roller rocker/valve spring/camshaft compatibility...

So the 4.7 blown stroker is getting closer (any day now )
I just received my 1:6 Mopar Roller Rockers...
I have a Comp Cam in the block with these specs:
Camshaft: (Intake/Exhaust) 254°/262° adv. dur., 210°/218° dur. @ .050" lift, .477"/.493" valve lift, 1000-5200rpm, 111° lobe separation

Any suggestions on valve springs? The head's already been ported/polished and sandblasted so I want to avoid any more machining, hoping to find a set of springs that'll drop in like the stockers (magnum springs ?)... Keeping the stock size valves

Also, anyone have any literature on the Mopar Roller Rockers as far as torque and clearance/adjustment specs? I got a real good deal on them but they came with no instructions or paperwork

Gil BullyKatz said:

Any suggestions on valve springs? The head's already been ported/polished and sandblasted so I want to avoid any more machining, hoping to find a set of springs that'll drop in like the stockers (magnum springs ?)... Keeping the stock size valves

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Use the same Mopar Performance valve springs #5249464, retainers #4452032, & locks #4529218 that I did. You can get them from http://www.mopartsracing.com/parts/ram.html
This page on the Crane cams site has helpful information on how to use the adjustable roller rocker arms to correctly set lifter preload. This is essential if your machining operations have altered valvetrain geometry.
You'll need to buy a valve cover spacer to raise the valve cover so that it clears the RR's. You can get it from Hesco for $80.

Dino,
Thanks for the lifter preset info. I was need that too.
Gil,
I'd be interested in if you can use your stock push rods. I also bought a set of RRs of E-Bay. They look simular to Hesco/Mopar. The guy sent a set of push rods with them. The stock ones are about 1/4 to long. The one sent are an inch to short. I cut up and machined some old one to fit.I figured I need ones that are 9-1/2 inches long. I think the stock ones are 9-5/8. Just inerested if its just me or if the RR's need different push rods.
Tom

Dr. Dyno said:

Use the same Mopar Performance valve springs #5249464, retainers #4452032, & locks #4529218 that I did.

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These items required no additional machining right? (I've heard of some valve spring sets requiring seat machining, even though they are sometimes sold as "drop-in" for 242 engines) if so, i think I might go that route

75SV1, as far as I know, and was told by Mike at Accurate, the stock length pushrods "should" be fine as long as the head or block hasn't been machined. he also told me, that the only way to be sure, and the way they build their motors is to mock up using adjustable length pushrods to determine the needed length. I'm also under the impression that the Mopar roller rockers I have allow me slight adjustment of pushrod length (am I wrong?)

Well, talking from experience, I recently rebuilt my mainly stock 87 Renix engine, and bought the Crane 753901 camshaft to put in as a little boost in performance. I measured pre load and found that the stock pushrods were too long. Since I am supposed to be between .030" and .060" I measured that I was at like .082" so I just bought some rocker shims....I am putting the engine together as we speak and I bought a set of .020" and .060" spacers from Crane, but I am not sure which one to use to be at a correct clearance, .022" or .052"? Anyone think one is safer than the other?

Gil BullyKatz said:

These items required no additional machining right? (I've heard of some valve spring sets requiring seat machining, even though they are sometimes sold as "drop-in" for 242 engines) if so, i think I might go that route.

Click to expand...

They drop straight in.

Gil BullyKatz said:

These items required no additional machining right? (I've heard of some valve spring sets requiring seat machining, even though they are sometimes sold as "drop-in" for 242 engines) if so, i think I might go that route

75SV1, as far as I know, and was told by Mike at Accurate, the stock length pushrods "should" be fine as long as the head or block hasn't been machined. he also told me, that the only way to be sure, and the way they build their motors is to mock up using adjustable length pushrods to determine the needed length. I'm also under the impression that the Mopar roller rockers I have allow me slight adjustment of pushrod length (am I wrong?)

Click to expand...

The HESCO, MOPAR and the ones I have do have an adjusting screw. THere's a good amount of adjustment. 1/8 at least. I don't know why I need shorter push rods. I figured 9.5 length. I think stock ones are 9.630 or so. I looked around and I think Ford 351M/400M will work for me. I only shaved .010 off my head. The roller tip looks right at just forward of the center of the valve stem tip.
Tom

karter74 said:

Well, talking from experience, I recently rebuilt my mainly stock 87 Renix engine, and bought the Crane 753901 camshaft to put in as a little boost in performance. I measured pre load and found that the stock pushrods were too long. Since I am supposed to be between .030" and .060" I measured that I was at like .082" so I just bought some rocker shims....I am putting the engine together as we speak and I bought a set of .020" and .060" spacers from Crane, but I am not sure which one to use to be at a correct clearance, .022" or .052"? Anyone think one is safer than the other?

Click to expand...

The stock pushrods shouldn't be too long unless you've shaved a total of at least 0.020" from the head and block.
Use the 60thou shims so that you have a bigger margin of safety.

Gil - I have the same 254 Comp cams cam with the Mopar Valve springs and retainers and stock rockers and pushrods in my stroker - aproaching 20,000 miles with no problems - this motor had no head or block machining.

On the Drag Race 4.0 with machined head and block I used an adjustable pushrod to measure legnth and ended up with 9.550" (big block chevy) pushrods and used Crane Mustang 5.0 shims (and .010 homemade ones) under the stock rockers to get the clearance needed. The MOPAR adj rockers would have been easier but not allowed in NHRA Stock class.

Pushrods - both Crane and Comp have pushrods in .050 lengths available for most everything - call them direct if needed.

A few points. The suggested Spring/Retainer/Keeper combo was vandied about a while back and I bought in. When we checked them out, pressures were higher than needed. They do drop-in and work though. I don't feel the need for increased pressure over-the-nose is required. Unless you have increased the rev limit or weight of the valves, it will only speed cam lobe, lifter, rocker and valve tip wear. I have an alternative. I also have affordable pushrods in .029" Long, .045" & .090" Short. Almost every 4.0 & Stroker we have checked or built, needed shorter pushrods. The after market cams are ground to a smaller base circle, you should (theoretically) need longer (.030 according to them). Since they almost never work out that way, I would suspect that the factory sets things up on the longish side. I have seen many threads about the "incurable valvetrain noises & tapping" maybe it is pushrod length all along. The rollers, being adjustable, should make it easier to come up with a workable solution. Good luck, MIKE