Best choice rocker arms
 

So, the season ended with a bad noise from the rear engine and I have now pulled both engines and started the search for the noise… first thing i found out was that one of the Jesel mohawk rockers had snapped right off. So now it’s time for new rockers and wonder if someone of you racers have input in which one to pick?

I have looked at the Jesel pro steel rockers. Are they a good pick?

the engines are from the beginning chief race engines dart big m 615cui, dart pro1 320cc heads, titanium valves, Jesel cam drive, Jesel lifters, 14-71 tbs blowers with coolers, dry sumped, and all the bells and whistles that comes with it.

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i have limited experience with roller rockers but i would think steel is the way to go.
nice engines!

Never seen one break like that. Contact Jesel, you may get a replacement. If your gonna switch you can sell a complete set. Only thing worth switching to is T&D.

We have a similar combo and have broken a few rockers call jesel they are awesome to work with, i also learned the adjuster can be no more than one or 2 turns down they were very firm on that and we had to get longer push rods if you send them all back they will rebuild them check them for cracks and reshot blast them its way worth the money!

pretty much have t&d, jesel. that about the best

crazy how it sheared

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Changing to steel
 

So, nobody think it’s a good idea to change to Jesel pro steel?

in my 55 Chevy I have solid jesel rockers and they seems stronger then the mohawk style by the looks.


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those are what i used on my 540. it was about the only thing i didnt break. the way the arm is configured seems way stronger. i would be willing to bet the way yours broke had to have some kind of flaw in casting or the manufacturing process

FYI in a past boosted engine I ran stainless with no issues.

how many hours are on those, solid roller ?

Yes, solid roller. Don’t know the hours. I did rebuild the engines last winter but didn’t change the rockers because they looked fine.

now I will change all and want to know if Jesel pro steel is the way to go or if you guys have some other input?

thankful for the help I can get from you guys that may have input.

The Mohawk is a lightened version. Not really the right application in an endurance application such as a boat. They're meant for drag cars that run for a minute or two, see 7500rpm, and get shut off. I'd move to a solid body. Jesel or T&D. Both excellent companies.
. Should you decide to part with the current set, minus 1, please let me know.

Aluminum has a much shorter cycle life than steel. if one went others may not be far behind. Crower makes a nice set of stainless shaft rockers.

Just curious, what wall thickness push rod are you running

I have 31 of those rockers sitting in a box in my garage. I went to the Jesel Steel series and am very happy I did. I sleep better after breaking an aluminum one.

Someone else mentioned it but there is a certain limit on turns on the adjusters.

Also, I'll recommend the LSM torque wrench - great product with a preset torque reading. Makes rocket replacement REALLY EASY even for a dumbass like me....

T&D steel shaft mount... can't beat them!!

I would send the whole set back to Jesel for rebuild and inspection... then ask them what they suggest.
My experience with them in the past has been stellar... with fantastic customer service.

If it were mine, I would have the strongest rockers available on there.

Nothing to do with your failure, but 320 cc heads on 615” motors with 14-71’s? Seems kinda small. What do they make for power?

I had T&D Studded Rockers on My Big Blower Motors. Never a Problem, They Made around 975HP with 1071s for your reference.

we run the Big Chiefs with 3 different offset intake rockers we also relieve the valve train for the winter not sure every one does that

Steel is definitely the way to go especially solid roller.

With aluminum Jesel has 3 types A, B and C:
https://www.jesel.com/pro-aluminum-series-shaft-rockers

In aluminum you`d want the full body no slots which is the strongest and you want the strongest rocker on the exhaust like they did on the one picture you posted.
Exhaust is working against all that cylinder pressure they take the most abuse.
You`re not the only one with this issue.




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Thanks for your reply’s
 

Thanks for your reply’s. Here’s what they made in the bench. Think I will order two sets of the pro steel from Jesel. Also will send the Mohawks to Jesel for rebuild and inspection, can’t hurt to stop in another engine. I live in Sweden so we don’t measure fuel octane like you and the engines where given 95 octane in the bench and I think that will compare to your 87 or 89? Timings @30 degrees
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I like the AFR`s alot better in teh first dyno pull, that second one especially at peak tq (highest cylinder pressure) is scary to me (almost 13 afrs) ... is the timing locked at 30* ?

It’s both engines. One sheet per engine. Timing’s not locked just set to max 30 degrees.

Go-Fast Valvetrain

simply the best at rocker arms.

You may want to look at that cam lobe and lifter.

Feel free to let us know why yours ‘are the best’ :thumbs

I`d richen up that lean engine asap.

if they use an a/f calculation based off actual fuel flow, and an air flow meter it usually comes in almost 1 full number higher than measured with a wide band in the exhaust or at least our super flow dyno is that way.

Eu 95 is the same as 91 Octane in North America... their EU98 is the same as our 93

It was hooked up with wide band.

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I followed his link to Chris Almonds website. Chris does spintron analysis, valve train design, has a fancy rocker arm for marine use etc. His website is a little vague, Ive conversed with him on fb post before, I imagine hes not cheap!

Smitty,

Still harboring the dream of building a monster some day. I'm very curious what pricing is, as well.

Thanks. Brad.
(937)545-8991

I have talked with Chris a lot, good guy with a lot of valve train engineering background from both the racing world and OEM design. As said pretty sure his stuff is expensive but if it holds up may be worth it.

Smitty, others,

According to the website, titanium is discounted as an option for marine specific rocker arms. I have titanium connecting rods in high output model boat engines on literally every continent except Antarctica. Knowing what I THINK I know about Ti, it should be an excellent alternative to steel. At about 60% the mass of steel, considerably better metal fatigue characteristics and almost double the specific strength, I wouldn't think it would be a problem for anybody with deep enough pockets. Anybody have any direct experience with Ti rocker arms? Genuinely curious and all ears. As I stated, I'm still harboring the fantasy of building a monster some day. Given my line of work, I often think of what I could make myself (mostly just for the pride of doing it), and this very thing crossed my mind. They would be a pretty yawn-worthy part for me. Thoughts?

Thanks. Brad.
(937)545-8991

Titanium is so rare in the US its got to be huge money. When they built the A12 and the sr71 they had to get the titanium from Russia through a CIA shell company. LOL

J272,

I can buy titanium by the truckloads. I could make a set of rockers out of titanium by this time next week. I've probably got a scrap piece of material on my stock rack, as I type, that I could make at least ONE from. Availability is not a problem.

President Titanium I've bought from them on many occasions.

Thanks. Brad.
(937)545-8991

Today it is less and attainable. yes you are correct. i didnt realize that.
What is the price of titanium in 2022?
How much is titanium worth per pound?
. 999 pure titanium, 1 pound. New condition.
...
Elemental 1 Pound Titanium Round. 1+ $49.99 $51.99. . It is a relatively expensive metal as a result of its high energy electrolysis refinement process. To boot, that is today’s price which has dropped dramatically since the SR-71 was created.
here is a link to more info on titanium.
https://wisconsinmetaltech.com/titanium-and-the-sr-71/

Anything is possible this has been done by many teams in the racing world to test most companies build a one cylinder version to see how it performs even Koenigsegg if that works you try real world, any volunteers? also ti is much stronger forged rather than machined anyone up to building a die to forge a few?