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post #1 of (permalink) Old 04-26-2000, 07:36 PM
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Roller Rocker Arms?

We are doing a frame up restoration on a 84 CJ7. We have Howell Fuel injection and are doing the 4.0L head conversion. My husband had American Automotive Machine Co do the decking and all that piston stuff I am not sure of the particulars but with us supplying a good block and the 4.0 head them welding the water hole on the head and the balancing it ran $2,000.00 to get it out of there so with all that. I would like to do the Team Rush ignition upgrade and we should be another month because we painted the frame and engine compartment with Black Poly and have painted the underside with Black Durabak painted the bed with White Durbak. We need to install the motor and paint the body and hard top. Of course we are now broke... My husband is really interested in the roller rockers looks like this will take another $500.00. Have any of you done this to your CJ's. What are your ideas?

1983 CJ7
Howell Fuel Injection
4.0 Head
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post #2 of (permalink) Old 04-26-2000, 08:41 PM
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Re: Roller Rocker Arms?

I'm not a 4.0 liter expert, but have built dozens of engines. I like to use roller rocker arms for a couple reasons. The biggest reason is that a quality roller rocker arm will give the desired rocker arm ratio. For example, many small block chevy stamped steel rocker arms are advertised as 1.50 ratio. I've done actual measurements on several different brands of small block chevy rocker arm ratios (including factory chevy ones), some only measured 1.42 and usually measure 1.47. The loss of ratio will result in less valve lift. Less valve lift will equal less engine performance. The camshaft timing can also be affected by less than full rocker arm ratio. For example, a camshaft I installed was advertised to open the intake valve at 5 degrees BTDC, but with the stamped steel rocker arm the intake valve opened at 1 degree BTDC. I then installed a roller rocker arm on the same camshaft and yes the intake valve did open at 5 degrees BTDC. The stamped steel rocker arm often requires a performance camshaft to be "degreed in".

The next reason a I like roller rocker arms is valve train wear. The roller will not "shock" the valve tips at high RPM's. The "shock" from stamped steel rocker arms will wear the valve guides and valve tips at a fast rate.

There are stamped steel rocker arms that have a roller tip. If your engine building budget is getting tight, there are several advantages to using roller tip stamped steel rocker arms also. The roller tip design costs less, gives very accurate ratios, and does reduce the rocker arm "shock" a lot more than a plain stamped rocker arm does.
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post #3 of (permalink) Old 04-28-2000, 12:23 PM
 
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Re: Roller Rocker Arms?

ditto on dave. When I built my V8, I went with some standard Erson 1.5's. Will be upgrading to roller's in the near future. They are definitely not a "necessity" but are a good mod when you have a few 100 bucks laying around.


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<font color=red>'88 YJ, 4" susp,3" body,33's,283 Chevy V8,TH350,4.11's,D30,D35c</font color=red>
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post #4 of (permalink) Old 04-28-2000, 12:43 PM
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Re: Roller Rocker Arms?

I can't refute anything that Dave said, but for a 4.0L I would hesitate putting high dollar, full roller rockers in. Unless there are lots of other high performance, high RPM parts in it, the cam is degreed, etc. it's just a waste of money. I would however, use the stamped rockers with the roller tip for wear prevention only. This engine will probably never see the high side of 4000 RPM and the valve lift is not a critical thing to consider on a daily driver rebuild. If you've got extra money just burning a hole in your pocket, go for it even though the gain realized will never recover the additional cost. If it slows down the progress or takes away from other necessary parts acquisitions, save the dough just because they look cool. That's my .02 and that's about all it's worth!

post #5 of (permalink) Old 04-29-2000, 03:54 AM
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Re: Roller Rocker Arms?

[img]/wwwthreads_images/icons/smile.gif[/img] I'm on the side of economy on this one as well. My 4.0 in 98,000 miles has seen 4000 RPM very few times......almost never...and this is towing as well as all kinds of other driving. Rollers ARE NICE, but really are a performance enhancer in the higher RPM ranges.[img]/wwwthreads_images/icons/crazy.gif[/img]

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