milky oil under valve covers..compression test
 

I have two 502 mags and in one engine last season i was noticing white milky stuff under the valve covers and in the breather hoses but nothing on the dipstick or in the pan.
The engine ran great, no missing, stalling and no loss of power. I changed the intakes over the winter thinking since they were aluminum and i thought they could be leaking some water in. They were pretty rotted around the water passage. I also did a cold compression test and found all cylinders around 165-170 except #4 @ 150 psi
I called my local engine shop and he said the compression test is ok and not to worry. As for the milky oil he said it was probably condensation. He said I could put a PCV system on it and at idle it will help draw out moisture..from the crankcase.
What bothers me is why ONE engine and not the other..:eek:

Any help would be appreciated
Thanks

I have seen engines with milky substance "moisture" under valve covers and oil cap. Condensation traps at the highest point after you ran the engine for a short period and the steam travels upward and collects. Many times it happens from not getting the engine up to operating temps.
You might possibly have a weak T/Stat and not letting the engine get up to proper operating temp.

Just my thoughts :)

Thanks for your reply.. Engine runs at 160 water temp and oil temp gets up over 200 cruising and higher on a hard run
Why only one motor?
I just did a wet compression test..and all cylinders came up 10-15 psi..I guess thats good

Check the exhaust riser gaskets.

Only one engine because only one has a water leak somewhere.

New EMI thunder exhausts ..looked in manifolds , no sign of water..and all plugs same tan color.

I'm going to put the PCV systems on and see if that corrects the problem..

How old is your exhaust? Any chances of a crack there? If both temps are the same and you feel confident that it is not in the thermostat and or getting up to temps then I would start ruling out some other things. Gils use to be known for cracking internally years ago however not sure if EMI has had any problems with that or not. Regardless I would pressure test them.

What kind of raw water pump do you have? Also is there a possibility of a cracked oil cooler? If you could pressurize your cooling system I would check that also. You could pull the oil drain plug after sucking the oil out and pressurize at around 20 psi and see if any water drops or anything drips out the hole. I've never tried that however you'd have to plug your water lines going to your exhaust.

Also do a leak down. Do you winterize your boat or keep it in heated storage?

I would make yourself a list of things to check and start checking them off one at a time. I would really lean toward a cracked oil cooler or exhaust manifold if your leak down is exceptable. These are easy quick checks. It's sometimes difficult to visually see any cracks in the exhaust as they will expand when heated up and then shrink back when cooled off. So make sure you do a quick pressure test.

Hope this helps you out a bit and keep us informed.

Good luck,
John

if any water is getting in the engine, it will settle to the bottom of the oil after it has set for a good while. back out the oil drain plug until it starts dripping and see what you got.

The exhaust was installed summer of 2009..I did notice that the water pressure increased with this system..I guess with the y pipes connecting 2 hoses to one outlet it will...After removing the old intakes and seeing the rot around the water passages I figured it was possible i was getting a liitle spray of water from the rot into the oil splash pan uner the intake in the oil lifter galley and possibly causing the milky stuff under the valve covers...I have to mention that i did not run the boat in the water since the last start up ...so running it on the garden hose may not of heated it up enough..I use 20-50 Amsoil..I haven't changed it yet..is it posible the oil stills have some moisture in it from last season with the old intakes?

As for the boat ..its in my garage winterized and it never drops below 33 inside...I get no steam coming out of the exhaust at idle.. Wouldn't the spark plugs be washed clean if i was getting water ???

Thanks Jay

as for the oil coolers...Oil pressure is 60-80 psi..Water pressure is 5-15 psi...I think I would loose oil into the water not water into the oil..but i will inspect them

Thanks

I took the risers off the EMI's, Both sides looked the same. Pics attached

I can't see any residue of water

There is less than 50 hours of running time on these manifolds