Bolt-on Full Roller Rocker for Gen III

[geoffinbc]

http://www.cranecams.com/?show=brows...ber=144750A-16 Looking at these rockers for the LS1/LS6 and new Vortec engines I am pretty confident they will bolt onto a Gen III engine without modification to the lower intake manifold. If you notice there is alot of extra relief on the back of the rocker which would normaly hit the LIM.

Its hard to see but the 2 rockers that are highest up are the ones that hit the LIM and clearancing the LIM is the only way to solve the problem. No while this task really isn't that hard it would be nice to have a simple bolt on.

So with the LS rockers you would get a 1.7 ratio which would be good for a bit more power. You can just order the rockers alone and then you would need to buy the crane conversion studs to convert the 10MM threads in the head to a 3/8 top. You would also need to aquire some Gen II guideplates in order to complete the install. This mod would also solve preload issues with reground cams.

Hopefully someone will try this one day.

[Guest]

RE: Bolt-on Full Roller Rocker for Gen III

Crane also makes ones for the 60 degree with the correct studs. $360. Its been done already.

And since they are adj would this solve all lifter preload with the reground cam? I dont' know

[sharkey]

RE: Bolt-on Full Roller Rocker for Gen III

yes the adjustable rockers will make up for a regroung cam.

i wanst aware that crane made a full roller rocker set for the 60*v6. i know they make roller tips, but not a full roller.

[geoffinbc]

No They do not fit. The reason I posted that is because the Crane rockers require modification to the LIM in order to fit. On Gen I and II the Crane rockers fit fine. On Gen III they dont. Trust me Lloyd and I are the first and I still think only ones to do the Crane Roller rockers on a Gen III. Also I have Installed them on Gen I and II aswell. Also on Gen III you need to add guideplates so you ahve to take them from a Gen II motor.

The advantage to the new LS series rockers is in the extra clearance on the back of the rocker. Also there is an increse in ratio from 1.6 to 1.7

[LA1 Z24]

So is this all go...they def fit? or is this speculation?

[Cliff8928]

The Gen III engines have guideplates for at least 2 years, so they don't HAVE to come from a Gen II


Cliff Scott
89 BerettaGT
04 AleroGX

[Rhedalert]

very tempting, would be good for even a stock cam/engine for the ratio alone.

[Guest]

the modding of the lim that you are referring to is some grinding on the inside of the intake with a dremel to remove some metal. I don't see how that is such a big deal.

Also on later Gen 3 LIm's as far as I understand you dont' have to because GM emoved material from teh factory casting in these locations to make sure their own roller rockers dont' hit the lower intake mani. Thre are pics of the different lowers where some are notched and some aren't from the factory.

[geoffinbc]

Man trust me I have done this. Yes GM machined a small amout of meterial from the later intakes but it is not nearly enough. The Crane rockers for the 60*V6 are very big and the back hits. You have to remove a good 1/8" of material from the LIM. It takes alot of time getting the right clearance and test fitting. Here is an intake ground down to fit the rockers.
This is the one Lloyd and I did. This intake had the GM machining done to clear the factory rollers but it is not nearly enough.

My Point is that the 60*V6 set from Crane needs modification to fit. However these new LS series rockers have a lot smaller back end on them so they should not need clearancing on the LIM. Then all you need are the correct studs (Which Crane, ARP and GM sell) and guideplates. This would make it a TRUE BOLT ON. Oh and it comes in a higher ratio.

[Guest]

Just because the rockers are adjustabe, does not make them 'perfect' for not needing prper length pushrods.

Geometry will still need to be checked and verified.

Any idea what the initial cost will be on these?

[geoffinbc]

Figure $400. All Gold Race rockers are expensive.

Very true that they will not compensate for incorrect geometry. However it should suffice for a regrind.

[Wolf]

. Then all you need are the correct studs (Which Crane, ARP and GM sell)

you wouldn't happen to have the part # for any of those

[AaronGTR]

betterthanyou was the first, but not the only. I was the second one to do this remember? He is correct that the ones designed for the 60v6 do not fit without modification. They come with the proper conversion studs to bolt onto the head, but they were designed for the inline valve head. So on the splayed valve head two of the rockers hit the lower intake manifold. I tried the route of grinding the manifold, but my rockers still wouldn't clear and I ended up going right thru the bottom of the runners. My solution was to grind a small radius on the top edge of the rocker itself. That is the part that hits, and you only need to remove a few mm of material to gain plenty of clearance. There is a lot of material there to work with so the integrity of the rocker is not compromised. It would certainly be nice to have a set of rockers that don't require moddification though.

He's also correct the adjustable rockers would solve problems with valve lash on a regrind. The stock pedastal style self-adjusting rockers are at a set height so you don't have to adjust valve lash when installing with stock parts. If you change something (cam base circle, valve stem length, etc) then the geometry would be off and you can't adjust it. With the new rockers you need the guide plates he mention though, and those still require custom pushrods. The stock GEN3's aren't heat treated and may fail if used with guide plates. The older pushrods are heat treated, but are a different length so they won't work. You may have to get a custom length too depending on what else you change. You just have to install the old length ones first and check the geometry to make sure the roller tip on the rocker stay in the middle 1/3 section of the vavle stem.

[geoffinbc]

. Then all you need are the correct studs (Which Crane, ARP and GM sell)

you wouldn't happen to have the part # for any of those

Cranecams Part Number: 99148-2
ARP Part Number 100-7221 w/ 3/8" top
ARP Part Number 135-7221 w/ 7/16" top and 1/4" longer if you think you are badass and need a 7/16" stud

Then GM number is a mystery but I know they sold them to convert press in studs to threaded ones on the 4.3L. They did have a metric bottom. But who cares because you can get em from 2 other sources.

[Guest]

. Then all you need are the correct studs (Which Crane, ARP and GM sell)

you wouldn't happen to have the part # for any of those

Cranecams Part Number: 99148-2
ARP Part Number 100-7221 w/ 3/8" top
ARP Part Number 135-7221 w/ 7/16" top and 1/4" longer if you think you are badass and need a 7/16" stud

Then GM number is a mystery but I know they sold them to convert press in studs to threaded ones on the 4.3L. They did have a metric bottom. But who cares because you can get em from 2 other sources.

How many studs come with those part numbers? 1? 2? I just checked my supplier and holy crap, cheapest one is $17 CDN,. hopefully that is a pair of them. Also do these part numbers include the nuts?