D9HP

Hello!

Are these rockers better than the stock rockers with the trunion upgrade?

They are very similarly priced from other vendors ($650-ish)
http://store.yellaterra.com.au/chevr...raulic-yt6670/

The motor will see 7,200RPM

Any help here would be great.

Thanks,
Dustin

bbond105

Yes. They have a roller tip, which gives you less side loading on the valve stem.

pantera_efi

iTrader: (1)

Hi Dustin, I DO NOT fit Aluminum Rocker Arms.

Lance

G Atsma

Both Comp and Texas Speed have steel roller tip rockers if you don't care to do aluminum.

D9HP

Awesome - thanks!

Thanks Lance. Is this a strength thing? Have you seen failures? All of the high end shaft mount designs have aluminum rockers, too.

I cannot find any roller tip rockers for the LS7 that aren't the $$$$ shaft mount style.

Do you have part numbers?

Thanks for the help!

G Atsma

OOPPSS! LS7.... Yeah I spoke out of turn! Sorry! Might have to go aluminum anyway..

D9HP

No worries! Thanks for responding so quickly.

I guess I'll have to do some more reading. The only other option for a roller tip design is the Harland Sharp setup, which is also aluminum.

Looks like the Yella Terra is my only option besides upgraded stockers.

G Atsma

You should be OK, YT seems to stand up well for their product in case of any quality issues. Tony Mamo likes them, and he is on top of things! Good luck my friend!

KW Baraka

iTrader: (7)

Those are not upgraded stockers....

KW

GTO1_OHIO

iTrader: (3)

Give Tony Mamo a call, he uses a 1.85 Yella Terra rocker with his MMS 265 LS7 heads.

pantera_efi

iTrader: (1)

Hi D9, sure it's strength THOUGH this changes with the Aluminum's HEAT TREAT. (T- 6511)
The aluminum material will last long at a constant temperature.
The PROBLEM is the Start/Stop (Cold/Hot/Cold/Hot/Cold/Hot) of normal engine operation.
This is the method that is used to Heat Treat Aluminum AND reduces strength.
There is a Fatigue Life in Aluminum material, just ASK Boeing.

NOW, "High End Shaft Rockers = Aluminum" is NOT TRUE

I fit Crower Cams Shaft Rocker assemblies MADE of Stainless Steel on race engines.

Lance

Che70velle

iTrader: (6)

Lance, do you build any street engines?
Most engines here...probably 98% of them...are street engines. I like the stainless Crower setups, but that is WAY overkill on a street engine.
OP is asking about rockers for a street engine, not a race engine.

G Atsma

I think I see his point. He DOES build race engines that might only have to live for a few hundred VERY intense miles. A street engine, on the other hand might be expected to live 50,000 easier, but still sometimes stressful miles. Aluminum rockers are KNOWN not to have very ling lives for the reasons above. Heat cycling "heat treats" aluminum the wrong way. It anneals it back to natural softness. This is why you NEVER see production aluminum rockers.

D9HP

Thanks for all the feedback!

I am going with standard GM LS7 rockers with the CHE upgrade kit after some reading.

The full shaft style rockers are sweet but I can make that upgrade a few years down the road when I switch to a solid roller setup.

Kind regards,
D

Che70velle

iTrader: (6)

Not arguing at all with what he posted, I just don’t want the guy or gal who’s new to these engines to be scared away from thinking that they want to run an aluminum rocker. Nobody was talking about race engines except Lance. The average person modding their engine usually isn’t going to drive it daily, and/or put 100k miles on it...it does happen...just not much. For the average build, stock steel rockers are adequate, and lighter over the nose anyway.
I’m not sure that aluminum rockers see the kind of heat required to actually make them softer. That would be a better scenario for a piston. The aluminum rockers life is more limited due to stress, more so than heat cycles, but heat cycles do have be taken into account in an extreme use situation, such as a race engine, although I ran aluminum shaft rockers in my dry sump circle track engines for years. OEM won’t use aluminum rockers due to cost...it ALWAYS comes down to costs with the auto makers.

G Atsma

NOT to argue with you, but most aluminum rockers start out as simple extrusions, then machined to final shape and function. And on a mass basis, it doesn't cost that much to make them, especially on CNC machinery now prevalent. I think there is still a very real long-term durability issue. If Lance(Pantera EFI) won't use them, there must be a good reason.

Che70velle

iTrader: (6)

Agreed. BUT it’s cheaper to cast or stamp out steel pieces.
Lance is talking about race engines, and that’s why I asked him if he ever built a street engine. He said he never fits aluminum rockers.

G Atsma

Agreed! And point(s) taken. Lance does stuff most of us can only dream/speculate about, and after a while likely gets into a mindset where he knows what works in the most extreme environments, and applies that to our more mundane stuff. Easy to do.
Always interesting to read his posts, IF you can understand/fathom them! lol

pantera_efi

iTrader: (1)

Hi G, thanks for the kind words.

I BELIEVE "velle" can not read !

The RACE engine starts/stops (temp-up/temp-down) NOT OFTEN in its life, constant internal temperatures. (Little Heat Treat)
The DD engine operates each day with OFTEN start/stops. (Much Heat Treat)

NOW, I do NOT "build" LS engines, I assembly LS engines.
I do BUILD (manufacturer) components.

NEXT, "Race Only" = NOT TRUE (about 20%)

Examples LS-x :
Trailer Queens = 10%
Driven each Day = 20%
Professional Racing engines = 20%
Produce Development engines = 10%
Genset/Pump engines = 15 % (25K hour life)
Toy engines = 10%
Military/other types = 15%

I worked with Carl Wegner on the NASCAR GN-West LS project.
We fit the GM rockers with CHE's, NEVER have had a problem to THIS DAY.

THUS D9, good choice.

Lance

G Atsma

Good props for the CHE upgrade! Thank you for the stats. Your line of work is interesting! Work? More like a labor of love.... mostly any way?