My mistake. I thought there was a ratio change.
Valvetrain Geometry
- Thread starter Earlie A
- Start date
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PRH
Well-Known Member
Looks like the new version of the PRW rockers should alleviate some of the rocker to retainer/spring issues that were prevalent with the old version.
New:
Old:
New:
Old:
It was supposed to be a ratio change.
Im heading to the shop as soon as I put on my sweatshirt. I’ll grab one of my rockers and take a picture of it and post it.
If someone is good with the computer maybe they can grab the pictures and post them side by each. And if they are really good maybe they can draw in the centers and check the nominal ratios.
I suck at the computer so I’m out on that.
There was supposed to be a ratio change with the new rockers according to Mike and the guy at PRW whose name I forgot. If EarlyA’s numbers are correct then Im doubting they increased the ratio.
I can’t check anything on my end because I needed a different correction for my new heads so I’m waiting for Mike to bang them out and get them here.
Once they are here I’ll mock my junk up for the millionth time and see what I get. With a .3875 lobe and a 1.6 rocker Im hoping beyond hope to net .580 lift before lash. If I get that I’ll be happy.
Earlie A
Well-Known Member
I like how the roller tip protrudes farther than the arms on the old design. With the new design the roller only protrudes a little bit on the bottom. With a 3/8" stem and high lift there is no room for side to side motion of the rocker. The arms will hit the valve stem quite easily.
New rocker design with 3/8" valve shown below.
Cuda416
Well-Known Member
What does the roller look like from the side. Seems to me the pic you're showing isn't really relevant since the valve will never see that position? (end of the rocker tip)
PRH
Well-Known Member
Yeh, I’m not luvin that either.
PRH
Well-Known Member
That was from several years ago……. But I believe it was two bushings.
That’s correct. Mine have a split bushing.
Also, the MASSIVE oil hole in the top of the rocker is way too big even for timed oiling.
I’m going to address that with a brass set screw and a .040 hole. 8 of those per side should put plenty of oil in the rocker boxes.
I really should plug them and move them to the spring side underneath the roller but it’s a SFT cam. If it was a roller cam and springs I’d move it.
PRH
Well-Known Member
Here’s a Comp pro magnum rocker from before they were bushed:
Earlie A
Well-Known Member
Here's the roller tip side view. If alignment isn't really close to perfect with a higher lift cam there will be contact between the arm and the valve.
Another thing I'm not crazy about with these rockers can be seen in the picture, especially the rocker on the top right. Whatever process is used to peen the ends of the roller tip shaft also bends the support arms. When the arm bends it twists the roller tip. This leads to point contact on the valve tip rather than line contact. I've checked a few on a measuring stand. The roller on some of them is twisted 0.0015"-0.002".
Earlie A
Well-Known Member
And the old Crane and Mopar Performance stuff was never bushed, correct? So just aluminum right on the shaft. Did higher spring loads lead to wear?
I have a MP solid aluminum rocker for a W2 head. I would think that a high spring load would be anticipated on a W2 head yet Crane and MP still made them unbushed. And all I ever see is raving reviews on the old Crane stuff.
Cuda416
Well-Known Member
Ahh, now that is a problem, thanks.
PRH
Well-Known Member
I never ran the Cranes with more than about 600lbs open……which is what they were rated for.
Only one combo I was involved with had issues earlier than I would have expected. Intake rockers on B1-BS heads would start to fail between 125-150 passes.
That happened with two new sets(same engine)…..…. They got replaced with T&D’s…….. never had another problem.
The unbushed steel Comps could end up welding themselves to the shaft with higher spring loads.
I used Crane rockers for years. The only reason I stopped using them was because I went to a 1.6 rocker and Norris was still making their steel rockers.
Or I would have bought Crane 1.6’s.
The seasons are all running together now but I was at least 320 on the seat with those and never had measurable wear after the initial wear was done.
I’m not sure but I believe I was told that anodizing is not straight or round. If that’s the case, then the initial wear was because the unit loading was so high until the high spots leveled off so to speak.
The other thing is I never run a plain or bushed rocker and a roller cam without full time oil to the shafts.
The way I do it, what ever the pressure is on the gauge is what’s at the shafts.
Low idle oil pressure will get a bushed rocker grabbing the shaft pretty quickly. So I always use full time oil it to any rocker with a roller cam.
I’m doing it on my junk this time because for no other reason than I want to stop pulling oil from the crank to feed the rockers.
Earlie A
Well-Known Member
And banana grooves?
PRH
Well-Known Member
My experience with valvetrain problems in general is it usually shows up on the intake first.
Heavier valves & they often get faster lobes and/or higher rocker ratios, all of which taxes the springs more and can result in less upper rpm stability, and added stresses that come from that.
Yes.
My experience also with the exception of power adder stuff. You can open the echos soon it starts hurting the exhaust side stuff.
But that’s the only time I’ve seen that issue. Never in NA stuff.
340six
King Of Bling
Is that small block? That may be version 2 before bushed. I have version 1 here. I can pull them out if you want a picture. Still unused just used to mock up 422ci to order push rods I can dig um out. Pictures I have are right after he degree the cam. Can't see much
Earlie A
Well-Known Member
I'd love to see 'um. Thanks.
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