cylinder wall pitting

The vertical lines in #s 2, 4, and 7 don't look ideal. Can you catch your fingernail in them? If not they are cosmetic and a simple ball hone can take care of even that. I can't really tell if you have ring ridge at the top of each cylinder. I have seen mild carbon buildup that looks like what I see in the pictures, and I have seen ring ridge that looks like what I see in the pictures. Ford manuals and Service Bulletins give limits for cylinder wear. If you are within those limits you should be able to do a "short job" with just rings, gaskets, and fix that one cylinder.
 
From just looking at the pictures, it appears you have some pretty good pits and scoring in other cylinders. Also, I can see evidence of corrosion on some of the piston tops - which usually means there was moisture in the cylinders at some point.

Since you have to take it apart anyway, I'd have the machine shop inspect ALL 8 sleeves and potentially replace them all, hone them and put new rings in the engine. Also, there could easily be some rust/pitting on the valves/seats . . . so I'd probably have them touched up as well. Also, when you have rust/debris that scores cylinder walls a lot of times it gets into the oil and scores the bearings.

This is how it usually goes for me . . . every time I think I'm going to get away with a few "band aids", I end up finding more issues. So, I then make the decision to do the job the right way and rebuild the engine. While I don't like to spend the money, I also hate to spend all the time and put the effort in and not have the best result possible.

I'd take it all apart and have everything inspected by a machine shop that knows flatheads.
I'd also be mentally prepared to rebuild the engine. You'll then have a really good running engine that should last the rest of your lifetime. Not trying to spend your money - just trying to be realistic and pragmatic.

Best of luck and welcome to Flatheads - they are fun engines!
B&S
 
It may just be the camera angle, but do the tops of the liners appear low in the bores? Is this something to be concerned about?
 
Deep pits allow a blast of extremely hot gas to burn though the pitted area. This will get worse quickly. Its almost as bad as a busted piston ring. It may run but it will burn there for sure and will damage the top ring and piston as well. Fix it now and the problem goes away.
 
Update: decided to have the motor rebuilt. My engine builder took it apart, cleaned it and took to his machine shop to have it magna fluxed . It’s crack free BUT sonic testing revealed cylinders to thin to bore. It can be re-sleeved back to a standard bore.

I also took engine builder a second short block just in case. Turns out this block is also crack free and passed sonic testing. Going with 3 5/16 bore on this one. Can’t believe how extremely lucky I am to have 2 usable blocks..!! I’ve read all stories about folks having to “go through” several blocks to find a good one.

Here is a link to the other block that I am using for the build: https://www.fordbarn.com/forum/showthread.php?t=303399
 
Last edited:
I've done a LOT of sonic testing on these blocks - would love to know the actual numbers that your engine builder acquired in sonic testing. I test each cylinder in 12 places - based on taking measurements on all 4 sides, in 3 locations (up/down) on the bore.

If you can get the info, would love to know the numbers that they are referencing?
 
>>>want to button things back up to see how it will run.>>> I can see a domino effect>>>


Yes. I can see that too, So if it was mine, I'd quickly button things back up to see how it'll run. 8^)
 
You must log in or register to reply here.
Back
Top