Aux. Cam Shaft Oil Seal

Hey Guys,
After replacing the front main seal on my 740 i found it was still leaking oil !

After stripping it down and inspecting it closer i found it was the aux cam seal, and it was totally stuffed !

I replaced it today and started in up with the cam belt on, but nothing else..
Ran fine, with no leaks for about 20-30 seconds!

then, pfft ! The aux cam seal got blown out !

Seems there is way too much pressure behind the seal !

I've read on the FAQ that the flame trap is often a cause of crankcase over pressure..
WTF is the flame trap ?? obviously part of the PCV system..

Has anyone else had this problem ??

thanks,
Cam

[Mike_Brace]

The flame trap is hidden behind the bellows below the intake manifold and ablack plastic box attached to the block. The box also gunges up sometimes so if flame trap (you'll probably need a new holder as well since the little pipe tends to break off). Its a sealed box so if it won't clean you'll need to replace it.
I have come across pressurising caused by worn valve guides as well.

Mike

Hi Mike,
thanks for the info, i'm still a little confused about this flam trap...

I found a little black plastic thing that was attached to the pcv outlet on the block today, it has 2 hoses coming from it, 1 big, that goes to the air intake, just below the belows. and another little hose that connects to the intake manifold.

The brass adaptor on the intake mainfold was completly blocked with old gungy oil crud !

So was the other black plastic thing attached to the block, it wasn't sealed, had a hose clamp around it to keep it in 1 piece, and inside was a very coarse filter, which was also very blocked ! Is this the flame trap ??
I wouldnt call it a box as it was round ! But it was where you described.

Seems to run ok now that these have been cleared !

Thanks,
Cam

[Mike_Brace]

The flame trap is like a circular plastic disc with holes drilled in it that fits in the black y piece - sounds as if you sorted those ok. The box I was referring to is bolted to the block and my suspicion is this will be blocked as well - to be honest from what you are saying about the muck the engine may not be in very good condition but it could just be very severe neglect. I've got an engine that's done over 250,000 and the breather hardly needs cleaning and I still use little oil - worn valve guides are the main problem.

Mike

Hi Mike,
I put it all back together today, seems to be running ok, but a little underpowered ? seems the same as before tho..

But i think your right, this motor hasnt been treated well ! its showing 312,000kms on the clock. To be honest i'm not too worried, all i need at the moment is to have a motor that runs and gets her from a to b. As i plan on replacing the motor in the not too distant future.

thanks,
Cam

[bbruneau]

My first post!

I also replaced the cam seal on the way to discovering blockage in my crankcase ventilation.
First of all as I replaced the timing belt (might as well) which had nice markings for all three pulleys, one of which was off! Maybe that is just US manufacturers but the camshaft marking was correct for no tension but was off a cog in timing when I tightened it down! All the timing marks refer to everything tightened down. That is not always intuitive.
About the "flame trap" and the black box on the bottom of the block. In my case the flame trap simply wasn't there - in my 86 740 GLE I assume it should be in the black box where the big hose goes out the top.
Finally, for something useful for your problem, do be sure that the hoses are all clear. The tiny vacuum hose (for the idle) on my car was stopped up and caused an amazing amount of oil to leak out.