Rocker Arms

[beppe180]

k i m at the final stages of my motor build and i got the studs, and my new comp 1.6 rocks, now i heard some ppl say u had to grind down the U part how much do i have to grind down? should the pushrod not touch the U at all .. thanks guys much help apprc

J..

[robby1870]

Im pretty sure the pushrod should not touch the U at all

[geoffinbc]

Whats a U? And what breed of 660 are we talking about?

[robby1870]

okay....on each pushrod guide, there are two fork things that guide the pushrods. Each one is a "U" shape. He's wanting to know how much to grind out of the bottom of the "U" where the pushrods will rub with the COMP 1.6s. I dont think the pushrods should touch the bottom at all, but Im not for sure

[v6h.o.]

you will have to grind the bottom of the "U" of the Guide plate to allow the pushrods clearance, it has to be done with 1.6:1 comp cams roller tip rockers, the pushrods will rub right against the guide plate if you do not clearance them

you have to grind basically down to the bottom of the U where the verticle bend upwards is.

i really should have taken pics of this back when i did mine, would explain better.

[robby1870]

Colin...on the stock setup, the pushrods dont touch the bottom of the "U" do they?

As far as grinding them....I'd install the COMP 1.6s, turn the motor over with your hand a couple of times, see whats going on, then take the guideplates off and grind them down. Just grind enough for what you need...dont grind a lot on them, you'll weaken the guide

[v6h.o.]

Colin...on the stock setup, the pushrods dont touch the bottom of the "U" do they?

As far as grinding them....I'd install the COMP 1.6s, turn the motor over with your hand a couple of times, see whats going on, then take the guideplates off and grind them down. Just grind enough for what you need...dont grind a lot on them, you'll weaken the guide

on stock 1.5:1 ratio rockers. no they dont touch at all.

trust me you have to take out a heap of material in the guides "u" part to clearance. you'll just be frustrating yourself from having to install them test fit, and remove them if your only trying to slowly take a small amoun off.

take off enough down to the bottom of the "u" to where the bend is.

ive never had any issues with guide plate breakage and they've been run hard for about 15,000 kms constantly up to 6+ rpm.

[geoffinbc]

Hmm must be a Comp Cams issue. Never had to touch my guides when I installed my Crane Rockers on my iron heads. Nor did we have to change anything when we installed them on Lloysd 3.1L in his Cavalier.

[sharkey]

if you put 1.52:1 rockers on, no you wont have an issue. if you step up to 1.6:1 rockers, thats when you get the pushrods hitting the guide plates.

[geoffinbc]

The Crane rockers are 1.6:1 ratio

[smilinguy99]

The Crane rockers are 1.6:1 ratio

Not quite true. The Crane P/N 25750 is a 1.5:1 rocker and the Crane P/N 25759 is a 1.6:1 rocker.

[geoffinbc]

No shit?

I have 1.6:1 ratio and so does Lloyd. They have been on my 2.8L and 3.4L his 3.1L and now his 3400 and we never had a problem with the guide plates.

[SPECIALGAGT]

Regarding "6+" rpm

I have seen no curve plot that shows any increase in HP or Trq above 49k or so. What camming are you running?? I want one !! None of the aftermarket goodie folks have ever printed a chart showing increased output at "6+". But I'd sure like some of that !! Gnome Sane?? How big are the 3100 Exh. valves??