cream in the oil?!

[mini64]

Need help diagnosing whether or not I have a cracked head or block. Details below, but let me give you the current symptoms. I find creamed oil in my catch tank plumed off the front of the cam cover and off the vent on the blanked off mechanical fuel pump boss, but NOT in the oil itself. I can drain the oil and see no problems in it. I can lift the cam cover and see good oil sitting atop the spring buckets, but sticking on the underside of the cam cover is a white emulsion almost as thick as yogurt. This white fluid is almost like it is spray coming out of the cam bearing caps from the location on the cover, but not all of them. Maybe 5 out of the 10, plus at the very back of the cams. Oddly only from one side of the bearing cap, generally the front side. But oddly I only see it stuck to the underside of the cam cover, not directly below the same area in the head. And there is none directly above the cam lobes, almost as if the splash from them is cleaning off the underside of the cover.

Again, this is only found under the cover and in the catch tank (this is a race motor). If it is elsewhere I?ll have to open the motor to find it. It is not in the oil. Sometimes I have found oil in the water, pretty bad. But I don?t believe always. I have actually swapped out heads on this car and still found the same problem, although not necessarily as bad. So I would think that means there is some sort of crack or porosity in the block, but then why don?t I find the mess in the oil drained from the block? I have replaced the head gasket more than once, put stop leak in the water (which I hate doing) which oddly seems to help, but as soon as I pull the head to change the gasket or swap heads it is real bad again.

One head is original to the car, lotus big valve, mild cams. The other is one built up as a race head in the 70?s, fully ported with larger valves. This head sat on a shelf from the mid seventies till last year, when I had it rebuilt by an experienced twin cam place. About 11.2:1 compression on both. Do I really have two cracked heads? Or is it a cracked block. Or something else?

[Tonyw]

Mini 64,

At the risk of stating the obvious the cream as you call it is water so you will need to find the source. It sems very slight at the moment and as such it will condense at the highest point of the engine which is the rocker box/tappit cover.

I see this sometimes on older engines where the engine is open to atmosphere and the climate is humid so when the engine cools it attracks fresh air laden with water which condenses inside your rocker box/tappit cover is it possble for you fit a PCV valve into your engine breathing system?

You say that you have changed heads so you would be very unlucky indeed to have two heads with the same problem. You could try pressuring your cooling system with an automotive radiator pressure tester and see if your system is holding pressue, if not then the water must be leaking somewhere, you do not say though if you are losing coolant? Do you have a missfire when you start your engine fron cold? if so you may be leaking water into your cylinder head as the engine cools.

good luck with this and remember if all else fails buy some strawberries

TonyW

[robertverhey]

Ditto from downunder. Wouldn't be without my Stant cooling system pressure tester. Great piece of diagnostic gear

In this case you could use the tester with the cam cover off, see if there's a visible leak at the top end. As tony says if it's only a slight leak, it might be enough to make cream at the top without finding it's way down into the oil....but that seems unlikely, gotta say.

Check your spark plugs and compressions too....if water is leaking into a cylinder, that plug will be clean as a whistle

[elansprint71]

How much have you run this engine? Mayo can appear even in hot climates in engines which have stood around or just been put together. What's the humidity in your part of TX?

[SJ Lambert]

I don't suppose you've got a crack in the block in or near a cylinder head bolt thread recess allowing coolant to creep up into the cylinder head?

Sounds like a crack somewhere in the block to me - the water wetter that some of us run masks the water in the oil "mayonaise" appearance of the oil for a while - two cups of cream in our catch tank turned out to be a big water leak for us a while back. Close inspection of the oil showed it had coolant in it too...........

[Tonyw]

Hi All,

One way to see if the oil actually has water in it is to take a sample to an oil analysis laboratory, most OEM heavy earth moving machine companies have them Caterpillar or Komatsu would have them and they have a test to detect water in the oil, by the way they can also use an ICP and tell you what wear metals are in the oil as well. For those keen to keep and maintain their engines in tip top condition it is not a bad diagnostic tool as after three tests you will see any trends, so do I do it?? no I am not that keen to be honest.

Tonyw

[mini64]

yes, its water getting in. I just called it cream as the emulsion is so thick.

I put a radiator pressure tester on and found no leaking or pressure drop, hot or cold. The idea of humidity is interesting as I live in a humid climate. But this past race weekend it was cool and dry. The engine does sit months between races and is always apart. Plus each weekend we do this, after swapping a head or head gasket (dont ask!), it is real bad at first then gets better, with no real problems a day or so into the race weekend. We do end up putting stop leak in the coolant each time. Could it really be curing a crack that gets upset each time i take the head off, or am i just boiling water out of the oil from humidity. Friday evening after a day of practise I wipped the underside of the cam cover clean. Pulling it apart today after unfortunately only 20 minutes running on saturday (got in an accident), all is still clean. Its hard for me to call it this and ignore everything. I've put too much money in this motor.

[rgh0]

Most usual synthetic oils ( polyalpha olefin base stock) appear to be more susceptible to formation of the cream like water / oil emulsion sludge than traditional mineral oils. Redline oils ( polyol ester base stock) appears less susceptiple to the cream like emulsion formation on a sample of 1 engine I have run on it long term

If you have large amounts of blowby - and many race engines do when running at high revs and full load - you get lots of water from the fuel combustion past the rings and into the oil regardless of the atmospheric condtions. If the engine is hot enough and most race engines are, this water then stays as vapor and forms the cream emulsion sludge with the oil spray in the head and vent tank and similar places while the oil in the sump is still OK. If the engine oil is cold then the water condenses in the oil in the sump and the emulsion forms in the bottom of the sump under the oil layer on top

regards
Rohan