I did a search and found one thread.

Is anyone using these? If so how did they hold up? Are they heavy over the nose like the HS rockers?

It says that anything over .550 lift might require a valve cover spacer

I have about .100 more than that....

 

Good question, you’re right, don’t hear too much about them, hopefully Summit will chime in with some more info.

 

The only reason I'm needing to go with a roller rocker is I just bought a set of TFS heads. I know it's recommended to use roller rockers with bronze guides.

I looked at the Yella Terra's and holy **** they are proud of them.... and I've heard nothing good about the HS.

It might be stock rockers for now till I recover from buying the heads.

 

Yup, this is a hotly debated topic for sure. Every time I think I have my mind made up, I read something else that changes it again.

 

Stock rockers ~$250

Harland Shape LS Roller rockers - no thanks

Summit LS Rollers ~$430, 20 reviews on their site, 2 reviews mentioned a rocker broke. That's really good cause people always complain if there's an issue. So probably many other sets with no issues.

Comp Cams LS roller ~$450, steel should be very durable rocker arm, might be worth a look?

Texas Speed ~$690 looks good, almost Yella Terra price

Yella Terra ~$775 gold standard

 

The Comp's "look" like a really nice rocker. I think I've always seen them listed with a 1.8 ratio though.

 

Yes, I think you're right they're 1.8's.

 

These? https://www.summitracing.com/parts/sum-g6980

IMO they look like the scorpin racing products.

https://www.summitracing.com/parts/s...1098?rrec=true

All the aluminum rockers have more meat in them so you will likely need to run a spacer or thicker gasket like the one YT sells.

 

@Summitracing could you shine some light on the sum-g6980 rocker arms?
Do they have a max spring pressure rateing?
Do you sell or offer the spacer or thicker valve cover gasket that will work for these?

 

Yeah hopefully they will come in and provide some more info on these.

 

@Summitracing Maybe they'll chime in if they have any specific customer info they can share.

 

Hey folks,

We'll try and shed some light on our SUM-G6980 rockers and the bronze guide/roller rocker topic.

Why is a roller rocker recommended with bronze guides?
- We'll start with a factory rocker. The factory rocker works great and lasts a long time with a factory lift camshaft on a stock powdered metal guide. They have a wide scrub/sweep as they cycle through the range of lift. A caveat to this is they induce a side load on the valve stem. It becomes more of a problem with bronze guides, especially with increased lift. Around .625" is the max recommended lift for a stock rocker. Around that point, the load is off the pad and on the square edge of the rocker. This will cause galling of the valve stem tips. A roller-tipped rocker eliminates this friction point and prevents premature guide wear.

Why do cylinder head manufacturers use bronze guides?
- Bronze is a great material for a performance guide. It is affordable, readily available, machines easily, easily replaced, and actually acts as a bearing material. It shouldn't seize or stick when subjected to high EGT’s. Bronze guides will wear but at a very slow pace unless the geometry isn't correct. They won't last 150k miles like OE powdered metal guides.

- Powdered metal guides are difficult to source in quantities smaller than OE levels. They are difficult to replace and to size with normal machine shop tools. With standard CNC porting tools they won't machine correctly where they extend into the port. If they wear and transfer metal to the valve stem as some did in the LS-7’s they will destroy an engine very quickly.


Onto our SUM-G6980 rockers

Will I need valve cover spacers over .550" lift?
- The bulkiness of roller rockers may require the need for a spacer or PCV baffle modifications on the pushrod side of the rocker arm. In most cases, they aren't needed but certainly something that needs to be checked.

Are these roller rockers heavy?
- Just about any roller rocker is going to be heavier than the factory rocker.The factory rockers are really light over the valve tip, the lightest actually. This is why for under .625" lift with stock heads you'll see us recommending factory rockers with maybe a trunnion upgrade. In the OP's case, Trickflow has raised the rate on their spring to increase open pressure. This is to accommodate the added weight of a roller tip rocker.

What's the max lift/spring rating for these?
- While we don't have a specific max lift/spring pressure rating these should be fine for street-driven hydraulic rollers.

Who is the manufacturer?
- While we can't disclose who manufactures them for us they are currently made here in the USA. If our name is on it you can be sure we'll stand behind it.

Thanks for raising questions on our rockers. We hope this cleared some things up about them along with the topic of bronze guides requiring roller rockers.

 

Ya gotta love a thorough answer...

 

They are available in both 1.7 and 1.8 ratios. They are a very well made rocker and don't have the potential fatigue issue an aluminum rocker might have. The nose weight of them isn't much different than stock rockers.

 

Holy crap! I had no idea rocker arm prices were up to that much nowadays. I should really look into selling those new in box Comp shaft mount rockers that have been sitting on the shelf since I decided not to use them 15 years ago.

 

I stand corrected, looks like they either never brought the 1.7 rockers to market or stopped making them. Not even listed on their site anymore.

Whatever the case, I have the 1.8 ratio rockers on my LS2 and they've been great.

 

Looks like I'm going to order a set.....

Damn you Summit.

 

Rockers, heads and gaskets showed up this week so hopefully I'll be throwing some parts at this thing this weekend.

I do have a question concerning shimming/wipe pattern.

I've read several threads about the YT rockers and how sometimes they need to be shimmed to obtain the correct/best wipe pattern across the tip of the valve. Does that pertain to any aftermarket rocker or something specific to the YT design?

This is my first venture outside of stock rockers on these engines.

 

Does Summit provide shims?
I’d check it at any rate.

I have YT 6645 iirc gen 3 on my 6.2 due to the AFR heads. Prob worth more used than what I paid for them new.

I’d love to put stock rockers on. I drive the car maybe 3000 miles a year. My cylinder head guy says AFR uses a very hard bronze alloy so no issue. Just haven’t been able to pull the trigger…..
The YT’s fit under the stock covers just fine

 

Ron,

They did not provide any shims and there wasn't any mentioning checking wipe in the instructions.