Burning Oil

[chrisg]

Mick by default there's only 2 places where oil can get into the cylinder, down through the valves/ guides or up through the piston rings. What is the oil usage like ? 944's do burn/ leak a reasonable amount of oil. You might actually find its just the valve stem oil seals that have hardened up with time and continued exposure to oil = not uncommon. Chris

 

[PSH]

Hi Mick Are you sure it's white smoke?... white is water thus head gasket issues while blue is oil so valve seals or rings. Is there any sign of the oil or water being contaminated? Even if there isn't it's possible that your head gasket is only just beginning to fail and due to the extra heat generated during a track day it's started to show. Let's hope it is water and the HG as it's a lot cheaper to fix than oil related problems. regards Pete

 

[Cater_Racer]

Hi Mick, have a word with Kevin or Alex at EMC they are very reasonable hey could put you on the right track? Gerry

 

[Swindon_Mick]

Hello all

I recently bought a 2.5 8-valve 944 race car originally built by EMC Motorsport in Birmingham for a bit of track day fun.

I took the car down to Castle Combe last Friday for the PCGB track day - my first time on track with the car. The car felt pretty powerful and pulled well, but it was burning oil when I lifted-off at high RPM (evident by a large cloud of white smoke behind the car as I braked for the corners!)

My initial thoughts are cylinder head - i.e. valve guides and / or valve stem oil seals, but are there any other potential causes I should investigate? By the way, the car has an oil catch tank vented to atmosphere, so there is no way that oil can get back into the throttle body from the breather.

Any suggestions welcome!

Thanks

Mick

 

[944 man]

I cant add anything beyond seconding what Pete and Gerry have said. Speak to Alex (he is easier to deal with than Kevin for some people) at EMC. If it needs looking at then this is where Id take it too. Their hourly rate is modest and no one will know the car better, after all. As Pete has said, white smoke isnt oil, but this probably isnt a disaster.

 

[Hilux]

Just a thought - the oil/water intercooler interface could be breached?

 

[bmnelsc]

ORIGINAL: Hilux Just a thought - the oil/water intercooler interface could be breached?

IMHO this wouldn't result in oil or water in the combustion chamber which must be happening for exhaust smoke. If oil and water is mixing it would show up as oil in the coolant and/or milky foamy sludge in the oil. If this is happening - it must be corrected ASAP as anti-freeze destroys bearings and therefore the crank/rods and cams are at risk.

 

[JM1962]

I would say, assuming it is oil smoke that it has to be valve stem oil seals or guides. If it was oil smoke on acceleration it is probably rings.

 

[sulzeruk]

Stem seals will have hardened and be US and the guides could well be shot if there are a few miles on the motor. Alasdair

 

[Swindon_Mick]

Thanks very much chaps for the responses and suggestions. I'm pretty sure that it is oil smoke (my description of smoke colour above being a bit vague!).The head gasket was replaced shortly before I bought the car and there are no signs of cross contamination in the oil of water. Here's a photo from the Combe track day (I'm braking for Camp corner so foot off accelerator):

From what you've suggested I think the evidence points towards valve stems / oil seals - I'm going to Castle Combe today to watch the PCGB racing and I'll try to find Kevin of Alex in the paddock. I'll keep you posted! Thanks again Mick

 

[944 man]

Wow. Guides & seals, I think.

 

[Mike_Pollock]

ORIGINAL: 944 man Wow. Guides & seals, I think.

+1! (Although I have seen that sort of smoke on a dyno which was later identified as being from badly scored bores)

 

[Swindon_Mick]

I had a chat with Kevin this afternoon (he was in quite a chirpy mood as Alex had just won class 2 in the first race!) When I explained the symptoms he thought it was more likely bores / piston rings than top end, although he said either way it was probably not worth taking the engine apart - his advice was to keep using the existing engine until something catastrophic happens, and then swap the whole engine for a second-hand one (which can be picked-up on ebay for around £250) - of course the risk here is that a second-hand engine may have the same problem! Kevin remembered my car, which was campaigned by Frank Cortes in the PCGB championship for several years in the mid 2000's. Kevin did not think that the engine had been rebuilt since the car was built (or if it had it was not by him), so it's probably had a hard life! Mick

 

[Neil Haughey]

He has some memory. I have seen pictures of Frank's old car from when he raced it on the wall at EMC. ISTR he has been racing a 964 in CSCC Deutsche Marques which is used to run in our club championship. I am fairly sure he is a customer of NineX so I guess via them or other mutual contacts you may be able to get some more history on the car. Fairly sure Frank told me the engine had been rebuilt on that car.

 

[Swindon_Mick]

Neil - thanks, from a quick bit of googling it looks like Frank Cortes is indeed racing in the CSCC Deutsche Marques championship (car no 77 - 964 Carrera 2). I'll ask NineX if they will pass my e-mail address onto him as it would be good to understand a bit more about the car. By the way, conditions at Combe yesterday were a bit changeable to say the least - qualifying for PCGB was dry (first thing in the morning), race 1 was drizzly, and race 2 was absolutely p***ing down. Sumpter won C1 from Morris in both, and as mentioned above Alex Eacock got C2 in the first race and I think he may also have got the class win in the second race as well. A couple of spinners but luckily no major accidents. Mick