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Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

Did some basic maintenance last week. Ignition coil, I had to transplant a connector from old coil to new as they were spaced too far apart. Distributor cap and rotor, plugs. Alternator and AC belt. I skipped timing belt but will get that after I get the car running a little better. I was running out of time to work on it.

The alternator belt was a real pita. It took everything to get on the pulley. I had the correct 1350 length but I swear it needs longer. Had the tension on the alternator loose and even tried standing on it while putting on the belt. Did I miss another place to loosen the alternator?

Still have an idle problem so took it to a local shop for help. That question here. 2 injectors firing Only injectors 3 and 4 are opening.
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1981 Weissach Edition #179

Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

I got some bad news yesterday. Car is running on 4 cylinders finally, but cylinder 1 gets oil soaked in minutes. Big time oil burning causing a smoke screen.

Also have a excess fuel. Mechanic thinks fuel problem washing cylinders caused a piston ring to seize. Plus this car was off the road for a few years. His next step is to pull the engine and rebuild. I will need to have fuel head rebuilt as well. He is working up a quote. There is a very good engine builder in town where the motor would go, if he can get me in.

Do I have any hope that ring gets unstuck?

Any other engine builders around? I just want a stock rebuild.
Any other piston options other than je or diamond?

I found this rebuilt engine with new pistons Automobile Atlanta is about an hour from me.

How many hours does it take to pull the engine?
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1981 Weissach Edition #179

Eric P · Joined: 21 Jun 2017 Posts: 175 Location: NY, USA

Start with the basics and take it one step at a time. What are your compression numbers? Is there any oil in your intake? Check your injectors for leaks.

If the fuel distributor needs a rebuild, tackle that first. Mine was fouling plugs 1, 3, and 4 then flooded out. It had 3 torn o-rings in the fuel dist. New o-rings sorted it right out. It might not have flooded with only one bad o-ring. I'm sure getting all the powdery gunk out of there helped it run better too. The fact that you have "thin" oil could point towards that cylinder flooding due to a bad o-ring. After opening up my distributor, I realized that it's much simpler than most people make it out to be. Just don't drop the piston!!

By the way, my car smoked something fierce when I first got it running. It took an hour and a half on the highway to get it up to temp and burn all the oil out of the exhaust from the previous owner flooding the crankcase.

If you're running on all 4 cylinders, you may not need a rebuild. If you do have low compression on one cylinder, pull that plug and put some marvel mystery oil in there every few days for a couple weeks. That usually frees up rings nicely if they're just stuck from sitting/carbon buildup. After a few weeks, change the oil and fire it up. Sometimes it takes a couple minutes for rings to free up. It can't be THAT bad if the cylinder is firing. That usually means you have at least 100 psi of compression. After running for a while, check your compression on all 4 cylinders again. They should all be within 5% of each other.

I personally wouldn't jump to a full engine rebuild if all 4 cylinders are firing and the engine isn't making any strange noises. Sometimes it just takes a bit of driving for everything to free up. These cars like to be driven.

The bottom line is that I would make sure you dot all your "i"s and cross all your "t"s before you assume you need a full rebuild that will set you back a few $1000 or more. If I had to pay a shop to do everything I've done to my car in the past year, I'd probably have been better off to buy a new p-car instead. And an engine rebuild isn't even on that list...
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1980 924 NA, US model
1987 924S, US model

Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

Thanks Eric.

If I'm dumping excess fuel down the cylinders that will get past the rings right? Will that then push oil back up to be combusted?

Fuel will get past new rings too right?

Could it be just the fuel system?

I don't know compression numbers, I'm not sure it's been checked. The guy I'm working with is pretty experienced, but maybe he's rushing. He's got a lot nicer Porsche's to work on in his shop.
I'll get the compression done to just rule that out.
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1981 Weissach Edition #179

Paul · Posted: Sun Nov 26, 2017 6:03 am Post subject:

That AA engine has rust in the bores....stay away from AA.
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Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

Thanks Paul, I wondered that myself. I emailed him and he said it was assembled long ago.
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1981 Weissach Edition #179

Eric P · Joined: 21 Jun 2017 Posts: 175 Location: NY, USA

There are a few different ways that oil could be getting into the cylinder. It's possible oil is getting past the rings, but I find it more likely that it might be coming out of the crankcase vent if any of the cylinders have flooded. Thin oil means the oil was very broken down, the wrong oil was used, or it was diluted with something, usually fuel.

If oil gets into the cylinders, the exhaust will have blue smoke. If oil gets in the exhaust, you may get a little white mixed in there due to lower temps. Oil in the exhaust can take quite a while to burn off.

I think you would be better off to pick one problem at a time and diagnose/fix it. If you get into too many variables at once, you may not know what causes each change. Check your compression, then do a thorough CIS test if the comp #s look good. There's no point in replacing the engine if you know you have an issue with the fuel system that you're planning on reusing.
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1980 924 NA, US model
1987 924S, US model

Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

I forgot too mention that oil squirts out of spark plug hole on cylinder 1. That may or may not change your opinion.
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1981 Weissach Edition #179

Eric P · Joined: 21 Jun 2017 Posts: 175 Location: NY, USA

I would still compression check it. There are a few areas that oil could be leaking in other than the intake. If compression is normal, it may just be a bad valve stem seal (They're cheap at $2/each!!). Low compression would indicate rings, and then it's back to square 1. A compression test will take 10-15 minutes and could potentially save you a good chunk of change. I always like to be 100% sure of what I'm fixing before I fix something. There's nothing more frustrating than rebuilding an engine only to find out that it didn't fix the issue you were having.
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1980 924 NA, US model
1987 924S, US model

Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

I called him, test should be done in the morning. We shall see.
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1981 Weissach Edition #179

Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

Compression test results:

1. 210
2. 185
3. 180
4.185

That was a cold engine. We think 1 has oil in it still causing the higher number.

I still can't figure why oil in only #1 other than a ring or valve problem.
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1981 Weissach Edition #179

Eric P · Joined: 21 Jun 2017 Posts: 175 Location: NY, USA

Based off those numbers, I highly doubt that the issue is your rings. 185 almost seems high. Mine tested in between 148 and 151 on all cylinders.

I would start by checking the fuel system for correct operation, then move on to figuring out where the oil is coming from. My guess is a dry rotted valve stem seal.

Looks like you may actually be lucky and. It need new pistons!

if the rings were shot, I suspect the compression numbers would be around 100 or less even with the oil.
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1980 924 NA, US model
1987 924S, US model

TJC · Posted: Thu Nov 30, 2017 12:49 am Post subject:

Compression testing is not a very reliable way of determining the condition of an engine as there are too many factors left to speculation...especially if the one who is doing the testing is in-experienced. Done cold only it is also not a good indicator. Done cold or warm without following up by doing a "wet" test tells you very little. In other words, you're spinning your wheels.

My suggestion is that you take it to someone who is well versed in diagnosing these issues and have them do a proper compression test and more importantly a cylinder leak down test. Also, make sure the valves are properly adjusted before doing so.
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Goldwolf · Joined: 25 Jun 2017 Posts: 264 Location: Athens,GA

It's been a while for me to post an update.

But engine block is complete. Cylinder 1 had pitting in the wall, looks like from water, probably from sitting for 10 years.

Oil was squirting from the spark plug hole was the symptom.

Fuel system rebuilt and ready to go on.

Just need main bearings!
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1981 Weissach Edition #179