Screw in rocker studs

[70 longbed]

When do I need to go to screw in studs vs the pressed in studs?

I currently have a 1.6 roller tip rockers with springs to match, but my problem is now the push rod touches the hole in the head. I need to either redrill the holes larger, or elongate them. While I have the heads off, I can do the screw in studs, but it is quite an expensive venture.

I have a set of full roller rockers off a corvette at my disposal; is putting in full rollers reason enough to re stud. The rockers are self aligning, so I do not need to do this for guide plates.

Keith

[c10crazy]

I'd be leary beyond .475 lift of the studs being pulled out while revving too high. 1.6 rockers could magnify the problem.

[nuke1]

i did screw in studs, once used press in stud, bad bad bad is all i can say, if you are gonna use full rollers go srew in studs, like c10crazy said extreme lift is no good.

[Billla]

The primary guide is spring pressure - anything over 120# (mild stock spring) and a screw-in stud is a good idea. Full rollers give no benefits for a street engine.

With a bit of care, you can absolutely do screw-in studs yourself. Summit makes a tool for removal and to act as a guid for the tap...which must be absolutely square wrt the boss. Note that this is intended for non-shoulder studs; shoulder studs (for guides) requires that the top of the boss be (lightly and consistently) faced.

http://store.summitracing.com/partde...6&autoview=sku

It's also no big deal to elongate the pushrod holes at home.

http://store.summitracing.com/partde...5&autoview=sku

[70 longbed]

Thanks for the responses.

Not sure why you say their is no benefit for a street engine. Roller tip reduces friction on the spring, and full roller just continues the less friction theory.

I know not to believe all the ads, but have heard from 10hp to 10% hp; any potential gain is appreciated with bolt on parts!

Keith

[Billla]

Originally Posted by 70 longbed

Not sure why you say their is no benefit for a street engine. Roller tip reduces friction on the spring, and full roller just continues the less friction theory.

I know not to believe all the ads, but have heard from 10hp to 10% hp; any potential gain is appreciated with bolt on parts!

I don't believe the ads either Dyno tests have shown very little gain for engines making < 1.2 HP/CID and turning less than 6000 RPM. CompCams claims 15-30 HP for roller tips - but I haven't seen it in any tests. Note that unless spring pressures are high (roller cams) the tip will typically glide (not rotate) on the oil film. Much of the lower friction comes from a machines (vs. stamped) surface where the rocker contacts the arm.

NO QUESTION that as you go up in power and RPM, these make more sense...but IMHO not in a street engine. Note the IMHO ;-)

I don't think roller tips are a BAD investment, but I wouldn't expect a significant power gain unless you're turning it pretty tight. As always, there's a lot of anecdotal "evidence" out there and I'm more than willing to change my mind...but I typically pop $60 for a new set of Crane 1.6 rockers with grooved balls and call it good unless you're over 1 HP/CID. IMHO, there are a lot of race parts going into street engines that rarely see the far side of 5000 RPM