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Discussion Starter · #1 ·
anyone know of a good 11:1 piston that would work with a hot rods +4mm stroker crank, because i read that they require a special piston do to rist pin location. also does anyone know why the rist pin is moved thanks ;)
 

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Hotrods does have a offset wrist pin/piston offset.
vitosperformance.com carry's a 719/720 kit that's set up to use what ever piston you want because it doen't have the offset. Nothing against hotrods. I think vito's kit has a 10.75:1 piston..basically a 11:1
the kit is more pricey than the hotrods because it contains the cam, valve springs, and jets
just giving you the upfront scoop..others here I'll give you first hand experience with them.
 

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If you buy that crank from Vito's you're going to overpay for it.

The crank on the Vito's site is a Barker crank/rod. Tim just worker a deal with Vito's because they are so big and can move so many of them. Anyway, any of Barker's distributers can get you that very same crank/rod or a 6mil which you can't get from Vitos.

To answer your question, the piston pin location has to be moved up in the piston 2mm on a piston that is going to be used with the hotrods crank/rod. On the Barker rod, you can run any off-the-shelf piston on it you desire. I prefer the Barker setup because the rod is indestructable and it allows you a broader piston selection.

Keep in mind that the regular pistons are speced on an 84mm stroke, if you add 4 or 6mils of stroke to that, its going to raise the compression ration above advertised. The 11:1 is actually going to be roughly 11.4:1 on the 4mil and 11.6:1 on the 6mil. I do some valve unshouding in a port job that removes some of the combustion chamber material so my 6mils actually run a 11.4:1 and they run fine on 93 octane pump gas all day long.
 

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cstande88 said:
anyone know of a good 11:1 piston that would work with a hot rods +4mm stroker crank, because i read that they require a special piston do to rist pin location. also does anyone know why the rist pin is moved thanks ;)
The CP piston that is made for the kit is a 10.5:1 or a 10.75:1, so it really wouldnt be necessary to worry about getting an 11:1 for it since the compression would be so close anyway.
 

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The reason why they have an offset pin location is for a better piston rod angelerity...it has less stress on the cylinder and piston rings.
 

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Angelerity??? ;)

The reason they have the offset pin is because they use an oem size rod. Now the reason they use the oem size rod may have something to do with thrust angles but I can't say for sure.
 

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thrust angle=rod angularity.....if you didn't all ready know (maddog you probably know this but for those who don't) you cannot increase your stroke by your rod length, only by your crank. Increasing your rod length only degresses your rod angularity thus saving your rings. As most of you know, when a piston goes up from bdc the rod is at an angle forcing it into the wall of the cyliner. before it moves up. Increasing the size of your stroke usually means having to use a shorter rod, which increases rod angularity, and wears your cylinder wall (sleeve) and rings tremendously faster. Offsetting the pin allows you to run a longer rod, or even the shorter rod with less rod angularity thus less force towards the cylinder wall. One of my old instructors at school does the offset pin for FSB 302 stroker kits like the 331 and 347. Supposedly it makes the last alot longer because it's less wear and tear on your piston rings, cylinder, and rod.
 

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Discussion Starter · #8 ·
WOW that makes alot of sence thanks guys :thumbsup:
 
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