1.6 Roller tip rocker arm installation advice

[cusideabelincoln]

First off I have a 92 Lumina with the 3.1 MPFI.

Alright I ordered a set of Comp Cams stamped steel 1.6:1 roller tip rocker arms along with a more aggressive cams from A.R.I engines. I orderd the phase 2: http://www.engine-parts.com/GMV6/GM28cams.html, and the specs are as follows:

Manifold Vacuum: 16-18
Duration @ .050", Intake: 204
Duration @ .050", Exhaust:214
Adv. Duration, Intake: 270
Adv. Duration, Exhaust: 280
Lift, Intake: .420
Lift, Exhaust: .443
Lobe Center, Intake: 107
Lobe Center, Exhaust: 117

I installed the roller rockers on some adjustable rocker arm studs (not the stock ones), and I turned the crank to see the movement. The pushrods seemed to very slightly graze the guide plates, so I grinded off a bit with no problems. I also installed new lifters.

My quandary comes from the valve lift and spring compression. The 1.6 rocker arms compress the valve spring much less than the stock rocker arms, studs, and lifters. I verified this by installing the old, stock rocker arms on one cylinder and the new rocker arms on another cylinder, and the stock one seems to compress the spring close to its maximum while the 1.6 one does not.

Is this a problem? I was under the assumption the 1.6 rocker arms would give more lift and compress the spring farther. Any information would be helpful, so thank you.

[geoffinbc]

They do compress the spring more. You may be running into lifter collapse of some of the lifters because there is no hydraulic pressure to keep the pumped up. Swap the rockers locations you are testing and take another look.

On a side note I really hope you are not using stock springs. Old Gen II springs cannot handle a cam and rocker combo like that.

[ForcedFirebird]

First off I have a 92 Lumina with the 3.1 MPFI.

Alright I ordered a set of Comp Cams stamped steel 1.6:1 roller tip rocker arms along with a more aggressive cams from A.R.I engines. I orderd the phase 2: http://www.engine-parts.com/GMV6/GM28cams.html, and the specs are as follows:

Manifold Vacuum: 16-18
Duration @ .050", Intake: 204
Duration @ .050", Exhaust:214
Adv. Duration, Intake: 270
Adv. Duration, Exhaust: 280
Lift, Intake: .420
Lift, Exhaust: .443
Lobe Center, Intake: 107
Lobe Center, Exhaust: 117

I installed the roller rockers on some adjustable rocker arm studs (not the stock ones), and I turned the crank to see the movement. The pushrods seemed to very slightly graze the guide plates, so I grinded off a bit with no problems. I also installed new lifters.

My quandary comes from the valve lift and spring compression. The 1.6 rocker arms compress the valve spring much less than the stock rocker arms, studs, and lifters. I verified this by installing the old, stock rocker arms on one cylinder and the new rocker arms on another cylinder, and the stock one seems to compress the spring close to its maximum while the 1.6 one does not.

Is this a problem? I was under the assumption the 1.6 rocker arms would give more lift and compress the spring farther. Any information would be helpful, so thank you.

Let me get this right, you are getting spring bind at full lift with the stockers?

I agree with betterthanyou, stock springs won't last.

That cam lift, is it calculated with the 1.6 rockers? If not, you are seeing more like .448 intake and .473 ehxaust.

[torq455]

yeah, i only added 1.6 roller tips, not the cam as well with my stock springs. does very well....so far. with age they get weaker, so i'm happy with the extra lift, i don't have any probs.

aren't the pushrods supposed to "graze" the guide plates since that's what they are there for, to guide the pushrods?

[1988GTU]

That's all I had to do to my guides. I've noticed a very slight lope added to the exhaust note.

[ForcedFirebird]

That's all I had to do to my guides. I've noticed a very slight lope added to the exhaust note.

HMMM, that's odd. I didn't have to grind mine when I had the 1.7rr's on there (went back to 1.6 because of spring bind). Even with the stock rockers, the pushrods touched the guideplates.

And yes there was a very slight difference in the sound from the rockers, and they shaved a whole .1 seconds off my 1/4 time, lol.

[torq455]

agreed, very strange, buuutttt i had to grind mine when i broke 3 exhaust guide plates. turned out when i broke another, we found out that the rocker studs were machined eccentric, therefore forcing the pushrod either to one side, or forward causing excessive friction. once good rocker studs were put on, there was plenty of clearance between the pushrods and guide plates. no more probs!