Main caps interchange

[Nacho-RT74]

Can the main caps be interchanged from block to block ?

situation... I had to get a 400 block to replace mine, but it seems caps are missed somewhere. I still have my own block to use those. I just want to be in peace knowing if the matching caps are definitelly lost I still can use mines.

Both blocks are same casting and even same year block

[cdr]

You can not just swap main caps, if you do , the block with the different caps MUST be line honed  

[Nacho-RT74]

Ok, so I guess aftermarket caps must be made on the same way.

[cdr]

Ok, so I guess aftermarket caps must be made on the same way.

Yes, any cap swap will require line hone.

[chargerbr549]

Hey Nacho these might be a good set of main caps to use for your 400 engine that you got with no main caps.

http://store.440source.com/Billet-Steel-Main-Caps-Set-of-5/productinfo/200-1039/

There is a difference between the terms "line hone" and a "line bore", generally if you have a block and main caps that came with the engine and no major damage to the main caps you can just cut the main caps on a cap grinder several thousands or whatever you need to clean up the mains and to get them straight and round you can "line hone" them with a stone mandrel, this is the preferred method since it generally keeps the crankshaft centerline pretty close to factory spec. Most likely when you have a spun main bearing or have to replace one or more main caps you will likely have to have it "line bored" since the new cap or caps will generally have extra material to cut out which you cannot remove by just honing, you will usually cut the main register in the block and that really  starts to move your crankshaft centerline and makes your timing chain loose if it gets excessive, then after you "line bore" it you finish it with a "line hone"

Kevin

[Nacho-RT74]

thanks!

actually I paid just that for the full block LOL. The block seller is still searching for the caps.

[John_Kunkel]

Any decent machine shop will have a precision straight edge to determine any misalignment in the main bores.

[Challenger340]

Hey Nacho these might be a good set of main caps to use for your 400 engine that you got with no main caps.

http://store.440source.com/Billet-Steel-Main-Caps-Set-of-5/productinfo/200-1039/

There is a difference between the terms "line hone" and a "line bore", generally if you have a block and main caps that came with the engine and no major damage to the main caps you can just cut the main caps on a cap grinder several thousands or whatever you need to clean up the mains and to get them straight and round you can "line hone" them with a stone mandrel, this is the preferred method since it generally keeps the crankshaft centerline pretty close to factory spec. Most likely when you have a spun main bearing or have to replace one or more main caps you will likely have to have it "line bored" since the new cap or caps will generally have extra material to cut out which you cannot remove by just honing, you will usually cut the main register in the block and that really  starts to move your crankshaft centerline and makes your timing chain loose if it gets excessive, then after you "line bore" it you finish it with a "line hone"

Kevin

Line Honing, at least when doing a good job of Line Honing ? is IMO, one of the most difficult jobs in automotive machining.(again here, to do well)
And most who are GOOD at it.... would never use one of their mandrels to try and remove more material from one cap or another..... a sure fire way to get their mandrel "out of shape" or the stones distorted end to end. The only way to protect mandrels and keep them true, is to machine the caps so ALL are within a couple of ten thousandths vertically BEFORE Line Honing begins, when honing ALL the Holes together back to within spec.

[John_Kunkel]

And, to be even more pedantic, the correct term is "align" boring/honing.

[ACUDANUT]

Can the main caps be interchanged from block to block ?

situation... I had to get a 400 block to replace mine, but it seems caps are missed somewhere. I still have my own block to use those. I just want to be in peace knowing if the matching caps are definitelly lost I still can use mines.

Both blocks are same casting and even same year block

Yes. The only issue is the correct "race" or bearing that matches the crank. It the Crank was turned .10, then you need races/bearings that are .10 Etc.. that fit on the caps.
Hope that helps.

[Nacho-RT74]

Updating! Found the caps!