73 911T - Rebuild Gone Bad?

[pcivalero]

Hey guys-
First, I'd like to say that I trust and love my mechanic....That being said I need some advice. My engine was rebuilt about 2 years ago and roughly 1,500 -2,000 miles ago. I even got the MFI rebuilt. While the car drives well, I still don't understand a few things:
1. I still have a small oil leak - mechanic says there is really nothing he can do about that? True/False??
2. At stop lights, I see white smoke coming out the back, I assume that is burning oil, but where does it come from?? Any why the hell should it since I rebuilt the engine??

3. Lastly and most importantly - I took the car in for the oil leak - to see if he could fix. Mechanic told me he gave me an oil change because the oil was black due to fuel getting in. He said he is not happy with whats going on with my car and didn't charge me for my oil change. He said the he thinks the seals are still not set and told me to drive the **** out of the car. Says also the fuel getting in has to do with the MFI and that it's hard to adjust which is why most people replace and go to carbs.

I am not mechanically inclined at all - so I gotta ask - do I need to ask him to open it back up and fix whatever is wrong? Frustrated cause I don't know what to do.....

Any help please...

[saxen]

why cant he fix the leak? because it takes work?
how bad is the smoke at a stop?
none of this adds up- good luck.

[E Sully]

The small oil leak may not be worth fixing if it is minor, and would require dropping the engine to repair. With no real description of where the leak is, there is no way to accurately say. Smoke from the exhaust could be from mfi needing adjustment. I have read that MFI has a tendency to run rich at times, causing the protective oil coating on the cylinder walls to be washed off and contaminating the crankcase oil. Do you have records as to who rebuilt the MFI and what was done?
You may want to post a new thread for recommendations for a new Shop that has experience with MFI. There are not many mechanics with the experience needed, and it sounds like you would prefer not to do it yourself.
Ultimate MFI resources thread

[vmn007]

Can you get the car on a lift and see if the leak is coming from where the block bolts together. If so that's a pain. Loctite was probably not applied correctly. Have the MFi tuned to see if that takes care of the smoke. Or oil may be leaking onto the exhaust and that's what you see. Oil burned off. Don't drive the **** out of the car. You risk your head studs pulling. I don't moo w why he told you that. I usually like to wait until 5k to start driving it harder. But that's just me. Good luck.

[Bob Spindel]

Here's what is probably an alternative view.

1) If by oil leak you mean the bottom of the engine looks a little oily, or that there are a few drops on your garage floor, then I'd almost consider it normal for a rebuilt 40 year old 911 engine. It's been my experience that it's almost impossible to seal these old cases so they are totally leak free.

2) Does the white smoke appear all the time, even when the engine is completely warmed up? If it goes away when warm, it's probably just moisture in the exhaust. Not to worry.

3) Black oil. I don't think this can be diagnosed without actually seeing the oil, but it doesn't take very long for engine oil to turn black all by itself, no gasoline needed. I don't think I've done an oil change, and I've done hundreds, when the oil didn't appear to be black. It's the nature of the beast.

[pcivalero]

Thanks everyone...Oil leak is small and he said the same, almost impossible to seal the old cases to be totally leak free.

on smoke - i don't see it when it first starts, but even when I drove it this weekend 60 miles, i got to a stop light and there was a back draft and saw the smoke come my way.

on the oil, i think there is fuel in the oil, don't know..he said it so I assume he's right.

Thanks again.. just wonder if I have to ask him to open it back up.

[bgyglfr]

I would venture to guess you're running rich. It could explain both the white smoke and the fuel in the oil. I would look into that first before opening the engine up.

[nickyclyde]

Look ,do not "ask him to open it back up" .you are jumping the gun to the 10th degree. Take it to a porsche specialist and get another opinion. What's wrong can most certainly be figured out. Does the fix involve "opening it back up"? You are a really long way from figuring that out. And when I say porsche specialist ,that doesn't mean a guy who lists 21 makes that he works on and 1 of them is Porsche. PM me if you like for a good mechanic.

[E Sully]

I see from past threads you have put a good amount of work in the car and engine. I see no reason to open it up. Most of us live with small oil leaks. If the Flywheel seal is leaking I would consider changing that out since it does not require taking the engine apart. From your current description it seems all you need to do is find an experienced tuner for the MFI. I would avoid driving it too much till you make sure it is not running rich enough to contaminate the oil and risking wear to the rings, journals and bearings.

[Rusty 356]

Analyze the exhaust, LM2 at various loads. Is all your hoses that heat the Injection pump hooked up? Smarter guys than myself have put a mechanical device for cold starts to eliminate the look rich running mode of the injection pump. I'm looking to do the same with mine. Forget about the oil leak until it seems to stop then check to make sure you have oil in the engine. Good luck, your mechanic seems to be okay, maybe just a bit rough. Drive it hard enough to load the rings and get the injection pump running in a lean mode. Sixty miles of city driving doesn't get it for the old timers.