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My 86 Turbo had some smoking and was consuming about a qt of oil for every 700 miles.
Trying to diagnose I did a home compression test which gave me decent results I think (150,149,149,145).
I also had the turbo replaced with a Lindsey rebuilt very recently.
Since I also saw some minor oil leaks from the crank pulley area I decided to do a front reseal and also do the head gasket preventive replacement and value stem seals replacement.
Today, finally the head is off, but now I am not sure if the smoke and oil consumption will be taken care off by the head refreshment and need your help on how to know the condition of my rings...
A friend suggested to put all pistons at the same height and top with diesel fuel and see if the level change in any of the cylinders over 8-10 hours.
Is this a recommended approach or is there another procedure I can try to help me decide how to proceed?
1qt in 700 miles is acceptable per Porsche (944 owners manual) for a car driven "enthusiastically"
but since youre in there, have the valve guides and stem seals replaced, valve job, and the head surface milled clean/flat, should cost $250 or so with parts at any machine shop.
those are good compression numbers but a leakdown test would have been a better gauge of ring condition, you can still do one after you get it together to rule out leaking from the valves.
clean up the block surface (wd40 and green scotch brite does really well for cleaning the aluminum, dont push hard just glide it around to get it clean, then clean off with carb cleaner) before applying the new head gasket.
I understand it would have been smarter to do a leak down test before the job, but at this point, I want to see if there is anything that can give me indication of my ring condition before I do the head refresh and close the engine.
Is there a downside/risk in doing my friends recommendation of filling the cylinders with diesel fuel and waiting to see if any of the cylinders leak it past the rings to the oil pan?
If I do see a leak, would it mean that I should be replacing the rings before I close back the engine?
I would avoid using Scotch Brite type pads to clean up the head gasket surface. They're made of nylon impregnated with aluminum oxide, which is an abrasive and will come off and get into places it shouldn't.
Reading various forums, some have experienced engine failures at 1000 miles as it collects in softer bearing materials.
I know some will claim success using them, but something to be aware of.
I wouldn't fill my engine with diesel personally. There is no body of knowledge on these motors about how to interpret the results, and putting an oil solvent in the crankcase never seems like a good idea. I'd refresh the head and put it back together and expect good results. You can then do a proper leak down test if still needed. Testing and/or repairing bad rings is not really a "while you're in there" task at this point. Even though it seems like you've torn the engine all apart, you haven't really scratched the surface of what it would take to fully rebuild it (which is essentially what you're looking at if the cylinders/rings are worn). And for what it's worth, the cylinders don't "look" bad in that one shot you posted...
Here are the four cylinders closeup photos. I can take more if it helps.
Is there a chance that the smoking will stop without touching the rings?
The smoke was mainly when the car warmed up and was mainly during gear shifting during spirited driving and sometimes when i idle at a stop light.
Not massive smoking but enough to annoy me...
BTW, 6 months ago I did rod bearings and put a rebuilt turbo.
I have added a photo of the turbo from today
If you are running the Lindsey turbo do you have an oil restrictor in the oil line to the turbo? If not, that may be your problem, and you are getting too much oil into the turbo. Common problem with non-KKK turbo swaps, due to the high 951 oil pressures. Your plugs do not look oil fouled, so I think the smoke you are seeing is turbo oil blow-by.
If you are running the Lindsey turbo do you have an oil restrictor in the oil line to the turbo? If not, that may be your problem, and you are getting too much oil into the turbo. Common problem with non-KKK turbo swaps, due to the high 951 oil pressures. Your plugs do not look oil fouled, so I think the smoke you are seeing is turbo oil blow-by.
This is very interesting for me.
I am using a Lindsey rebuilt unit of a KKK26.6 turbo (Not some hybrid).
Do I need to use a restrictor? I was not aware of it and I do not use such thing.
cylinder bores look good, you could buy a ring set and drop a new ring in there and measure the gap. I personally would get the head rebuilt and thoroughly clean everything else and get it back together. dissemble the head and look at the valve stem seals, that could be attributing to smoking.
After carefully going over the advices I received here plus analyzing the effort ahead of me if I decide to move on and do the rings, I decided to take the advice and focus on cleaning and restoring different items such as heat shields, hard and soft water hoses and seal everything I have easy access to (balance shaft, crankshaft, camshaft, water pump, oil cooler, oil filter housing, oil pressure sender...), close the head and see how it feels.
Thank you all for the useful information and advice.
BTW, The engine has about 120K miles on it. The last 10K are mine. It a weekend car for me and I use it was mainly spirited driving
09-24-2017, 05:57 PM
Took off the head, need advice on how to proceed
, but at this point, I want to see if there is anything that can give me indication of my ring condition before I do the head refresh and close the engine.
