LS1 rocker arms

[project60degree]

Does anyone know if LS1 rocker arms would fit on 3100 heads. They have some in JEGS that are full roller and are 1.8 and im pretty sure they are 7/16

[bszopi]

RE: LS1 rocker arms

http://www.60degreev6.com/index.php?name=PNphpBB2&file=viewtopic&t=5714

[geoffinbc]

They are 3/8 stud and they dont work. The center distance from the stud to the stem is different on the LSx engines.

[project60degree]

so even if i just get the rocker arms and get a conversion kit would it work then?

[project60degree]

is there anyway i could make those rocker arms work?

[Doubt_Incarnate]

you already bought them didnt you?

if you could somehow move the stud to a location as to line the rolor up on the valve properly, sure, but if not, then your sol. and last time i looked it would be difficuly to pull off

[project60degree]

could i use 1.7 rockers full roller rockers for a BB that is 7/16?

[Doubt_Incarnate]

as long as the stud to valve length matches up. most people just use the sbc rockers or the ones actually made for our motors. it would be cheaper to just get a cam than buy rockers that dont fit and try to make them work only to no avail.

[smilinguy99]

I've never seen an LSx rocker arm in person, but I've seen a few postings mentioning the use of SBC rockers on this motor.

I'll just throw this into the mix. Here's what I know for sure:

I measured the center to center distance of the trunnion (the main axle) to roller tip on both a Crane V660 rocker and a Harland Sharp SBC rocker.

The c-c of the SBC rocker was 1.400" and the c-c of the V660 rocker was 1.375". The measuring instruments used were a Starrett vernier height gage on a surface plate. The parts werel clamped in place with precision angle plates and measured in two different ways. These are small parts so it was kind of a pain to do. I'm pretty confident in the accuracy of the measurements.

I was investigating the possibility of using an SBC rocker on this motor.

The .025" might not seem like very much, but it made quite a difference in where the roller tip landed on the tip of the valve, and how they interacted through a lift event. The measuring intstruments I used for this phase of the test were my eyeballs. All throughout, the V660 rocker kept the roller noticeably closer to the center of the valve tip than the SBC rocker.

What's the point? Lots of things will physically fit and seem to work, not all of them may work correctly.

sg99

[RacerX11]

A small amount of difference can be corrected for by changing the height of the rocker pivot in relation to the contact point of the valve stem. Changing this height affects the angle of the rocker, moving the roller contact point on the valve stem laterally. This is accomplished by using different pushrod lengths and adjustable rocker studs.

Marty

[smilinguy99]

A small amount of difference can be corrected for by changing the height of the rocker pivot in relation to the contact point of the valve stem. Changing this height affects the angle of the rocker, moving the roller contact point on the valve stem laterally. This is accomplished by using different pushrod lengths and adjustable rocker studs.

Marty

Yes, I fiddled with all kinds of vertical positionings and I did not like any of them. Moving the trunnion up and down just changes the place where the roller tip is out of position.

You can move it down some, but if you move it up, you start using fewer and fewer threads on the stud. Not good.

Let me swerve this thread off in another direction.

The pushrods on the aluminum head are leaned over pretty far. As a result, when using the Crane rockers (or any stud mount rockers you choose) the pushrod has quite a bit of side load on the guides.

The production guides are kind of on the thin side (.100".) and it isn't hard to imagine that under heavy spring pressure these guides failing and making a mess of things.

How about a pedestal rocker such as the 3.8L Ford rocker in the photo I've attached. I'm not advocating using this rocker, but IF the mfg. (Harland Sharp) could be persuaded to make one like this but suited to the Gen3 pedestal style heads, perhaps even using stock pedestals, would anyone be interested? And how much would you pay for such a thing? Likely won't be cheap.

On the rocker in the picture, lash adjustment is made over the pushrod.

sg99

[project60degree]

is there any 1.7 or 1.8 rocker arm sets that i can get?

[Doubt_Incarnate]

try looking at the 3.8L supercharged motors from a gtp. search thier forums. i think i heard somewher a long time ago they were experimenting with 1.9. the gtp rockers might be a closer fit, emphisie the MIGHT.

[bszopi]

The LSx and GTP rockers are pretty much identical...

[Doubt_Incarnate]

there you have it, more usefull info.