Clearancing for 76mm crank

[Chris]

What are the areas that will need attention if I building a motor with a 76mm crank with vw rods?

[Geoff]

Depending on make of crank, It will need the usueal areas but much less than the 78-84 cranks. (cast cranks tend to have a fater cheek/counterweight) No cam clearance will be needed. I think I have a link somewhere and will add it if I can find it.

Case Clearancing for a 74mm case is minimal, the bigger the bore the less clearancing you'll have! If you have a small bore, you may have MINOR clearancing for the rod nuts, at the cylinder spigots. Normally the 74mm crank is DROP IN with no clearancing needed. 76mm needs slight clearancing worst case.

[getgeoff]

I had to clearance the top of the case and the cam as the rods were hitting these areas. I would recomend use a race rod style instead of stock rods as they have more of a chamfere at the bolts ends and thats where most of the clearance problems were noticed. Also keep an eye out where the counter weights of the crank swing as they get fairly close to the sides of the case near where the barrels go. You might also want to go with a B piston as I had to max out the barrel spacing plus put a copper shim under the head to get the clearance and the compression just right. It is a bit of a frankinstein motor in my opinion.