Main Bearing Caps

[Ianashdown]

My engine project has aftermarket steel main bearing caps and the markings on then is quite ambiguous, there is no Front Arrow. It had been previously disassembled and the caps had been replaced inconsistently.

My question is: Should the main bearing tangs be on the same side or on opposite side of the crank? It seems there is no consistent practice manufacturer to manufacturer, or so I’ve read. There are no obvious witness marks on the block or cap, but these will have been line bored in a specific location so it important to get them back correctly.

I’d appreciate any guidance from those that know! Failing that, I do have a stock 120E engine that I could pul a main cap to observe the tang setup. I’d rather not though.

Thanks,

Ian

[2cams70]

The tang cutouts sit opposite either side of the centre line of the block. That's only part of the puzzle though as you'll still have to determine which cap belongs to which bearing in the block

[nmauduit]

Sounds like you're going to spend an afternoon with plastigauge to sort out how best to install the caps back...

[Ianashdown]

That you for confirming what I previously believed. It seems logical, but I saw that other manufacturers specified both on the same side. Strangely I have not found any reference in any book or manual I have, only to put the arrow forward on the standard caps. Fortunately the caps and block are numbered, so their location is clear. Both the block and the caps are stamped with Q and the number. Anyone know a shop who uses the letter Q?

Back to the garage!

Ian