foaming oil

[nicolas]

i am breaking in the new engine and i have now installed the oil cooler as well, so i had to run it it again to crank for pressure first and then run it. because f the oil cooler i added oil to the engine and when i ran it for 5 minutes (over 3000 rpms and a few revs higher up to 5500) i checked the oil level if it wasn't too low. but when doing this i noticed the oil on the dipstick to be full of small air bubbles. i can't make out if this is bad or not, but to me it isn't the way i expected it to be.
so maybe the oil is bad (the grade is 15w40, mineral, for all purposes), it isn't the kroon oil i normally use, but an equivalent i was told.

so before this is an expensive mess or maybe it is just fine, let me know is this is normal.

[MC Dyno Don]

Hi Nicolas, Glad to know all is up and running... all is normal especially when there is more than the regular amount of oil present as the crankshaft usually whips up a storm when the crankcase is full.  Keep us posted on your driving impression and good luck..!!

[kb]

What size is your oil pump?`What cover are you running?

[nicolas]

What size is your oil pump?`What cover are you running?

26mm shadek with a berg cover. type3.

why do you ask?

[Martin S.]

Foaming in the oil normally happens when there is moisture in it, from the air. The moisture disperses usually as the engine gets warm.

[kb]

What size is your oil pump?`What cover are you running?

26mm shadek with a berg cover. type3.

why do you ask?

There are some that say the oil system will "cavitate" (oil will mix with tiny air bubbles) if you run too large of a pump. But I doubt it would happen at that RPM with a 26mm pump. From what I understand, we're more into the 30mm(+) oil pump range before that's really a problem.

[nicolas]

Foaming in the oil normally happens when there is moisture in it, from the air. The moisture disperses usually as the engine gets warm.

OK, so i need to really drive it and get decent temperature in the engine then.

What size is your oil pump?`What cover are you running?

26mm shadek with a berg cover. type3.

why do you ask?

There are some that say the oil system will "cavitate" (oil will mix with tiny air bubbles) if you run too large of a pump. But I doubt it would happen at that RPM with a 26mm pump. From what I understand, we're more into the 30mm(+) oil pump range before that's really a problem.

didn't know this, so thanks for the info. but i am at lower rpms (under 5800, it's a type3)

[Donny B.]

I noticed foaming back in the day when I was running a 1600 engine.  Coming home to Phoenix from California I would push it hard.  Everything seemed fine except near the end of the journey the oil pressure would fluctuate and was just lower than normal.  After I changed the oil everything was back to normal.  I did notice foaming in the oil.  I always ran valvoline before the flat cam syndrome.  In those days I didn't run a breather system at all and that may have contributed to the issue.  I personally don't think foaming of the oil should be disregarded.  I believe it can be a problem and should be investigated if it continues.  It can affect oil pressure.  Maybe you don't have foaming to the extent that I had it, but be careful.  Foamed oil isn't going to protect your expensive parts like straight oil without the air will.  JMO

[Jesse Wens]

I did some tests on this in a research facility.
I used X-ray based measurement equipment to look at the amount of air in the oil.
I'm talking 12 liter dieselengines here.
I found that load was more important then RPM to a certain point.
High revs without load was OK, comparable to idle,
at full load there was a huge difference to be seen, a giant sump will cure this a long way.

A different engine all together but perhaps my results hold true for an aircooled VW

[nicolas]

i am getting nowhere with the foaming oil… i changed the oil for kroon 20/50 mineral oil that i have used before and it didn't go any better. i still have the air in the oil even after a few seconds (really not even a minute) so i  am either getting paranoid or having a different issue.

so i am still in the garage getting it all sorted out, but any input is much appreciated.

[Felix/DFL]

Hi nicolas,

It could be a problem in your suction system, that you suck air in. Maybe the suction tube is loose in the case, or the pump body has too much radial play in the case. Do you use an o- ringed pump?
 Have you checked the pump / the axial play?
Best greetings,
Felix

[nicolas]

Hi nicolas,

It could be a problem in your suction system, that you suck air in. Maybe the suction tube is loose in the case, or the pump body has too much radial play in the case. Do you use an o- ringed pump?
 Have you checked the pump / the axial play?
Best greetings,
Felix

the suction tube is glued in, but the pump is not O-ringed… so i need to look at it deeper. if this persists and nothing comes up i will have to tear the engine down as this doesn't seem to be right.

[Martin S.]

Good idea having the o-ring because it can help stop air being sucked in. Do you have a deep sump? It's like a poor man's dry sump and could help too.

[nicolas]

Good idea having the o-ring because it can help stop air being sucked in. Do you have a deep sump? It's like a poor man's dry sump and could help too.

i have a empi or likewise sump. i'll see what comes up this weekend. oil pressure seems to be plenty though…

[nicolas]

Allright!

i have been working on and off for the last few weeks in shifts of 5 to 10 minutes on the car, but i have it running it keeps oil pressure. i have had a huge problem with oil filters that blew (wrong filter type), AND i think i got to the point where i found out what causes the oil to foam.
i must say i was not keen on tearing the engine down again, so i looked at all possible causes and i found that by clearancing the oilfiller tube that hit the exhaust (a turbo thomas stainless 1 5/8" that was made for me years ago and which is of a great quality besides the oilfiller rubbing), i went too far and made a pinhole and that sucks in air, right where you  have the dipstick. so i need to fix this in on of my 5 minute sessions.
i also had a drive in it and that went really really well, but i'll post more of it in the porsche power tread.

[Bruce]

i changed the oil for kroon 20/50 mineral oil ....

Your problem is that you're using the wrong oil.  20W-50 tar should never be used in a new engine anywhere in Belgium in December.  That's also why you are blowing filters.

Put some 5W-30 in it.

[nicolas]

i changed the oil for kroon 20/50 mineral oil ....

Your problem is that you're using the wrong oil.  20W-50 tar should never be used in a new engine anywhere in Belgium in December.  That's also why you are blowing filters.

Put some 5W-30 in it.

i must admit that it 20-50 is what i have at hands and what i know is good for the engine. but i can't help but think it is thick indeed. from what i have learned from the gearboxes at work (static rpms and not engines, more gearboxes and electro motors) i know that thicker isn't better for sure.
nonetheless the filter was wrong anyway, i should never have used it, i wanted a HP1 or similar, but in a smaller body, the one i got was smaller but wasn't matched to anything as it was what i had at hands and just gave it a try…
the reason i want a smaller filter is that the bracket is mounted too low and the filter is too much in sight and too low for my liking. it isn't the lowest point (the header is lower), but it's something i want to change in the future for sure.

thanks for the info on the oil.