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After getting my 84 GSL on the road after 16 years of sitting it has been going downhill the more I drive it. After the second drive of about an hour without any issues I noticed that the car hiccupped momentarily when pulling a hill. The second drive it did the same thing but worse when pulling a hill. I dove it around on flat ground, it got worse and worse. Pulled the plugs, they were fouled with OIL. I figured that I might have premixed too much, so I drained about 10 gallons of fuel from the tank. The gas looked like it had a little too much premix in it but nothing that would foul the car out this badly. I then put about 4 gal of fresh gas in the tank. I went ahead and checked the whole ignition system, coils, rotor, cap, and replaced the plugs. While nothing was confirmed good I was getting a good spark and everything seemed to be working properly in the ignition system. I did check that the timing advance worked. I also disabled the OMP to ensure that it was not giving the carb too much oil.
Took the car for a spin and it made it about 1/2 mile down the road before completely fouling out, the car would not even run. Front leading plug was wet with oil, rear leading was badly fouled with oil but not as wet. Both trailing were covered in oil but not wet to the touch.
After sitting so long I am fearing that the 40 year old oil control rings have gone out. THE CAR HAS DROPPED IN OIL PRESSURE not too much but probably about 5-10 psi depending on RPM. I will add that after some new plugs the car can idle forever but as soon as it is under load or higher RPM it fouls out.
If the engine is original and my mileage is correct the engine only has 82 thousand miles. Last time I compression checked it with my rotary compression tester it had 100-110 psi on all rotor faces.
Here is my leading plugs after 1/2 mile of driving, they were cleaned thoroughly with sandpaper before the drive. The bottom was the front rotor top was rear, both were leading plugs.
I am pretty certain that it is internal. Could it be anything other that the oil control rings? Looks like I am going to get to build a 12a sooner than I thought.
Edit: Forgot to add that the car barely smokes at idle, it does smoke more when revved but not a significant amount.
I think you both may be right. I've only ever owned cars with the FMOC setup, and the lines from the OMP go into the middle section of the carb. This diagram of a Bee Hive system seem to show the lines going into the base of the carb. (maybe the illustration is just simplified too) Not sure of the plumbing / operating differences btw the two systems.
If it sat for 16 years with zero engine movement, the Oil Control Rings are the culprit. The worst thing you can do to any machine is let it sit for decades untouched. The oil on your plugs is the telltale sign, as the premix and blowby oil are getting burned in the catalytic converter, hence you're not seeing as much smoke as you'd expect. Recognize also that the Oil burning residue is building up in your cats and will soon clog the system if you keep running it this way.
How much has the engine oil level dropped on the dipstick in how many miles? That will give you a blowby consumption rate. Additionally, unless you're racing on a track and want to ensure reliability under high RPM racing conditions, hook up your OMP and stop pre-mixing. There's almost zero benefit to street cars by pre-mixing.
I'll also bet if you did another compression test today, it would look okay except that at high RPM your compression is leaking into your oiling system past the Oil Control Rings. If you open the hood after a drive, you may find your dipstick has been shoved out of its hole, with possible oil spray on the underside of the hood.
If it sat for 16 years with zero engine movement, the Oil Control Rings are the culprit. The worst thing you can do to any machine is let it sit for decades untouched. The oil on your plugs is the telltale sign, as the premix and blowby oil are getting burned in the catalytic converter, hence you're not seeing as much smoke as you'd expect.
How much has the engine oil level dropped on the dipstick in how many miles?
I believe that the car was turned over by hand a few times while it was sitting.
The car is catless and has a racing beat header, a presilencer and a racing beat muffler.
The oil level has not noticably moved, I have only put about 70 miles on the car since it has been on the road.
I only disabled the OMP to ensure that I was not adding any additional oil into the engine, just to eliminate that possibility I will put it back together one I figure everything out.
There are two things I should mention also. Firstly the car has been running and driving for about 3 years without problem, it has not been on the road so I was not able to drive it any significant amount but it was ok before.
Secondly I did overfill the oil, when I did the last oil change a few months ago, the car stills about 1/8in over full on the dipstick. I doubt that would do anything but I just wanted to give as much detail as possible.
Does anybody have any other guesses? I understand the oil control rings are suspected but after reading up on the the typical symptoms of oil control rings failure I am unsure. The car has almost no smoke from the exhaust, the only real smoke is condensation. And my brand new Racing beat muffler shows little soot on the tips. Also from what I see when oil control rings go the car will still run. Is it possible that ignition spark/timing is so poor that I am leaving behind my premix + OMP oil on the plugs?
I will add that originally I believed that the poor running was caused by a fueling issue.
i believe there may be a fuel issue at play here as well. you very well may be burning oil, but even if you aren't seeing it, i think you should be smelling it - especially if it's enough to foul you out while driving. you can also check at some of the exhaust joints.
another thing i thought about is if it's getting a chance to actual warm up in the trips you're taking. i know you said you've covered about 70 miles in 3 years, but you also mentioned running it for 1/2 mile during one of your trips.
at any rate, did you change the fuel filter before or since you put the car back on the road? what about the carburetor? maybe it needs cleaning or has a sticky float or something?
Just some other thoughts, too much oil in the pan shouldn't hurt things, but 1/8" over full is probably close to 1/2 a quart of oil too much. It's probably not helping things, either. I would drain out 1/2 quart from the pan and get that to where it needs to be.
Secondly, when you drain that oil out, does it smell like gasoline? If yes, your air/fuel mixture is getting past the Oil Control Rings and into your oil system, diluting it. That could also explain an increase in measure oil level on the dipstick, but you haven't driven it that much - and stated that you overfilled at the last oil change...
ETA: bad Oil Control Rings will suck oil into the combustion chambers on deceleration and make a smoke screen behind the car. At idle, and even cruising, the combustion chamber pressure is high enough to overcome oil pressure at the Oil Control Rings, and this is where your compression is leaking, whereas on deceleration at higher engine RPM (*letting the engine brake the car from 3-4k RPM), the vacuum in the combustion chambers sucks oil past the Oil Control Rings.
If you're not seeing that, I'd suspect clogged fuel filter or fuel float valve problems as next most likely causes.
i believe there may be a fuel issue at play here as well. you very well may be burning oil, but even if you aren't seeing it, i think you should be smelling it - especially if it's enough to foul you out while driving. you can also check at some of the exhaust joints.
another thing i thought about is if it's getting a chance to actual warm up in the trips you're taking. i know you said you've covered about 70 miles in 3 years, but you also mentioned running it for 1/2 mile during one of your trips.
at any rate, did you change the fuel filter before or since you put the car back on the road? what about the carburetor? maybe it needs cleaning or has a sticky float or something?
I have gotten the car to temp before I took it for a drive. That is the weird thing, only normal smoke and not too bad of a smell.
The 70 miles have been in the mast month since the car has been registered. Before when it was just a weekend project for me I would just move the car around the property, from storage to shop, etc.
I put a new fuel filter in the car when I first registered it. As soon as I noticed the hiccuping I installed another new fuel filter in the car. The new filter probably has about 3 miles on it.
I will say that I did rebuild the carb with the Walker kit, this was my first time ever rebuilding a carb. I do think that a stuck or poorly adjusted float very well could be an issue.
I will add that according to my gauge the pump is flowing a little more than 4psi. It should run on that at least right?
Update: I got the car to run again. Tested fuel pressure at >2 psi tried my spare pump, same thing. Took my air compressor and blew out the line from the pump back put everything back together and now it is showing ~4 psi. I don't believe the pickup has a sock on it so that will be addressed soon enough. Engine will idle but doesn't like to rev. My father was able to spray some starting fluid in the carb while I revved it and the engine started to rev no problem, like the car is not getting enough fuel. I Pulled plugs and here is what they looked like. This is from zero miles just fooling around in my garage.
Front is ok, rear is BAD. The way it is running I believe my rear float to is messed up and rear rotor is not getting much fuel. I'm planning on taking the top off of the carb to check the floats.
Right now I suspect carb, it wouldn't solve the problem of the oil that was on the plugs earlier but mabie I was premixing too much? Thanks everyone for your help!
Before you take the carb apart, maybe just view the sight glass for the back (and front). FWIW I've never adjusted the floats but I've read on here that it is very touchy, and if they are okay now it would be best to know that and avoid the extra work.
Update: took the top of the carb off and I believe I have found my problem. The rear float bowl is clogged. Both fuel bowls have a considerable amount of sediment in them, it looks like bits of my fuel tank sealer. The rear float bowl is clogged and doesn't drain to the bottom with the jets. I tried sticking a piece of mig wire into each jet to see if i could unclog it but had no luck. I am planning on pulling the rest of the carb apart tonight and will clean out the jets and passages.
You can see the difference in fuel height.
You can also see how dirty the carb is, when I rebuilt it it was super clean.
Update: Pulled and cleaned the carb, there was lots of fine sediment in the bowls and the fuel passages seemed partially clogged. I readjusted the floats, put it all back together, and and took it for a drive, the car ran beautifully. Then after a faster well gripped corner the car fell flat on its face and died. After getting towed back to the garage I pulled the fuel filter, cut it apart and found this.
That was after ~5 miles of driving. I believe I have found my problem.
I installed another new filter and a second filter right before the carb (the second filter should catch some junk from going into my carb and will tell me what my fuel flow is looking like). Took it for a drive and it started stuttering, drive it back home and the new filter already has a lot of sediment in the bottom.
Current plan is to drain the tank and flush it a few times, probably going to pull it and replace the pickup tube sock. The sediment is mostly little bits of the tank sealant and rust.
Glad I found the problem, on the upside I was able to adjust the carb better and replace my leaking OMP lines. When the car is running it is running better than ever. Thanks everyone for the help. I am glad it turned out to be the most simple (stupid easy) solution. Thankfully after all of this I don't see any more oil on my plugs and they aren't fauling out. I guess I was premixing and OMPing too much? I swear this car Is screwing with me every time I work on it.
02-26-24, 09:17 AM
