Installing roller bearings in stock rocker arm assemblies...

GOT-Torque

GOT-Torque

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Jul 2, 2007
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Anyone seen this done or tried it?

My shafts are worn and so are my rocker arms. I hate to spend the money to buy new stock parts and still have the stock setup, so why not have my rocker arms machined to accept roller bearings and just put new rocker shafts in...

I thought someone had some for sale in the classifieds a while ago (that a shop did) but before I could get any info from him they were sold...

I'm talking about installing a roller bearing into the rocker arm like in the picture below...
 

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They are well oiled, i wouldnt think this would be a heavy ware item unless you had oiling issues??
 
They have 145,000 miles on them. Just rebuilt the engine, going to be turning more rpm this time....

I just happened to pull the shaft out a few days ago and noticed the wear. They won't be going back in as is...

I'll have to post a picture. You can actually feel the drag the wear causes when you rotate one in your hand.
 
I just went out and snapped some pics (just chose two rockers at random). Doesn't look as bad in the pictures as they do in person...

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That is galling, and is common; the loose fit is in fact desirable to some extent , I have several sets of rockers tell me how many you need , I’ll send them

,I have a ARP 8mm stud package with 12 point nuts and washers that really works well. Dr Performance, Industrial Injections and Pure Diesel Power have these in stock, along with my MaxSpool Chrome Molly push rods in standard + .100 , and + .150 as well as my MaxSpool dual spring package with Chrome Molly standard or titanium retainers as a upgrade .

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Unless there's tremendous stress opening the exhaust valve in these diesels I can't see the roller bearing deal being necessary in these situations. In ls1 (gm late model v8) applications the stock needle bearing rocker assembly can be replace in the stock rockers for about $250 but you're talking alot more spring pressure and rpm vs. our slow rpm sissy valve spring pressure diesels!!!
 
NickTF said:
Unless there's tremendous stress opening the exhaust valve in these diesels I can't see the roller bearing deal being necessary in these situations. In ls1 (gm late model v8) applications the stock needle bearing rocker assembly can be replace in the stock rockers for about $250 but you're talking alot more spring pressure and rpm vs. our slow rpm sissy valve spring pressure diesels!!!
Click to expand...

The exhaust rocker is the problem, opening to cylinder pressure. I have roller rockers made by Harland Sharp for the 24 valve Cummins and the CR , but they are only beneficial because of added rocker ratio on the intake side

Remember a 24 valve Cummins has two springs to deal with so unless you’re running big springs on your LS 1 then you aren’t quite there. The slow engine speeds of a Cummins are deceiving on spring requirements, the short seat timing and quick acceleration ramps need spring rate and damping and control valve train movement.

This was a big consideration in my choosing a dual spring instead of a less expensive singles. The different springs reach their first and second order resonance at different points and do a great deal more in preventing destructive uncontrolled valve train motion.
The dual spring required a custom retainer to locate the inner and outer spring
 
Like Greg said, that looks common for stock 24v rockers. Try woodruffdiesel.com for roller rockers. I've seen a very nice setup down at his shop...
 
Greg, thanks for the offer. I may take you up on it. I heard Harland Sharp was making rockers for these but couldn't find them on their site or a few of their dealers? I'll do some more looking tomorrow.

The rest of your discussion on studs, pushrods, springs, and retainers will do no good with me as your parts are already here :Cheer:(thanks to Pure Diesel Power).

Here's a couple teaser shots of the build... too bad such a pretty engine will be going in such a dirty truck :hehe:

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COMP461 said:
The exhaust rocker is the problem, opening to cylinder pressure. I have roller rockers made by Harland Sharp for the 24 valve Cummins and the CR , but they are only beneficial because of added rocker ratio on the intake side

Remember a 24 valve Cummins has two springs to deal with so unless you’re running big springs on your LS 1 then you aren’t quite there. The slow engine speeds of a Cummins are deceiving on spring requirements, the short seat timing and quick acceleration ramps need spring rate and damping and control valve train movement.

This was a big consideration in my choosing a dual spring instead of a less expensive singles. The different springs reach their first and second order resonance at different points and do a great deal more in preventing destructive uncontrolled valve train motion.
The dual spring required a custom retainer to locate the inner and outer spring
Click to expand...

I'm new to this diesel stuff, but did consider the exhaust being a problem. I never thought about the 24 valve with two springs though, obviously that makes it even more of a problem. Harlan Sharp I believe also does the ls1 rockers. Realistically anything over 150-200 on the seat and 450 maybe to 500 pounds open and ls1 rockers are replaced for something else. Not sure what the spring pressures are like in two 24 valve springs.

Am I to believe that a cummins cam lobe is more agressive then a hydraulic or solid roller cam lobe? I know the cummins flat lifter probably affords more agressive ramp rates then a flat lifter of a gas app as the cummins has the huge pancake (so to speak) tappet instead of a tappet which is the same diameter as that of the lifter body in flat lifter gas applications. But are they more agressive then roller applications in gas motors? Ofcourse the lower rpm diesels would afford more agressive lobes given their short rpms ranges!

If resonance is such a problem and with diesels not seeming to require serious spring pressure why isn't there a behive spring on the market for them? Or is this something in the works? Obviously the retainer would shrink but they are the best at resonance control it seems.

I'm just trying to learn, like I said, I'm new to this diesel stuff:Cheer:
 
Nick draw two pictures with cams and then use one with a roller on it and one with a flat tappet. The roller cam can have a sharper profile, but visualize the movement of the tappet. On the roller you have two ramps coming togther(radius of the wheel, and the cam). On the flat tapped you only have cam profile.
 
zstroken said:
Nick draw two pictures with cams and then use one with a roller on it and one with a flat tappet. The roller cam can have a sharper profile, but visualize the movement of the tappet. On the roller you have two ramps coming togther(radius of the wheel, and the cam). On the flat tapped you only have cam profile.
Click to expand...

Dan, I'm not sure I'm following what you're getting at here? Are you suggesting the flat tappet moves the valve more agressively? That's opposite of everything I and many others know about flat vs. rollers. :what:
 
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