Hello everybody,
I am building an engine with a 76mm crank and a webcam 86b cam, should I be expecting clearance issues with it ? If so where ? logic states that 2.5mm of extra stroke each side shouldn't cause that much of an issue but I have no idea.
Thanks
76mm crank
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wreck
- Posts: 512
- Joined: Thu Aug 14, 2014 12:07 am
Re: 76mm crank
with a 2 lt rod journal I would not think you would have any clearance issues at all , the only way is to dry assemble the bottom end with the rods attached , use rubber bands through the small ends to centralise the rods on the head studs and slowly turn the crank , the main issue ,if you have one will be #2 rod touching a cam lobe . what you could also do , if you haven't already is put on a piston (no rings) and cylinder , then verify that the TDC you have is accurate .
No matter where you go , there you are !
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subtaf
- Posts: 70
- Joined: Wed Jun 24, 2009 5:53 am
Re: 76mm crank
Ive ran a 76mm crank with stock 2L rods before. I used stock Mahle 2L pistons with 2L AMC heads. This resulted in a 2.5mm shim under the barrels to get a mild 8.0:1 compression ratio.
The stock 2L conrods were somewhat clearenced by DPR machine shop at the time O bought the crank and rods together. On the 1st mock up a very minor amount of clearance between the case and one or two rods was required. The cam profile was ground onto a stock new billet and there was no clearence issues there. It was a good little bus motor with good torque when I wanted to punch-it past long trucks with trailers on our single lane country roads.
The stock 2L conrods were somewhat clearenced by DPR machine shop at the time O bought the crank and rods together. On the 1st mock up a very minor amount of clearance between the case and one or two rods was required. The cam profile was ground onto a stock new billet and there was no clearence issues there. It was a good little bus motor with good torque when I wanted to punch-it past long trucks with trailers on our single lane country roads.