop and do a compression test at least. Any good garage could do a leakdown test for you so that you know for sure.[]

 

[Frenchy]

Cam belt £14 and balance belt £40 from my local motor factors Gates Powergrip, a friend ordered his belts from OPC which turned out north of £150, he received a set of Gates Powergrip belts in Porsche boxes, turns out to be expensive boxes, one of my cars getting belts this weekend and if necessary rollers.

 

[edh]

I had sort of assumed Kev would be doing this already & it didn't need saying...if he's capable enough to do the belts & headgasket I assumed he'd have a compression tester

 

[peanut]

I expect that you are right edh but it hadn't been mentioned anywhere. I think there maybe a tendency to jump to conclusions and think the worst case scenario sometimes when its so simple to verify with a quick compression test. []

 

[Eldavo]

I agree. Not one person has mentioned that it was probably just his car choosing a new pope.

 

[GPF]

ORIGINAL: peanut I think there maybe a tendency to jump to conclusions and think the worst case scenario sometimes when its so simple to verify with a quick compression test. []

I don't think anyone is leaping to conclusions, and what do you expect him to do with a compression tester??

 

[zcacogp]

ORIGINAL: GPF

ORIGINAL: peanut I think there maybe a tendency to jump to conclusions and think the worst case scenario sometimes when its so simple to verify with a quick compression test. []

I don't think anyone is leaping to conclusions, and what do you expect him to do with a compression tester??

Erm, check the compression in the various cylinders and see whether this points to a blown head gasket? Oli.

 

[peanut]

ORIGINAL: GPF I don't think anyone is leaping to conclusions, and what do you expect him to do with a compression tester??

well you could stick it where the sun don't shine []...............in his cylinders of course ..[][][]

 

[GPF]

My point is that a compression test may not prove anything either way. You can have a slight HG leak that will not show up as low compression, and you can have low compression for other reasons. Using a compression tester is not a simple verification! Plus, if a load of water has now drained from the cylinder to the sump and you vigorously crank the engine to do 4 compression tests, how far does any water get? What surfaces are now not adequately coated with good oil? Why do you think garages use the test for Hydrocarbons in the coolant?