Don Terrill’s Speed-Talk

I have some drilled out restrictors ( .040 ) in the back end of a circle track sbc & have been wondering if these are old school, old tech that should be changed out. Should a guy drill them out farther or just put the old threaded plugs in and let'er flow. I'm using roller rockers and a med to high spring pressure set-up.

If your not using valve spring oilers in the valve covers I would not use restrictors as your valve srings will run cooler with the extra oil.

how about on a drag car? I run mine drilled to .100. Solid roller with about 275 seat pressure 1.550 springs.

I have been told yes and no. Would love to hear what some of the pros on here say about this subject.

Sorry for the tread jack

Just my opinion,as I'm no pro,but you do not want to restrict oil getting to solid roller lifters.Period !!!
Guy

In my opinion this is 60's "technology" & something perpetuated over the years by magazine articles & internet experts.
Or,,
If it gets written about or repeated enough times it becomes fact

I do not use or recommend restricting the oil to your lifters especially roller lifters & this goes even more so in an endurance engine

What exactly is it your are trying to accomplish?

If you feel the need to restrict the oil to the top end so your springs can run hotter for some reason there are pushrods made that will do this

Wolfplace wrote:In my opinion this is 60's "technology" & something perpetuated over the years by magazine articles & internet experts.
Or,,
If it gets written about or repeated enough times it becomes fact

I do not use or recommend restricting the oil to your lifters especially roller lifters & this goes even more so in an endurance engine

What exactly is it your are trying to accomplish?

If you feel the need to restrict the oil to the top end so your springs can run hotter for some reason there are pushrods made that will do this

I think you answered your own question in the first half of your post

BTW: Mine will be coming out this next week, if the answers keep coming as they are now

norton wrote:
I think you answered your own question in the first half of your post

BTW: Mine will be coming out this next week, if the answers keep coming as they are now

Actually at .100" /bank I think you are probably closing on little to no restriction so I would not be too concerned with yours

I had bought a motor with these in the block & left them in since it was built by a known builder, until I re-ringed & bearing it this winter but kept them out on the rebuild thinking about valve life since stepping up the valve train & heads for this year. but started secound guessing myself & wanted to pick some brains. thanks

oh yea I forgot to mention that these restrictors were "red anodized aluminum"!! brite shinny too!! Kinda like the fishing tackle isle @ wally world if you know what I mean!

klw_71 wrote:oh yea I forgot to mention that these restrictors were "red anodized aluminum"!! brite shinny too!! Kinda like the fishing tackle isle @ wally world if you know what I mean!

Have you seen the GREEN anodized ones?


No one can there in behind the trans. hahaha

We don't use them at all in anything.

Tom

Look down the drain holes in ends of the heads and make sure they are not half blocked by the block.If you have a high volume oil pump and don't have enough oil capacity it could suck the pan dry.

RCJ wrote:Look down the drain holes in ends of the heads and make sure they are not half blocked by the block.If you have a high volume oil pump and don't have enough oil capacity it could suck the pan dry.

A HV pump bypasses far more oil than it pumps to the top of an engine. Since the bypass in a HV pump dumps strait back into the oil pan, explain to us how it could pump the pan dry?

Even with the cyl heads end returns completely blocked, if it filled both heads up 100% to the valve covers, (their capacity might be about 5qts) so even with a stock pan and HV pump I think it would be mighty difficult to pump a pan dry.
Will