LS1 rocker arms

[project60degree]

not 2 saound like an ass but if the LSx and the GP rocker arms are the same and the LSx rocker arms wont fit how is that useful?

[geoffinbc]

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

Today I compared a Stock 2000 3400 rocker arm to a stock 2002 4.3L (SBC) rocker arm. From every andgle and measurement they were identical. The stamping was even the exhact same. There were only 2 differences. One was the fact that the 4.3L rocker had an 8mm stud hole. The seconds was the 3400 rocker had the pushrod cup closer to the trunion because of the increased 1.6 ratio. So a SBC rocker does fit a 660 quite well. There was not a .025" difference when comparing stock to stock

[project60degree]

So SBC rocker arms will will fit???

[geoffinbc]

Yes. Infact the rockers Crane Cams sell for the 60* V6 have the same number stamped on them as the SBC rockers. They are the same. But you need conversion studs and some other modifications for them to fit a gen 3.

[Doubt_Incarnate]

usefull cuz now you know they won't and you dont have to find out the hard way.

[smilinguy99]

Today I compared a Stock 2000 3400 rocker arm to a stock 2002 4.3L (SBC) rocker arm. From every andgle and measurement they were identical. The stamping was even the exhact same. There were only 2 differences. One was the fact that the 4.3L rocker had an 8mm stud hole. The seconds was the 3400 rocker had the pushrod cup closer to the trunion because of the increased 1.6 ratio. So a SBC rocker does fit a 660 quite well. There was not a .025" difference when comparing stock to stock

So, you are comparing a stamped rocker to a stamped rocker, right?

Sigh.

I measured the C-C of the trunnion axle to the roller tip axle on two full roller rockers. The 3400 and 4.3 have no roller tip. The valve stem tip slides across the radiused portion of the stamped rocker's nose. You could use the same stamped rocker on two different motors and get two different ratios. It just depends on the distance of the valve centerline from the trunnion axle center. Stamped rockers with no roller tips are somewhat forgiving of variations in geometry. The "effective" centerline of the tip is an inch or so above the valve. Effective in this case meaning the center point of the radiused face of the tip.

What you are doing is comparing your apples to my oranges and saying my oranges are really apples. In this case, there is no clear comparison.

sg99

[SappySE107]

I hate not having time to read forums. So what do we need, a modified hardland sharp or other company rocker arm? Or has anyone looked at other engines and their rocker arms? Just wondering how far we are looking on the rocker arm search. The DOHC stuff I found so far is not from GM, so I would think the same could very easily be true for the pushrod. The dodge 318 valve stem seal fits the newer 3400 and 3100 heads...what else is out there

If we truely do need custom, do we know what coil binds we have to play with, and the valvetrain geometry using higher ratios? Wow...I have been away from pushrods for way too long! I have no idea where everyone is at on the gen 3s (are we still talking about gen 2s around here?), so hopefully I still have some ideas no one else has attempted yet With the cost of a custom cam, hopefully we can find a cheaper alternative. Regrind + higher ratio could give some interesting offset grinding results. I could be stupid too so who knows:P Full roller only I assume if we want accuracy? How bad are stamped? How bad are stock stamped? Been so long since i thought about rocker arms, and I forget stuff if I don't keep it in my head. I should have made an article on them, then I could read this now and remember something.

[geoffinbc]

Today I compared a Stock 2000 3400 rocker arm to a stock 2002 4.3L (SBC) rocker arm. From every andgle and measurement they were identical. The stamping was even the exhact same. There were only 2 differences. One was the fact that the 4.3L rocker had an 8mm stud hole. The seconds was the 3400 rocker had the pushrod cup closer to the trunion because of the increased 1.6 ratio. So a SBC rocker does fit a 660 quite well. There was not a .025" difference when comparing stock to stock

So, you are comparing a stamped rocker to a stamped rocker, right?

Sigh.

I measured the C-C of the trunnion axle to the roller tip axle on two full roller rockers. The 3400 and 4.3 have no roller tip. The valve stem tip slides across the radiused portion of the stamped rocker's nose. You could use the same stamped rocker on two different motors and get two different ratios. It just depends on the distance of the valve centerline from the trunnion axle center. Stamped rockers with no roller tips are somewhat forgiving of variations in geometry. The "effective" centerline of the tip is an inch or so above the valve. Effective in this case meaning the center point of the radiused face of the tip.

What you are doing is comparing your apples to my oranges and saying my oranges are really apples. In this case, there is no clear comparison.

sg99

What Im saying is the 2 motors use the same identical rocker (except for the pushrod location). So in this case a Smallblock rocker fits a 660 engine and vise-versa. I guess what I should have done is actually measure the distance from stem to stud on both motors. That is what will really tell us if a smallblock rocker will indeed fit a 660. Crane uses a regular smallblock rocker in their kit for the 660 motor (I have compared part numbers from my Crane rockers made for a 660 and rockers out of package for smallblocks). So if your harland sharp rocker is .025 longer why is that? Is it intentional? Is it something Harland does for a reason?

[smilinguy99]

What Im saying is the 2 motors use the same identical rocker (except for the pushrod location). So in this case a Smallblock rocker fits a 660 engine and vise-versa. I guess what I should have done is actually measure the distance from stem to stud on both motors. That is what will really tell us if a smallblock rocker will indeed fit a 660. Crane uses a regular smallblock rocker in their kit for the 660 motor (I have compared part numbers from my Crane rockers made for a 660 and rockers out of package for smallblocks). So if your harland sharp rocker is .025 longer why is that? Is it intentional? Is it something Harland does for a reason?

The Harland Sharp is for an SBC and the Crane is for a V660. Yes, the SBC rocker will physically fit and if you don't look too closely you might think it fits well. But look closely. It doesn't fit the same and I personally wouldn't use it.

As far as the numbers on the extrusion, I would be careful. The numbers may be the same and the actual extrusion may be the same, but machined differently.

The Cranes I have don't have the P/N stamped on them. Instead they have "10-1.50" along with some cryptic numbers. "B -01" on one rocker and "A -12" on the other.

If you put SBC rockers in the V660 would they work? It is likely. But would they work well? Time and wear patterns would tell.

Measuring the stem to the stud will certainly help us.. Unfortunately the stem and the stud are not parallel (and in some cases don't even look like they are on the same plane) so the point on the centerline of the stud and the point on the centerline of the you choose to measure from can vary the results a lot.

I'd like a simple solution as much as anyone. I'd like a rocker that maintains geometry and is in no danger of contacting the manifold on Gen2 and Gen3 motors. And lastly I'd like them to be as plentiful and as cheap as SBC parts. Out of frustration with this very problem, I've been making 3D drawings of the rockers I'd like to have. If there is anyone out there that could make them, that would be swell. I approached one local CNC shop and they are jammed with a big order for a carmaker. I suppose I should get hustling and get them made one way or another, but life gets in the way sometimes.

Here's a profile of the thing I've been working on. Notice the odd looking tail area? It is drooped down to clear the manifold. Probably need custom pushrods. No biggie.

sg99

[eliteweapons]

Hey guys. I have been looking for 1.8 or 1.9 ratio rollers for my 3100 gen III and so far haven't found one off the shelf. But.... jesel said that they could make a set for me but for about $850.00 I just had to send them the head. The price is steep but I might have to do it to get the ratio I need because I couldn't get what I needed out of the regrind. I can't tell if you guys are saying the cranes will work on the gen III or not because the threads seem to be bouncing all directions.

[geoffinbc]

LS1 Rockers do not fit.

smilinguy99

Is it possible HS makes their rockers longer than Crane for some reason? Im gonna call Crane and ask them on Friday. See if the 660 rockers are infact the same as their SBC rockers. I compared the 2 by P/N on the rocker and physical appearance. They were identical. But that was 3 years ago so memory is foggy.

[eliteweapons]

Thanks for the input guys but I think I am just going to go with the jesels for the lower profile and the strength with the shaft system. seems like using the others is going to be a pain setting up and getting the geometry right. Too much trial and error and I don't have the rockers to do it with. This project has been a major pain. I have been waiting on my crankshaft since november.

[geoffinbc]

You ordered from J-Body?

Expect it next november. Thoes tools are fo fucked its not even funny.

[eliteweapons]

yes unfortunalely. I was going to get a billet crank from Tom at molex but they told me 16 weeks out and j-bodys was only 4 weeks and was cheaper but forged. good enought for my application so i went for it. now I could of had the motor running already with the billet one. You can only go by someones word with this stuff.

[geoffinbc]

Nothing wrong with J-Body products... However their customer service, delivery time and often pricing are horrid.