What kind of valvetrain components should be used in 7500 rpm red line engine? Are shaft mount rockers a must, or can good quality roller rockers be used as well?

 

shaftmounts, solidroller cam/lifters, good/expensive valvesprings and pushrods, no opti, aftermarket pcm, etc, etc

 

Shaft rockers are NOT a must.......Motors have gone up that high long before shaft mounted rockers were around. Alot of folks still use stud girdles, this helps to mitigate some of that risk and to ensure stability on the upper end. I think your question like any other needs to be looked at from a budget and usage standpoint. How much do you want to spend on your upper end to take on 7500 rpm and how long/many times are you going to keep it up there. I'm sure that many ways to achieve your goal, some WILL cost more than others. Goodluck.

Noland

 

Not sure why you want to turn 7500RPM, but more power to you.

I have Jesel and T&D on two different motors. Both are quality pieces, both are on big SBCs, both are solid rollers with 700+ open seat psi and neither spin past 6600RPM. I am not sure I would want traditional stud mounted rockers in these applications.
Aaron

 

w/AKS. Youre going to need some heavy duty parts, best springs you can get your hands on. Got the Jesel SS 1.6 here. THey are heavier than an aluminum rocker but you can bet your but they arent going to break and are rebuildable. Stability like a ****
Its a few hundred more than a real good rocker and can prevent thousands in damage....

 

What would you say is a good price for shaft rockers. I've seen Jesel and Brodix prices are around $1500 or more and that's a bit high for me.

However, Crane has some shaft rockers for ~ $800.
What do you think of those?

http://store.summitracing.com/partde...1&autoview=sku

 

If they use that teflon bit in place of a bearing...Dont know. Ive seen more than one failure but that was years ago, maybe they have improved since then.
Jesel SS series roughly $800

 

All good advice above... If I was going to run 7500 often, I'd think hard about useing a Shaft mount... shop around for prices. I don't think it's been mentioned yet, but light weight valves; AFR is using LS type valves in it's Eliminator 23* heads. Lighter retainers help too; Comp Cams has a good light one avaliable. Good strong Pushrods, 7/16 Studs w/ Stud-Girdle. And as was mention Solid Roller Lifters, and GOOD springs..... Or you could just build a bigger motor and not have to turn it so high, for the same power.

 

I agree, all good advices, and I appreciate them very much.


You think that they could be had for that amount? New?

 

Shows how long ago I bought them. Just called, they are now $891
unless you bought them through someones resale#

http://www.jeselonline.com/v2/index.php?categoryid=14

 

Thank you, $900 is still good price. Looks like I'll have to go with Jesel's

BTW, very nice looking engine!

 

You do have a bottom end that could handle that rpm....right...

 

For now I only have Callies Dragonslayer crank, but with time, I'm sure that I'll have everything else needed!

And I have block that's waiting for splayed main caps!

 

i was wondering that also. when you look at factory motors that can turn those RPM's, like what's in an acura NSX, everything is braced and reinforced. bearings are tight, zero balance, siamised cylinder walls. you will need hardcore parts and most likely an aftermarket block. i would be nervous as all hell turning that high on a factory block.

 

I won't be using this engine for circle track racing, so it won't be in 7500 most of the time, but I intend to use it for some road racing.
I did some research, and there are a lot of gen I sbc's built for high rpm's but I didn't see any block-related problems reported.

If you have some more input on that, write on, I still haven't started to work on this engine, so maybe there is something I can improve.

I do intend to short fill the block, to strengthen it!

 

355

 

on the factory block GM actually has rpm recomendations. part of the reason is the webbing but the main one is likely bearings. at that high of speed the main area has to be extremely solid. look at the old zr-1 or an NSX etc..those blocks have major reinforcement in order to handle the sustained high rpm use. the other thing i was going to ask is why it needs to go that high. more cubes and 6500rpm redlines will live far longer and can make sick HP. high rpms would only be suited to class specific cubic inch rules. that or the coolness factor of spinning that high.

 

or you could go with the 377 (350 crank in 400 block).

 

^^ Pretty much the reason I'm so infatuated with the lucky number 7. The ZR-1s and the LS7 don't do much to deter my thinking. IF I were in the market for a new power plant, I could be happy with something 6500 rpm. 7K is lofty but who on here doesn't love hearing an Chevy v8 going that high? We just don't have the money to make a similar setup.

And it's not just the engine, everything else on the car has to be upgraded to keep up. I've seen a few pictures from CF posters of their halfshafts twisted apart. Sliding, if you do go through with your engine build, post pictures!

 

I've made up my mind, and allready bought the crank, so it'll definitely be 383, and I definitely want it to rev past 7000.
Why?
I want to get max. power out of it, and is there any other way than with high revs?
Sure, with more cubes, but I've allready decided to go with 383. That looked like best compromise to me. I could've gone 396 way, but then I would want to rev that past 7000, and that would be even more difficult.

355 would also be interesting, but since I needed a new crank, I decided for a little bit longer stroke.

377 is my favorite combo, but I couldn't afford aftermarket 400 block, and going so radical with revs in stock GM casting that is prone to overheat and have a lot of casting issues would be too risky.

I sure will. It'll be some time before I start with this project, but when i decide somethinh in my head, it'll be done sooner or later.


BTW, I found one very interesting combo in car craft magazine.

Wild-570HP 383

Lunati 4340 crank
Lunati I-beam Pro Mod rods
Wiseco flat top forged pistons
Dart CNC 227 heads
10.9:1 CR
CompCams XR 292 mech. roller cam (254/260, .622/.628, 110LSA)
Holley single plane
Holley 750 cfm carb
Hooker 1-3/4" headers

That combo made 496 lb-ft@5000 and 571 hp@6900 (crank)
It would probably require 4000 stall TC to get decent launch, but I don't need a drag car.