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Camaro Research Group Discussion => Originality => Topic started by: zman1969 on April 24, 2013, 01:50:21 PM

Title: 0 rocker arms BIG or small 0 ? differences?
Post by: zman1969 on April 24, 2013, 01:50:21 PM
I just bought a set of 0 rockers for my 302 and a few of them have a different style 0 some large and some small - I was wondering what the difference was if any?
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on April 24, 2013, 02:08:59 PM
From what I have read recently the big O were fefore 69 and the small O was 69 and after. As for material differences I don't believe there are any.


I just bought a set of 0 rockers for my 302 and a few of them have a different style 0 some large and some small - I was wondering what the difference was if any?
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: zman1969 on May 01, 2013, 12:33:19 PM
anyone else have any more info?
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 01, 2013, 02:23:23 PM
I found where I read it. If you have Jerry M's revised 4th edition Definitive book on page 26 there is a pic of both versions of the 'O'. It says research shows the 67 Z28 had the larger 'O' than the 68 and the 69.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: JohnZ on May 01, 2013, 02:48:51 PM
Chevrolet used 240,000 stamped rocker arms EVERY DAY; it's highly unlikely that there was only one supplier or one set of precision progressive-die tooling.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 01, 2013, 05:46:03 PM
At least that explains why I have a few rockers with the 'O' horizontal, vertical, small and large. Wow. Can I assume they were mixed this way on a given engine?


Chevrolet used 240,000 stamped rocker arms EVERY DAY; it's highly unlikely that there was only one supplier or one set of precision progressive-die tooling.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: x77-69z28 on May 01, 2013, 11:54:21 PM
Yes
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 68camaroz28 on May 02, 2013, 02:35:12 AM
Umm, let's see some O's.....
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-069S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-069S.jpg.html)
70 Z/28
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-070S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-070S.jpg.html)
72 LT1
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-071S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-071S.jpg.html)
11A 69Z small O sideways
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-072S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-072S.jpg.html)
Mixture of O's
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-066S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-066S.jpg.html)
\
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 68camaroz28 on May 02, 2013, 02:39:21 AM
One More:
TRW rocker
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-068S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-068S.jpg.html)
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: tmodel66 on May 02, 2013, 02:45:16 AM
Has anybody ever saw an O with a line thru it? I've got a set in a box in my shop. I replaced them with Crane's cause they are in a Crane box. I can't remember what they were for though.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 02, 2013, 03:20:12 AM
Exactly what I have too.



Umm, let's see some O's.....
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-069S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-069S.jpg.html)
70 Z/28
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-070S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-070S.jpg.html)
72 LT1
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-071S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-071S.jpg.html)
11A 69Z small O sideways
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-072S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-072S.jpg.html)
Mixture of O's
(http://i192.photobucket.com/albums/z117/1-2-b-67L89/GM%20different%20O%20Rockers/MVC-066S.jpg) (http://s192.photobucket.com/user/1-2-b-67L89/media/GM%20different%20O%20Rockers/MVC-066S.jpg.html)
\

Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: canadair on May 02, 2013, 09:38:59 AM
the rockers with the triangle are they also high performance rocker arms ?
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 02, 2013, 01:00:34 PM
Honestly,don't really know anything about them. Mostly installed on low performance engines. Just a guess though but probably didn't get a process that the 'O' rockers received.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: jdv69z on May 02, 2013, 01:06:56 PM
Here's my original set.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 02, 2013, 01:38:42 PM
Just out of curiosity, I have heard it's best to keep the same pivot ball to the same rocker. Are there any exceptions or is it a must to get new pivots? Mine are all mixed up in a box, all look fine with no blueing, cracks, galling or score marks. I'm using roller tip stamped steel 1.5's at the moment and probably will continue using them when I finally pull the 350 and install the 302, but what if I did go back to the 'O' rockers?
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: lynnbilodeau on May 02, 2013, 03:09:20 PM
the rockers with the triangle are they also high performance rocker arms ?
That is correct.   Chevy sold them over the counter for many years.
Have compared three different looking "O" sets (litte, big and sideways) with a "V" set side by side with calipers and micrometers, and can find no appreciable difference among any of the four.

Gary.  I always keep ball and rocker in sets.   But... I would not be afraid to use a set that had been mixed.  Just get them really clean, install, and reset your valve lash after initial run in and again in 500 miles (which you were going to do ANY WAY, right?)
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: zman1969 on May 02, 2013, 03:31:31 PM
Gary I would try to keep them matched up. on a side note the set i just got have groovedballs for better lubrication, all SB i have seen prior were not like this - OE or A/M? I can get some pics up later if needed I assume they are A/M 
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 02, 2013, 03:34:20 PM
Yes I was. I'm a fanatical solid lifter fan since I was able to sit behind a wheel and drive, especially four speed cars. I was 10 when I got to move my first big tracker and trailer truck for my dad and 12 when I was able to drive a 4 speed hotrod on the road and in traffic (my dad wasn't pleased with those guys who let me). Since then any slight ticking sound coming from the rocker covers, I was in there and still am.

the rockers with the triangle are they also high performance rocker arms ?
That is correct.   Chevy sold them over the counter for many years.
Have compared three different looking "O" sets (litte, big and sideways) with a "V" set side by side with calipers and micrometers, and can find no appreciable difference among any of the four.

Gary.  I always keep ball and rocker in sets.   But... I would not be afraid to use a set that had been mixed.  Just get them really clean, install, and reset your valve lash after initial run in and again in 500 miles (which you were going to do ANY WAY, right?)
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 02, 2013, 03:40:52 PM
I've seen both, but I don't think chevies had grooved ones installed, those were more aftermarket. Just like Lynn said, I have heard it was ok as long as there are no problems with the surface of the rocker socket and the ball face, this information coming from some really old engine builders I knew growing up in Atlanta too.


Gary I would try to keep them matched up. on a side note the set i just got have groovedballs for better lubrication, all SB i have seen prior were not like this - OE or A/M? I can get some pics up later if needed I assume they are A/M 
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28-RS on May 02, 2013, 05:43:45 PM
Just out of curiosity, I have heard it's best to keep the same pivot ball to the same rocker. Are there any exceptions or is it a must to get new pivots? Mine are all mixed up in a box, all look fine with no blueing, cracks, galling or score marks. I'm using roller tip stamped steel 1.5's at the moment and probably will continue using them when I finally pull the 350 and install the 302, but what if I did go back to the 'O' rockers?
It's very easy to run the balls/rockers on a wire or string as you take them off an engine... you can even clean them that way  and they will come off in the correct order as well.. :)     I would suggest using a little molybdenum disulfide on the metal/metal wear surfaces on installation; especially with the mismatched ones..  it should help the two rubbing parts develop an 'affinity' for one another pretty quickly.. :)
I also keep lifters in order, when the come off a cam I'm going to reuse; just put them in a small box ordered in the correct fashion, and label the box for front and L/R side..  *(and moly works great on lifter/cam wear surfaces as well during breakin..)
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 02, 2013, 06:11:35 PM
Yes, lube and lube and lube and lube.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 67 RS Ragtop on May 02, 2013, 06:57:02 PM
It's always best to keep mated running parts together, as they develop wear patterns at the mating surfaces, such as a flat tappett does at the cam lobe, (which should not be mixed up, if you intend to reuse).  In the case of the pivots for the rockers, it's note quite so important, as long as there are no signs of discoloring, scratches / scoring, which you can "catch with your fingernail". JMO
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: lynnbilodeau on May 02, 2013, 11:34:34 PM
Agreed.  Best to keep the parts matched.  However, mismatching parts without excessive wear is no reason to discard them, in my humble opinon.

And yes, the grooved balls are aftermarket.   The old GM hipo catalogue even encourages them on high lift cam apps.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 68camaroz28 on May 02, 2013, 11:43:38 PM
If rebuilding an engine I'd not use used rockers. Why take a chance?
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: z28z11 on May 03, 2013, 04:23:28 AM
If rebuilding an engine I'd not use used rockers. Why take a chance?

My original "O's" are still together after all these years, and I won't hesitate to use them again. I don't want to spend $600.00 on some NOS set from a speculator if I can keep from it. I rebuilt the engine in '75, and among the parts I changed in upper valvetrain were the springs, lash caps, keepers and retainers, but not the rockers. Kept all the original parts and ratholed them. I had a Sig Erson Hi Flow IIH stick, hydraulics and titanium retainers, double wound Erson springs. I'm going back all original from cam to upper train - I really missed soaking the splash aprons with oil and listening to solids sounding like a frantic Singer sewing machine. 20W50 Union 76 racing oil was pretty cheap in those days; I loved the purple color on the driveway after adjusting valves. Stock oil pump in the engine would push 80 psi on my Stewart Warner mechanical gauge at about 2500 rpm, and until I bought a set of Erson lash caps to fit over the oiling holes, would just about empty the pan of a quart or two from one side to the other. Had to work quick -

Regards,
Steve
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 68camaroz28 on May 03, 2013, 10:38:04 AM
If rebuilding an engine I'd not use used rockers. Why take a chance?

My original "O's" are still together after all these years, and I won't hesitate to use them again. I don't want to spend $600.00 on some NOS set from a speculator if I can keep from it. I rebuilt the engine in '75, and among the parts I changed in upper valvetrain were the springs, lash caps, keepers and retainers, but not the rockers. Kept all the original parts and ratholed them. I had a Sig Erson Hi Flow IIH stick, hydraulics and titanium retainers, double wound Erson springs. I'm going back all original from cam to upper train - I really missed soaking the splash aprons with oil and listening to solids sounding like a frantic Singer sewing machine. 20W50 Union 76 racing oil was pretty cheap in those days; I loved the purple color on the driveway after adjusting valves. Stock oil pump in the engine would push 80 psi on my Stewart Warner mechanical gauge at about 2500 rpm, and until I bought a set of Erson lash caps to fit over the oiling holes, would just about empty the pan of a quart or two from one side to the other. Had to work quick -

Regards,
Steve
I agree about not paying the $600 for NOS ones but why use them?  Are most of using a NOS cam (crazy $), bearings, lifters (another crazy $), valves, etc.? I'd be surprised to note any reputable engine builder that would want to use worn rockers but I've been wrong before. :) Geometry is key! 
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: jdv69z on May 03, 2013, 12:57:44 PM
I've actually read somewhere that those simple looking stock rockers are a heck of a fine piece of engineering, and that it's almost impossible to improve on them. Not sure, but I think maybe even Jerry M runs them on his stocker.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: CNorton on May 03, 2013, 01:37:34 PM
I, along with Jerry M. and several hundred other small block Chevrolet Stock Eliminator racers, have been using stamped steel rockers on 7000+ RPM Stockers since the late 1980s when rules regarding valve spring pressure and lobe duration were relaxed.  Within the past couple of years, NHRA bowed to pressures from racers and manufacturers to permit the substitution of stud-mounted roller rockers.  Over the course of time, I've sorted, literally, through bucketsful of used rockers looking for sets that bear the identical markings, I've mixed and matched rockers and pivot balls, I've used a die grinder to open the rocker arm slot to fit over 7/16" studs, I've routinely put 425# of open spring pressure on them and and generally violated most of the generally accepted common sense "rules of thumb" regarding valve train longevity.  At this point, I can safely say that the total number of parts failures related to rocker arm/pivot ball failures that I've experienced could be counted on one hand. 

Many years ago, cam grinders for our sport began to grind extra lift into camshafts to accommodate the issues of inherently inconsistent rocker ratios so, I'm positive that if I were to switch the rockers on my Stocker motor to rollers today, I'd have go go through the entire motor to reset the components for legal lift measurement as read off the retainer surface.  It has been my experience that the weakest link in GM's stock valve train stability has typically been the studs, not the rockers.  Big blocks and other engine-makes have not been so fortunate when it comes to valve train stability and it is my opinion that those are the racers who urged the liberalization of the rules to permit roller rockers. 

The above statements should not be interpreted as an indication that i have any knowledge about the details of Jerry's engine program.  Having said that, I've always known him to run legal motors so the fact that his Z28 twisted over 8000 using stamped steel rockers without major problems is merely a given.

Chuck
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28-RS on May 03, 2013, 04:28:19 PM
I've had 030 over 302's.. that would wind above 10,000 rpm with stock components... including stock rockers... :)
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: lynnbilodeau on May 04, 2013, 04:13:11 PM
If rebuilding an engine I'd not use used rockers. Why take a chance?

I have never considered it as taking a chance.  As noted, they are not the weak link.   I can't imagine any issue related to using a good used set of rockers and balls.  As long as there is no surface galling, there shouldn't be much to worry about.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: tmodel66 on May 04, 2013, 05:10:13 PM
I've never replaced rockers on a stock engine rebuild unless there were signs of wear or galling where the oiling had been inadequate.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: z28z11 on May 04, 2013, 05:44:07 PM
Gary,

    They should be kept together, for the same reason as when you pull a cam/lifters/pushrods - I remember reading this in the overhaul manual (many) years ago, that stated the wear-in or hone pattern that develops between the contact surfaces are unique to those parts, and that the parts have to go through the same process if they are mismatched on reassembly, which could cause accelerated wear/premature part failure. I believe that to be on the high side of extremely remote - if you use assembly lube, and lubricate everything like it should be, they'll probably be fine. I still keep mine together, marked or cataloged.

     I don't consider myself as a professional engine builder, but I built my first one ('57 PowerPac 283, 30-30 solid GM cam, 327-300 heads, 11:1 TRW pistons, original stamped rockers, 43 years ago; multiple small blocks and big blocks (even a couple of FoMoCo's) since. I have never had a reused stock rocker fail, but I have checked them all for problems before reinstalling them. Last I heard, the original 283 was still at it. It's just a matter of personal preference - I know roller tips are better for geometry and reduced internal friction, but I still will use my "O's" until they give up the ghost, or I do.

Just my opinion -
Steve
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 04, 2013, 06:44:14 PM
Some are freaked out about using them mixed and some aren't. Personally I think I would use as is as long as the rubbing surfaces are all good on the rocker and the pivot. I have some big 'O' and little 'O' rockers. Does anyone have any little 'O' to trade for big 'O' rockers?


Gary,

    They should be kept together, for the same reason as when you pull a cam/lifters/pushrods - I remember reading this in the overhaul manual (many) years ago, that stated the wear-in or hone pattern that develops between the contact surfaces are unique to those parts, and that the parts have to go through the same process if they are mismatched on reassembly, which could cause accelerated wear/premature part failure. I believe that to be on the high side of extremely remote - if you use assembly lube, and lubricate everything like it should be, they'll probably be fine. I still keep mine together, marked or cataloged.

     I don't consider myself as a professional engine builder, but I built my first one ('57 PowerPac 283, 30-30 solid GM cam, 327-300 heads, 11:1 TRW pistons, original stamped rockers, 43 years ago; multiple small blocks and big blocks (even a couple of FoMoCo's) since. I have never had a reused stock rocker fail, but I have checked them all for problems before reinstalling them. Last I heard, the original 283 was still at it. It's just a matter of personal preference - I know roller tips are better for geometry and reduced internal friction, but I still will use my "O's" until they give up the ghost, or I do.

Just my opinion -
Steve
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: lynnbilodeau on May 05, 2013, 02:42:13 AM
I have a pile of each, so I am sure I have some little "O"s I can trade you.

Send me a PM and let me know how many.  It may be a few days before I dig them out.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: 69Z28 on May 05, 2013, 03:44:22 AM
That's cool Lynn. I gotta dig mine out as well. Maybe we all can get together and make some complete sets. I'll PM you when I find out what I have and what I need. Years ago I had two full sets of the small O's but I can't remember what the heck I did with those things. I'm still scratching my head on that one.


I have a pile of each, so I am sure I have some little "O"s I can trade you.

Send me a PM and let me know how many.  It may be a few days before I dig them out.
Title: Re: 0 rocker arms BIG or small 0 ? differences?
Post by: zman1969 on May 06, 2013, 01:46:34 AM
my set has 5 of the big 0's and I'd like to have them match if anyone's wanting bigs for their smalls