Re: stroker 360 with factory rods? why not?
[Re: dirt]
#348301
06/16/09 03:29 PM
06/16/09 03:29 PM
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Joined: Dec 2006
Posts: 1,178 Indy
FlyFish
super stock
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super stock
Joined: Dec 2006
Posts: 1,178
Indy
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I just don't think this is a wise place to cut corners and pinch pennies. Scat I-beams are $270 on ebay for a 4340 steel rod...and no I'm not a salesman for them, they are just a heck of a deal for a quality rod (I put a set in my current engine). If you must go with the stock rod, at least get a good light weight piston to give the rods a better chance of living a long life…but those pistons aren’t cheap.
67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
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Re: stroker 360 with factory rods? why not?
[Re: FlyFish]
#348302
06/16/09 03:39 PM
06/16/09 03:39 PM
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Joined: Jan 2005
Posts: 12,419 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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I also had a set in my 4 inch stroke 318 and they needed ZERO grinding the block to fit, during assembly I tried a stock rod to see and it would have needed a lot of grinding.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: stroker 360 with factory rods? why not?
[Re: HotRodDave]
#348303
06/16/09 04:32 PM
06/16/09 04:32 PM
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Joined: Jan 2003
Posts: 16,123 Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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AFAIK, 340's and 360's use the same basic forging, but the 340's were bushed for a floating pin from the factory, 360's were pressed pin.
if it's going to be a pretty mild street motor, nothing revved to the moon, I wouldn't have a problem using stockers that have been redone. the only issues I can see would be these:
1) you'll most likely need to grind the block a lot more using them w/a 4" crank vs. say, the SCAT I beams (hotroddave didn't have to grind the block at all for the SCAT's).
2) balancing, the heavier rods might make it more expensive to internal balance, or you'll have to balance it externally to 360 specs, not a big deal if it's not being revved to the moon IMHO (Don, B3422W5 ran his old motor for what, 3 seasons running 10.70's externally balanced, and to 7K rpm without issue)
3) if they're currently pressed pin, finding a reasonable cost piston for pressed pin app to work with the closed chambered eddies. looks like the KB745 is your best bet. otherwise you need to bush the small end, adding to the cost.
4) the KB's need the small end narrowed to 1" (magnum rod width, also what most aftermarket rods are, since they're based off of a 6.125" SBC forging). that additional machining will add to the cost, or it will drive you to more expensive options (SRP, Diamond, etc)
I guess it all depends on how much time (block grinding) vs. ability to do yourself (do you have access to a mill?) vs. money you want to spend. cheapest and easiest might be to buy one piston and just fix your stock stroke motor.
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: stroker 360 with factory rods? why not?
[Re: emarine01]
#348306
06/17/09 11:43 AM
06/17/09 11:43 AM
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Joined: Jan 2005
Posts: 3,635 Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
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Quote:
At face value it all sounds right but there are other factors that come to play , the starting and stoping forces are greater as the dwell time at the top and bottom of the stroke change and the rod angle changes with the longer stroke, some say it makes no diff and others say it does ,Thats why the better rod is worth the bucks cause I think nobody knows for sure
That's true, but if you do the calculation the tensile g-forces on the 4" crank motor with a 6.123" rod at 6,000 are actually about 12% lower then the 3.58" crank motor with a 6.123" rod at 6700 RPM even though the Average piston speeds are nearly identical.
I was trying to use average piston speed for calculation because it's easier to understand then going through the kinematic calculations for peak acceleration forces.
Here's an online calculator, you can plug in the numbers yourself.
http://www.slowgt.com/Calc2.htm#PistSpeed
I'm not trying to start a war with anyone, but God forbid, what did people do for 30 years before you could buy a $270 set of rods?!
Plenty of w2 360 motors were built with stock rods/ARP combo, and lived to tell about it.
I'm all for buying quality parts where needed, but I also hate to see people spend money just because...
A better question is, who on the board has broke a stock rod, (stroker or not), and under what conditions did it happen? (RPM, HP, Piston weight, etc...)
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Re: stroker 360 with factory rods? why not?
[Re: emarine01]
#348308
06/18/09 09:31 AM
06/18/09 09:31 AM
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Joined: Jan 2003
Posts: 4,448 Phoenix, AZ
MoparBilly
master
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master
Joined: Jan 2003
Posts: 4,448
Phoenix, AZ
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Dirt,
My question would be, are you going to save money by buying the pistons and crank seperately, or would it be just as inexpensive to buy a ready to go kit with new rods??
FWIW, I have a 3.79 stroke 340 with stock rods, 6400 shift point, 10.70's in a 3000lb A Body. Well over 500 runs on this motor.
"Livin' in a powder keg and givin' off sparks"
4 Street cars, 5 Race engines
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