Author Topic: really long rod stroker 427  (Read 6199 times)

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TomP

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really long rod stroker 427
« on: February 04, 2021, 07:54:38 PM »
I am trying to use up some of the parts i've got hanging around. So today i just picked up the crank from the machine shop. I had a 390 crank that spun a bearing. I figured some day i'd use it in a 390 with the 351M rods and 410 pistons but have a set of 4.28 bore pistons with a 1.14" compression distance and a 64 top oiler block bored to fit them. Hmmm. So i calculated it out. A 7.1" long rod is the longest normally available and with a 2.20" journal there should be plenty of space to offset that crank to a 3.84" stroke and make a zero deck with those pistons. I could have used a longer stroke but then rods would be a custom size. This saves an otherwise useless crank and pistons.


Stangman

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Re: really long rod stroker 427
« Reply #1 on: February 04, 2021, 09:38:31 PM »
What would that be in cubic inches

Joe-JDC

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Re: really long rod stroker 427
« Reply #2 on: February 04, 2021, 10:14:36 PM »
4.28  x 4.28 x 3.84 x 6.2832 = 441.977 cubic inches.  1.848958 rod ratio.  Should be a  quick revving combination.  Joe-JDC
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TomP

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Re: really long rod stroker 427
« Reply #3 on: February 04, 2021, 11:25:50 PM »
I looked at leaving the stroke standard but offsetting the pin bushings to make the rods 7.13" but this seems easier and didn't cost much more than a regular crank grind. The pin bushings still need to be done as the pistons use a .985" early Hemi pin.

Apparently those long rods are mostly used on 440 Mopar strokers.

This is getting ported C4AE-G heads and an Edelbrock F427 intake so it's not some max effort deal. Mostly using up the parts i've accumulated before I die.

winr1

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Re: really long rod stroker 427
« Reply #4 on: February 05, 2021, 05:14:30 AM »
Cool.. cant wait to see the results :-)



Ricky.

blykins

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Re: really long rod stroker 427
« Reply #5 on: February 05, 2021, 06:31:11 AM »
I use 6.800-7.100" rods on some short stroke FE's.  It's the only way to keep the piston weight down with a tall deck block.

This engine used some 7.000" K1's:

http://fepower.net/simplemachinesforum/index.php?topic=9078.0

It was a 4.350" x 3.780" combination, using a custom Superlight Scat crankshaft.

https://www.youtube.com/watch?v=mQ3tRJdDwFQ
Brent Lykins
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My427stang

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Re: really long rod stroker 427
« Reply #6 on: February 05, 2021, 07:22:00 AM »
Sounds awesome, but before you buy any parts, but look close at oil feeds on the rod throws when you cut a stock crank that much. 

The longer throw of the 390 crank likely makes the oil feed more steep (and better for this) but Brent can certainly chime in with experience on what happens when the crank doesn't want a 2.20 journal

Also, you need to go wider too, not just smaller.  Sorry if I am pushing out info you know already, but I haven't gone this way with factory cranks due to cost of fitting the rods

If it works though, should be a fun machine
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

blykins

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Re: really long rod stroker 427
« Reply #7 on: February 05, 2021, 07:40:38 AM »
Sounds awesome, but before you buy any parts, but look close at oil feeds on the rod throws when you cut a stock crank that much. 

The longer throw of the 390 crank likely makes the oil feed more steep (and better for this) but Brent can certainly chime in with experience on what happens when the crank doesn't want a 2.20 journal

Also, you need to go wider too, not just smaller.  Sorry if I am pushing out info you know already, but I haven't gone this way with factory cranks due to cost of fitting the rods

If it works though, should be a fun machine

He should be ok on the oil hole location because he's offset grinding.  Cutting the width down is always a booger though.
Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
www.customfordcams.com
502-759-1431
Instagram:  brentlykinsmotorsports
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My427stang

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Re: really long rod stroker 427
« Reply #8 on: February 05, 2021, 07:54:37 AM »
Sounds awesome, but before you buy any parts, but look close at oil feeds on the rod throws when you cut a stock crank that much. 

The longer throw of the 390 crank likely makes the oil feed more steep (and better for this) but Brent can certainly chime in with experience on what happens when the crank doesn't want a 2.20 journal

Also, you need to go wider too, not just smaller.  Sorry if I am pushing out info you know already, but I haven't gone this way with factory cranks due to cost of fitting the rods

If it works though, should be a fun machine

He should be ok on the oil hole location because he's offset grinding.  Cutting the width down is always a booger though.

 8)
---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

mike7570

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Re: really long rod stroker 427
« Reply #9 on: February 05, 2021, 12:34:14 PM »
Sounds awesome, but before you buy any parts, but look close at oil feeds on the rod throws when you cut a stock crank that much. 

The longer throw of the 390 crank likely makes the oil feed more steep (and better for this) but Brent can certainly chime in with experience on what happens when the crank doesn't want a 2.20 journal

Also, you need to go wider too, not just smaller.  Sorry if I am pushing out info you know already, but I haven't gone this way with factory cranks due to cost of fitting the rods

If it works though, should be a fun machine

pic of oil feed holes on my 3.99 stroke crank 2.20 journal and 1.900 width (wasn't a problem on mine, still for sale btw)
He should be ok on the oil hole location because he's offset grinding.  Cutting the width down is always a booger though.

blykins

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Re: really long rod stroker 427
« Reply #10 on: February 05, 2021, 12:46:56 PM »
Sounds awesome, but before you buy any parts, but look close at oil feeds on the rod throws when you cut a stock crank that much. 

The longer throw of the 390 crank likely makes the oil feed more steep (and better for this) but Brent can certainly chime in with experience on what happens when the crank doesn't want a 2.20 journal

Also, you need to go wider too, not just smaller.  Sorry if I am pushing out info you know already, but I haven't gone this way with factory cranks due to cost of fitting the rods

If it works though, should be a fun machine

pic of oil feed holes on my 3.99 stroke crank 2.20 journal and 1.900 width (wasn't a problem on mine, still for sale btw)
He should be ok on the oil hole location because he's offset grinding.  Cutting the width down is always a booger though.

Big difference between a steel crank and a cast crank.  If you offset grind, it's one thing, but if you cut the journals down to 2.200" and keep it standard stroke, the oil holes on a cast crank can move right into the journal radius. 
Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
www.customfordcams.com
502-759-1431
Instagram:  brentlykinsmotorsports
YouTube:  Lykins Motorsports

TomP

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Re: really long rod stroker 427
« Reply #11 on: February 05, 2021, 04:14:31 PM »
The holes did move outward but shouldn't be a problem, he did a nice job radiusing the oil holes toward the center. They are not widened so i'll have to get the rods narrowed.

mike7570

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Re: really long rod stroker 427
« Reply #12 on: February 05, 2021, 04:42:35 PM »
Sounds awesome, but before you buy any parts, but look close at oil feeds on the rod throws when you cut a stock crank that much. 

The longer throw of the 390 crank likely makes the oil feed more steep (and better for this) but Brent can certainly chime in with experience on what happens when the crank doesn't want a 2.20 journal

Also, you need to go wider too, not just smaller.  Sorry if I am pushing out info you know already, but I haven't gone this way with factory cranks due to cost of fitting the rods

If it works though, should be a fun machine

pic of oil feed holes on my 3.99 stroke crank 2.20 journal and 1.900 width (wasn't a problem on mine, still for sale btw)
He should be ok on the oil hole location because he's offset grinding.  Cutting the width down is always a booger though.

Big difference between a steel crank and a cast crank.  If you offset grind, it's one thing, but if you cut the journals down to 2.200" and keep it standard stroke, the oil holes on a cast crank can move right into the journal radius.


Okay, I wasn't following the reason to reduce the journal without offset grinding. Since it needs new BBC rods anyway gaining stroke seems like an easy thing to do.
« Last Edit: February 05, 2021, 04:58:56 PM by mike7570 »

blykins

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Re: really long rod stroker 427
« Reply #13 on: February 05, 2021, 06:04:06 PM »
The holes did move outward but shouldn't be a problem, he did a nice job radiusing the oil holes toward the center. They are not widened so i'll have to get the rods narrowed.

I've seen it be a craps shoot there.  I had a 352 crank cut down to BBC journals and one oil hole ended up in the fillet.  Grinder didn't catch it. 
Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
www.customfordcams.com
502-759-1431
Instagram:  brentlykinsmotorsports
YouTube:  Lykins Motorsports

frnkeore

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Re: really long rod stroker 427
« Reply #14 on: February 06, 2021, 01:08:07 PM »
Yes, it is just common since that the oil hole will move in the direction of the angle that it is drilled at if, the radius of the journal is reduced, w/o offsetting the center line to make up for it. Offset grinding has been around, at least 100 years but, it's usual purpose is aim at as much stroke increase as possible, there by leaving the outer surface in place, minus the material for clean up and I wouldn't remove more than .020, from that surface. Equivalent to a .040 under bearing and using however much you do take off that surface, to increase the journal radius.

With 2.25 journals you can have a FE rod journal offset ground to 3.96 stoke. It can be done for $250 + shipping, in Reddind CA. That's the price I got 1 year ago.

It doesn't help the OP but, a easy offset grind would be a 414/416 ci engine, using 390 Cad rods (2.25 dia x 7/8 wide x 6.5 long) 3.96 stoke with a 390 crank. Used in combination with a 410, 1.660 CH piston (1.660 + 6.5 + 1.98 = 10.140).

It's a little harder but, you could also do it with a Pontiac, 6.625 long x 2.25 dia rod (but they are a little wider on the big end) and .080 over SBC pistons, 1.56 CH, with bushed small ends (1.56 + 6.625 + 1.98 = 10.165).

Just food for thought.

Edit:
One other combo, I forgot to mention, is using the 317/368 Linc rods (if you could find them), they are also 2.250 journals and 7/8 wide. That would work out this way, 1.98 + 7.065 + 1.125 CH = 10.17. There are all kinds of SBF & SBC pistons, with CH's of 1.09, 1.100, 1.125 and 1.130.
« Last Edit: February 06, 2021, 06:11:44 PM by frnkeore »
Frank