Cylinder Base Oil Leak

930 Turbo · 03-12-2005, 12:36 PM

I have a 1985 930 turbo (European) with approximately 65,000 miles. Recently, the copper seal from cylinder six has begun to leak oil (a few drops on the garage floor). My mechanic has told me that the leak will get worse over time until oil begins to drain from that cylinder. He suggests that I rebuild the engine (approximately 6K). I was hoping to get another few years out of the engine prior to doing any major work. Is there a temporary/permanent solution (ie. additive, sealant, solution)? Also, does this sound common with such low miles. Additionally, when the weather outside rises above freezing (garage is currently 35 to 45 degrees during the winter), could expansion occur and solve my problem?

Any thoughts/suggestions or comments would be much appreciated.

magic930 · 03-12-2005, 12:56 PM

Pull the valve covers and check to see if any head studs are broken. If not then the leak will not get much worse very quickly.

350HP930 · 03-12-2005, 02:59 PM

I second magic's opinion.

One of my base gaskets also didn't start leaking till the adjacent head stud broke.

I kept driving mine even after it was an oily mess. It was only when the starter ring gear lost a few teeth that I decided to do the rebuild.

rotorhead · 03-12-2005, 11:36 PM

I have a 88 930 that presented the same problem. See my thread here

I elected to rebuild the engine, when I got it out it looked like the leak may have been coming from the crankcase breather gasket area and running around cylinder #6 then appearing as though it was dripping from the base gasket. If you leak is Cyl #6 I would check the crankcase breather at the top of the engine first.

Steve

LeRoux Strydom · 03-13-2005, 08:35 AM

My SC also developed a cylinder base leak from a split copper gasket at #6. It probably leaked more oil than it burned. This fact coupled with what turned out to be a cracked rocker shaft resulted in an engine rebuild.

If you have eliminated all other sources of leaks and you are certain that it is the cylinder base gasket, it will only get worse. Your copper gasket may well turn out to look similar to mine:

You should seriously consider rebuilding the top end at this stage. If your budget does not allow it, at least get the gasket on #6 replaced along with all the usual "while I'm in there
items.

LeRoux

Porschephd · 03-13-2005, 03:54 PM

Also watch running too high of boost. This will start to lift the headand cylinder. This in turn will cause the base seal to move and rotate. 3.00 part, 3000.00 fix! Of course a broken head stud would do the same thing. I only mention this because I have had several with this issue.

930 Turbo · 03-15-2005, 05:43 PM

I wanted to thank everyone for your suggestions. I had the valves adjusted/head tightened and was told it is the copper gasket. Could the copper gasket be patched/sealed/replaced? If not, does anyone know how much a rebuild would cost?

LeRoux Strydom · 03-15-2005, 07:47 PM

I don't think a patch or seal would work on the base gasket, it sees a lot of engine oil pressure, not so? To replace the base gasket means removing the offending cylinder, thus also the cam tower and head. I guess you could just replace the gasket and re-assemble everything including re-timing the cams if you're on a budget (keeping the piston inside the cylinder to avoid disturbing the rings). Once you are so deep into it, however, you might as well look into the rest like replacing rings, valve guides, valve stem seals and so forth, which is what I just did. I also replaced the clutch while the engine was out.

Do a leakdown and compression test to determine the condition of the rings & valve guides before deciding how to proceed.

The extent of your repair/rebuild will determine the cost. Our host here has a nifty utility on the parts webpage that lets you put together a rebuild kit based on your need, to give you an idea about the cost of the parts.

Good luck,

LeRoux

rotorhead · 10:05 PM

I am half way through doing the exact job mentioned above

How to Rebuild and Modify your Porsche 911 Engine - $34.95

Gasket Kit - $400 (aprox)
Rings - $100
Valve Guides - $60
Tool to remove chain gears - $70
Dial Guage + Z Block - $100
Machine work to heads - $600
Chain Guides - $30
Cam oil lines - $50
24 Steel Head Studs - $240
Fastners - $50
Powder Coasting Tinware $75

Thats around $1700

Doing it yourself - Priceless

Other expenses to do the job
High lift Jack
Air Compressor and Impact wrench
Torque Wrench
Mapp Gas Kit
Set of good Wrenches/ Offset wrenches/ Sockets
Engine Stand
Digital Camera

Other items I added
Engine Mounts
CV Joint
K27 7200 turbo and adapter
Borla Muffler
Magnacore Ignition Leads
Plugs
Filters

PM me for any info you may need

Steve