Peculiar problem, I tried to install some slightly used Comp Cam Pro Magnum 1.6 roller rockers over the weekend. I was adjusting the valve lash with the motor running, and started with the driver's side since it has the easiest access.

I did one cylinder at a time, to make sure each cylinder was set before going on to the next set of RR. When I finished that bank, I noticed that overall the motor sounded much louder, almost as if some of the hydraulic roller lifters were rattling or bad. So I took them all off and put the original aluminum roller rockers back on and it was a lot quieter.

Has anyone else noticed that the CC pro Mag RRs are noisier than aluminum ones? I call CC's help line, but they didn't have much to say about it.

One interesting aside they said not to worry about though - the underside RR contact points on the 1.6 Pro Mags is actually a little closer together than the blockier Harlon Sharp knock-off 1.6 intake RRs I had on the motor. Since the steel vs. alum thickness is different, they said not to worry about it. Does that make sense?

Also for what it's worth, I have 1.6 aluminums on the intakes, and 1.5 currently on the exhaust.

Sorry for the length here, but wanted to give as much info as I could so the gurus here could take their best shot at this. Thanks in advance for everyone's time on this!


- Vern

 

Thats funny. I always wondered if I had a bad batch too...

I put in my 1.6 promags in last fall and they have been adjusted 3 separate times. Always noisy -- like theyre loose.

I thought it could be an exhaust leak also but new gaskets said it wasnt.

Does the noise quiet down with a warm engine? mine seem to a little but not much.

Maybe I didnt prime the lifters right... I dont know either.

Just glad they dont set off my knock sensor.

Not sure what you meant by this
One interesting aside they said not to worry about though - the underside RR contact points on the 1.6 Pro Mags is actually a little closer together than the blockier Harlon Sharp knock-off 1.6 intake RRs I had on the motor. Since the steel vs. alum thickness is different, they said not to worry about it. Does that make sense?
Can you elaborate the difference?

 

Sure - I flipped over both knids of 1.6 RR to look at the underneath side. The aluminum rockers have a longer distance between the points where the pushrod and the valve stem contact the rocker than the Pro Mags do. Difference was probably a little under 1/8th inch, but still enough to be noticed by the naked eye.

So I asked CC about that, and the guy told me that the angles and thickness of the PMs is differetn than the aluminum RRs, and not to worry about it.

This weekend I'm hoping to try putting them on again on a cylinder or two. I want to check the clearance on the pushrod slots in the heads (especially on the exhaust side) and on the guide plates while turning the motor over by hand.

Thanks for the reply! I was wondering about a header gasket just like you were at first. Glad to hear I'm not the only one who thought they were noisy enough to be loose!!!!!

Any one else notice this?