Forged Rotating Assembly---advice needed

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Mar 7, 2006 | 11:39 AM

oregonsharkman

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Melting Slicks

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From: Keizer Oregon

Forged Rotating Assembly---advice needed

My block is going out next week to be Magnafluxed and cleaned up...new bearings..etc......My existing rotating assembly is: Eagle cast steel stroker crank 3.75" , PM 5.7" rods, Silv-o-lite "Claimer" pistons

I was just looking for opinions/advice on upgrading to something like a 4340 forged crank with forged 4340 H-beam rods and forged pistons.

The motor was previously rated (by AR Racing

) at 440hp@5100 rpm has aluminum RPM heads and ran pretty strong until water magically appeared in the oil after <1500 miles.

Obviously the benifit of a forged rotating assembly is strength..........Any drawbacks?? the car will not be a daily driver and will see only nice weather cruising and occasional track time.

Any favorite products??? What about matching components??? Internal vs. External Balance??? 5.7 vs 6.0 rod length???

Last edited by oregonsharkman; Mar 7, 2006 at 11:42 AM.

Mar 7, 2006 | 11:51 AM

The_Dude

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From: Here to make friends

St. Jude Donor '11, '16-'17

Sorry to hijack, but what did AR have to say about all this? Did they offer you any support? Who's your machine shop?

Mar 7, 2006 | 12:09 PM

oregonsharkman

Thread Starter

Melting Slicks

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From: Keizer Oregon

Quote:

Originally Posted by The_Dude

Sorry to hijack, but what did AR have to say about all this? Did they offer you any support? Who's your machine shop?

Well I overheated the motor pretty badly once.....So I am not going to directly place the blame on AR, but during dissasembly I have found some signs of "assembly in a hurry" to say it nicely........For instance the pistons are not what they said...instead of KB hypers they are silvolite claimers....the edel 750 carb was a reman....paint was left on the surface of numerous gasket interfaces (like the heads)...etc.....

Honestly I would rather just cut my ties to AR, use the good components that I have and build a real motor (like I should have done the first time)....My machine shop is Davis auto in Salem.....All I need them to do is inspect for cracks in the block and install cam bearings......Everything else I will do myself-------except for the heads which will go to Louthans Competetion Shop

Mar 7, 2006 | 12:48 PM

The_Dude

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From: Here to make friends

St. Jude Donor '11, '16-'17

You should also think about having your rotating assembly dynamically balanced. Either Davis, or Louthans should be able to do this for you.

Mar 7, 2006 | 01:33 PM

Solid LT1

Le Mans Master

Joined: Dec 2003

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From: Fremont CA

I sent you a Email about Sallee Chevy in Oregon. I buy parts from them. I would go with Mahle pistons if your shop has the "good guy" pricing like my local shop on them. Really nice pieces. Use Manley or other American brand connecting rods ONLY! in my opinion. Scat cranks are OK but Competition Products has good quality American made stuff within $100 of the Chinese forgings Scat imports to machine here.

Mar 7, 2006 | 03:41 PM

enkeivette

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I'm using a Scat 383 forged crank, Scat 6" forged rods and SRP forged aluminum pistons with no problems yet, 6" rods I am told are better for high rpm. Good luck.

Mar 7, 2006 | 04:13 PM

Gordonm

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From: Forked River NJ

Quote:

Originally Posted by torqvette

I'm using a Scat 383 forged crank, Scat 6" forged rods and SRP forged aluminum pistons with no problems yet, 6" rods I am told are better for high rpm. Good luck.

I am using this also. I went with 5.7 rods. There is no HP to be gained by using 6 inch rods and the 6 inch rod puts the pin up in the ring land. A spacer is needed for the rings. The engine builder is running these in a drag motor that runs 7600 rpm and has 2 seasons on them with no failure. Either way you can't go wrong. These rods have 7/16 rod bolts and are rated to 700HP.

Mar 7, 2006 | 06:34 PM

enkeivette

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Quote:

Originally Posted by Gordonm

My understanding is that 6" rods have more dwell at TDC which yields more high end hp. But I'm sure with a street strip engine, the difference is minimal.

http://www.musclecarengines.com/Rod_Ratios.htm