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cliveawn
Samba Member
Joined: December 07, 2010
Posts: 481
Location: Southern Sweden
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 Posted: Fri Mar 20, 2015 4:05 pm Post subject: Ally vs Chrome molly |
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Whats the difference in using Chrome molly pushrods or aluminium ones?
benefits and downfalls of each type.
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Green 78 Westfalia Helsinki,
2056 with 41 x 34 valves,ported heads
Fully balanced
8,5:1CR
JPM Custom made cam
JPM 7075 dual taper pushrods
IDF 40's with 28mm venturi's
Python CSP 42mm exhaust.
115 HP
Daily driver 2017 Volvo V60 D5 hybrid
Rica stage 2 tune 345hp.
''Funny thing about common sense is that its not very common''
Seismic gun mechanic |
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scotth17
Samba Member
Joined: January 30, 2012
Posts: 335
Location: Bedford Texas
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| Posted: Fri Mar 20, 2015 4:16 pm Post subject: |
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| Chromoly- strong, heavier, noisier when hot, smaller diameter...Aluminum- kinda strong, lighter, quieter when hot, larger diameter... |
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SoCalJes
Samba Member
Joined: November 02, 2011
Posts: 1093
Location: Broward, FL
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| Posted: Fri Mar 20, 2015 5:46 pm Post subject: |
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| scotth17 wrote: |
| Chromoly- strong, heavier, noisier when hot, smaller diameter...Aluminum- kinda strong, lighter, quieter when hot, larger diameter... |
Also they reduce valve train weight reducing valve float at high rpms and when hot they are supposed to have less stretch than steel rods.
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Jesse
71 Ghia
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Just because it didn't come that way, doesn't mean it shouldn't have. |
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modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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| Posted: Fri Mar 20, 2015 5:54 pm Post subject: |
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| scotth17 wrote: |
| Chromoly- strong, heavier, noisier when hot, smaller diameter...Aluminum- kinda strong, lighter, quieter when hot, larger diameter... |
Exactly.
Also steel is less $$ than aluminum, for same quality |
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cliveawn
Samba Member
Joined: December 07, 2010
Posts: 481
Location: Southern Sweden
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| Posted: Fri Mar 20, 2015 5:55 pm Post subject: |
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Thanks!
_________________
---------------------------------------------------------
Green 78 Westfalia Helsinki,
2056 with 41 x 34 valves,ported heads
Fully balanced
8,5:1CR
JPM Custom made cam
JPM 7075 dual taper pushrods
IDF 40's with 28mm venturi's
Python CSP 42mm exhaust.
115 HP
Daily driver 2017 Volvo V60 D5 hybrid
Rica stage 2 tune 345hp.
''Funny thing about common sense is that its not very common''
Seismic gun mechanic |
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Quokka42
Samba Member
Joined: December 02, 2010
Posts: 3117
Location: Melbourne, Australia
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| Posted: Sat Mar 21, 2015 2:01 am Post subject: |
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Love your sig, BTW - Little Britain fan by any chance?
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There has only ever been one man who was perfect, and they nailed Him to a cross. |
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cliveawn
Samba Member
Joined: December 07, 2010
Posts: 481
Location: Southern Sweden
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| Posted: Sat Mar 21, 2015 1:47 pm Post subject: |
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Yes,I like Little Britain! got the "the only bay in the village" sticker on the rear window.
Not sure the Swedes get it over here.....
_________________
---------------------------------------------------------
Green 78 Westfalia Helsinki,
2056 with 41 x 34 valves,ported heads
Fully balanced
8,5:1CR
JPM Custom made cam
JPM 7075 dual taper pushrods
IDF 40's with 28mm venturi's
Python CSP 42mm exhaust.
115 HP
Daily driver 2017 Volvo V60 D5 hybrid
Rica stage 2 tune 345hp.
''Funny thing about common sense is that its not very common''
Seismic gun mechanic |
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bugguy076
Samba Member
Joined: December 11, 2007
Posts: 1068
Location: Dover, PA.
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| Posted: Sat Mar 21, 2015 4:02 pm Post subject: |
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If you are looking for 8,000 RPM using dual springs, use C/moly.
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Grubby Fingers Racing
1976 Drag Bug
1967 Street Bug |
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cliveawn
Samba Member
Joined: December 07, 2010
Posts: 481
Location: Southern Sweden
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| Posted: Sat Mar 21, 2015 4:31 pm Post subject: |
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I will keep that in mind but 8000 revs would put me in warp speed on the motorway,that would be a scary ride!
My motor is being built for a max rev of about 4500.
little more power but not too much to spoil the reliability aspect.
_________________
---------------------------------------------------------
Green 78 Westfalia Helsinki,
2056 with 41 x 34 valves,ported heads
Fully balanced
8,5:1CR
JPM Custom made cam
JPM 7075 dual taper pushrods
IDF 40's with 28mm venturi's
Python CSP 42mm exhaust.
115 HP
Daily driver 2017 Volvo V60 D5 hybrid
Rica stage 2 tune 345hp.
''Funny thing about common sense is that its not very common''
Seismic gun mechanic |
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Sun Mar 22, 2015 11:05 am Post subject: |
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my cr's are quieter than any aluminum Ive heard......... I think cb's hd aluminum ones would be fine for your build....depending on your pushrod tubes and rockers  I wonder what the weight diff in the hd aluminum& the .035&.058 is on the same length rod? and just think nascar uses 4x as thick as we do..and therer are also 1/2" WALL PUSHRODS!!! more rocker ratio makes running stronger thicker pushrods easyer and still rpm . |
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7229
Location: Videbaek Denmark
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| Posted: Sun Mar 22, 2015 11:55 am Post subject: |
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| mark tucker wrote: |
| my cr's are quieter than any aluminum Ive heard......... I think cb's hd aluminum ones would be fine for your build....depending on your pushrod tubes and rockers I wonder what the weight diff in the hd aluminum& the .035&.058 is on the same length rod? and just think nascar uses 4x as thick as we do..and therer are also 1/2" WALL PUSHRODS!!! more rocker ratio makes running stronger thicker pushrods easyer and still rpm . |
If your Cromo´s are quieter than Ally´s youre either using old Bugpack´s which were and are crap, or you are doing something wrong.
Dont know the CB´s. Havent tried them yet. I kinda stay with ACN/Smith Bro´s because I know they work well.
T |
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bsairhead
Samba Member
Joined: October 08, 2008
Posts: 3590
Location: viroqua wi.
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| Posted: Sun Mar 22, 2015 12:16 pm Post subject: |
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| chrome molly. One less tool in the box, unless you still have points. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21521
Location: Oklahoma City
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| Posted: Sun Mar 22, 2015 12:39 pm Post subject: |
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Just for information.....there are several types of Chromolly and several methods and grades of hardening.
The method of hardening (and chromo is a through hardening metal and not a case/surface hardening metal) and level (how hard)...coupled with how the part was shaped (wrought versus, cast, versus extruded etc......all will change the way they sound when struck or vibrated.
If you look through Manton's site you will note there are a few different ways they harden and form the 4130/4135 Chromolly they use.
Also....
Chromolly density: .283 lbs per cubic inch
2024-T3 aluminum: .1 lbs per cubic inch. (most typical high performance aluminum pushrod alloy I could find).
Interestingly...I'm surprised that the high strength aluminum PR manufacturers are not using (or maybe they have tried)...some of the newer/better alloys that are even harder and stiffer and lighter like 7033 and 7050. but they are hard to work with.
On the side...my real hobby...is inline skate racing (road racing...I do marathons). My older late 90's skate frames were triple extruded, heat treated 7033 alloy made in Holland. Ugly expensive.
They have a most unique sound when struck by anything. They sound like work hardened magnesium. Totally different from the sound of unhardened or single/double extruded 7033 and 7050 alloys.
Its the same with any worked metal. The outer skin density that comes from extrusion, forging etc...coupled with the level of heat treating makes the sound transmission totally different.
Ray |
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Sun Mar 22, 2015 1:53 pm Post subject: |
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| not in my ca..r but other vw's that rattell like hell most of the time even with aluminum rods.but thats usualy the owner or whoo ever isant adjusting them.but crom's can be quiet too. |
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cliveawn
Samba Member
Joined: December 07, 2010
Posts: 481
Location: Southern Sweden
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| Posted: Sun Mar 22, 2015 2:01 pm Post subject: |
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| mark tucker wrote: |
| my cr's are quieter than any aluminum Ive heard......... I think cb's hd aluminum ones would be fine for your build....depending on your pushrod tubes and rockers I wonder what the weight diff in the hd aluminum& the .035&.058 is on the same length rod? and just think nascar uses 4x as thick as we do..and therer are also 1/2" WALL PUSHRODS!!! more rocker ratio makes running stronger thicker pushrods easyer and still rpm . |
JPM is doing the motor and is fitting his dual taper billet pushrods,I just made this post to find out the difference between the two types.
Im learning alot!
_________________
---------------------------------------------------------
Green 78 Westfalia Helsinki,
2056 with 41 x 34 valves,ported heads
Fully balanced
8,5:1CR
JPM Custom made cam
JPM 7075 dual taper pushrods
IDF 40's with 28mm venturi's
Python CSP 42mm exhaust.
115 HP
Daily driver 2017 Volvo V60 D5 hybrid
Rica stage 2 tune 345hp.
''Funny thing about common sense is that its not very common''
Seismic gun mechanic |
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neil68
Samba Member
Joined: March 17, 2007
Posts: 3440
Location: Calgary, Canada
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| Posted: Sat Mar 28, 2015 7:49 pm Post subject: aluminum pushrods |
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| raygreenwood wrote: |
Interestingly...I'm surprised that the high strength aluminum PR manufacturers are not using (or maybe they have tried)...some of the newer/better alloys that are even harder and stiffer and lighter like 7033 and 7050. but they are hard to work with.
Ray |
I've been looking at using aluminum pushrods to get rid of the large lash that occurs with my chromoly pushrods after the engine warms up...I've seen 0.015" lash.
Here are a couple others that are 7075 aluminum. How does that compare to the 7033 and 7050?
http://logmech.se/eng/products/engine/pushrods/
http://www.csp-shop.com/cgi-bin/cshop2/front/shop_...=&all=
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Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
12.5 seconds @ 107 mph
Dynojet Test: https://www.youtube.com/watch?v=M9B_H3eklAo |
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bugguy1967
Samba Member
Joined: January 16, 2008
Posts: 4343
Location: Los Angeles, CA 90016
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| Posted: Sat Mar 28, 2015 9:52 pm Post subject: |
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| bugguy076 wrote: |
| If you are looking for 8,000 RPM using dual springs, use C/moly. |
If JPM is using Aluminum dual tapers with success, then their aluminum pushrods are seeing over 8,000 RPM. Our industry is changing for the better. There's a lot of good products out today that have gotten a bad wrap becuase of having similar properties. You can't argue one side until you know the other side better than the other person.
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"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine" |
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cliveawn
Samba Member
Joined: December 07, 2010
Posts: 481
Location: Southern Sweden
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| Posted: Sun Mar 29, 2015 5:16 am Post subject: |
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Johannes knows his stuff,i wasnt quite sure of how well known his products are but now I can see how many people use his stuff.
I think my motor is going to be pretty sweet...
He isnt cheap but its just pure quality the work getting done and he is a really nice guy!
_________________
---------------------------------------------------------
Green 78 Westfalia Helsinki,
2056 with 41 x 34 valves,ported heads
Fully balanced
8,5:1CR
JPM Custom made cam
JPM 7075 dual taper pushrods
IDF 40's with 28mm venturi's
Python CSP 42mm exhaust.
115 HP
Daily driver 2017 Volvo V60 D5 hybrid
Rica stage 2 tune 345hp.
''Funny thing about common sense is that its not very common''
Seismic gun mechanic |
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ALB
Samba Member
Joined: August 05, 2008
Posts: 3483
Location: beautiful suburban Wet Coast of Canada
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| Posted: Sun Mar 29, 2015 8:24 am Post subject: |
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| cliveawn wrote: |
Johannes knows his stuff,i wasnt quite sure of how well known his products are but now I can see how many people use his stuff.
I think my motor is going to be pretty sweet...
He isnt cheap but its just pure quality the work getting done and he is a really nice guy! |
If more people thought like you our hobby wouldn't be filled with the cheaply made crap that's out there....
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On a lifelong mission to prove (much to my wife's dismay) that Immaturity is Forever!! |
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bugguy1967
Samba Member
Joined: January 16, 2008
Posts: 4343
Location: Los Angeles, CA 90016
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| Posted: Sun Mar 29, 2015 11:56 am Post subject: |
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| cliveawn wrote: |
Johannes knows his stuff,i wasnt quite sure of how well known his products are but now I can see how many people use his stuff.
I think my motor is going to be pretty sweet...
He isnt cheap but its just pure quality the work getting done and he is a really nice guy! |
If JPM were in my area, I'd be there every day hounding Johannes every day for a job and soaking up as much knowledge as I possibly could from him. I need to plan a trip to Sweden to go there.
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"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine" |
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