Bolt-on Full Roller Rocker for Gen III

[geoffinbc]

I would not use LS6 springs. Simply not needed. LS1 spring maybe.

Get conversion studs (M10 bottom 3/8 top)
Get requires valve seals if changing springs
Get Gen II or early Gen III guides
Early Gen III pushrods.
The rockers are fully adjustable I would go with the 1.7 ratio Crane Gold Race. They come with adjusting nuts.

[mfuller]

I wonder if these new Crane LS series gold race rockers would work for me.....

I had Colin do up a set of heads for me recently, with LS1 springs and Viton valve seals, but I also had him mill the heads .020". The stock 1.6 roller rockers should work fine (stock cam), but would 1.7 Cranes be too much with my milled heads? I'm not smart enough to figure out if I'll have clearance problems with the extra valve lift.

[geoffinbc]

You shouldn't have a problem but there is no way to tell for sure. You could go out and buy a cheepie stamped 1.7 rocker and test it out. Or if you have the engine apart then do the old playdough test on top of the piston and see how close a stock rockers comes and then you can calculate wether or not a higher ratio one will work.

[Cliff8928]

I would not use LS6 springs. Simply not needed. LS1 spring maybe.

Get conversion studs (M10 bottom 3/8 top)
Get requires valve seals if changing springs
Get Gen II or early Gen III guides
Early Gen III pushrods.
The rockers are fully adjustable I would go with the 1.7 ratio Crane Gold Race. They come with adjusting nuts.

Well, why not use the LS6 springs? I'm in there, might as well... They're not that much of a difference in price. Also, the 1.8s might cause clearance issues?

I'll check the price on all that stuff next time I'm at work, and probably order it up.



Cliff Scott
89 BerettaGT
04 AleroGX

[TurboZ24]

On the crane gold rockers on the Fiero valve covers. Mine fit under the stock Fiero covers without any clearance issues at all, even with the .62/.60" lift on the valve, still clear fine. I did have too clearance the rockers for the valve springs I run, but that was it.

[geoffinbc]

Clif you just dont need that much spring pressure. It is a complete waste of effort and you are only going to create more valvetrain wear and loose power to the springs. Shit I dont think anyone has yet to prove the stock ones inadequate.

I did have to clear my fiero covers for the crane rockers on the tips because they touched the covers ever so slightly. I did it after I started the motor and could hear it. It was just a little bit of material I had to remove. Its not during lift it contacts, it is when the valve is in the closed position.

[Stevesr]

Ok.I haven't been following this thread too closely,but this is the direction I am going with my Porsche V6 project but now you guys are confusing the hell out of me. I have a GenII block "94" 3100 heads and"00" intake manifolds. so I've got the guide plates,what else do I need to put these new rockers on my engine?

SteveSr

[geoffinbc]

Studs. And of course the rockers them selves.

[Stevesr]

Studs. And of course the rockers them selves.

So,with my 3100/3400 top end and these rockers I would'nt have to grind clearance on the LIM?

SteveSr

[bszopi]

Well, that's what we aren't sure of. They LOOK physically smaller and able to clear the lower manifold without any grinding. But, until someone actually tries it, we won't know.

[geoffinbc]

Well, that's what we aren't sure of. They LOOK physically smaller and able to clear the lower manifold without any grinding. But, until someone actually tries it, we won't know.

Agreed. I went to a few parts stores already to try and compare them but no one has any of the new LS Series in stock. Once I look at them I will be able to tell. I spend alot of freaking time looking at rockers for these engines.

[Cliff8928]

I'll see if i can't order a set when i get into work today... Then i'll take pics and measurements.


Cliff Scott
89 BerettaGT
04 AleroGX

[AaronGTR]

Clif you just dont need that much spring pressure. It is a complete waste of effort and you are only going to create more valvetrain wear and loose power to the springs. Shit I dont think anyone has yet to prove the stock ones inadequate.

I got it on good confidence from a GM engineer that the stock springs could get some minor valve float at high rpm (near the stock redline), especially if they have some miles on them and are starting to fatigue. Thats why I recommend if someone has a DHP pcm with the raised redline and they are doing heads anyway that they upgrade to the LS1 springs. The stock LA1 springs and LS1 springs have almost the same closed seat pressure, but the LA1 installed height is .1" shorter so the LS1 spring would be compressed more and have more initial pressure. That should be enough even for 1.7 rockers I think. I am using LS6 springs when I install my cam though because I will be running higher lift with a steeper ramp than stock. I don't think they will cause too much valvetrain wear with the roller lifters, full roller rockers, and heat treated chromoly pushrods I have.


Just for reference:
-stock LA1 springs, 75lb @ 1.701" closed, 230lb @ 1.26" open.

-stock LS1 springs, 76lb @ 1.8" closed, 220lb @ 1.32" open.

-stock LS6 springs, 90lb @ 1.8" closed, 294lb @ 1.25" open.

stock 3400 cam lift is .2727" int/exh, which is .4363" valve lift with 1.6 rockers, and .4636" with 1.7 rockers.

LS1 valve lift is .472"int/.479"exh, and LS6 valve lift is .552"int/.548"exh, both with stock 1.7 rockers. If you subtract the .1" install height difference from either of those lift numbers, they are still greater than the amount of valve lift with a LA1 with 1.7 rockers and stock cam, so either spring should have enough compression to work.

[geoffinbc]

The cam you get will have recommendations for seat and open pressure. Pick the spring that will work best.

[Froggx]

The cam you get will have recommendations for seat and open pressure. Pick the spring that will work best.

I wish they had shared that with me on my regrind