New heads on a Nikasil M60 - BMW Forum

540John · 09-30-2009, 01:33 PM

I have a 540 with just at 200k mi. It looks like the valve seals are leaking pretty bad. A lot of white smoke on acceleration after idling. 5 of the 8 plugs were black when I pulled them out.

I checked the compression and all cylinders are around 240psi. This seems ok.

Is it a good idea to rebuild the top end of a nikasil block engine or drop a used, warrantied alusil engine.

I guess I'm asking how long will the lower end last? The car is typically driven gently by my wife.

Thanks,
-j

marti5 · 10-01-2009, 02:09 AM

It sounds as if the oil separator valve/ aka PCV is the problem. This is why it doesn't smoke at tick-over, there isn't enough air-volume to lift the oil from the engine. When the revs get up (especially when a bit of throttle is applied) the blow-by gasses can lift the oil from the engine straight into the inlet manifold.

540John · 10-01-2009, 09:46 AM

Interesting thought. Replacing the PCV/Oil Separator valve is a lot easier than pulling the heads.

On one side of the engine, the 2 rear plugs were black, on the other side the 2 rear were black and the next one forward was dark brown. The remaining were clean burning.

That brings up another question. How are the cylinders numbered? I looked in the Bentley manual and couldn't find it.

I also have an '89 Porsche 928. I had to do some rerouting of the vent hoses because I was getting pooling of oil in the intake manifold. After a spirited run and shut down the blow by oil would pool in the intake. At start up it would smoke like a crop duster because the oil was already there. I also had some smoke under hard acceleration. It's all fixed now.

I'll replace it and let you know

Thanks,

540John · 10-01-2009, 09:59 AM

I found this link describing how to test for failed OSV.

engine noise, whine, howling, oil separator valve

Cheers,
-j

marti5 · 10-01-2009, 10:18 AM

From the front of the car.

Bank 1 left, plug no's 1,2,3,4

Bank 2 right, plug no's 5,6,7,8

firing order 1,5,4,8,6,3,7,2

marti5 · 10-01-2009, 10:22 AM

Quote:

Originally Posted by 540John

I found this link describing how to test for failed OSV.

engine noise, whine, howling, oil separator valve

Cheers,
-j

He doesnt mention any smoke,which is a sure sign thats its the PCV, Smoke appear when its totally gone, he seems to have changed his just before it was a total gonner, also after you change it it will take around 200 miles to clear any remaining oil from the intake.

540John · 10-01-2009, 10:24 AM

Hi Marti5,

When saying from the front, is Bank 1 left on the US drivers side? Or is it on the left when looking at the engine from the front bumper? (without the hood)

Thanks,
-j

marti5 · 10-01-2009, 10:28 AM

Whether your in the UK or USA.

Looking straight at the car Headlights, bank 1 is on the left. basiclly look at my car pic below,left is road side.

You should really use the proper way of looking at a car as the engineers do which is from the rear so Bank 1 would be on the right, but I always tell people from the front as they get a bit confused.

540John · 10-01-2009, 10:54 AM

I'm an engineer and like to make sure from which perspective you are looking. Great stuff!

I thought it was odd that 5 of eight plugs were black and this was a sudden event, not developing over time.

OSV on order from BMA. Hopefully I'll get it installed this weekend and the 540 will be back on the road with the engine intact.

I'll report back.

Thanks,

540John · 10-05-2009, 10:20 AM

I pulled the OSV and found the diaphragm had a tear. I also found about 1/2 cup of oil in the intake ready to be sucked into the cylinders. I can see why the rear plugs were so black. And, the strange sound was the damaged diaphragm humming like a reed instrument.

When the car started smoking and sounding strange, my wife had it towed to Dinan in Morgan Hill, Ca to have it checked. They said it was most likely the valve seals or rings. The suggested we drop another engine in since it has just under 200k miles.

Hmm, OSV or new engine.

I'm waiting on a gasket. It seems when you buy a new OSV, it doesn't come with a new gasket.

Thanks,

witeshark · 10-05-2009, 10:23 AM

Best of luck with it!

marti5 · 10-05-2009, 10:24 AM

Thats good news, now when you have fitted the new OSV it will take around 200 miles for all the oil to burn out, so dont worry if its a bit smokey for a while, I never trust any garage.....it will also run a bit lumpy, I would suggest you leave the old plugs in and change after its burnt all the oil away.

540John · 10-07-2009, 01:31 PM

Here is a photo of the diaphragm I removed from the old OSV.