Pulled the heads, have a few issues

02x72 · Sep 21, 2013

In an effort to find out why my motor would not reach operating temp and was using a lot more fuel than usual the past few months I pulled it suspecting a head gasket issue. Well the gaskets look fine, but theres a few things i found wrong. First off, pistons 1,5,7,2,6,8 all have cracks in them where the valve sets into it. 7 and 8 being the worst. all of those cylinders had an awful amount of corrosion build up on them as well, mostly in the valve recess and around the edges. Its a white powders substance. The valve seats on the heads are all corroded as well, 7 and 8 again being the worst. My rings are shot, as several streaks of oil is being left on the cylinder walls on the down-stroke, which explains my oil consumption. However, the cylinder walls look really good, can still see the cross hatching in 80% of the surface area so cavitation seems to have been avoided. Motor has 250,000 miles and a hypermax tubo from day one, and was used fro towing primarily before I got it so its had a rough life I can imagine. What do you guys think I should be looking at? Comments? I have some pics but have to wait for the cord to get here this afternoon and I'll upload them.

icanfixall · Sep 21, 2013

First off there are no valve reliefs in the top of the pistons. What you see is a Ricardo cup. Its there for the combustion of the fuel as its blown out of the precup. As for the cracks.. Not good but not really bad either. The piston domes are 560 thousands thick at the middle where its the thinnest. The edges are much thicker. The corrosion is a mystery to me but I'm thinking its water getting in somehow and the engine sitting. Then rusting. Valves have a rotater under the springs to keep the seats clean. The valve actually will move in a circle as the engine is running. Yours may be not working well if at all. You posted its been used to tow but the rings are shot. Might be the rest of the engine is very well worn out too. Glad the cylinder crosshatch is still visible but whats the crank look like.

02x72 · Sep 21, 2013

I havent pulled the bottom end apart yet to get a look at the crank, hopefully get to that tonight. What is strange to me is that a few of the head studs, the ones near 7, 2 and 6 come out extremely rusty, like they had been sitting in the rain, and the pushrods for 3,5 and 7 have a significant amount or rust and scale on them. So I don't doubt water is getting in there somewhere.

02x72 · Sep 21, 2013

Finished pulling the oil pan and got a look at the bottom end for a few minutes. Didnt pull the caps yet so this is all mostly visual. The cam looks to be in good shape, no wear of any kind really to be seen. The rods that I can get my hand on, I am able to shake the piston back in fourth in the cylinder proably 1/32". I expected this with the oil i saw on the cylinder walls, but how much is normal for an IDI in terms of play? Again, I havent pulled the caps off the rods yet, so we'll see what that looks like soon.

8 and 6