Fuel in oil on new engine rebuild

[78 280zcar]

I checked the oil in my car the other day and found out that there is gas in the oil and the oil is very thin:mad: . I have a fuel injected Z and just rebuilt it 2000 miles ago. What would cause this and should I change the bearings again. I am leaning towards the injectors but need to know if I have to take the engine out again:paranoid: HELP

[montoya_fan01]

not a good thing!

cant help with the why as I only experienced this on a carbed Toyota truck (accel pump on carb was stuck).

If you've run the engine long with this condition, I'd worry about bearings, cam, crank, and rings.

[kenz240z]

Did you rebuild the engine yourself, or have a shop do it? If it was done at a shop, did it come with a warranty? Have you talked to the shop?

Running on thin oil could definitely damage the parts Montoya mentioned.

[78 280zcar]

I done it myself. well I know where my tax return is going:mad:

[Fun_in_my_z]

This could be due to a blown head gasket, a cracked block, or stuck vavle. Or it could be a number of other things.

Take a flashlight and go over the block very closely if its cracked you should be able to find it.

[MikeW]

Bad fuel pump? It's not like there are many places where fuel could get into the oil.

Edit: I see now that you probably have an electric pump so it has to be somewhere else. Are all of the injectors working properly?

[240ZX]

This could be due to a blown head gasket, a cracked block, or stuck vavle. Or it could be a number of other things.

Take a flashlight and go over the block very closely if its cracked you should be able to find it.

Bill, you post whore you. I applaud your efforts on possible causes but, I don't think a blown head gasket, a cracked block, or a stuck valve will cause fuel to enter the oil system!!! However, an overly large set of boobs could do it! How you might ask......being distracted during engine assembly!!?

[Ed]

This could be due to a blown head gasket, a cracked block, or stuck vavle. Or it could be a number of other things.

Take a flashlight and go over the block very closely if its cracked you should be able to find it.

Say what? How?

[ezzzzzzz]

The only thing that comes to mind is a stuck injector flooding a cylinder.

[MikeW]

The only thing that comes to mind is a stuck injector flooding a cylinder.

That's what I was thinking. Of course, if he's not getting a spark then it would be even worse. How's the car running?

[78 280zcar]

Thanks for the comments, I dont think the block is cracked, I had it checked when I had it torn down along with the head which was cracked.

It runs pretty rough at idle, I was thinking it was an injector too, that was the only thing I didnt change on the rebuild, except for one that had a cracked tip and I just changed that one with a pick and pull special. Since I have the JSK fuel rail on there I can just take the rail off with the injectors still on it and check it for leaks after I build up pressure, or is that a bad idea? I just hope that it is not one of the rings.

About the gas being in the oil, I checked it again today, it doesnt smell like there is alot of gas in there. Do you guys think that I can drain the oil and put in new oil and filter run it for a few minutes and change the oil and filter again? Please tell me something good, I really dont want to have to change the bearings again!:disappoin

I will do a leak down test and compression test of course before I touch anything.

[MikeW]

I think you should pull and examine all of the spark plugs. I'm guessing that one of them is going to be different than the others ...