7 replies to this topic

[dbcool20]

hey guys,

After removing my spark plugs last time on my SPI, i looked in the plug holes and realised i have a little puddle of oil at the bottom of my dished pistons... the engine has been fully rebuilt about 3k miles ago. I thought it was my valve seals so removed the cylinder head, changed all valve seals, and new head gasket, but no improvements there. I did a compression test on all four cylinders and get around 14.5-15 Bar at all 4 cylinders which is quite good. If my rings were the problem would I be able to have such high compression values? Thought it might be the engine breathers throwing oil back in the Throttle body so tried driving with the breathing system disconnected and going in a can, but no real results there aswell still oil in my cylinders. Feeling a bit confused, Anyone have any suggestions? PS: the car doesn't even smoke that much really.

 

cheers

[brivinci]

I have had two sets of oil seals arrive out of dimensions and did not/or would not seal correctly. I never installed the second set as it was clear they were not correct. The state of the parts we have available is really shocking these days. I'd really confirm that the seals have the correction tension around the stems.

 

I would run the car around till it gets warm. Put some miles on it so you are sure you burned any of that pool of oil. Stop the car and pull the plugs and inspect. If there is no oil then let the car sit several hours/overnight and then check again. Obviously, if there is oil present then its coming from the top end. If there is oil right after you stop the car, it could be either seals or rings.

[dbcool20]

The seals installed are the later Viton type seals. but indeed they did seem to be not that tight when I installed them. I did try something similar to what you mention above and each time i drive and remove the plugs i see oil in the cylinders, no need to wait..

[brivinci]

Well, that really only tells you that you are getting a lot of oil in there, not really where it is coming from though. Is one cylinder more oily then others?

 

My car tested with decent compression but I in fact, need a rebuild. If you can get a scope, would be nice to get a good look at the cylinder walls to see what they look like.

 

Not sure if this will work but what if you try and clean off the top of the cylinder while its sitting. Then remove the valve cover and pour oil all over one cylinders valves. I guess they would have to be open for this to work so only could test one valve seal at a time. Maybe this idea wont work but the idea is to see if more oil gets into the cylinders after the car is stopped. That would maybe give you a better idea.

 

In the end though, whether it is the valve seals or the cylinders at fault, the head will need to come off. With the head off, you should REALLY be able to see whats going on. Cylinder walls will be worn or valve seals can be tested on a bench. Its a pain but might be the best bet. Do a leak down test first while the engine is still together though. Might give you a few answers as well.

[minidaves]

take it apart inspect and replace/machine as required

[brivinci]

But do EVERY test you can before you dismantle the car. Once its apart, you will not be able check certain things again

[dbcool20]

I did take it apart, as i was pretty damn sure it was the valve seals. Cylinder walls were quite decent... Cleaned everything real well, stripped the head completely as it was full of burnt oil. cleaned the valves and reground them. changed all the the valve seals, and put everything back together.

same thing still oil in the cylinders after just a short drive. and same quantity in all 4.

Last week i used our borescope from work and inserted it through the throttle body and all the way in the inlet ports and seems there is a bit of oil there and behind the inlet valves as well... Oil in the inlet now I am really thinking of my valve seals again, i doubt oil could come from the cylinders and back in my inlet... But strange with brand new Viton seals on all 8 valves.. (PS Its not from the breathers blowing back oil in the throttle body, its the first thing i disconnected and routed in a bottle to be sure.) I Guess I ll be taking the head off again...

[brivinci]

Oh man. Keep us posted. Interested to hear where you net out.