I finally got around to disassembling the 400 from my 79 this morning.

When I bought the truck, I was told that the fuel pump was leaking into the engine oil. After changing the pump and the oil, the problem persisted and the truck was parked for 2 years before I bought it. That's the story, anyway .

I brought it home, hooked a battery to it, gave it a hint of ether and it fired right up, but was smoking badly with raw oil coming out of the exhaust.
Compression test showed 5, 6 and 8 to be dead and going into the crankcase.
I drained about 9 qts of fuel diluted oil from it.

Here's what I've found on disassembly: Bent pushrods on 1 and 3. One of them just laying in the lifter valley. Original timing set with fiber gear. One spun rod bearing and a couple others that were not far behind. And the typical main bearing wear. Cam had very little wear.
The engine had either 70K or 170K. And had no signs of ever being apart. The truck is stock down to single exhaust with a cat.

My main question is, how much fuel in the oil does it take to wash the cylinders to the point of causing the rings to pass this much oil? I feel like I am missing something because I expected to see more damage.

I have yet to do any measuring. I'm hoping that the crank will clean up with polishing. The block had just a little ring ridge, so I'm hoping I will only have to bore to the next oversize. Are there any pistons available to bump the compression a bit without machining or major changes? Will go with a mild cam and a straight up timing set to get a little more out of it.


Thanks,
Jason

 

Get a good double roller timing set, and install it 'straight up'. A Comp cams 255DEH or XE256 cam, and a set of pistons from Tim Meyer. Don't be afraid to go +0.030" on the bore.

TMeyer, Inc. - Machine Shop Prices

When you're ready get a 4 barrel manifold and headers.

 

Since you spun a rod bearing I'd say your chances of just polishing the crank is about O%. Sorry to bust your bubble on that. Putting used lifters on a new cam is a bad idea.

 

I'll have to see what the machinist thinks he can do with the crank. There is very little damage to that journal. But without any measurements, it's just a guess at this point.
Not sure where you came up with running used lifters on a new cam. But it is a bad idea.

Jason