Stock Mopar Rocker Assembly... Sheeesh!

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pastortom1

pastortom1

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Hey guys........ I just changed the lifters and pushrods in my 318 (one was done for.....the infernal "tick tick").........Put in a set of Comp Hydraulics and ball rods.........Very nice......smoothed out a bit, and very quiet....like 'em.............BUT, the stock Mopar rocker arms are a bloody joke............I cannot believe the lousy alignments on these things........probably a little worn too, not too bad, but plain lousy quality.

WHAT rocker assembly would you guys recommend for this motor? It has a Mopar Cam (purple series, probably a 480 or so....nice "lope" at idle).....an Edelbrock Performer series intake and carb (450 cfm if I remember correctly).........working Ram Air (operative dual snorkel, into a non-restrictive filter set-up), and full Flowmaster duals, w/o the crossover pipe.

I don't want to go broke, BUT this rocker assembly has to go down the road (to the dumpster)..........Help me out here, and explain to me the difference between a 1.5" and a 1.6" ratio on the rockers.........???? Which one? Why?

Thanks guys................... Doc
 
I have had good luck with the Crane forged doctile iron rockers. Very strong and inexpensive. The 1.5 verses 1.6 ratio, The pushrod is moved closer to the pivot(fulcrum) this gives more lift @ the valve from the same motion from cam(lifter). I believe there is no cost difference between the 1.5 and the 1.6 ratio. Slight increase in duration, but very little. In my engine the duration @ .050 increased only 1 and a half degrees using the 1.6 rockers over the 1.5. Good luck, Terry.
 
I run stamped mopar rockers that are 34years old, about 130,000miles on them, i daily drive it HARD, and go to the track about monthly with no issues. There is nothing wrong with them if you ask me. Friend of mine runs a similar setup with no issues. Mopar overengineered a lot of their parts, they are built not to break...there is nothing wrong with your rockers, unless your running some kind of crazy spring pressures (which you shouldn't be). Mopars rocker shafts were so far superior to what the competition was running from the factory. I'll use them on any mild motor i ever build. Have you properly checked your lifter pre-load?



o/t - You have the carb that will feed a 4bbl slant six, not a cammed, alum intake, worked exhaust 318. I run 650cfm on my 318. You should be around 600cfm, not 450, way under-carbed if you ask me.

Just my two cents. Oh and I've heard good about Crane golds, but overkill and unecessary for your setup if you ask me. I'll be running them on my ~400rwhp roller 360 :salute:
 
Gotta agree with GoodysGotaCuda the shaft mount rockers are definately superior to pedistal mount according to everyone in the know. I agree they look cheap and funky like they belong on a 6 cyl Chebbie but as goody said they really do work . You can get a identical rocker from MaMopar with a heavier cross section to it which is only about $75-90 for the set that makes them a little stronger with out being noticably heavier or more expensive. I been running them way past the recommended lift - duration and rpm with out one problem.

again Gooy is right the 450 cfm is not near adequate for a warmed over 318 with that cam and manifold (I bet it is crisp as hell on the throttle but lays down about 4000 rpm ) . I run a worked over 750 dbl pump on mine and could use more but I too like the crisp throttle response of too small a carb for low rpm driving ...LOL
 
Never been a fan of the "aluminum roller rockers" that everybody seems to think that they need. The factory rockers are really pretty good. If you need adjustability, a set of adjustable pushrods can be found at usually a pretty decent price at swap meets. Some people buy them and are too lazy to actually use them. I have them on my 383 duster now. More of a pain to adjust than normal adjustable rockers but I think that I only paid $50 for them. Lots cheaper than new rockers. I'm putting a set of ductile iron rockers on this fall. Just bought a set of rocker holddowns from Hughes engines. Really impressed by the quality of the product. Includes studs for the shafts, 12 point nuts and lock washers, rocker side shims and really beefy steel rocker hold downs. $75.

don
 
If you want ultimate over kill and expense then consider the comp cams steel roller rockers - magnums I think they call them. You wont ever need another set of rockers. You could also consider the knocks offs that CAT and some other outfits make that copy the comp design about half the cost on ebay around 230-240 bucks.
 
pastortom1 said:
Hey guys........ I just changed the lifters and pushrods in my 318 (one was done for.....the infernal "tick tick").........Put in a set of Comp Hydraulics and ball rods.........Very nice......smoothed out a bit, and very quiet....like 'em.............BUT, the stock Mopar rocker arms are a bloody joke............I cannot believe the lousy alignments on these things........probably a little worn too, not too bad, but plain lousy quality.

WHAT rocker assembly would you guys recommend for this motor? It has a Mopar Cam (purple series, probably a 480 or so....nice "lope" at idle).....an Edelbrock Performer series intake and carb (450 cfm if I remember correctly).........working Ram Air (operative dual snorkel, into a non-restrictive filter set-up), and full Flowmaster duals, w/o the crossover pipe.

I don't want to go broke, BUT this rocker assembly has to go down the road (to the dumpster)..........Help me out here, and explain to me the difference between a 1.5" and a 1.6" ratio on the rockers.........???? Which one? Why?

Thanks guys................... Doc
Click to expand...

If the alignment is off on the stock rockers they were probably on wrong. I have taken off plenty a mopar valve cover to find all of the "LFT" rockers on the left side of the engine and the "RT" on the right side of the engine.
 
GoodysGotaCuda said:
I run stamped mopar rockers that are 34years old, about 130,000miles on them, i daily drive it HARD, and go to the track about monthly with no issues. There is nothing wrong with them if you ask me. Friend of mine runs a similar setup with no issues. Mopar overengineered a lot of their parts, they are built not to break...there is nothing wrong with your rockers, unless your running some kind of crazy spring pressures (which you shouldn't be). Mopars rocker shafts were so far superior to what the competition was running from the factory. I'll use them on any mild motor i ever build. Have you properly checked your lifter pre-load?



o/t - You have the carb that will feed a 4bbl slant six, not a cammed, alum intake, worked exhaust 318. I run 650cfm on my 318. You should be around 600cfm, not 450, way under-carbed if you ask me.

Just my two cents. Oh and I've heard good about Crane golds, but overkill and unecessary for your setup if you ask me. I'll be running them on my ~400rwhp roller 360 :salute:
Click to expand...

Yup I to agree with Goodys comment on the Mopar stock rockers and shafts. I've used them for years on 383's and 440's with no problems and my current 383 is running the 509" MP cam. Sometimes it's the devil you know. Also if you're actually running a 450 carb I'd recommend switching to a 650, you'll notice a big difference. :headbang:
 
i have never used anything other then mopars factory rockers... i re use them from the motor, after I rebuild it and never have a problem... if you are on the track looking for every last one thousandth of a second, i'd say they would have to go.. but for what your doing your observations on thier quality, and craftsmanship are mistaken.

put your 200- 600 bux you could spend on rockers and buy a carb and you'll actually improvve your performance.
 
Out of alignment?!? Not sure how that can happen unless they were assembled incorrectly (They are handed left and right). Or totally worn out.

Anything more than the heavy duty OEM style and new shafts would be a waste of cash on your setup. Roller rockers are really hyped up, but generally the increase in performance is due to a massive lightening in the drivers wallet and not reduced friction.

Roller rockers are seldom much lighter, but move weight out over the valve tip, exactly where it is most detrimental.

Increased ratio will increase lift for a given duration, but also increases load as seen at the cam, lifter and pushrod. This increase is exponential as RPM rises. Make sure your springs can handle it.

Stiffer springs use more power, and put a higher load on everything, make sure your timing chain can handle it.

Better bet would be to reduce mass of valvetrain components. That way you could run a lighter spring, and the stock rockers would flex a lot less. But within the RPM range of that cam, stock parts will be your best bet.

Fully rolerized rockers use a caged needle bearing on the shaft. If one of these lets go, all those little needle bearings are loose in the engine and will head straight for the oil pump. Stamped or bushed rockers make less shrapnel, and fail less often.

Roller rockers sure look cool, but they are real hard to see with the valve covers on.

Double check your carb CFM, I bet it's a 625. If you are running a 500, a carb swap will gain you more than any high-zoot rocker setup.
 
Some good points there C130Chief. The factory stamped rockers are durable enough, but I stopped using them because the ratio is way off. They are listed as 1.5's but are really closer to 1.4's. I have check hundreds over the years. The solid '273' rockers are a good solid setup too...but out of the many I have checked the best was 1.51 and the worst was 1.41. most were in the 1.43/1.44 range. I know, it will not matter on a street car if you lose .030 lift, ..but you are. That .509 cam isn't 509 anymore. The aftermarket rockers are much more accurate in thier ratio's. The Crane forged doctile iron rockers are a very solid piece and I think I payed 169. bucks for a set of 1.6 rockers. Some have had issues with the adjusters..I havn't but some have. Again, it matters little for a street beater but if you are putting together a hot street/strip machine..you need ALL of the lift that expensive cam offers. Chief..are you a load master? I served in the USAF also. Good luck, Terry.
 
I appreciate the comebacks guys, but all of you but one missed the point......the ALIGNMENT is screwy...SO screwy that I have a pushrod/guide issue with a few of them......I've worked on a lot of small block Mopars, but NEVER seen a mess like this........

What I'll have to do is a complete re-alignment on them, trying to use what I found inside...........wish I had another set lying around, but I'm in a RV park right now, and don't have my spare parts with me........

I've run drags (in the 70's) in N/SA and P/SA, mostly at Lebanon Valley by the Mass border.........My Belvedere convertible was 2/10s off the national record, and I was using stock parts religiously, except for the cool can and tie-down........I never had a problem either.....BUT, if I posted a picture of this alignment, you guys would have a bird.............Literally.

I suppose it's possible that some Bozo took them all off and just mixed them up...........If so, it's my fault for not checking all of them before buttoning it up...........I didn't notice a problem until I got to the passenger side........drivers side is good........Looks like a sad case of eeny meeny miney moe...........I figured that when they rebuilt the motor, they knew what they were doing, and put them in the same way they came out.

At least I know what I'll be doing at 8 AM tomorrow............steel dominoes.

Does Mopar offer direct replacements per chance? Anyone?
 
I think Mopar Performance sells replacements. Next choice for low buck would be the crane Ductile adj, Then the Comp Cams steel if you want to spend $$
 
I'm not bashing aftermarket rockers as having no value, as they in many cases do. And yes, the ratio of OEM rockers tends to be a bit under the spec. I guess my point was not to dismiss the factory hardware strictly because it is stomped out of sheet metal and looks low tech. They work well, and last a long time. Bang for the buck wise on a small block MOPAR, roller rockers are well down the list. The last .030 of lift, especially if it is beyond .500 on OEM castings is pretty much academic. You'd be hard pressed to notice it, much less measure it on a dyno. If you have taken the time to measure the lift at the valve exactly, and calculate the true rocker ratio, then I imagine you are also the type who has had their heads flowed and determined the lift at which port stall occurs. A cam grinder can make one heck of a good grind selection given this info!

Within the limits of common pushrod length and lifter diameter, I'll take lobe lift over rocker ratio any day.

Optimum pushrod length and rocker geometry is another matter all together, so besides having the rocker tip centered on the stem at 50% valve lift, lets not get into that here. Aftermarket rockers with adjustment screws can fudge for a lot of really bad geometery, but seldom correct it.

I'm not trying to bash any particular product, or tell anybody they are making a mistake. I just get somewhat tired of seeing guys spending their hard earned bucks on gee-whiz parts that promise to offer some specific horepower or ET gain. "5-10 horsepower gain" compared to what? A totally worn out factory piece which was already costing you 15 horses? The best product offered by their competition? Will it work THAT much better than something that was already working just fine? Was that particular part the limiting factor in your setup? Swapping 1.6 rockers onto an otherwise well balanced mild 318 might just hurt ET's and trap speeds when the valves now go into float at the 1000 foot mark. Just a thought.

Not a Loadmaster. As my screen name indicates I was formerly a Crew Chief, however I am currently finishing up with Flight Engineer school. I started out jumping out of them, then spent many years working on them, and now I fly on them. Hope I am going the right direction!
 
As I stated earlier, stamped steel stock rockers are durable enough, they have proven that. Just not a performance part. Yes I am the type that checks everything...twice. I have to get my flow chart out for this one.....my heads flow 226 cfm @.475, and 240 cfm @ .500, and 254 cfm @ .525 and holds that thru .550 lift and then stalls. My cam is the comp XE 275HL (.525 lift) It measures .544 @ the valve with the 1.6 cranes I am using. If I used the stamped rockers this cam would give .476 @ the valve. With the small block Mopars we are already losing .010 lobe lift because the lifter is not in plane with the pushrod. The calculator says .350 lobe lift with this cam..but it only measures .340 . I would lose 28 cfm of flow. Using the Super Flow formula, thats aprox. 57.68 horsepower. Would I change rockers for "5-10" horsepower..no. Would I change for 50 some horsepower...well..I did. Like I said, for a street beater, sure the stamps are good . I used them for years myself. And for a low buck hot rod use them. I was just informing others that there are better rockers out there that don't break the bank. And deliver more performance for the investment. m. At 169.00...they arn't much more than a set of new heavy duty stamps. As always, JMHO. Use whatever you choose...I do.

Pastortom1, sorry for getting off your subject...just trying to put some informative related tech out there.

C130chief, good luck on your flight eng. school.
 
correction, that should read pushrod lift. not lobe lift. We lose lift @ the rocker end of the pushrod. Because of the offset between lifter and pushrod.
Terry.
 
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