Thread: Engine inspection with heads off – what do you see?

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Info:
SBC with 300ish miles since last winter install of the engine (new head gaskets and external refresh)
Rebuilt who knows when (seller says only a few thousand miles, I don’t agree) to .030 over
Head gaskets were good (they were pretty new)
I know I was running very rich
There is no lip at all at the top of the cylinder bore
I see there is cylinder wall scoring, but I don’t want to tear engine down further, so I am leaving it.


How do I clean the crap and carbon off the heads and the cylinder tops?
Do you see anything else of concern?

Yep - running rich and also might be worn valve guides or failed valve stem seals to put down that much carbon.

To clean, bring the piston to the top of the bore, and if the deposits are fairly soft, use a piece of hardwood (oak, or ash or similar) about 1.5 time as thick as a paint stir stick. It needs a good sharp edge like from a fresh table saw cut. Vacuum and wipe out. Do the heads the same way. If the carbon is real hard, a piece of brass will work. Neither will do damage to either the piston or head.

As far as the scuffs on the cylinder walls, if you can't catch a finger nail, they are only scratches. If you catch a nail - another decision has to be made - i.e. do I tear it down and hone a thou or two and clean most of it off or do I $pend the big buck$ for another rebore

In my opinion you need longer plugs and just wipe off the top of pistons and forget it. Your plugs look to be shrouded or maybe you got them loose already. Do you ever fish the Rabbit? Ben there a few times.

A brass brush in a drill will clean off the piston tops.

Chase your cylinder head studs with a new tap to clean up the threads and put a chamfer on top of the thread holes to stress relieve them.

I see you are running a good mix of antfreeze which is good.

And those are not the plugs that you run in those heads are they? From the look of the dirty plug threads thay are way to short !!!!!

Originally Posted by bigdude

In my opinion you need longer plugs and just wipe off the top of pistons and forget it. Your plugs look to be shrouded or maybe you got them loose already. Do you ever fish the Rabbit? Ben there a few times.

All good suggestions, thanks. I will use my brass and nylon brushes.

The plugs were not in all the way, Only threaded in a bit to protect the combusion chamber from the elements during work. New plugs are going in to replace those rich ones (which actually are proper length).

The intake valves look pretty thin, and sunk into the seats. Also the walls show the wear line of the second ring, as well as the top one. It has quite a few thousand miles since a cheap redo.
Why did you tear it down?