Difference in Blocks

[LJ851]

does anyone know how much the bottom of the bore/cylinder can be notched for rod shoulder clearance before you break through?

I cut a block up and posted pics in a new thread here:

http://www.r3vlimited.com/board/showthread.php?t=285315

[tinkerputzer]

I remember talking to Pete McHenry years ago about building an M20 for my 2002 and he mentioned early ETAs had a large core plug on the rear of the block behind cylinder #6 and was a less strong casting. The later blocks did not have the cast in hole or plug.

Yes this is true. The '86 and later didn't have it.

they have the same deck height so it would mean the cylinder is not as deep which is not good as at BDC more of the skirt is unsupported if that is true. i though the extra internal clearance on the eta block was in a different area more to do with counterweights as the 84mm big counterweight crank rubs on the sides of the block.

The B25 block i have is 206.2mm deck height and 135 mm deep cylinders. Anyone got a eta block they can measure from top of deck to where the bore finishes?

the auxiliary shaft needs to be machined but not sure how much. it is a fat mother compared to the the actual small drive shaft to the pump so i imagine a fair bit can be machined down

I used a '86 eta block for my 3.1L and the clearencing was minimal. There are some details in my build thread.

http://www.r3vlimited.com/board/showthread.php?t=265471