402 Engine question: Rod/Piston: Pressed Pin

Ialone · Feb 11, 2020

Curious I am putting together another 402, the only Forged pistons I can find in the 13CC done are the Sealed Power pistons with Pressed Fit Pins. I wanted to use the Scat 6.135" COMPETITION SERIES CONNECTING RODS # 2-ICR6135-7/16 These state they are for floating bronze bushed pins.

Will these rods work with these pistons? I am assuming if it is pressed fit pin in the piston, then we need a rod that will allow the movement to happen? Is this correct? I have only ever used completely stock parts or full floating, so this is new issue for me...

Any help would be very appreciated.

Wolfplace · Feb 11, 2020

Ialone said:
Curious I am putting together another 402, the only Forged pistons I can find in the 13CC done are the Sealed Power pistons with Pressed Fit Pins. I wanted to use the Scat 6.135" COMPETITION SERIES CONNECTING RODS # 2-ICR6135-7/16 These state they are for floating bronze bushed pins.

Will these rods work with these pistons? I am assuming if it is pressed fit pin in the piston, then we need a rod that will allow the movement to happen? Is this correct? I have only ever used completely stock parts or full floating, so this is new issue for me...

Any help would be very appreciated.

No
Press fit refers to the rod not the piston
Pin always floats in the piston
Floated design must have a piston with lock grooves or some way to contain the pin
You need a press fit rod for the piston without provision for pin containment

MikeN · Feb 11, 2020

I bet the stock Chevy rods would be fine.

Ialone · Feb 11, 2020

Wolfplace said:
No
Press fit refers to the rod not the piston
Pin always floats in the piston
Floated design must have a piston with lock grooves or some way to contain the pin
You need a press fit rod for the piston without provision for pin containment

Thank you very much....

Thats what I was unsure about.

Wolfplace · Feb 11, 2020

Ialone said:
Thank you very much....

Thats what I was unsure about.

You are welcome
The rod you want for your piston is 2ICR6135P

Saltherring · Feb 11, 2020

I don't know what you are using this engine for but for street engines the Chevrolet "Dimple" rods work fine. I run them above 7,000RPM in my L78 396. You can usually find a set on eBay.

Any engine that will run above 6,000 should be balanced. And new rod bolts are a must also. I'm running ARP Series 2000 bolts/nuts.

Wolfplace · Feb 11, 2020

Saltherring said:
I don't know what you are using this engine for but for street engines the Chevrolet "Dimple" rods work fine. I run them above 7,000RPM in my L78 396. You can usually find a set on eBay.

Any engine that will run above 6,000 should be balanced. And new rod bolts are a must also. I'm running ARP Series 2000 bolts/nuts.

Totally true & I don't disagree but........

Maybe it's just me but unless you are a machine shop or have one that does stuff for free I fail to understand why anyone would go to the trouble of buying new $70 bolts & spend another $200+ on reconditioning a set of stock nut & bolt rods these days when you can have a new 4340 steel doweled set of rods complete with ARP capscrew fasteners for under $300... especially if you don't already have a decent set of core rods to do.....

25C 70 · Feb 11, 2020

I used the 396 .060 21cc pistons in my 402.

blue_69_malibu · Feb 11, 2020

Does anyone have any experience running this rod, piston AND AFR 265cc Heads?

Assuming you have piston to valve clearance, I'm guessing the compression is rather high.

But I've always wondered what these heads will do to a 396/402.....even though they're a better "fit" for a 427 or 454/468.

Wolfplace · Feb 11, 2020

blue_69_malibu said:
Does anyone have any experience running this rod, piston AND AFR 265cc Heads?

Assuming you have piston to valve clearance, I'm guessing the compression is rather high.

But I've always wondered what these heads will do to a 396/402.....even though they're a better "fit" for a 427 or 454/468.

Which piston?
With the 112cc head
The 13cc one would be about 8.5 & the 21cc one would be about 9.1

GOSFAST · Feb 11, 2020

Ialone said:
Curious I am putting together another 402, the only Forged pistons I can find in the 13CC done are the Sealed Power pistons with Pressed Fit Pins. I wanted to use the Scat 6.135" COMPETITION SERIES CONNECTING RODS # 2-ICR6135-7/16 These state they are for floating bronze bushed pins.

Will these rods work with these pistons? I am assuming if it is pressed fit pin in the piston, then we need a rod that will allow the movement to happen? Is this correct? I have only ever used completely stock parts or full floating, so this is new issue for me...

Any help would be very appreciated.

Hi Andy, if you have a 118cc head you need a 30cc dome. I thought I read you were working with a 102cc chamber, this would need the 20cc's. Also, to correct the finished bore size with our pistons, they are 4.145" not 4.155" mentioned in the message.

For a 20cc dome/118cc head you'll wind up with about 8.5:1, not really that good for you.

Also, always use a floated wrist pin if possible, we rarely press pins any longer.

The 20cc dome size is correct for a smaller chamber head (100 or so)! It appears you do need the 30cc domes??

Thanks, Gary in N.Y.

P.S. Sorry about the wrong bore size on our pistons earlier? Exactly what are the head chambers you are using??

68Chevele · Feb 11, 2020

Georgia69 said:
I bet the stock Chevy rods would be fine.

3/8" GM rods would be fine for that 402. If they can hold 700hp in some of the stuff my buddies have built I am sure they would work well. Heck, I still have a set of 7/16" rods on the shelf and they will hold even more HP.

Ialone · Feb 12, 2020

GOSFAST said:
Hi Andy, if you have a 118cc head you need a 30cc dome. I thought I read you were working with a 102cc chamber, this would need the 20cc's. Also, to correct the finished bore size with our pistons, they are 4.145" not 4.155" mentioned in the message.

For a 20cc dome/118cc head you'll wind up with about 8.5:1, not really that good for you.

Also, always use a floated wrist pin if possible, we rarely press pins any longer.

The 20cc dome size is correct for a smaller chamber head (100 or so)! It appears you do need the 30cc domes??

Thanks, Gary in N.Y.

P.S. Sorry about the wrong bore size on our pistons earlier? Exactly what are the head chambers you are using??

HI Gary- My heads have a 102CC chamber, they were milled at the factory. Trying to keep Compression low, in the 9-9.5 range. Using the Compression ratio calculators I have 102CC Chamber, 4.155 Bore x 3.766 Stroke with 13.9 CC dome and a Compressed gasket of .039 , Piston .005 in the hole, I come up with 9.47:1 thats about what I want it to be.

Ialone · Feb 12, 2020

Wolfplace said:
Totally true & I don't disagree but........
Maybe it's just me but unless you are a machine shop or have one that does stuff for free I fail to understand why anyone would go to the trouble of buying new $70 bolts & spend another $200+ on reconditioning a set of stock nut & bolt rods these days when you can have a new 4340 steel doweled set of rods complete with ARP capscrew fasteners for under $300... especially if you don't already have a decent set of core rods to do.....

This is why I settled on a new set of Scat Rods.

Not that there is anything wrong with the GM stuff, but by the time I get them gone over with new bolts... I am already there on price.

Saltherring · Feb 12, 2020

Wolfplace said:
Totally true & I don't disagree but........
Maybe it's just me but unless you are a machine shop or have one that does stuff for free I fail to understand why anyone would go to the trouble of buying new $70 bolts & spend another $200+ on reconditioning a set of stock nut & bolt rods these days when you can have a new 4340 steel doweled set of rods complete with ARP capscrew fasteners for under $300... especially if you don't already have a decent set of core rods to do.....

I guess that's fine if you like buying Chinese parts. I try not to...but it's getting harder to do.

Wolfplace · Feb 12, 2020

Saltherring said:
I guess that's fine if you like buying Chinese parts. I try not to...but it's getting harder to do.

Ok,,, I do not usually comment on these kinds of posts as it adds nothing to the original question but since this one was directed at me I will make an exception :grin2:
I assume you realize that in this day & age that argument is moot,,,,,,,,,,,,
Buy a new car, new GM, Ford or Chrysler crate engine.... where does half of it come from?

BTW,, How is that USA made computer you are using to post about Chinese merchandise working?
Or the cell phone, TV, wife's washer?
Like it or not it is a global economy & at the least Scat is employing one hell of a workforce right here in the good old USA
Or doesn't that count?

GOSFAST · Feb 12, 2020

Ialone said:
This is why I settled on a new set of Scat Rods.

Not that there is anything wrong with the GM stuff, but by the time I get them gone over with new bolts... I am already there on price.

Hi Andy, with all those number of yours I would consider a "Hyper-390" KB-160 (17cc dome), it will work and put you where you want to be exactly with the C.R. and still have the floated setup!!

I can't help you with the piston size due to the bore already larger than what I keep on the shelf (4.145")!

The KB's would also lower the piston/rod pkge cost substantially, if I can help just get back to me.

Thanks, Gary in N.Y.

P.S. Normally we don't recommend using the "Hyper's", but they would work here in your case! Might make for a very easy balance job also, for the shop anyway??

Saltherring · Feb 12, 2020

Wolfplace said:
Ok,,, I do not usually comment on these kinds of posts as it adds nothing to the original question but since this one was directed at me I will make an exception :grin2:
I assume you realize that in this day & age that argument is moot,,,,,,,,,,,,
Buy a new car, new GM, Ford or Chrysler crate engine.... where does half of it come from?

BTW,, How is that USA made computer you are using to post about Chinese merchandise working?
Or the cell phone, TV, wife's washer?
Like it or not it is a global economy & at the least Scat is employing one hell of a workforce right here in the good old USA
Or doesn't that count?

Gee, all I said was that I try to buy or use American parts if I can, while noting it was getting harder to do.

25C 70 · Feb 12, 2020

I used the Scat rods on my original motor build. My machinist checked them out and said the machining on them was good. I also used the Speed Pro 21cc .060 396 pistons with my original 290 heads along with a Lunati 60203 cam.

Wolfplace · Feb 12, 2020

Saltherring said:
Gee, all I said was that I try to buy or use American parts if I can, while noting it was getting harder to do.

Saltherring said:
I guess that's fine if you like buying Chinese parts. I try not to...but it's getting harder to do.

Not exactly how you worded it but it's all good :thumbsup:

402 Engine question: Rod/Piston: Pressed Pin

Ialone

Wolfplace

MikeN

Ialone

Wolfplace

Saltherring

Wolfplace

25C 70

blue_69_malibu

Wolfplace

GOSFAST

68Chevele

Ialone

Ialone

Saltherring

Wolfplace

GOSFAST

Saltherring

25C 70

Wolfplace

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