74 2.7L 911 Oil Foaming Problem

[foamy911]

Just picked up a 74 911 that has been sitting for over 15 yrs. I cleaned the fuel system, electrical, and changed the oil. Fired it up and it runs well................................... Right up to when it gets a little hot, then it does a fantastic rendition of Mt. St. Helens by spewing foamed oil into my airbox, which gets sucked into the intake and smokes like chimney. I checked the dipstick and it's just over half way to the max level. Ok now to show my ignorance, should I be using a special oil with anti-foaming additives? The engine has little to no blow-bye and was rebuilt less than 10K ago. I'm baffled and frustrated. Any help is appreciated !

[Steve@Rennsport]

I'd bet anything that you overfilled the tank,....

This is THE most common owner error so you are in fine company.

Here are THE four rules for checking oil level:

1) Engine must be idling and at operating temperature; 180 Deg F.

2) Car must be on level ground.

3) Car must have idled for 2-3 minutes before checking with the dipstick.

4) NEVER, ever trust the oil level gauge. Its a "red herring". The dipstick is "The Gospel".

Drain a few quarts from the tank and recheck, as above.

[foamy911]

I checked it warm at an idle and it was NOT over the max mark. Is it possible the dipstick is the wrong one ? I do not know the history of the vehicle (other than what the previous owner has told me. I'm going to pull 1 qt out and see what happens. Thx for the reply Steve.

[Steve@Rennsport]

If the oil level is between the marks when hot, then I would perform a leakdown test to see if the rings are sealing properly.

[foamy911]

I can do a leakdown, but with non sealing rings I would expect a mass amount of blowby coming from the breather, is that not the case ?

Pat

[Paulporsche]

I think the problem comes from the car sitting so long. There is probably water (condensation) in the system, which is what causes the foaming. You may have to do several fills to get it all out. Ordinally not getting the engine up to temp enough is responsible for this, but it sounds like you are waiting for the temp to rise before you see it. Check the cooler, lines and thermostat (if you have them), and change to another brand of oil. My old 2.7 engine used to foam w/ Castrol but not w/ other brands. BTW did you change the oil filter?

[azasadny]

I've had my '74 911 for close to 5 years and I've never seen foaming in the oil. I would change the oil, be careful not to overfill (get Wayne's "101 Projects" book first), then get the car up to operating temp (180 degrees), then check the oil level. i use AMSOIL 20W50 synthetic oil after using Castrol 20W50 and both oils work well. I have the frontfender-mounted oil cooler, which helps keep the temps lower. Good luck and don't be shy about posting here and searching for answers... Welcome aboard and post some pics (required!).

[foamy911]

I think the moisture idea may be right on track. I'll change the oil a few more times and hopefully that will do it. Here she is when she came home. It needs alot of work. If anyone has interior parts.......... I need almost everything !!!!!!!!!
[img=http://img126.imageshack.us/img126/6194/img9863zg2.th.jpg]

[Paulporsche]

Let us know how you make out.

BTW I am not slamming Castrol in any way. I used the same oil in 3 other cars w/o foaming. I am just pointing out (and have heard/read this several times over the years) that sometimes some oils do this and others don't, just as some cars do and some don't. In my case, switching the oil made a difference.

[foamy911]

Well it's still foaming but not nearly as much. When it's just barely warm the oil is 5 mm above the min mark, when she is hot it's 15 mm below the max mark. Is this normal expansion, or is the moisture still causing this ? So what is normal expansion for this motor ?

thx
Pat

[Steve@Rennsport]

Pat:

Tha expansion is normal and I'll tell you if your rings haven't seated or are sticking from improper storage, you will get a ton of blowby that pushes a lot of oil into the intake.

If thats the case, I'd suggest installing a catch tank instead of venting the oil tank back into the airbox, at least for the present.

[Paulporsche]

Pat,
When you say "it's still foaming" what do you mean? What's changed?

[foamy911]

I changed the oil 2 more times, letting the engine get quite warm before each change and leaving off the fill cap for moisture to escape, there appears to have been alot of moisture. So 2 cases of oil later.............. I think I good to go. I'm going to drive her around a bit as soon as my new tires and wheels come in. I'll keep you posted.

Pat

[azasadny]

Pat,
Very cool! Be sure to take lots of "before" photos because something tells me the car won't look like that for long! Another Targa, woohoo!!

[foamy911]

2nd pic is during pedal cluster rebuild (brake pedal frozen).

[tab tanner]

Nice mid-year!! Welcome to the board

[azasadny]

Looks great1 Where did you get the chrome trim rings for the headlights?

[foamy911]

I found the trim rings in the trunk under some cardboard. Cleaning this thing up is like a treasure hunt. I am finding all kinds if tidbits and parts.
but still need alot of interior pieces and rear bumber trim. So if ANYONE has updated their body and has original stuff laying around............

Pat

[Dan in Pasadena]

Pat, Nice Middy!

Is that original paint? If so, what condition is it up close because it looks pretty good for a car that's been sitting a long time.

For what its worth, when I got my '76 2.7 back from the body shop I took it immediately to my wrench for the Carrera chain tensioner upgrade and a new clutch, a few more things. All in all, the car didn't run for over 6 months and when it was first started it smoked like a mutha. Tooker her our on a 20 minute run and it all cleared out. Now?
When hot and checking the oil I DO see some tiny bubbles gathered on the dip stick but it doesn't smoke in the least. This is a 127,000 mile original 2.7 with no external oil cooler....but (ofcourse) the thermal reactors were looong since tossed and an 11 blade fan installed. Your car's going to be REAL nice. Stick with it. It just had my interior redone at a small shop and it made all the difference appearence-wise.

[foamy911]

That is the original color, but not paint. The previous owner had the engine gone through with "all the updates" but the receipts are not available (i'll explain why). After getting it back it went out for paint (this all happened in the 1990's). While at the paint shop his house burned to the ground along with most of the interior/exterior trim. So the car sat while he rebuilt his house, then just sat for a long time.
Thanks for the info on the tiny bubbles as I still see those and was fearful she was going to spew again.
She has the 11 blade fan and air box poppet installed, so I can assume the previous owner was truthful about the engine. She looks to have been well cared for in her former owners hands and they were very helpful. I do need to repaint the right front fender as it has some chips.
My new tires/wheels (fuchs replicas) should be in today, so I'll snap some pics with her new rubber and wheels.