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Aluminum Main Cap Usage #2676009
07/09/19 02:44 PM
07/09/19 02:44 PM
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Minnesota
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RROD Offline OP
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I have a question concerning aluminum main cap usage. Will aluminum caps survive (Longevity) on a 600 hp street motor? Occasional strip but mostly street and lengthy (out of state) highway trips. Or would it even matter for my intended usage? All this talk about cap walk, harmonics and aluminum caps absorbing a lot of stress of a high performance setup have me thinking overtime.

Re: Aluminum Main Cap Usage [Re: RROD] #2676015
07/09/19 03:19 PM
07/09/19 03:19 PM
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Las Vegas
Al_Alguire Offline
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Yes they will be fine in a street strip car. I did a 451 years and years ago with aluminum caps. Car is still street driven now as well as the occasional race pass. When I sold it 16 years ago it logged 5500 street miles and 120 laps at the track running mid 10's in a 65 Belvedere and still does.


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Re: Aluminum Main Cap Usage [Re: RROD] #2676165
07/10/19 08:08 AM
07/10/19 08:08 AM
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Marion, South Carolina [><]
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I have no doubt they'd be fine, but they're a waste of money for your application IMO.


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Re: Aluminum Main Cap Usage [Re: an8sec70cuda] #2676241
07/10/19 12:32 PM
07/10/19 12:32 PM
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Bend,OR USA
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Originally Posted by an8sec70cuda
I have no doubt they'd be fine, but they're a waste of money for your application IMO.
iagree
OP, if you keep the motor in a good state of tune with no detonation, especially at WOT, you won't have main cap issues at that HP level.
Let it detonate a little or a lot and you will work


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Aluminum Main Cap Usage [Re: Cab_Burge] #2676252
07/10/19 01:07 PM
07/10/19 01:07 PM
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North Central, Indiana
Roughbird72 Offline
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Originally Posted by Cab_Burge
Originally Posted by an8sec70cuda
I have no doubt they'd be fine, but they're a waste of money for your application IMO.
iagree
OP, if you keep the motor in a good state of tune with no detonation, especially at WOT, you won't have main cap issues at that HP level.
Let it detonate a little or a lot and you will work


Cab, at what point would it be a good idea to change to ductile caps?


72 Plymouth Roadrunner 11.08@123.25
Re: Aluminum Main Cap Usage [Re: Roughbird72] #2676264
07/10/19 01:46 PM
07/10/19 01:46 PM
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junction city oregon
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Originally Posted by Roughbird72
Originally Posted by Cab_Burge
Originally Posted by an8sec70cuda
I have no doubt they'd be fine, but they're a waste of money for your application IMO.
iagree
OP, if you keep the motor in a good state of tune with no detonation, especially at WOT, you won't have main cap issues at that HP level.
Let it detonate a little or a lot and you will work


Cab, at what point would it be a good idea to change to ductile caps?



You likely already have ductile caps 😉

Re: Aluminum Main Cap Usage [Re: Roughbird72] #2676398
07/10/19 08:48 PM
07/10/19 08:48 PM
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I haven't found any one now making Ductile iron caps any more. Mopar stopped making and selling them and Milidon doesn't offer them either any more whiney
Milidon does offer steel caps, so does 440 Source, but I'm leery of using steel caps on a cast grey iron block twocents shruggy
I have one of the Koleno high nickel blocks that I am planning on using soon for all out N/A build, hopefully the main caps on it will work for my power level luck
I wish Dart, Brodix or some other good quality manufacturer would make a good Mopar V8 race block out of cast Compact Grey Iron like they do for our competition in the Chevy and Ford camps whiney

Last edited by Cab_Burge; 07/10/19 08:49 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Aluminum Main Cap Usage [Re: Cab_Burge] #2676546
07/11/19 11:56 AM
07/11/19 11:56 AM
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North Central, Indiana
Roughbird72 Offline
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According to their website, Milodon still offers ductile iron caps.
Milodon caps


72 Plymouth Roadrunner 11.08@123.25
Re: Aluminum Main Cap Usage [Re: Roughbird72] #2676668
07/11/19 10:11 PM
07/11/19 10:11 PM
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Originally Posted by Roughbird72
According to their website, Milodon still offers ductile iron caps.
Milodon caps

I saw that on their website also last year, according to Tom they don't have them anymore when I called to order several sets, just steel now down whiney


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Aluminum Main Cap Usage [Re: RROD] #2676702
07/12/19 01:12 AM
07/12/19 01:12 AM
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Oregon
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Originally Posted by RROD
I have a question concerning aluminum main cap usage. Will aluminum caps survive (Longevity) on a 600 hp street motor? Occasional strip but mostly street and lengthy (out of state) highway trips. Or would it even matter for my intended usage? All this talk about cap walk, harmonics and aluminum caps absorbing a lot of stress of a high performance setup have me thinking overtime.


You are overthinking it. Put some ARP main studs in it, have the shop torque them to spec and then line hone it and call it good. Save your money for something that matters.

Re: Aluminum Main Cap Usage [Re: RROD] #2676703
07/12/19 01:28 AM
07/12/19 01:28 AM
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What block are you wanting to use?


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Aluminum Main Cap Usage [Re: Cab_Burge] #2676726
07/12/19 07:43 AM
07/12/19 07:43 AM
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North Central, Indiana
Roughbird72 Offline
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Originally Posted by Cab_Burge
Originally Posted by Roughbird72
According to their website, Milodon still offers ductile iron caps.
Milodon caps

I saw that on their website also last year, according to Tom they don't have them anymore when I called to order several sets, just steel now down whiney


Huh, why list them as ductile? shruggy Summit and Jegs have them listed as ductile. I wonder how many have been purchased under that assumption?


72 Plymouth Roadrunner 11.08@123.25
Re: Aluminum Main Cap Usage [Re: RROD] #2676808
07/12/19 12:52 PM
07/12/19 12:52 PM
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Syracuse,NY
CompWedgeEngines Offline
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You dont need aluminum caps. Stud it, align hone it properly, balance the rotating assembly correctly, and tune it. Yours is simply not an application where it really benefits from it. Good luck.


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Re: Aluminum Main Cap Usage [Re: AndyF] #2676812
07/12/19 01:01 PM
07/12/19 01:01 PM
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Aurora, Colorado
451Mopar Offline
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Originally Posted by AndyF
Originally Posted by RROD
I have a question concerning aluminum main cap usage. Will aluminum caps survive (Longevity) on a 600 hp street motor? Occasional strip but mostly street and lengthy (out of state) highway trips. Or would it even matter for my intended usage? All this talk about cap walk, harmonics and aluminum caps absorbing a lot of stress of a high performance setup have me thinking overtime.


You are overthinking it. Put some ARP main studs in it, have the shop torque them to spec and then line hone it and call it good. Save your money for something that matters.


iagree

Been using stock caps with ARP studs on 600 HP street engines. On a street engine, your not normally at WOT all the time anyway. Save the money you would have spent on caps and get a light weight rotating assembly that will take strain off the block and caps.

Re: Aluminum Main Cap Usage [Re: 451Mopar] #2676913
07/12/19 08:52 PM
07/12/19 08:52 PM
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Minnesota
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Thanks for all the advise everyone. With all the different ways and opinions to build a mouse trap I do tend to overthink the available options.

Last edited by RROD; 07/13/19 05:48 PM.
Re: Aluminum Main Cap Usage [Re: RROD] #2676926
07/12/19 09:23 PM
07/12/19 09:23 PM
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Originally Posted by RROD
Thanks for all the advise everyone. Will all the different ways and opinions to build a mouse trap I do tend to overthink the available options.

It is way better to be careful on engine builds than not work up grin


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Aluminum Main Cap Usage [Re: Cab_Burge] #2676959
07/13/19 12:31 AM
07/13/19 12:31 AM
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Balt. Md
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My 440/493 has been in my car running fine since June 2011 and I used 440Source billet steel main caps with ARP main studs and that's all with a main cap align bore of course. Mine is a street car that only gets raced once or twice a year. Its held up great as I have had no problems at all with it and it will run 10.70's best in full street trim. I agree aluminum caps will work fine but they are not needed for your application. Good luck with it , Ron







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