good For a 3500??

[mickaz]

i found this

http://www.summitracing.com/parts/CCA-1618-12/Application/?query=Year|2006&prefilter=1

will it work on a 3500?

[mfuller]

Interesting.......very interesting.
Application chart says yes, but the 3/8" stud mount has me concerned, as the factory rocker arms bolts are 8mm.
3/8" is about 9.52mm, and I don't know if there's enough meat on factory heads to re-tap them for 3/8" rocker studs.
Or maybe I'm just an idiot - are the studs "swaged" to that they are 8mm on one end (the "base thread") to thread into the head without mofification, and 3/8" on the other end?
Also, will there be clearance issues with the valve cover? The nut that secures the rocker to the stud is fairly tall.
Who's gonna be the first to try 'em?

[FallenZ24]

I believe you can get 8mm-3/8 rocker studs. Thats how people use the small bodied sbc rockers. Or maybe you can get those rockers and swap the factory pedestals and bolts onto them.

Personally I don't see it being worth the work and money for a 1.6 rocker. If they were 1.8 ratio and fully roller, that would be another story.

[geoffinbc]

It "will" work but it takes some modification. Also the trunnions may be too wide but other narrow body rockers are out there that work. But the concept is the same as putting full roller rockers on a 3400 which has been discussed before.

ARP sells the conversion stud you need. 8mm to 3/8 or 10mm to 3/8
Gen II cylinder heads have the guide plates you need.
Hardened pushrods are needed
Manifold clearance is an issue with some brands of rockers. But it can be ground to fit.

[bob442]

the only gain i see is a roller tip. a 1.7 ratio would be worth it.

i really wish we could push the motors more ( in a N/A application)but i think the next thing to be done is getting a stand alone harness to run VVT on the 3500. or possibly hybrid a 3400 with vvt. if it can be done with the LSX, why not the 60*V6

[geoffinbc]

Harland Sharpe makes 1.7:1 ratio. It has been discussed but never attempted as far as I know.

[Superdave]

the only gain i see is a roller tip. a 1.7 ratio would be worth it.

i really wish we could push the motors more ( in a N/A application)but i think the next thing to be done is getting a stand alone harness to run VVT on the 3500. or possibly hybrid a 3400 with vvt. if it can be done with the LSX, why not the 60*V6

People can push these engines much further but most choose not to.

[Joseph Upson]

the only gain i see is a roller tip. a 1.7 ratio would be worth it.

i really wish we could push the motors more ( in a N/A application)but i think the next thing to be done is getting a stand alone harness to run VVT on the 3500. or possibly hybrid a 3400 with vvt. if it can be done with the LSX, why not the 60*V6

Given the limitations of a fixed lobe camshaft with VVT I don't believe trying to take advantage of it is worth it given the other options available for performance improvement. I believe the cam grind has to be within a specific range for it to work properly if my Desktop Dyno simulations are anywhere near accurate and it also seems that raising compression reduces its positive effects on low end torque. The engines that really have a lot of potental with VVT are those with independent intake and exhaust valve control. I looked into this sometime ago and saw that the LSx engines without VVT actually had better performance numbers than the engines with it.

[geoffinbc]

Valve lift and duration needs to be kept in check so when you advance and retard the cam the valved don't smack the pistons. The more you increase lift and duration the less you can phase the cam. COMP sells VVT specific cams for the LS engine with phase limiters to keep all the parts dent free.

[bob442]

well i remember talking to ben about specing a cam in, and he had to change the LSA so the car could actually start(as he refurred to bleed off) so thats what i was looking at, maybe i have some mis understanding.

I've never looked to indepth about it, but from what i gather the Erod LS3 is VVT and produces its 480 CHP, and passes emissions so well and produces those numbers at the same time due to the VVT, and also the 2 CATs only inchs from the manifold help alot too.

[Joseph Upson]

Valve lift and duration needs to be kept in check so when you advance and retard the cam the valved don't smack the pistons. The more you increase lift and duration the less you can phase the cam. COMP sells VVT specific cams for the LS engine with phase limiters to keep all the parts dent free.

That goes without saying. From what I recall Comp cams' VVT camshafts are comprised of a single unit with independent intake and exh variation through a tube insert design I believe for their aftermarket cam, not sure what application it was for. It's been a while since I looked at it. Another member who's name I do not recall also indicated through the stock OE LS engines that they converted to non vvt that the non vvt product produced more power. That's what prompted me to look into it and find that the Camaro LS motor with VVT produced less power than the non VVT LS motor.

In my case the benefits of the higher compression ratio have pretty much made it an unnecessary option. Someone stated and I have since read that the VVT function was designed mostly for emissions and that's why the engines with it are able to run clean without an EGR valve. If you can control it I don't see why it can't potentially exceed the fixed cam performance, I just don't recall seeing GM demonstrating it and the later VVT 3900 and 3500 is rated with a little less power than the first release not sure why that is.

[bob442]

there ya go, no EGR is power in your pocket hahaha jokes

[geoffinbc]

Yes they primarily do it for emissions, economy and smooth torque. It make the car "nicer" but VVT could easily be applied to get bottom end grunt and high end power all in one cam.

[mickaz]

maybe we could use this to retrofit onto the non vvt engine?

http://www.youtube.com/watch?v=0uiDmcPEekc

that would make the engine more powerful that is certain!

[AaronGTR]

i found this

http://www.summitracing.com/parts/CCA-1618-12/Application/?query=Year|2006&prefilter=1

will it work on a 3500?

Someone would have to order them and try. I know it says they fit those V6 engine sizes, but I wonder how much research they put into that and if they were really test fitted, or if they just extrapolated those applications because they fit an earlier version of that engine? Seen it happen before, where they didn't take into account changes in head design etc.

That is probably just a stock pic as well, and it would be nice to have some actual pictures and dimensions on them. The pic looks just like their steel body roller tip SBC rocker, which I've tried myself and know they do not fit. The bodies are too wide and they hit each other on splayed valve heads. That's why the narrow body aluminum rockers work. They have larger diameter fulcrum bearings allowing them to be narrower and handle the load, but they have to be thicker vertically because of that and because aluminum is weaker than steel and must be thicker at the roller tip. Also what makes the clearance problem with the LIM. If these are narrow enough at the fulcrum and will fit without hitting each other, then I'm sure thety would clear the manifold no problem since the tip on the steel rockers is much shorter.

Honestly I don't think it would be worth it though. You might gain some strength and a tiny bit more precise ratio over stock rockers, but you'll also be gaining weight and losing the pedestal mount which means you have to set the pre-load on each individual cylinder when you install them and have the hassle of having the add guide plates and change pushrods. The roller tip won't make a ton of difference in friction and heat unless you are running much higher than stock rpm or running high rpm for long periods like in endurance racing. For a street car, I don't see it being worth the cost unless someone can make some out of aluminum or chromoly in a higher ratio and with decent weight, and better yet a self aligning design. Just not a lot of demand for it though.

maybe we could use this to retrofit onto the non vvt engine?

http://www.youtube.com/watch?v=0uiDmcPEekc

that would make the engine more powerful that is certain!

Not really. That design is only used on the viper V10 and it's main purpose is to help it meet emissions requirements with the cam size required to make their HP goals. It won't really add any HP or improve the torque curve with the limitations of a single cam in block engine. Plus you'd have to add the mechanism to control it and have room to fit it on the front cover, plus the oil plumbing for it, and have enough oil pressure, and the electronics to control it, and extensive dyno time to setup it's operation... you get the picture. Not within a normal persons budget.