Just removed 97 psd passenger side head to take to pressure test at machine shop. gonna be about two weeks until get parts needed for complete motor reassembly. Have cylinders covered up with thick gauge plastic taped up real well with a blanked ontop of it. Should I cover the cylinder walls with anything to prevent rust, or will oil or be grease be sufficient? Had to remove the entire #3 piston with a bent connecting rod. Thankx again, Ron

 

I'd say it would be fine.these thing's when you take then apart have oil all over them.i should have taken pics when i tore the last one down.oil all over the floor no matter how hard i tryed to keep it clean.

Do you need a rod?

 

What happened?

 

bought the truck as is with a knocking/ miss . The compression test revealed that # 3 cylinder had only 200 psi while all other cylinders have 380 psi ( 128k miles). Upon removing head the top of piston (#3) has circular contact impressions from valves on piston. My guess would be starting fluid pre ignition damage. All the rockers and pushrods are straight. Having the head testes to make sure valves aren't bent, soon to inspect for possible bent connecting rod or cracked piston.

 

None of the other pistons had valve contact marks on them? I've seen this before on a 220k mile engine that was running fine.

 

None of the other pistons had valve contact marks on them? I've seen this before on a 220k mile engine that was running fine. If the source of the problem was the valve contact, the pushrods should have bent before the connecting rod would have I would think.

 

only #3 had impressions on the piston, just had the valves checked today and they are good. At this point , seems to be either spun bearing on crank or excessively high rev's . Am in the process of cutting the crossmember and drop the pan to inspect crankshaft. Also did notice that it appears that the piston made contact with the head. perhaps one of the 2 halves of the main bearings spun and they are both on the same side, or when the valves made contact they caused the connecting rod to bend. Wild guess for now, until i drop the pan.

 

Was on it today and used a sawzall and tongesten carbide blades on the center section directly below the oil pan to be able to drop and inspect. Am going to do that tomorrow. Did notice on the top side of the cylinders that the #3 piston does rise higher in the cylinder than the others and am leaning toward spun main, although yet to verify.

 

# 3 rod bearing worn paper thin, head and valves straight

 

So are you going to pull the engine and do machine work and get everything back right or are you going to try just a new bearing? I'd be surprised if the cylinder didn't suffer some damage as well.

 

Cranks probably hurting and needing a turning too if that bearing is that bad.

 

Agree with the above sentiments, but to answer your original question, wax works well. Just apply a nice coat and don't bother to buff it. Then cover with your plastic and you're good to go.

 

To answer the what now, long tern will get another motor to replace this one. And for now just slapped in another piston/rod from a parts motor, cylinder wall is perfect . This is just to be able to run it around town for a few months . I figure the crank surely needs turning , and metal flakes are most likely throughout the entire engine it wont be long until it's completely shot. Would be interesting to see how long it will last. Actually cut the frame center section out with a sawzall and could just keep replacing the rod bearing every 10,000 miles.