Just installed engine...now it leaks!!!

WERK I · WERK I's Garage

I just finished running the 20 minute run @ 2K RPM only to find this leak running down between cylinders 2/3. It looks like the leak must be somewhere above cylinder 3, running down both side of the barrel. It wasn't there at first, it took approximately 5 minutes before the leak reared its ugly head. I drained the oil and changed the filter after it had cooled sufficiently. Added fresh filter and oil. Started it up...a few minutes later, the leak started. The drop(2 actually) appears approximately every 15 seconds. I would really appreciate any ideas from all of you experienced builders out there. TIA
Pic of underside cylinders 1-3 below. I fear the worst...the cam tower.

911pcars · 06-03-2003, 05:35 PM

Could be from the cylinder/spigot joint or from anything above (oil pressure sender, thermostat). An oil leak at the cam housing will be evident at the cylinder head/cam housing joint. Check the easy stuff before disassembling the engine.

Did you or your builder equalize cylinder heights before assembly?

Sherwood Lee
http://members.rennlist.org/911pcars

WERK I · WERK I's Garage

Sherwood,
I am using the original cylinders in their original positions. The oil thermostat, temperature sender area is dry. Can the case thru-bolt seals cause this problem? If so, can they be serviced without removing the cylinder bores? Thanks.

john walker's workshop · 05:54 PM

there is really nothing that would leak oil above 2 and 3. clean if off with brake kleen, let it dry, and get under the area with a flashlight when it's running, and see where it originates. the oil switch, t/stat, and breather hose leak down the other side if they're bad. the thru bolt seals could certainly have been damaged. that's a teardown to the case to fix, unfortunately.

WERK I · WERK I's Garage

John,
I did as you suggested earlier today and it is difficult to determine it's origin since the cylinder air baffles block my view.

john walker's workshop · 05:58 PM

well, you could bend them out of the way. you kind of have to if they're in the way. upper thru bolts can be seen thru the alternator/fan housing hole, after it's been moved out of the way.

WERK I · WERK I's Garage

Can the thru-bolt be removed to replace the inner seal without removing the cylinders?

Wayne 962 · Wayne 962's Garage

I don't think that the thru bolts can be easily removed and replaced with the engine in the car...

Draw an arrow on that pic showing the leak?

-Wayne

snowman · 06-03-2003, 08:30 PM

I have rebuilt over 50 engines before I did a 911, the ONLY one that ever leaked for me. These things are a real pice of whatever when it comes to oil leaks. I recently just tore down a 911T, all the way, just to fix the oil leaks. No problems with the case halfs. Just the cam covers, valve covers, cam towers, oil vent seals, whatever. I put the thing back togaher with 574 for the case halves, but I added a thing coat of silicone to everything else, and used silicone valve cover gaskets. No leaks now.

ChrisBennet · ChrisBennet's Garage

Dave,
Is the leak is only on the left side of the engine, the side that has the nuts on the thru bolts? If so, maybe you don't have to completely tear the motor down.
I forgot to install the air deflectors on an engine before I bolted on the cam towers once (OK, maybe more than once!

). To salvage the situation, I unbolted the head bolts and the bolts holding the chain box to the engine. I was then able to pull things apart far enough that I could remove the oil return tubes and install the air deflectors. In your case, you will need to make sure the pistons don't come out of their cylinders when you do this.
Call me if you need some thru bolt O-rings.
-Chris

Doug Zielke · 06-04-2003, 08:10 AM

[QUOTE]Originally posted by snowman
..... I added a thing coat of silicone to everything else....

MORE BAD ADVICE.

Your motor will be a mess when the "thing" coat of silicone comes unstuck and finds it's way into every orifice in the motor.

I just did my first 911 motor too. I followed the advice of a couple of professionals, along with the info contained in the Factory manuals. My motor does not leak.

If you would have built your 911 motor with care using accepted Porsche methods, you would have had no leaks at all. They are different than Fords. You seem to have yet to learn that.

snowman · 06-04-2003, 06:40 PM

I don't know how "BAD" this advise really is. I know a couple of Professional Porsch Mechanics that use nothing other than silicone and they have to guarentee their work.

The trouble with some older Mag cases seems to be they are no longer straight, anywhere. THerefore the original gaskets will not seal properly, no matter what you do. I even had the heads resurfaced for sealing purposes and it sitll leaked because when I bolted everything down it deformed just enough.

If you are careful and diligent with the silicone it WILL NOT get everywhere and clog up everything. Been there done that and so far NO problems.

snowman · 06-04-2003, 08:29 PM

"Doug Zielke

I just did my first 911 motor too. I followed the advice of a couple of professionals, along with the info contained in the Factory manuals. My motor does not leak. "

Lets look at the MISINFORMATION here. First Porsche Factory Produced cars, the older ones, 1965 thru 198? all had one common problem, THEY ALL LEAK!! So logically you are saying, if I do every thing exactly like the factory did, my engine will not leak? How do you reconcile this with the facts? If you do them the way the factory did THEY WILL LEAK! How do you explain the turbo valve cover requirement, the fact that silicone valve cover gaskets are almost a necessity, the differen't types of gaskets, green, grey, whatever.

YOU sir are presenting misinformation if you say that if you do it like Porsche did ,it will not leak.

As to silicone. It can be trouble, but only if misapplied. are you saying everyone reading this forum is to stupid to follow directions and observe cautions? If you are careful silicone is the BEST sealant. Its reputaition for clogging stuff up is due to ham handed idiots mis using it.

HOw do you explain why the top auto manufacturer in the WORLD is using nothing but silicone to seal everything? Its not just less expensive, its better!

Even a numbskull can use a preformed gasket, but I would suspect that the Porsche crowd is a step above and could observe some simple precautions in the use of silicone and not allow a bunch of it to fall off and clog up everything. Maybe you do not think so but I do.

Doug Zielke · 06-04-2003, 08:38 PM

You don't read very well do you?
I said I did everything by the book, and my motor does not leak.

You always seem to know better than anyone else on this Board, so go ahead and use all the silicone you can find. I could care less.

snowman · 06-04-2003, 08:42 PM

It will tomorrow.

john walker's workshop · 06-05-2003, 09:20 AM

no sense argueing with jack, he's never wrong and will continue a thread into oblivion to try to prove his point. the engine forum has turned more argumentative than informative lately, mostly because of this.

speeder · 06-05-2003, 11:52 AM

Mr. Snowman, The factory engineers had more important things on their minds than the possibility of oil leaks years into the future, such as the way that an extremely tiny particle of silicone crap will find its way into a cam squirter line and block a hole. Even if it only blocks it for a minute or two at 7000 rpm in a race, goodbye cam lobe.

You think that you can build better motors than the factory? What are your racing credentials, vs. theirs? Endurance racing-wise? And BTW, they don't "all leak". That is what people who build lousy motors say.

WERK I · WERK I's Garage

Wayne,
Sorry, I just realized you had posted a question to me. The pic below illustrates the leak. The blue lines show the paths and the arrows show the lowest point of their paths before they let go...

It originates somewhere between the air baffles on cylinders 2&3. I removed the alternator to peer into the shroud, but it showed nothing. I could not see beyond half of cylinder barrel 2.
So I am in the dropping the engine once again so the shroud can be removed to see if the leak is coming from the top thru-bolt seals.

snowman · 01:34 PM

Quote:

Originally posted by speeder
Mr. Snowman, The factory engineers had more important things on their minds than the possibility of oil leaks years into the future, such as the way that an extremely tiny particle of silicone crap will find its way into a cam squirter line and block a hole. Even if it only blocks it for a minute or two at 7000 rpm in a race, goodbye cam lobe.

You think that you can build better motors than the factory? What are your racing credentials, vs. theirs? Endurance racing-wise? And BTW, they don't "all leak". That is what people who build lousy motors say.

I don't think anyone used silicone when these engines were designed. I have used it in my race engines and street engines (only when the std gaskets do not seal well) and never had a piece of it clog anything because I am careful on how I use it.

So in response how do you explain all oil spots under all the factory done Porsches (the pre 198? ones)? I even remember seeing a couple leaking on the showroom floor, about 1969-70, not years into the future.

snowman · 02:05 PM

Quote:

Originally posted by john walker's workshop
no sense argueing with jack, he's never wrong and will continue a thread into oblivion to try to prove his point. the engine forum has turned more argumentative than informative lately, mostly because of this.

Seems to me that two or three people are in the constant "attack" mode. Even when I post something reasonable, and using silicone is reasonable, widespread, and used by real Porsche mechanics all of the time. Its use, on certain o rings, is even suggested in Wanes book. I am guarenteed a response starting with something like MISINFORMSTION or another form of personal attack. Could it be they respondants are incapable of generating a valid technical response on the merits of the topic? A responsible response may have been something like the following:

Silicone has been responsible for clogging many engines. Because of this I do not use it for anything. Here is how I fix an engine with std gaskets and keep it from leaking. blah, blah, blah. Or in extreem cases purchasing special aircraft grade solid silicone gaskets or whatever. But instead I get

"MORE BAD ADVICE."
blah blah blah

I have refrained from responding in this way, except for the last couple of days, where I turned it around a couple of times, and thats to make a point very clear. That it is not nice to start out a topic with a personal attack. Point seems to have been made.

I do like DISCUSSION which is an entire different matter. Differen't points of view can be discussed without personal attacks. Generally speaking personal attacks are generated by those who lack the ability to discuss things based on merit. Take DEMOCRATS for example when they discuss our Pres.