fuel in oil on 1957 corvette
I dont drive my 1957 fuel injection corvette much but the last year it seems to accumulate fuel in the oil. quite bit. I just changed the oil after 9 months of mostly sitting and starting up just to warm up and there was at least 1 qt of fuel in the oil maybe two. the car starts and runs fine. could this be the fuel pump leaking into the crankcase? thanks David Foreste member 50620
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Re: fuel in oil on 1957 corvette
David,
Better be careful here, there are quite a few people with fuel injected cars that have ruined a engine because of hydraulic lock when a cylinder gets gas and on start up the piston trys to compress the liquid and the connecting rod bends.
Best to discuss this with a fuel injection rebuilder, there are a few that will read your post. The fuel pump could also cause the problem but I would think it would leak externally as well. -
Re: fuel in oil on 1957 corvette
Possibly a leak from the fuel pump.
Do you have a siphon breaker on your fuel unit?
If not then you might be sucking fuel into a cylinder after shutting off the engine , then it will either hydraulically lock a cylinder or possibly leak past the rings into the crankcase over time.
Neither situation is good as you could bend a connecting rod when starting the car with the hydraulic lock situation.
Concerning warming up the engine, I have taken the advice of fellow Forum members and just let my car sit over the winter. It starts up just as easily after 5 months as 5 days. I have a 250 HP Powerglide fuel car.
If you can't take the car out for a long ride don't start it.Comment
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Re: fuel in oil on 1957 corvette
As previously stated, starting and "warming" up the engine without taking it out for a good drive is a bad operating procedure. Engines can easily survive without any consequences months if not years of non-use in a non-condensing humidity enviroment.
With FI, owners should definitely watch out for signs of fuel siphoning, but if you don't want to take it out and drive it for at least 20-30 minutes, let it sit, but drive it enough to consume at least a tank of fuel per year if at all possible.
Keep a battery tender on it or charge the battery once a month and just before starting. Also, modern Zerex G-05 antifreeze and brake fluid should be changed every five years, even if the car is rarely driven. The clock runs on antifreeze and brake fluid whether the car is driven or not.
DukeComment
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Re: fuel in oil on 1957 corvette
Thanks for replies, it does have siphon breaker installed. I believe its working properly because I had taken the fuel injection unit off two years ago to replace some parts and forgot to rehook the wire up on the siphon breaker and the car would not start. I think thats the way its suppose to work. Good advice on warm up and maintenance. I believe what ever is happening with fuel leaking into engine is actaully happening while it sits. I am running an experiment now with oil drained. I will drain again in two weeks to see if there is mostly gas in residual in pan. thanks and let me know if you ave any other ideas.Comment
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Re: fuel in oil on 1957 corvette
David,
Be sure to post the results of your experiment.
Bruce BComment
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Re: fuel in oil on 1957 corvette
...just to clarify my previous post, starting the engine and running it in the garage for 5-10 minutes will usually get the coolant up to normal temperature, but it takes load from driving to get the oil up to the normal 180-220 degree range, which is high enough to boil off blowby fuel that condenses in the crankcase. In mild temperatures it takes at least 5-10 minutes of around town driving beyond when the coolant reaches normal temperature to get the oil temperature up to the normal operating range.
Cold starts can create significant crankcase fuel dilution, and non-PCV engines are more effected since the old fashioned draft tube is a very inefficient crankcase ventilation system. Pre-'63 owners should consider converting the draft tube system to PCV using the '61-'62 PCV parts that were required for Corvettes delivered in California.
Bottom line is that starting up the car in the garage and running it for five or ten minutes is more harmful than just letting it sit until you are ready to take it out and drive it for at least 20-30 minutes.
DukeComment
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Re: fuel in oil on 1957 corvette
Hi David, Hate to tell the world this but the siphon (syphon) breaker kits we sold for an eon are starting to fail. Seems that ethanol is effecting the solenoids.
Luckily there are new kits out for ethanol/alky.
Don't run your car anymore David until you solve this issue. If you are lucky you will just bend a rod or two. If you are not your will throw a rod thru the block or pan.
Listen to what Dan and Duke said. Fuel Injection cars do not make great collector cars if the owners are just going to put them in a line up and not start and run them hard regularly.
57 to 61 FI's do NOT have a choke. The first FI choke was in 1962. The 57's to 61 have a cold enrichment setup. You need to run the car a long time for all the warm up stages are completed. And if you let the car sit over 4 months with ethanol you are living dangerously.
Siphon breaker solenoids. Some think that any old solenoid will do. Some put the 64-65 skinner valve starting solenoid on the older units and expect it to do the job. Those Skinner solenoids were designed just for starting. They were not designed to run wide open all day long.
Sounds like your 57 has either a clogged/dirty solenoid or an inferior one or one that ethanol has done it in.
The other day I talked about expanding a 7/16 hose to 8/16 aka 1/2" in less than a day just by soaking the hose in ethanol.
Google the evils of ethanol and find out more than you want to know. JohnComment
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Re: fuel in oil on 1957 corvette
well I have never been one to be too patient so I opened the drain plug on the oil after having drained it yesterday and guess what, I got 4 to 6 ounces of gasoline! so the gas is leaking in to the crankcase when the car is sitting. you guys think fuel pump?Comment
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Re: fuel in oil on 1957 corvette
i will change or rebuild the fuel pump. thanks!Comment
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Re: fuel in oil on 1957 corvette
Duke,
Does your advice about brake fluid apply regardless of type? I see that you didn't mention DOT 3, 4 or 5.
Thanks!
JoeComment
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Re: fuel in oil on 1957 corvette
Can one check for a bent rod by carefully checking the piston pairs, 1-4 and 2-3... through the spark plug holes? If the rods are not bent the depth through the plug hole to the top of the piston should match no?Comment
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Re: fuel in oil on 1957 corvette
It applies primarily to DOT 3 and 4 since they are hygroscopic (absorb water). Dot 5 silicone is not hygroscopic, but it may be a good idea to change DOT 5 periodically on disk brake models that are driven in the rain since water can apparently get past the seals.
Duke
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