Anyone ever hear this? I was putting my engine together. Had it built a few years ago by Jim Burek in ElPaso, TX. He used a double roller timing chain and said if I use a mechanical pump, I have to elongate the holes in the fuel pump to move it over to the left 1/16" to keep the arm of the pump from hitting the chain. He said do that or use an electrical pump. Thoughts?
What he is telling you is correct, the arm will likely rub the chain. It's a simple issue to address. The arm on my GM Stage 1 pump rubbed the chain just slightly. A little bit of grinding on the arm is all I had to do. Some people will say "oh don't grind the arm!" but mine has been that way since 1997 without issue. It was a very small modification. Depending on the brand of chain set, the maker of the fuel pump, plus stack up of manufacturing tolerances, may result in needing to elongate the holes on the pump body slightly in some cases. I would not run an electric pump just to avoid this very simple task. Only run an electric fuel pump if there are other compelling reasons.
Does this advice only apply when using a Stage 1 pump? What if you have a the double roller set, but a stock (OEM) BBB pump? Is clearance still an issue in that case? I really don't want to have to open up the front of my engine just to check on it, if there's little chance of a problem existing. Looks like it's time for me to invent, and for Jim W. to make and sell, the Transparent BBB timing cover.
The issue applies anytime you use a double roller chain, it is thicker. It is a very simple thing to slot the 2 fuel pump mounting holes, with a rat tail file, so that you can move the fuel pump FORWARD 1/16". I would do that. Grinding on the arm is a lot harder IMO. The TA cover already moves the pump forward, so it is unnecessary with the TA covers.
Test fit it first; I’ve run double rollers on several different engines and never had interference. Patrick
