big m oil restrictors

[kirk]

i would like to get some opinions on what size if any oil restrictors i should use on big m block clearances are .0035-.0037 main .0025-.0027 rods crower lifters jesel rockers. Undecided on oil pump as of now 8 quart moroso pan. Thanks

[Awesome Bill]

.001 per inch of journal is fine.

[kirk]

.001 for oil restrictors or bearing clearance? It is solid roller. Thanks

[Awesome Bill]

bearing clearances, your restrictors are usually .060. We do not use them at all unless we are instructed to. With todays bigger pans, you want to flood the top of the engine with oil to help keep the valve train as cool as possible. There is no real power loss with this. A broken valve spring will cost way more than a set of restrictos.

[coloradoracer]

I would stay away from restrictors if at all possible. I don't use them in ANY engine I build. Bill's right on this one, you need to keep the valve train cool, and oil is the only thing you've got to do that. I also believe (this is my own opinion) that using anything that takes oil flow from critical components is a bad thing. With the newer block designs and priority main oiling, restrictors are a thing of the past. The only real reason they were used before was in older blocks to help get more oil to the mains, and only if you had solid roller lifters. That need is gone now. As far as an oil pump is concerned, my personal preference is Titan first, Moroso Professional Gerotor second. Run a spur gear type pump if you don't have the budget for either of those, as they can be a bit spendy. Dry sumps are the way to go if you have the cash and your class rules will allow them.

Mark

[kirk]

Looks like no restrictors, thanks. Kirk