Ductile iron rockers vs. aluminum roller rockers?
#2918772
05/05/21 09:36 AM
05/05/21 09:36 AM
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Joined: Dec 2013
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GY3
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Has anyone seen a performance comparison done between the two types of rockers?
It seems the norm to put high-zoot aluminum race rockers on an engine that is driven on the street anymore and it always make me cringe.
'63 Dodge 330
11.19 @ 121 mph Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
9.92 @ 135mph with a 350 shot of nitrous and 93 octane pump. 1.43 60 ft. 3,750 lbs.
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: Stanton]
#2918798
05/05/21 10:32 AM
05/05/21 10:32 AM
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Joined: Jan 2003
Posts: 14,531 So. Burlington, Vt.
fast68plymouth
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I Live Here
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Near the end of the Crane ductile iron big block rockers being something that were actually “available”, they were $500...... without the shafts or any hold down hardware.
Yeh....... no thanks.
The last set I used that were reasonably priced was in 2005, and on that set the adjuster screws failed on the dyno........ so another close to $100 was spent to put some Smith Bros. adjusters in them. All said and done...... had pretty close to $500 in that rocker set up.
I’ve also seen plenty of those iron rockers that had some fairly serious galling going on with the shafts.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: GY3]
#2918800
05/05/21 10:32 AM
05/05/21 10:32 AM
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Joined: Jan 2003
Posts: 31,200 Oregon
AndyF
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I Win
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Oregon
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Has anyone seen a performance comparison done between the two types of rockers?
It seems the norm to put high-zoot aluminum race rockers on an engine that is driven on the street anymore and it always make me cringe. There isn't any difference in performance but steel should outlast aluminum by a long time. I have one engine with Comp steel rockers that runs 9's in a B body. Those rockers have held up well for the last 4 seasons.
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: AndyF]
#2918825
05/05/21 11:39 AM
05/05/21 11:39 AM
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Joined: Dec 2003
Posts: 23,269 Here
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
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I regret installing Crane Alum rockers on a mild SB decades back, with no fulcrum bearings or bushings. They looked cool. .
As mentioned below, I used new I thought quality shafts in my application that left me rather unsatisfied with the galling.
Last edited by jcc; 05/05/21 10:50 PM.
" All sorts of things can happen when you are open to new Ideas" Inventor of Kevlar
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: GY3]
#2918834
05/05/21 12:00 PM
05/05/21 12:00 PM
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Joined: Oct 2007
Posts: 4,219 New York
polyspheric
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New York
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Why aluminum? 1. lighter (actually the difference in reciprocating weight is limited to the ends, isn't significant) 2. cheaper to make 3. cheaper to alter to fit another application 4. you must buy them again or risk failure 5. shiny!
Boffin Emeritus
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: Stanton]
#2918977
05/05/21 06:01 PM
05/05/21 06:01 PM
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Joined: Jan 2003
Posts: 6,163 Melbourne , Australia
LA360
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In most cases steel is better. The Comp steel rockers are pretty good from what I've seen. The only time I've heard of an aluminium arm being better was on a Comp Eliminator engine, they swapped the intake arm from steel back to an aluminium arm, and it cleared up a valve train issue they were having.
The aluminium arms are easy to produce typically, the extrusions are probably used by many different companies as well.
Alan Jones
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: GY3]
#2918987
05/05/21 06:21 PM
05/05/21 06:21 PM
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Joined: Jul 2008
Posts: 615 Boise
Moparteacher
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mopar
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I sent my ductile rockers to RAS (now RAU) and had bushings installed. They'll blue-print the ratio for a few bucks more. It included undersize banana grooved thick shafts and hold-downs. I have another set with some light galling that will be sent in to be bushed, or I'll get their stainless roller tip set for about $1k. DVORAK Machine offers a do-it-yourself kit. http://www.dvorakmachine.com/rockerarms.shtml
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: LAD 524]
#2920332
05/09/21 10:46 AM
05/09/21 10:46 AM
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Joined: Dec 2009
Posts: 339 Gilroy,CA.
mopardude318
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enthusiast
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Gilroy,CA.
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I had RAU rebuild and bush my 273 rockers, touch up the rocker pad, hard chrome the shafts, spot face and install locknut adjusters and threw in billet steel hold downs.
408 Stroker 533 HP 520 FT LBS...........................1970 Dart RMS AlterKation
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: carrman]
#2921842
05/12/21 08:16 PM
05/12/21 08:16 PM
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Joined: Dec 2004
Posts: 10,607 Rittman Ohio
fourgearsavoy
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How much for the blue printing? They quoted me as follows: Total price for the complete assembly: (Hard chrome plated shafts, bronze bushings, re-face contact tips, steel hex hold downs and spacers kit with shims) $549.00 + S/H. Thats about what I spent on my Isky rockers when I sent them to RAS about 8 years ago maybe I love them and I'm currently running them with a 620 lift SFT cam. I only lash my valves spring and fall and they always are dead on.
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: carrman]
#2921914
05/12/21 10:32 PM
05/12/21 10:32 PM
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Joined: Dec 2013
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Any idea if these work with stock valve covers? The Crane ductile iron ones do.
'63 Dodge 330
11.19 @ 121 mph Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
9.92 @ 135mph with a 350 shot of nitrous and 93 octane pump. 1.43 60 ft. 3,750 lbs.
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: carrman]
#2921931
05/12/21 11:11 PM
05/12/21 11:11 PM
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Joined: Jan 2003
Posts: 1,908 Nebraska
4406bbl
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top fuel
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Nebraska
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Any idea if these work with stock valve covers? Sometimes you have to drill holes in the baffles right where the adjusting screws are.
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Re: Ductile iron rockers vs. aluminum roller rockers?
[Re: 4406bbl]
#2921957
05/13/21 01:07 AM
05/13/21 01:07 AM
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Joined: Mar 2003
Posts: 9,112 Rogue River, OR
Jeremiah
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I use stock 68 chrome 383 valve covers on my Dart with a set of those black rigid Felpro gaskets doubled up to clear the adjusters. I adhered two gaskefs together with ultra black and used longer bolts to ensure proper thread engagement.
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