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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Looking for something that will fit under the factory height valve cover. There's so many options out there some are bound to be junk.
I don't think you can wrong with COMP. At least I can say I've never had an issue with several sets both in high RPM and high mileage applications.
I prefer steel over aluminium. Oner is for fatigue resistance (although many have reported many successful miles on the street, the engineer in me says no thanks). The aluminum bodies tend to wider as well and fitting under a stock centre bolt valve cover is problematic.
As it is, these COMPs below require a small amount of trimming of the cross brace under the valve cover. Quick work with a die grinder to narrow the support about 1/16th or so. Height is not an issue.
I don't think you can wrong with COMP. At least I can say I've never had an issue with several sets both in high RPM and high mileage applications.
I prefer steel over aluminium. Oner is for fatigue resistance (although many have reported many successful miles on the street, the engineer in me says no thanks). The aluminum bodies tend to wider as well and fitting under a stock centre bolt valve cover is problematic.
As it is, these COMPs below require a small amount of trimming of the cross brace under the valve cover. Quick work with a die grinder to narrow the support about 1/16th or so. Height is not an issue.
The full roller is pricey for sure. I can't comment on the less expensive brands like Summit or Procomp.
That said, you don't necessarily need a full roller. Plenty of happy customers with a roller tip only.
Thanks for the recommendations. Those steel comps with the roller tip looks like a good bet
Remember that the valvetrain geometry should be revisited with any change in one component. It may not amount too much or it could cost you a set of valve guides. And a valve job.
Remember that the valvetrain geometry should be revisited with any change in one component. It may not amount too much or it could cost you a set of valve guides. And a valve job.
I'm getting new heads with valves in them so I'll be getting an adjustable pushrod to figure out what length I'll need. However I now have a new concern since removing the intake manifold. I discovered a small amount of peeling paint in the lifter valley. It was painted 20 years ago with that Glyptal paint. The area where it peeled is on the China wall, front and back. I hope this didn't bung anything up. I'll have to clean that up really well and recoat the area. The engine is staying in the car for this head and cam swap. Always something
Peeling Glyptal?
That could be nasty. I can't say how I'd address it. Maybe go at the peeling edges with a scotch brite. Then treat the bare cast iron with a really good solvent. Paint again as needed. But I wouldn't go so far as another coat altogether. You'd hate to start an avalanche of further peeling if the new coat doesn't bond well on the old paint.
Peeling Glyptal?
That could be nasty. I can't say how I'd address it. Maybe go at the peeling edges with a scotch brite. Then treat the bare cast iron with a really good solvent. Paint again as needed. But I wouldn't go so far as another coat altogether. You'd hate to start an avalanche of further peeling if the new coat doesn't bond well on the old paint.
That's exactly my plan. I just hope what peeled didn't go and bugger the oil pickup screen. My oil pressure has always been consistent. I'm going to brake clean the hell out of it and scrub as you mentioned then overlap the coat. It's high up the China wall. The valley itself is fine
The Scorpion aluminum roller rockers have been the quietest roller rocker I have used.( the full body RACE series) These are very well made.
I have not personally used the small body aluminum roller rockers but would expect them to perform the same.
It is the stainless steel roller rockers that I have found to be noisey at idle.
The Scorpion aluminum roller rockers have a life time warranty. Not cheap but fair priced.
Made in USA. They will out live you in this street perf application.
The full roller is pricey for sure. I can't comment on the less expensive brands like Summit or Procomp.
That said, you don't necessarily need a full roller. Plenty of happy customers with a roller tip only.
Over 95% of the friction and heat created is in the pivot ball and rocker cup, a roller tip by itself is basically a waste of money if you want improved efficiency, it's only redeeming qualities are more consistent ratio from piece to piece, but you can get that without a roller tip, Howards has some very good quality long slot stock style rockers. Think about the LS, even the Ford Godzilla, they have roller trunnion rockers with no roller tip. If gm could reduce heat and increase efficiency even 1% with a roller tip they would do it. But seriously, if you spent the money on good heads and a good cam spend the money on a set of shaft rockers and be done with it. I hate to spew cliches but it's true, setting up shafts is so much easier, and once you buy a set you're not ever going back to stud mounted rocker arms for anything except a 100% stock rebuild in a low rpm truck engine. A set of decent heads is 1200-2500, shafts are another $1200-$1600. By the time you buy 7/16 studs, guide plates, 7/16 stud rockers, a girdle, tall poly locks, and the needed tall valve cover for it you haven't saved much at all. Talk to Shelton Barr's at lgm, he makes a great sportsman shaft rocker set, based on the old probe industries stuff, he bought the design and tooling, for most 23° sbc heads he's got you covered, usually 20-25% less than jesel or T&D.
And I'd say that shaft rockers are a little excessive at this level. Not sure where you get your price points from.
OP asked for something that fits under an OEM valve cover. I can't think of a shaft system that fits that bill.
Full rollers with poly locks definitely will.
As for roller tip only and GMs approach, GM wants to save money on production engines. Go to a high zoot LS build and it's full roller all the way. Isn't that what you've seen as well?
I won't deny that achieving proper geometry is simplified with a shaft arrangement but it's not terribly difficult with a stud mounted full roller either. A few measurements are all that's needed. I've done it countless times. Once you get past all of the misinformation posted about method and what's right, it's generally clear sailing.
Of course, YMMV.
Did anyone get into "Self Guided" vs having Guide-Plates for the Rocker Arms?
I don't believe the discussion has come up here however that's something I've mulled over more than once having converted a set of OEM Vortecs to guide plates.
If I were to do it again at the previous power levels (< 400 HP), I would have stuck with guided rockers. RPMs were low as was the valve lift.
I think though, as RPMs increase ( north of 6k), the further along the mid span of the pushrod for support, the better.
Most People who are familiar with Stock Engine and Mild Performance Engine Rebuilding would say that the Roller-Tip of a Rocker-Arm is pointless.
To an extent it would be.
However with higher Lifts (Over 0.6000" at the Valve), higher Spring Rates (Over 400 Lbs Open), higher Power Output, and especially Valve-Guides that are other than Iron...
The Roller-Tip (using Guide-Plates) actually makes a significant difference in the life of the Valve-guides, Seals, and Valves.
A Non-Roller-Tip can push the valve forwards and backwards... causing wear and tear on the Guides Etc.
The Roller-Tip (using Guide-Plates) greatly reduces this wear and tear.
Also the Self-Guided Rocker-Arms can cause wear and tear, pushing the Valve from side to side.
Last edited by vorteciroc; 12-27-2022 at 04:30 PM.
I don't believe the discussion has come up here however that's something I've mulled over more than once having converted a set of OEM Vortecs to guide plates.
If I were to do it again at the previous power levels (< 400 HP), I would have stuck with guide plates.
I think though, as RPMs increase ( north of 6k), the further along the mid span of the pushrod for support, the better.
While I have used self-aligning in the past, I generally convert everything to guide plates now. The self-aligning stuff is IMO garbage or close to it even in the factory application. Properly setup up guide plates hold far better rocker alignment and thus less valvetrain deflection and wear on the valve guides. Its not a huge issue with something that runs in the low-mid 0.400s in lift, but as you approach 0.500 and over it almost becomes mandatory. I like some of the factory aluminum castings for this reason. GM gave some of them screw in studs and a cheesy guide plate that only served use for assembly but self-aligning rockers. I swap the guide plates for real ones, hardened pushrods and non-self-aligning rocker arms on these.
I'm down to the Scorpion narrow body aluminum or Summits all steel full roller....made in china. What's the life like on the aluminum rocker? I'm kind of leery about using those. the COMP 1618-16 are self aligning and the new heads use guide plates. The other version for Comp is out of stock, or I'd go with those
I belive that the Scorpion rockers have a lifetime warranty.. Something for you to check.
These rockers typically out live the engine in the street strip hi perf application.
The oem style ball stud stamped steel rocker
only show high friction when they are brand new.
Once they break in and create a seat in the rocker for the ball to ride on the friction is MUCH LOWER.
It is then not much different than a roller rocker at the same street strip friendly valve spring forces.
Any hyd roller cam and springs are fine. Use the long slot type for higher valve lifts.
The name brand rockers like Howards or Isky are good good quality. At street strip valve sprung force and rpms these ball stud stamped steel rockers will out live the engine.
Just like any flat tappet cam and lifters these rockers need a break in period to seat.
Lots of oil flow and light spring force for break in helps... I recomend a moly anti wear additive in your oil. EG: MolySlip E oil supplement in all engines with flat tappet cams/ lifters and stamped steel rockers. It works. Its the same anti wear moly additive that is in heavey duty ball joint, tie rod and supension bushing chassis grease for long service life but this stuff is made for engine oil.
I agree about the roller tip. It likely does not actually roll back and forth, but it does no harm.
I hope they do.
But in the event that they do fail, please post so we have an idea of their longevity.
I am re-using a cheap set of Jegs 1.6s that have ~40K miles on them in the 350 Vortec I am currently building. They were run in an engine that had 0.536 lift and LS7 blue springs. Those rockers probably have more like the equivalent of 60-70K miles on them if they were in a F-car. My van had 5.13 gears and frequently towed heavy trailers. Even though they did not have alot of miles they had alot of cycles on them with ~3,000 rpm @ 70 mph. Van also had a lot of idle hours on it from heavily congested roads and city driving in DFW, Austin, San Antonio, Houston and the like. There were many times it would idle for close to an hour to get 10 miles, take your foot off the brake, idle forward 100 ft, then repeat. Rockers still look and feel like new.
I have the GMPP 1.6 rollers in a zz430 clone. They've been good. Simple install and no complaints. Definitely sounds like a sewing machine a little at idle. Quiet while driving in the car. I adjusted them while it was running after the initial build and no sound difference. They are close to the aluminum center bolt valve covers but as long as they're centered they're fine.
I am re-using a cheap set of Jegs 1.6s that have ~40K miles on them in the 350 Vortec I am currently building. They were run in an engine that had 0.536 lift and LS7 blue springs. Those rockers probably have more like the equivalent of 60-70K miles on them if they were in a F-car. My van had 5.13 gears and frequently towed heavy trailers. Even though they did not have alot of miles they had alot of cycles on them with ~3,000 rpm @ 70 mph. Van also had a lot of idle hours on it from heavily congested roads and city driving in DFW, Austin, San Antonio, Houston and the like. There were many times it would idle for close to an hour to get 10 miles, take your foot off the brake, idle forward 100 ft, then repeat. Rockers still look and feel like new.
Crower Enduro stainless steel here.
I've no concerns about metal fatigue but I was a little surprised the trunnion bearing are worn out. They've seen a varied service life with stop and go traffic like you've described, tens of thousands of highway miles and hundreds of WOT high RPM passes.
Rebuilding now required at 25,000 miles.
12-04-2022, 09:54 AM
