Thread: Which rocker arms?

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if your valve train is light then you do not need as much spring and can go faster with less spring less chance of pushrod flex stud flex and every thing else flex. but when in doubt in run abit more spring in the sand drag engines i see things hit that never should

there is some things wrong i think with the big block heads as to how the rocker studs (stud rocker arms) are not at the same angle is the valve guilde you would think this would be the way you would want it ?? i have spent hours checking things at mid lift and working with the contact foot print i have a hard time with the rocker is on one side of the stem valve now it is over here now it should be right there ?? well

I'm just running the stock springs on these heads:

Trickflow PowerOval

Another guy running a 8.9xs Chevy II with the motor built out of the same shop is running .8xx lift in a ~650ci all aluminum big block that spins to 8000+ with 450# on his springs (but that's a whole different ball game )

I know you know your stuff, Jerry, I'm just trying to reconcile the differences... I think most of the bracket racers (did I detect a tone of disdain there? ) with roller cams are up here in the same ball park with the springs. BTW I'm not on the throttle stop (and won't run in the classes that are) and still footbraking (to a 1.670 60' last time out hope I can get closer to 1.60 but we'll see).

I'm guilty of putting way too many street miles on what really is more of a race motor and I should expect to break stuff when I do that

Thanks,

-Chris

well i do not know one damn thing i run the isky 1.625 240 @2000and 685 @1.250 part #9685 i run them in both street cars for over six years but have SS valves and heavy roller lifters with no rev kit i do not think this is to much but it is alot. could less work? maybe but it works to 7500 rpm this i know

... forgot to mention I also am running a rev kit... apparently I don't need it but does it make a difference in all this?

-Chris

oh you will just wear out your roller lifters faster you may want to look at them sounds like yours could be on the way out

I like my throttle stop!!!! Best way I know of to keep the thing at 9.90!!!!

Originally Posted by jerry clayton

Yep--and broken rockers, pulled studs, extruded keepers/retainers, bent pushrods, busted lifters----
Bracket racing???? come on --half the time they are on a throttle stop

I only ran around 200 seat pressure on 800 + lift that saw 9500= several times

I would like to know who made those springs and a part number.
In or USMTS engine that see's 8,200 lap after lap we run Isky Tool Room Gold Strip springs.
Part number 9935.Seat pressure is 245 lbs. and open pressure is 590 lbs.
We run a Jessel system and we have had no broken rockers,pulled studs,extruded keepers/retainers,bent pushrods,busted lifters etc.
In one race on a 1/2 mile track we have five hot laps,ten laps in the main,twenty laps in the feature.
In two nights of racing we will put on more time than an averge bracket racer does in half a season of bracket racing.
At around twenty nights we are putting in new springs.

No distain for bracket racers--just that those engines don't need as much to race---I think that most are buying way more engine than they need to run the brackets they do.

I ran probably one of the very first Jesel setups for BBC--rocker system and belt drive--Spring part numbers I don't remember but we used Isky's that Van Luven had stashed in the rafters when he worked there---

Did not use a rev kit!!!!

With racers running so much seat pressure---lots of them are getting into coil bind and this breaks parts big time---first a stud or rocker, then bend a valve, hang open and smack piston and then the biggie---all because of trying to run a high seat pressure with components that didn't match

I'm not saying this as slam toward anyone, but many times I've seen results of very sorry parts choices--and other times we get info on things like spring pressure, bearing and wall clearance, cc, etc that aren't even remotely close to actual engine specs and they wonder what went wrong.

Erik---I also have thousands of springs off late models and stock block Indy car engines---probably keep them because they cost so much I can't just throw them away--wish they were gold!!!!

Originally Posted by jerry clayton

I also have thousands of springs off late models and stock block Indy car engines---probably keep them because they cost so much I can't just throw them away--wish they were gold!!!!

yes i have some boxs of PSI springs to there getting recycle i using them in my streets engine if they check out there fine for me

Originally Posted by jerry clayton

No distain for bracket racers--just that those engines don't need as much to race---I think that most are buying way more engine than they need to run the brackets they do.

I ran probably one of the very first Jesel setups for BBC--rocker system and belt drive--Spring part numbers I don't remember but we used Isky's that Van Luven had stashed in the rafters when he worked there---

Did not use a rev kit!!!!

With racers running so much seat pressure---lots of them are getting into coil bind and this breaks parts big time---first a stud or rocker, then bend a valve, hang open and smack piston and then the biggie---all because of trying to run a high seat pressure with components that didn't match

I'm not saying this as slam toward anyone, but many times I've seen results of very sorry parts choices--and other times we get info on things like spring pressure, bearing and wall clearance, cc, etc that aren't even remotely close to actual engine specs and they wonder what went wrong.

Erik---I also have thousands of springs off late models and stock block Indy car engines---probably keep them because they cost so much I can't just throw them away--wish they were gold!!!!

Jerry,you are preaching to the choir.
There is very little difference in a Late Model engine and a USMTS engine.
If racers are "getting into coil-bind" it is plain to me they have a spring that is to weak for their application.

Thanks everyone for your insights... I'll talk this all over with my engine builder and keep a close eye on everything in the meantime... double check lash every week and examine all the parts...

Here's a video of what happened:

http://videos.streetfire.net/video/F...ter_159857.htm

-Chris