Seeking Head to Case Oil Leak Advice

[tito911s]

Gents --

A little more than a year ago I purchased a 1984 Porsche 911 that had an oil leak on the drivers side over the exhaust. Here she is:



With some help, I fitted some flashing to divert the leak which seemed to be coming from the engine, near cylinder #1 at the camshaft end. Odd. But like many of us, the oil just continued to bother me and I decided to tackle it properly.

After putting some dye in the oil, it seemed that the oil leak was coming from near/around cylinder #1. Since it was about time to do a valve adjustment anyway, I pulled off the valve covers I noticed that the head studs were clearly not the original hex pattern.

First question -- the star pattern studs lead me to believe these are not original, and at least, a top end rebuild was done. Is that right? Can anyone help me identify the head stud and the proper tool that fits it?

In addition, there is clearly blackened oil on cylinder #1. But it looks like the oil is only on the intake side (see picture directly below) rather than the exhaust side (see pic below that). This confuses me since I would think that the oil would leak from the head down to the exhaust.

Second question -- do you think that the oil can drip down from the intake on my exhaust? do you think re-torquing heads is a good idea to try to fix leak? Or is there another approach I should consider?

Intake


Exhaust


I look forward to any advice, opinions or recommendations you all have.

[T77911S]

DONT put dye in the oil. that is NOT how you find an oil leak.
i have never heard of an oil dye, what did you use? just curious.

to find an oil leak buy some engine degreaser and soak the engine, then wash it off. either with a hose or at a car wash. then look for the fresh oil leak.

its probably one of the rocker shafts that is leaking

check the head bolts while you have the cover off. just put a wrench on them, no need to torque them. you are just looking for broken studs.

those could be original bolts.

[yelcab1]

They don't have bolts, they have head studs with the head nuts. Those are not the head nuts that came with the 84 Carrera. The original head nuts are allen (6 pointed) barrel nuts.

What you have is 12 pointed internal nuts which I have never seen before.... Someone got there before you did.

[Reiver]

Originally Posted by yelcab1

They don't have bolts, they have head studs with the head nuts. Those are not the head nuts that came with the 84 Carrera. The original head nuts are allen (6 pointed) barrel nuts.

What you have is 12 pointed internal nuts which I have never seen before.... Someone got there before you did.

Which could be a very good thing as your studs may have been replaced....check of a leak at the rocker arms.

[gomezoneill]

Originally Posted by T77911S

DONT put dye in the oil. that is NOT how you find an oil leak.
i have never heard of an oil dye, what did you use? just curious.

to find an oil leak buy some engine degreaser and soak the engine, then wash it off. either with a hose or at a car wash. then look for the fresh oil leak.

its probably one of the rocker shafts that is leaking

check the head bolts while you have the cover off. just put a wrench on them, no need to torque them. you are just looking for broken studs.

those could be original bolts.

They make a special dye used with a black light that illuminates the oil so a leak is easy to spot. Your leak could be camshaft seal, rocker shaft out of position and not torqued properly.

Here's the tool:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiww9zxtrvLAhWMXh4KHUxHCkIQFgg-MAA&url=http%3A%2F%2Fwww.amazon.com%2FTracer-Products-TP34000601-Fluorescent-Detection%2Fdp%2FB000JFHNTM&usg=AFQjCNFBNRM1ENCJJ0dbUJUatonDEDe1-w&sig2=0hvKbZN0iyBD7GsqLJye2Q

[tito911s]

Many thanks for the responses. I used the correct dye and degreased the engine, as suggested, to isolate the leak at cylinder #1.

The first, easier question, is how do I find out what head studs I have? As YelCab1 pointed out I DO NOT have the allen (6 pointed) barrel nuts. Instead I have what appears to be a star pattern like a 964 from this Rennlist post here:



I need to know what barrel nut it is so I can buy a tool to get in there and see if I have any broken studs (I think).

You guys all seem to suggest checking rocker arms. If you have any posts you think summarize the process well, I would greatly appreciate those.

I will also check myself. I saw DRACO had a recent post regarding his errant walking rocker arms.

Thank you all for your help. I'd really like to try to DIY on this one.

[gtc]

Looks like they might be a triple-square nut... you can probably rent a set at your local auto parts store to check. I think harbor freight has cheap sets as well. Look for some long, narrow bits, as the socket portion might not fit into the recess in the head.

[tito911s]

Interesting. I also just noticed while doing my valve adjustment that my rocker arms have a wider shoulder that extends to where the rocker arm meets the cam lobe. This may be a longer road than I thought . . .

[Flat6pac]

They are definitely C2 head nuts
I need to see pictures of the rockers you are talking about.
Bruce

[tito911s]

Thanks, Bruce. Let me know what you think. Micrometer shows 7 mm wide (rough estimate).

[tito911s]

Does anyone know what size the C2, triple squared bit should be? 8mm? 10mm?

[tito911s]

I was able to determine that the C2 triple squared head stud requires a 12MM bit, which I have obtained. I also determined head studs all good (PHEW!).

I went in to try to loosen the rocker arm shaft with the 5mm and 8mm allen wrenches, but, even with all my strength, I am unable to loosen.

In addition, I found that the orientation of the 5mm/8mm allen bolts on cylinder #1 is different from cylinder #2 and #3, which makes me think that the rebuilt engine was not put together properly.

Shouldn't all rocker arm shaft hardware be installed the same way (with 5mm allen bolt facing the rear of the car and 8mm allen side facing toward front)? Would incorrect orientation be the cause of my oil leak? This would be consistent with my other findings of the oil leak coming down between #1/#2 cylinder.

Lastly, any recommendations on how to loosen the allen bolts? I will shave my 8mm, per advice on other threads. I am hoping to do this while the engine is in.

Thanks again, gents.

[john walker's workshop]

The 5mm end points inward on both end cylinders and out of the narrow boss on the center one. That's so you can do related repairs easily. The 8mm end will not loosen the shaft. Only the 5mm will.

[Flat6pac]

The rockers look to be stock. There were several different companies producing them all with a little differences but in spec.
You need a set of triple square to remove flywheel, adjust doors, some pressure plate bolts, and to drive into a 5mm Allen set that has been stripped. Get a set at NAPA, autozone,, etc
Bruce

[tito911s]

Apologies for delayed response. After installing RSR seals, completing valve adjustment and stitching the car up, the oil leak continues.

It seems to leak while car is running and under pressure. Less so when it is sitting with engine off.

Any advice?

[Alex973]

oil leaks always come from above. you can start at the breather, better if the engine is out
so you can do a full service with the usual suspects behind the throttle body, O rings and gaskets
rear main seal, S hose, sending unit O rings also....
it happened to me, I was scared that it needed engine overhaul, lucky for me it was easy job. good luck

[tito911s]

Appreciate the feedback, Alex. There's a wealth of information to do the partial engine drop to get at the breather hose, idiot light, etc. I suppose that is my next task.

[tito911s]

I spent some time today looking in back...where the infamous triangle is. Looked pretty darn dry. It does NOT look so dry when I look up toward the engine tin that is facing toward the front on the drivers side. Odd. I cannot find anything on the forum that speaks to what sort of leak might be localized in that region.

Anyone have any ideas?


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[A horse with no name]

Hi...Did you find the leak?

Just a thought if you haven't...It is not uncommon for the valve covers to become warped, which will cause an oil leak. Tightening them wrong way, when replacing them, can also end up warping them.

You may want to take the bottom ones off so as to be able to check to see if they are warped. Using a straight edge will show you if they are warped. If warped, you will need to replace them. Due to the bottom's being the exhaust valves - hot- they are the only ones that tend to warp. The bottoms ones are relatively inexpensive. I think that our host sells them some where around a hundred dollars.

[theiceman]

if its coming from cylinder one area try reving the engine and look at the back of the chain housing , if you see a stream of oil running down its likely to be the cam seal oring or chain box gasket.