07-04-2018, 07:37 AM
(07-04-2018, 06:42 AM)bob46320 Wrote: If the block is that bad, you would have to go to 3/8" helicoils/ then make special studs which were 3/8" in the block and 5/16" for the head. Is there enough metal in the block to do this as the O/d is about 0.468" for a BSF threaded helicoil. Because the diameter is increased, you could go BSF instead of traditional BSW in cast iron. Slightly smaller than 3/8 inserts would be to choose 8 or 8.5 mm ones.
It sounds like even the good holes would benefit from being helicoiled back to 5/16" BSW if you are going to this sort of trouble.
Hi, thanks for comments.I have never seen BSW studs in an A7 block, they are always BSF.
Stepped studs are readily available from our cherished suppliers, 3/8 BSF X 5/16 BSF.
As the holes are off centre I may drill them out oversize off centre, locktite a short length of studding in the hole, then retap to 5/16 BSF in the correct position.
I have Helicoil kits for 1/4 and 5/16 BSF, and 1/4 UNC Timeserts which I use for 1/4 BSW holes.
Just being lazy in asking if a drawing exist, I can work out the position from a cylinder head.