All, I need some help desperately... I rebuilt my 86 5.0 (Mustang engine) - EFI - and below are the mods I made. The problem is, when I start the thing up, it bilges oil to the intake and the exhaust BIGTIME.

- bored .040 over
- crank turned .010 under
- block decked .010
- 1.6:1 roller rockers
- MAC timing gear set (2° cam advance)
- removed A/C
- removed AIR pump

The first time this happened, I thought it was the rings, so I took the mill apart, replaced and triple-checked the new rings, and re-installed. IT DID IT AGAIN!!! I am thinking that it might be the heads, as those were never touched and have 150k hard miles on them, but I can't see anything. Has anyone else ever come across this? If not, can anyone tell me what could be wrong? My machinist is clueless, and so am I... Please help, any addvice would be MUCH appreciated! Thanks guys!

Mike

 

Sounds like you've got a head gasket leak between one of the cylinders and the lifter valley. Pull the plugs and see if you can detect a cylinder that isn't firing well. Then do a compression test on that cylinder.

Good luck.

 

all cylinders have 180 +/- 4 psi compression

 

what do you mean by-bilges oil to the inake and exhaust? do you have an oil passage plumbed to the intake or vacuum port? 150K on the heads, were they rebuilt or no? is it possible the oil is flowing through the valve guides?

 

After I rebuilt my motor I had some broken plug wires that allowed a couple of cylinders not to fire, they poured oil out until I got it fixed. Cheack all cylinders for good fire and see if this helps.

 

OK, all cylinders SHOULD be firing. The injectors all spray nice, the plugs all fire on their own wires, the compression is great. There is WAY too much oil going through for it to just be valve guides. I heard that the head gaskets for that engine can go on only one way. I'm almost positive I put them on right, but if I didn't, is that a possibilty? Thanks again guys...

 

the mustang 5.0 intake has a pcv passage in the middle of it, but that's not where it's coming from. It's not any of the vacuum lines either, it is coming into the combustion chambers first.

 

 

Did you replace the oil pump with a High volume one?

Nordo

 

Just a thought, you said your block was milled, check to see if your intake is lining up correctly. It might have to be milled also to bring the correct port alignment back.

 

The new pump is a Melling High Volume, and the intake lines up perfectly. Even though I can't see any reason as to why one of the cylinders aren't firing, I think I will try to give her some good old Ether and see if that helps.

 

Well, I got it fixed. I tried to spray Ether, but it started bilging oil from the first crank, so the ether didn't have a chance. What I did was disconnect the coil wire, drop 2 qts. of Slick 50 in the pan, and crank it over for about 30 seconds. Then, I drained the oil, re-connected the coil wire, and fired it up. After about 10 seconds, I heard ALL of the cylinders fire up, so I let it run for another 30 seconds or so, then started adding oil back into the pan. It took about 2 minutes to get all 5 qts in, and by that time, it continued to run flawlessly, and no longer pumped oil. I ran the engine for about 45 minutes to make sure the oil rings were properly expanded and it wouldn't happen agian. I let it sit for about 2 hours to cool down, then re-fired the engine. Runs like a champ now!

 

Hmmm, interesting technique, glad it is working.

 

I was at my wits' end... I HAD to try something...