VetNutJim

Hey guys ,

I've got a set of these Chevy Aulminum Roller Rockers. 1.6 Ratio.
What I need to know is the correct stud diameter these were made to work with.

I have some 3/8 studs but the micrometers say they will be just a little 'loose' with those.

Somewere I've read 10mm is the correct STUD size.

I just got off the phone with Chris at Superior and he didn't know.
He's showing one part number for LT1 & LT4 engines for the rocker STUD.

Anybody know "FOR SURE" ? I don't want to be guessing and end up having to do this twice to get it right....
Also don't want them to sound like solid lifters when I'm through. I don't think I could take that noise anymore.

Part number? Please . . . . .Please ....
The weekend is coming up and this may be the 'weekend' mod project.

Help.... please.....

Edit:
"Aulminum"... that's the NEW way to spell it. :)


[Modified by VetNutJim, 12:51 PM 12/2/2003]

scorp508

Measure the whole in the rocker and that'll tell you. Its going to either be 3/8" or 7/16". Whatever is closest is it.

65Z01

The stock L98 studs are 7/16" at the thread but 3/8" at the rocker; the upgrade stud is 7/16" on both ends. For this engine I've only seen RRs listed for either of these two sizes.

I would assume that the LT1/4 studs are similar. The 3/8" studs are close to 9.5mm but 7/16" studs are closer to 11.5mm, which would be way big.

Your best bet is to find out what stud size those RRs were made for; all RRs have this data in their specs.

STL94LT1

[QUOTE]I've got a set of these Chevy Aulminum Roller Rockers. 1.6 Ratio.
What I need to know is the correct stud diameter these were made to work with.
QUOTE]

If they are the stock LT4 rockers, they are 10 mm. If they are the GMPP aftermarker roller rockers they are 3/8.

VetNutJim

Sounds like I don't really know what I have....

These are aluminum, silver color, with a little bowtie emblem engraved into the top on the valve end. Says 1.6 on the same end.

They are full roller rockers...

I have measured the hole in the Rocker Trunion with an inside snap gauge and a mic.
I've aslo measured some of the 3/8 Screw in Studs I have left over from a few engine builds of the past.
I can't remember what I measured last night but the clearance between the trunion hole and the smooth part of the stud was looser than I wanted.....
I think 10mm will be about 'just right' but I'd like to know for sure.

There seems to be a lot of folks on here who have installed these things (roller rockers) and then had them make noise.
I'm wondering if making sure the correct stud size is utilized will keep this from happening.

It's awfully close..... one COULD even use the 7/16 rockers on a 3/8 stud but it wouldn't be 'right' although it'd probably run forever sounding like a sewing machine.

How can I tell what I have vs. what I need, guys?
These were bought from a forum member a couple years ago so I don't have any real data on them......

PurpC4 ??? Are these your old rockers????

Have I got the GMPP Rockers? LT4 Rockers ??? :nonod: :nonod:

shotchkiss

I've got a set of LT4 rockers sitting in my garage, unless someone beats me to it, I could get a pic of them and post them in another hour or so, so you can see if they look like yours do.

If I remember right, they have a little bowtie emblem on them and also are stamped "CR" right below them.


[Modified by shotchkiss, 4:44 PM 12/2/2003]

VetNutJim

Hey schotchkiss,


Would you please post that picture? I haven't a clue where my old Kodak DC120 is.

Thanks much!

edsalinas

Hey there Jim,
It's about your thread "title"?

:lolg: :lolg: :lolg:

:cheers:

Hope you figure out your size bro, been getting complaints or what? (Just havin' fun, don't take me serious)..........

shotchkiss

Here's the pics, all my rocker have dates on them, they don't say the ratio that I could find. I'm sure they're from an LT4 beacuse they have the oddball stud size, and you can't adjust the lash on them.





[Modified by shotchkiss, 6:14 PM 12/2/2003]

C4Crazy787

LT1's have 3/8th stud's LT4's have 7/16th stud's, when I bought my GMPP rr's I made sure the parts man knew they where for a LT1' and GM# 12370839 is what I got.
Hope that helps :seeya

VetNutJim

Hey schotchkiss,

THAT IS THEY !! THEY IS THEM!!!

I've got the twins to yours.
Mine say "1.6" where yours say "CR".

The numbers on the end are "04" "99"....

Part number???

Can't adjust the lash??? Uh-Oh... gotta come up with a work around for that.:cry :cry :( :(
Looks like regular polylocks would allow adjusting.... but I don't know for.
There's got to be a way to get these on these L98 Heads.

That's the ones I have anyway.....

LT4?? 10mm stud??

Any suggestions/advice on the no lash adjustment dilemma?

RichS

A Factory LT4 does not have 7/16th studs. They are 10mm and not adjustable.

If you put a 3/8 stud with a 10mm rocker trunion it will too sloppy. I bet you have a set of 10mm factory LT4 rockers.

18carfan

If yours have "1.6" where the "CR" is on schotchkiss' then you have the "add-on" GMPP rockers. Most likely, the 3/8" ones just like you need. Don't be fooled, they are not a "precision" fit. -Jeff

RichS

This is a pick of my 10mm factoryLT4rocker.

I could take a pick tomarrow of my GMPP 1.6 rockers with 3/8 studs. They do say 1.6 on them.

[Modified by RichS, 10:31 PM 12/2/2003]


[Modified by RichS, 10:32 PM 12/2/2003]

C4Crazy787

I stand corrected, Thanks :seeya

shotchkiss

I think you have the GMPP rockers that fit the 3/8" stud also.
My guess is the number on the rockers is a date code, week and year I think, and yours would seem to be several years too new to be factory LT4s.
This is just my best guess, hopefully someone more of an expert can chime in here.

btw, my forum name is "shotchkiss" without the "c" :lol:

VetNutJim

Hey 18carfan and everyone,

1.6 IS on mine where the "CR" is on shotchkiss rockers.
3/8 seemed AWFUL CLOSE with just a 'touch' of clearance and 7/16 was to much so I thought I may have the 10MM ones.

I have here on my desk, a 3/8 stud, the roller rocker and a polylock all stuck together and it all looks like it will work but the determining factor looks to be the spring height which will determine the operating point of the stud in the rocker slot..

If these are the ones for the 3/8 studs then I'm a happy, happy guy.
I don't remember who I got them from but they appear to be brand new. Don't look as if they've ever been installed.

BTW. You guys are very kind to help me out on this. BIG THANKS to you ALL.

So. To this point you all think these are the "GMPP" rockers that were designed to use a 3/8 stud and polylocks?
I HOPE that's what I have. :blueangel: :blueangel:

scorp508

Damn! GM loves to make things just different "enough" to mess with you don't they? :)

VetNutJim

Hey RichS,

Would you please post that picture of the 1.6 rockers you have?
The ones that use the 3/8 studs.

Thanks!

STL94LT1

VetNutJim, If you bought your roller rockers from an educated forum member, and they were the factory LT4 10 mm's. I would think he would know enough to also send the 10 mm rocker studs.

So, I am going to guess you have 3/8 rockers.