VX BLOWING OIL

[Glenn Wheeler]

This is my first posting to this forum, so here goes.

 

I own a CKD Kit built VX HPC on Carbs (1995)(M17 SOK), the rocker cover oil breather pipe has always been open to the atmosphere, passing down to the bottom rail near the gear box. Since building the car only light oil mist has ever exited this pipe. Returning home from Brands (albeit rather quick!) last week I noticed that proper oil was all over the underneath of the car obviously having come from the breather. This was reminiscent of an old supersprint I use to own, on this I just passed the pipe into an oil catch tank as racers do. As the engine has only done 12000 miles I am a bit concerned, is it normal for a VX engine that is getting a bit looser to do this or have I cooked the oil rings? Any opinions or solutions please, Roger King are you reading this?

[Roger King]

Glenn,

 

If you give the engine a good pasting, this sort of thing is more likely to happen, but the Vauxhall is not as prone to the problem as the Crossflow.

 

If you have been indulging in hard cornering and braking this can make the problem worse too.

 

I am assuming that the engine is wet sump. If this is the case, an oil level that is too high will not help.

 

I strongly recommend that the breather is fed into a catch tank anyway. Apart from saving you from dropping oil onto your own tyres (don't laugh, I know someone who spun off on his own oil because of this), it will allow you to see how bad the problem is. A small amount of oil can look like a lot when spread on the chassis.

 

You may then find that the problem is very minor, but if the oil level is correct and you really are throwing out a lot of oil at least you will know.

 

If this proves to be the case, you will have to investigate further (possibly with a cylinder leakage test).

[Alex Wong1697456877]

SBD recommend modifying the plate inside the cam cover. They essentially advise removing it and cutting it to leave a square of plate over the breather exit. This reduces the amount of oil being breathed out. Don't forget that the engine was designed to be mounted transversely across an Astra or Calibra engine bay. The seven generates much more lateral g than an astra does in acceleration. I figure the mod makes sense in order to make it stop breathing so easily although this is just my own amateur logic!

 

I also had a problem with the foam sump baffle getting caught in the crank and fairly large chunks of it got caught in front of the crank sensor wheel. This blocked two oil return channels from the top to the bottom of the engine. I think what happened was that as the engine ran harder, all the oil went to the top of the engine thus causing very heavy breathing and also oil surge due to a lack of the stuff in the bottom end. I'd check the baffle and replace it regularly. I think this is a pretty rare cause of breathing though.

 

Alex Wong

alex.wong@lotus7club.co.uk

www.alexwong.net

Home : 44-(0)121-440 6972

Fax : 44-(0)121-440 4601

[Glenn Wheeler]

Thanks for the quick replies.

 

Since my first posting, I have deliberatly tried to induce the loss of oil, but guess what? it wont do it any more. I think it may have been overfilling with oil, as you suggested Roger. We will wait and see.

Thanks again.