Hello fellow gear heads I'm having an issue with a set of roller rockers on my freshly built chevy 383 stroker I've got afr 1050 heads with pac beehive springs all arp hardware the issue is that the rocker trunion doesn't have a nice fit on the studs meaning when I place the rocker down on the head you can actually move the rocker side to side intake to exhaust a pretty good amount it's giving me valve train noise and causing a couple of rockers to kiss the inside of the valve covers has anyone seen this before because I haven't in my 30 years of being a mechanic the rockers are elgin pro stock stainless full rollers 1.6 ratio on a 7/16 stud my concern is rocker geometry changing along the stroke and the trunion beating up the rocker stud or am I just overthinking it and it's fine any thought and input would be appreciated
Sounds to me like the hole in the rocker is too big or the stud is too small. Are you sure they aren’t 3/8 studs?? I assume that is where you are saying they are loose.
Have you got the shaft they pivot on the right way round? One side usually has a machined recess for the adjuster and one should side doesn’t.
Have you checked the diameter of the hole in the trunion? Also, in looking at Elgin rockers online it appears that there is clearance between the snap ring and rocker on both sides allowing lateral movement. I’m not clear on what you are describing, could either of these issues be causing it?
Just measured the arp stud is .430 and the rocker trunion hole is .447 pretty loose fit is this normal
It looks like the stud is small and the hole is big. The stud should be .437 and the hole should be just slightly larger. What if you put a 7/16 drill bit in the rocker hole? Or another 7/16 bolt.
If the poly lock is seated in the recess in the trunnion properly, that should keep it centered on the stud, provided you are running hydraulic lifters. Solid lifters could give you an issue though. Roller rockers are a little more noisy than stamped, but the difference isn't deafening. As far as the rockers kissing the valve covers, where are they hitting and would spacers or taller covers solve the problem?
It's a hydrolic roller cam .560 lift and the pushrod side of the rocker is touching the valve cover they are the gm performance aluminum ones my main concern is the geometry not being consistent due to the .017 play on the stud I can't see the rocker not dancing around on it maybe im better off biting the bullet and getting the comp cams rockers for 500 bucks but idk the rocker hole size on those either does any one have a set they can mic up for me
The Elgin rockers are produced in China, it may be possible that they use a 12mm drill instead of a 7/16. But regardless of that wouldn’t different valve covers or even thicker gaskets as @427 sleeper has suggested solve your problem?
With the lifter on the heel of the cam, can you move the rocker? If not, It shouldn't be an issue. As far as the interference problem, like with all aftermarket part's, some need to be modified to fit and some don't. Sound's like you have some that need to be clearanced.
Junk Rocker's ,The Comp Chromoly are decent for the $$, On some aluminum valve covers you need to notch/clearance valve cover on the inside to clear SBc/BBc rocker on push rod side .
That's a good point I called elgin tech support and apparently those are the only rocker arm thay offer that comes from China and different covers would take care of the clearence issue but doesn't correct the problem
Yes when the lifter is on the heel and rocker adjusted half turn past zero lash you can grab the rocker and move it up towards the intake and down towards the exhaust
I just ordered a set of comp cams ultra pro magnum rockers I'm going to mic them and post the results if they are the same .447 which I doubt I'll return them and just go shaft rockers I guess it's my bad cheaping out on the elgins I'm about 20k into this beast so what's another thousand lol
Shaft over Kill unless over 7,500 , Most of time I over Kill,, Same with shaft Junk & Good , So pick wisely @ one time I was spinning a BBC little over 10k ..
Just my opinion, if it were mine I wouldn't run them. I can think of ways to save requiring a lathe, mill and carbide. And time. But if they are available from another source? I'd be stubborn enough to fix. Why 1.6 ratio?
We’ve left single stud rockers for the T&D sport comp shaft rocker system and never looked back. We no longer need guide plates and overall the price for what you get is well worth it. I realize there is a substantial price difference for a street engine. If I was building a new street SBC I doubt you would find a GM part in it including the block. Before we changed from the single stud trunion style the ones we used were not only flat but had a recess for poly lock to enter centering the trunion on the stud.
My heads flow best at 650 lift and with the 1.6 rockers it brings me closer to that with my cam plus the higher ratio gives me better off the seat flow
The only thing gm on this engine is the H.E.I distributor and that's also heavily modified for computer control lol
Ok so the comp cams rockers are in and the trunion hole measures .440 only .010 bigger than the stud that little bit made a huge difference and the comps are 5 grams lighter but not lighter on the tip where it counts they also clear the valve cover by a mile I think I'll keep them
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