Can this engine be repaired?

[nuwala]

I've bought this engine as "a well restored engine" about a year ago to replace my aging engine in the Model A. This winter should have been the winter to swap engines. Removed the head and everything looked fine, 4 new valves - except cylinder #3, two about 1mm deep scratches.


Can this block be rescued?



Sadly I'm in Europe and Model A engines are really rare

[V4F]

you can sleeve it or bore it if it will clean . I myself would run it . that's a shame ........ steve

[BILL WILLIAMSON]

I've seen similar scratches in engines that ran PERFECTLY, for YEARS.
Bill W.

[flatford39]

Well I would at least pull the piston to look at the rings and try to determine what caused it but like others said that could go away with a new bore or just run it the way it is.

[Kurt in NJ]

Looks like the mark the end of a wrist pin makes ---check rod alignment, circlip, piston
I have seen much worse not have problems running as long as the root cause is cured

[Fullraceflathead]

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The groove is from the wrist pin coming lose or never was locked in place to begin with.
I would not run it anymore without at least fixing the wrist pin. It will keep wearing the groove deeper if you just leave it.
You can remove just that one piston Rod assembly and see if they left out the retainer lock.
It maybe the type that lock into the rod also. Once you re lock the pin you could put it all back together and run it. That cylinder will be down on compression and use oil though.
The best fix would be to sleeve that one cylinder and have it machined to the current piston size.
If the other bores are not in good shape I would do a complete rebuild with a sleeve and new Pistons and rings.
My engine has had all four cylinders sleeved back to standard bore size.

[nuwala]

Thanks guys. The rod alignment and the piston looks fine.

I'm mainly worried about reduced compression in no. 3 when gases pass the piston rings going into the oil. That scratches are 0.04 inch deep. I was planning to put a 6.5:1 head on.

Would it be fine to just bore / sleeve cylinder no. 3 - or shall all cylinder be done?

[harleytoprock]

Believe it or not those wrist pin grooves will eventually fill with hard carbon and will seal fine. Until that happens, it will smoke and have low compression. Who ever did the rebuild should hide their head in shame.

[H. L. Chauvin]

Per reply #8, saw engine carbon & old oil fill groves like that before where it was not a problem.

[eagle]

Can't see very good, but does it look to others like the cylinder was honed at least some AFTER the grooves were made?

[H. L. Chauvin]

FWIW:

I remember having an oil burning, smoking Model A engine years ago in my well-used coupe which I bought as a teenager.

A kind neighbor over 55 years ago gave me a new set of piston rings that he had stored for about 20 years ...... but .... they 0.010" larger than my engine bore.

I asked a vintage professional machinist/mechanic if he thought installing these rings could harm the engine.

He said the cylinders may become slightly egg-shaped ...... but since this is a Model A, rest assured that these oversized rings will never be the next thing to go wrong with a Model A.

Unfortunately, he was correct.

[Dodge]

Its out and the head is off. You could just sleeve that one cylinder and bore it to fit the
piston in it. It looks like it was apart already and some one tried to hone it but didn't
get any cross hatch in it. You might as well pull the motor down and check everything
out so you know what your starting with. If your lucky it has new rings in it already.
If the taper is not bad on the other cylinders and the bearing look good. Put a Model B or
touring cam in it with your 6.5 head and go....

[hardtimes]

Well, so much for 'well restored engine', eh !
Did you ever get a chance to talk to seller and happen to ask , about who did the engine work on this engine ?
IMO, it looks like someone (amateur ?) did take engine apart. The grooves may have been worse and honed a bit. The hone job , alone, tells a big story here...i.e.-not what a hone job is supposed to be and/or look like !
So, the 'hone' job in indicative of a guy who dismantled/maybe did some cleaning/adjusting to best of his ability, and reassembled.

Here is where I differ, with the others who say run it. If this is what / how was done....what else
Since it is partially disassembled already, out of the car and somewhat clean...take the pan and valve cover off and check further before even thinking of running. Just one opinion, but once this is in the car it will be a whole lot of work to undo 'stuff', that may be wrong, then.
Now.....if all else is to your liking, I'd run it with these 'grooves', as I done that myself in the past and like said, it ran in fine

[Kohnke Rebabbitting]

I think the piston part has already been fixed.

You can see where they used a hone, with out cross hatching.

You can see where the hone droped in to and out of the two grooves.

The grooves extends to high in the cylinder, not to burn oil.

Herm.

[WestCoast]

it looks like the marks were there when the engine was rebuilt by looking at the hone lines, looks to me it was honed over the marks, just run it the marks will probly get filled in with carbon

[andyfresno]

If you run this, it will get worse. The wrist pin is loose and "falls" to the rear. Over time, It will wear to the water jacket if you let it.

My view is, once you find a mistake in an engine, it's usually got other problems. How do you know the other wrist pins are right? - -Where'd the clip that retains the wrist pin go?

I'd take everything apart. If that's the only problem, I'm with the guys who say you can sleeve this one cylinder. You've got to take it mostly apart the bore it anyway - -

I can't tell from the pics, but I'd put in stainless steel valve seats if you don't have them already.

[tbirdtbird]

you avoid valve seats in an A and especially a B at all costs unless absolutely necessary...

[Kohnke Rebabbitting]

We have put valve seats in every A, B, and T block, and every engine that we ever built, and never had one come out, or leak.

You just have to know how to do them.

Herm.

[RandyinUtah]

tbirdtbird could you please justify your statement about valve seats. I have also replaced all valve seats in four engine with no problems.

[tbirdtbird]

my statement stands. do you think everyone knows how to do them correctly? ever seen a B ruined? many shops do them to charge more? in case no one noticed this thread began asking a question about a bore?