pistons/rings need input

[Belgian1979]

Couple of photos after I took my heads off:






Need an honest assessment on where to go from here. Piston crowns are wet. Soot could be rubbed off. Plug side of heads also wet. Piston number 2 had quite an amount of oil pooling on top which has me stumped. Others had some oil there as well but a lot less.
Engine sat for about 2 weeks since being fired up last time.
Light marks in the cylinder on the work side (outboard)
All cyls look about the same.

Compression test yielded 183-185 psi overall. Leakdown test yielded 7-8% overall.
I tried to measure blowby with a welding gas flow meter and it gave ca. 13 l/min.

Intake valves have black crud on them (all). Nothing on the exhausts.


Rotated the engine and it seems to take away the oil and only leave some of it on the top.

Heads need to be redone as I think the guides are shot.

[1980RS]

Looks like my 461 BBC did before I rebuilt it. Had a HV oil pump in the pan and mine looked like you engine. After I rebuilt it with a Std. volume pump all is well now.

[Belgian1979]

Looks like my 461 BBC did before I rebuilt it. Had a HV oil pump in the pan and mine looked like you engine. After I rebuilt it with a Std. volume pump all is well now.

Was the HV the cause?
What did you do to rebuild it? Oversize boring, honing, pistons,....?

[1980RS]

Looks like my 461 BBC did before I rebuilt it. Had a HV oil pump in the pan and mine looked like you engine. After I rebuilt it with a Std. volume pump all is well now.

Was the HV the cause?
What did you do to rebuild it? Oversize boring, honing, pistons,....?

I just freshened everything up, new rings, bearings, light hone and a std. oil pump. I pulled the heads this past summer to test a new set of heads and all the pistons and cylinders were clean and pretty dry. I will no longer use a HV pump as you don't need them and they just suck up HP. Do the test with the 2 pumps and a oil shaft spinning the pump with oil in the engine, the std. pump take half the effort of a HV pump.

[Belgian1979]

Couple observations:
- intake runners have yellowish color in the bown area.
- The discoloration seems to leave a trail right up to the place where the rocker stud protrudes into the runner.
- one runner still had a drop of pure oil hanging in it.
- combustion chamber on some cyls shows washed away soot on the plug side of the intake valve.
- over time I noticed that when taking plugs out of the engine, they were mostly dry when taken out if run right before. When taking them out after some time the engine has sat, they were wet with pure oil hanging on the outside ring.

yeah, might take the block out completely and try to rehone if the pistons are still good.

[superpursuit]

Couple observations:
- intake runners have yellowish color in the bown area.
- The discoloration seems to leave a trail right up to the place where the rocker stud protrudes into the runner.
- one runner still had a drop of pure oil hanging in it.
- combustion chamber on some cyls shows washed away soot on the plug side of the intake valve.
- over time I noticed that when taking plugs out of the engine, they were mostly dry when taken out if run right before. When taking them out after some time the engine has sat, they were wet with pure oil hanging on the outside ring.

yeah, might take the block out completely and try to rehone if the pistons are still good.

Are you sure your rocker studs are not leaking oil into the ports?
What did you use to seal them?
Silicon does not seal threads.
You should use Loctite on clean and dry threads.
Make sure you torque the studs to spec.

I hope this helps.
Allan.

[mag2555]

7 to 8 percent leakage is totally unacceptable, period!

I would only use Permatex number 2 sealant on the rocker studs and both contact surfaces must be free from oil.

It sounds like due to your wet plugs after shut down thaf you have both a valve guide and rocker stud hole leakage problem.

Carefully check your valve stems for ware, if they are warn .001” then consider them toast, especially intake valves!