BARN FIND / Help ID this Engine

Calahan

Calahan

Member
Can anybody identify this engine? The Engine Number ID shows *AAxxxxxx*. There are many differences in this engine. Attached are some photos. It has a different Oil pan; the camshaft has more journals, and takes a look at the piston skirts. There’s a split on the skirt with a small spring clip on the inside of it. I am guessing a tractor motor. Thanks for looking, Calahan
 

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The pan and cam shaft are definantly 28. The pistons have the skirts modified to use skirt expanders. That is what the spring inside the skirt of the piston does. It expands the skirt for a good fit in the cylinder to prevent piston slap.
 
Thanks guys,,,,,,,,,The Engine Number is *AA268077* Looks like a late Dec-29 date. I just checked the bore/ Mains and rods and believe it or not they are standard ?#. Never seen skirts like that,thanks dfish. Whats up with those x rods?
 
It is not a real early 28 as the pan has the rienforcing strap where the pan to block bolts; very early pans do not have this strap.

Ron
 
I believe the x rod design, was a carry over from the Model T. The very early Model A engines used that style of rod extensively. Probably also uses the center spring clip on the wrist pin also, unless the person who overhauled the engine previously went with the outside piston pin retainers.
 
Thanks Barry B for pointing out the 6 digits. Yes It looks like June of 1928. Thanks guys for helping out. Well now off to the machine shop. Thinking about updating the bottom with insert main bearings.
 
Calahan said:
Can anybody identify this engine? The Engine Number ID shows *AAxxxxxx*. There are many differences in this engine. Attached are some photos. It has a different Oil pan; the camshaft has more journals, and takes a look at the piston skirts. There’s a split on the skirt with a small spring clip on the inside of it. I am guessing a tractor motor. Thanks for looking, Calahan
Click to expand...
1 Split skirts were common in the early days even up till the 60's. I throw them away, there is a reason they are not used today.

2 Piston expanders are another common fix for engines that were worn past usefulness. These were installed by builders and mechanics, along with new rings, to save the owner some money.

3 The center ring keepers for the wrist pins were in all original motors and many aftermarket piston and wrist pin sets. This motor has been patched up more than once since it has 2 different types of rods. Ever wonder why the x rods were discontinued?

4 The cam looks like it is out of a block with 3 cam bearing journals. This would be another indication it has been "helped" over the years. If I could see pictures of the block, I could tell if it was ever renumbered or not.

5 Looks like it is a good candidate for rebuilding into a good motor, if the block is not cracked. Many AA engines were left out with coolant in them and cracked or just rusted from the inside.
 
Thanks James for passing down good information. I never seen split skirts. I have overhauled motors in the past and have knurled the skirts, never split them. Seems to me it would allow a piston slap. Today I will have to look inside the block to see if it has 5 cam supports inside. I would guess the replacement I beam rod has more strength/ longevity.
 
Calahan said:
Thanks James for passing down good information. I never seen split skirts. I have overhauled motors in the past and have knurled the skirts, never split them. Seems to me it would allow a piston slap. Today I will have to look inside the block to see if it has 5 cam supports inside. I would guess the replacement I beam rod has more strength/ longevity.
Click to expand...
The split skirts are manufacturer done not customer mod. Just the way they were done in the past.
 
James mentions that split skirt pistons aren't made anymore for a reason, but doesn't clarify what that reason is. I am curious what the issue might be because I have opened up a number of older engines with split skirt pistons of Ford or other aftermarket make and could not find anything to fault the design. My last A engine had split skirts, over 30,000 miles since the last rebuild, and had only 0.006 of taper in the worst cylinder.

I realize that this design and older aluminum alloy would not be appropriate in a modern engine but why is it not good in a Model-A engine? Any thoughts?

I should mention that I have acquired several sets of old split skirt pistons and had been planning to use them at some point, so there's my disclaimer.
 
Let me be a bit more clear. I didn't say the split skirts aren't being made anymore as I don't know about that. I just don't believe they are being used or sold in quantities like they once were. Just like the center lock pistons, out dated by more modern parts. The only times I used split skirts, I have had problems. There seems to be more expansion in the piston alloy and all the ones I have done with them were prone to locking up. I had to hone several extra thou out of the bore to get them to run.
 
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