Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
Ductile iron rockers vs. aluminum roller rockers? #2918772
05/05/21 09:36 AM
05/05/21 09:36 AM
Joined: Dec 2013
Posts: 4,651
Wichita
G
GY3 Offline OP
master
GY3  Offline OP
master
G

Joined: Dec 2013
Posts: 4,651
Wichita
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.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: GY3] #2918787
05/05/21 10:18 AM
05/05/21 10:18 AM
Joined: Nov 2003
Posts: 7,348
Mt.Vernon ,Ohio
VernMotor Offline
master
VernMotor  Offline
master

Joined: Nov 2003
Posts: 7,348
Mt.Vernon ,Ohio
I have had a set of Ductile iron rockers on my car for 30 years. race car. has a 640 lift cam in it now. I am building a new engine now and I bought new set of Harlem sharp rockets for it. We will see. I hope I am not disappointed.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: VernMotor] #2918789
05/05/21 10:20 AM
05/05/21 10:20 AM
Joined: Oct 2005
Posts: 8,828
Ontario, Canada
S
Stanton Offline
Don't question me!
Stanton  Offline
Don't question me!
S

Joined: Oct 2005
Posts: 8,828
Ontario, Canada
Where would you even buy a set of ductile iron rockers these days ? That's why aluminum is the new norm !

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: Stanton] #2918798
05/05/21 10:32 AM
05/05/21 10:32 AM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
F
fast68plymouth Offline
I Live Here
fast68plymouth  Offline
I Live Here
F

Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
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
Re: Ductile iron rockers vs. aluminum roller rockers? [Re: GY3] #2918800
05/05/21 10:32 AM
05/05/21 10:32 AM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline
I Win
AndyF  Offline
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
Originally Posted by GY3
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.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: AndyF] #2918825
05/05/21 11:39 AM
05/05/21 11:39 AM
Joined: Dec 2003
Posts: 22,695
Bitopia
J
jcc Offline
If you can't dazzle em with diamonds..
jcc  Offline
If you can't dazzle em with diamonds..
J

Joined: Dec 2003
Posts: 22,695
Bitopia
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.

Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
Re: Ductile iron rockers vs. aluminum roller rockers? [Re: GY3] #2918834
05/05/21 12:00 PM
05/05/21 12:00 PM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
master
polyspheric  Offline
master

Joined: Oct 2007
Posts: 4,205
New York
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
Re: Ductile iron rockers vs. aluminum roller rockers? [Re: polyspheric] #2918949
05/05/21 04:46 PM
05/05/21 04:46 PM
Joined: Oct 2005
Posts: 8,828
Ontario, Canada
S
Stanton Offline
Don't question me!
Stanton  Offline
Don't question me!
S

Joined: Oct 2005
Posts: 8,828
Ontario, Canada
I think a lot of the galling had to do with guys using them on used or crappy stock shafts. In the early '70's I bought an Isky kit that came with cam, lifters, pushrods and rockers - but no shafts. What the hell did I know ...I stuck them on the original shafts! While I didn't have any galling issues (luckily), when I took them off after the first season I noticed they were hard to remove (tight around each bolt hole). That's when I realized stock shafts needed to be replaced for any performance application. In those days TRW made a pretty decent, inexpensive replacement shaft. I liked the hardened tips on the Iskys, I've seen MANY cranes that were badly worn at the valve tip. To this day I'd buy a used set of Iskys in a heartbeat if I could find them (reasonably priced).

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: Stanton] #2918977
05/05/21 06:01 PM
05/05/21 06:01 PM
Joined: Jan 2003
Posts: 6,130
Melbourne , Australia
LA360 Offline
master
LA360  Offline
master

Joined: Jan 2003
Posts: 6,130
Melbourne , Australia
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
Re: Ductile iron rockers vs. aluminum roller rockers? [Re: GY3] #2918987
05/05/21 06:21 PM
05/05/21 06:21 PM
Joined: Jul 2008
Posts: 606
Boise
M
Moparteacher Offline
mopar
Moparteacher  Offline
mopar
M

Joined: Jul 2008
Posts: 606
Boise
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

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: Moparteacher] #2919160
05/06/21 01:10 AM
05/06/21 01:10 AM
Joined: Feb 2008
Posts: 45
Medford, OR
carrman Offline
member
carrman  Offline
member

Joined: Feb 2008
Posts: 45
Medford, OR
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.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: carrman] #2919161
05/06/21 01:38 AM
05/06/21 01:38 AM
Joined: Jul 2008
Posts: 606
Boise
M
Moparteacher Offline
mopar
Moparteacher  Offline
mopar
M

Joined: Jul 2008
Posts: 606
Boise
I don't know what they charge for blue printing the rocker ratio. It's been about 10 years since I had the work done. I didn't have the blue printing of the ratio performed. I didn't think it was important at the time. It's really something for someone whom needs valve lift to be exact such as a stock eliminator engine. Mine are pretty close, but not perfect in rocker ratio.
I am super happy with the quality of work.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: Moparteacher] #2919165
05/06/21 02:12 AM
05/06/21 02:12 AM
Joined: Sep 2005
Posts: 620
Deep DEEP SOUTH
LAD 524 Offline
mopar
LAD 524  Offline
mopar

Joined: Sep 2005
Posts: 620
Deep DEEP SOUTH
I wont use alum rockers in anything resembling a hi perf engine with decent spring pressures.....seen em break too many times.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: LAD 524] #2920332
05/09/21 10:46 AM
05/09/21 10:46 AM
Joined: Dec 2009
Posts: 339
Gilroy,CA.
mopardude318 Offline
enthusiast
mopardude318  Offline
enthusiast

Joined: Dec 2009
Posts: 339
Gilroy,CA.
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.

62A7E6F7-F1C7-4B11-9208-C3EA10CD0A94.jpegD54F2289-501A-42DE-918F-8E9778AF9B54.jpeg9F375C86-F906-4C4C-9E1D-F66D1762C22D.jpeg56471D78-3B22-49A6-9531-FABF50CEB0ED.jpeg

408 Stroker 533 HP 520 FT LBS...........................1970 Dart RMS AlterKation
Re: Ductile iron rockers vs. aluminum roller rockers? [Re: carrman] #2921842
05/12/21 08:16 PM
05/12/21 08:16 PM
Joined: Dec 2004
Posts: 10,549
Rittman Ohio
fourgearsavoy Offline
I Live Here
fourgearsavoy  Offline
I Live Here

Joined: Dec 2004
Posts: 10,549
Rittman Ohio
Originally Posted by carrman
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 shruggy 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.

004-001.JPG002-1.JPG

64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: Ductile iron rockers vs. aluminum roller rockers? [Re: fourgearsavoy] #2921908
05/12/21 10:15 PM
05/12/21 10:15 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 43,007
Bend,OR USA
both times i used RAS and RAU I was disappointed and over charged from the original quote on both time and money down NO MAS twocents
I've used a bunch of Harland Sharp aluminum roller rockers on many different motors for a long time now with no bad results, current bracket motor has 840 Lbs. over the nose with 325 lbs. on the seats with Manton series 5 7/16 pushrods, pulls hard up to 7300 RPM with no issues of power dropping off up
I'm going to try shifting it at 7500 RPM this year, raising the low gear shift RPM last year from 7000 RPM to 7300 made 2 MPG increase in the 1/4 mile with almost no ET gain, 8.862 at 148.?? MPH shifting at 7000 RPM. 45 minutes later in the other lane shifting at 7300 it ran 8.866 at 150.?? MPH confused shruggy


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Ductile iron rockers vs. aluminum roller rockers? [Re: fourgearsavoy] #2921911
05/12/21 10:21 PM
05/12/21 10:21 PM
Joined: Feb 2008
Posts: 45
Medford, OR
carrman Offline
member
carrman  Offline
member

Joined: Feb 2008
Posts: 45
Medford, OR
Any idea if these work with stock valve covers?

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: carrman] #2921914
05/12/21 10:32 PM
05/12/21 10:32 PM
Joined: Dec 2013
Posts: 4,651
Wichita
G
GY3 Offline OP
master
GY3  Offline OP
master
G

Joined: Dec 2013
Posts: 4,651
Wichita
Originally Posted by carrman
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.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: carrman] #2921931
05/12/21 11:11 PM
05/12/21 11:11 PM
Joined: Jan 2003
Posts: 1,908
Nebraska
4
4406bbl Offline
top fuel
4406bbl  Offline
top fuel
4

Joined: Jan 2003
Posts: 1,908
Nebraska
Originally Posted by carrman
Any idea if these work with stock valve covers?


Sometimes you have to drill holes in the baffles right where the adjusting screws are.

Re: Ductile iron rockers vs. aluminum roller rockers? [Re: 4406bbl] #2921957
05/13/21 01:07 AM
05/13/21 01:07 AM
Joined: Mar 2003
Posts: 9,091
Rogue River, OR
Jeremiah Offline
master
Jeremiah  Offline
master

Joined: Mar 2003
Posts: 9,091
Rogue River, OR
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.



Page 1 of 2 1 2






Powered by UBB.threads™ PHP Forum Software 7.7.1