TR2/3/3A Center main cap engine

[charleyf]

While starting to tear down an old engine to use in my TR project, I was surprised to find the center main cap missing. So my question is--can I use a center main cap from another engine? This is a TR3 block TS50000, is this main cap interchangeable with a TR4 or TR4A or even another early TR 3 engine?
Charley

 

[Andrew Mace]

My understanding is that yes, you can use a cap from another engine, but it would need to be specifically fitted / align-bored to your block.

 

[TR3driver]

What Andy said. The caps were nominally the same for all TR2-4, but each was machined as a unit with the block it goes with. Given the cost of line-boring, it might be preferable to pick up another block that has all it's bearing caps.

 

[mallard]

You may get away with using plastigage in multiple locations especially were the two halves come together, and top and bottom on both sides of the bearing when installed. Do not turn the crank. Remove the cap and take measurements to see if they are all the same. You can keep the gage in place with a small dab of grease.

 

[charleyf]

Thanks to all. That was what I was concerned about. I'll now switch to a different block. Hopefully nobody has molested the internals on that one.
Charley