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Stroker pistons, AKA "hockey pucks"

Posted By: Cab_Burge

Stroker pistons, AKA "hockey pucks" - 06/09/11 06:38 AM

I'm in the middle of assembling my next low deck stroker motor, 505 C.I.bracket motor. It is a 400 block I bought several years ago from AndyF It will have a 4.25 stroke Ohio Crankshaft CO. crank, bore is 4.350, 6.700 CAT forged steel H beam rods with BB chevy sizes on both ends and a set of custom Diamond pistons that should end up around 12.5 to 1 comp. ratio depending on which cylinder heads I use and the CC of the chambers. I thought I would post the pictures and some information on them, this is the first high compression bracket motor I've built from scratch since I moved to Oregon back in 2005. The pistons are not a max effort class pistons, but there not a shelf piston either They weigh 722.25 grams with the rings,spacers, retainers and wrist pins. The pins are the standard .990 pins as far as I know, not the real good stuff like the ultra lightweight tool steel short rascals that are avialble from Diamond, maybe next time The piston in the rear is a 1970 TRW 383 +.060 Magnum stock replacement piston. BTW, I remember why I don't like dual spiral locks on stroker pistons for low decks using long rods Enjoy

Attached picture 6673863-MVC-036S.JPG
Posted By: Guitar Jones

Re: Stroker pistons, AKA "hockey pucks" - 06/09/11 10:28 AM

They look purty.
Posted By: DragDart360

Re: Stroker pistons, AKA "hockey pucks" - 06/09/11 12:08 PM

Sounds like a sweet build Cab. I'd guess it will run pretty sweet too.
Posted By: JohnRR

Re: Stroker pistons, AKA "hockey pucks" - 06/09/11 02:42 PM

What's the CH of that puck ? I'm too lazy to do the math right now ...
Posted By: supercomp

Re: Stroker pistons, AKA "hockey pucks" - 06/09/11 03:00 PM

About 1.145 on a 9.970 block with 0 deck.
Posted By: Cab_Burge

Re: Stroker pistons, AKA "hockey pucks" - 06/09/11 05:25 PM

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What's the CH of that puck ? I'm too lazy to  do the math right now ...


The piston information sheet shows the compression hieght as 1.150 , the dome volume is 5.7cc and I opted for 1.5 MM compression rings,both 1st and 2nd and 3.0 MM oil rings This is the first time I'm going to be using these smaller rings, I hope there is some power as well as and good sealing with them
Posted By: supercomp

Re: Stroker pistons, AKA "hockey pucks" - 06/09/11 09:19 PM

If you have to cut the block deck to square it up you'll have a positive deck height. I hope your going to run a vacuum pump with those rings.
Posted By: LSP

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 04:08 AM

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I hope your going to run a vacuum pump with those rings.
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Why is that?
Posted By: Cab_Burge

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 04:57 AM

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If you have to cut the block deck to square it up you'll have a positive deck height. I hope your going to run a vacuum pump with those rings.


The deck hieght is -.009 on one number 1 and right at +.003 on number 6 That was doing a quick check to see what it ended up at, I will check all 8 tomorrow I wasn't planning on running a vacume pump on this motor due to being told that these rings are the stock ring sizes used in the new car motors like the LS1, 3rd. gen Hemi and the modular Ford V8 Diamond furnished the rings with the pistons, I told the rep I work with that I wanted a standard tension oil ring, not a low tension oil ring The oil rings are tiny and they don't seem to have a lot of tension when moving them around in the piston ringlands with my fingers I guess I'll see BTW, are you or have you used this size rings in a motor and if so what where your results?
Posted By: supercomp

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 02:58 PM

They will have less wall tension and less contact. With crank case pressure instead of vacuum it will make the rings job harder. Pressure makes it harder for rings to stay seated against bottom of ring groove. Yes we've used them with good success, but with a pump. JMO
Posted By: Quicktree

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 04:37 PM

how much hp are expecting out of this one Cab?
Posted By: Cab_Burge

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 04:42 PM

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how much hp are expecting out of this one Cab?


At least 400 It depends on which heads, intake, carb and the dyno More than anyone in Florida can make with the same parts
Posted By: topfueldart

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 05:51 PM

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Quote:

how much hp are expecting out of this one Cab?


At least 400 It depends on which heads, intake, carb and the dyno More than anyone in Florida can make with the same parts



Posted By: PorkyPig

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 05:56 PM

Quote:

They will have less wall tension and less contact. With crank case pressure instead of vacuum it will make the rings job harder. Pressure makes it harder for rings to stay seated against bottom of ring groove. Yes we've used them with good success, but with a pump. JMO



Are you saying this about any 1.5 mm, 1.5 mm, 3.0 mm ring pack? I'm asking because Mahle sells a bunch of PowerPack replacement pistons with this same pack and these are intended to be pistons for street cars that I wouldn't expect to be using a vacuum pump.
Posted By: RemCharger

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 06:12 PM

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Quote:

how much hp are expecting out of this one Cab?


At least 400 It depends on which heads, intake, carb and the dyno More than anyone in Florida can make with the same parts


Makes perfect sense. If you can get it up to 550, you should be able to make mid 9s.
You go balls to the wall, make 650 horse, you're staring at low 8s
Posted By: moderncylinder

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 06:51 PM

the thinner rings like a 3mm or even a 2mm have more conformability to the bore... aslong as you have enough relief capacity in the land for the application and enough tension,, it will be fine

i run a 2mm oil ring with no vac pump and everything is as dry as a bone

for that cab,, id start with 15-18lbs with a fresh hone though,, i doubt those pistons have alot of relief capacity
Posted By: 440Jim

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 07:04 PM

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I opted for 1.5 MM compression rings,both 1st and 2nd and 3.0 MM oil rings This is the first time I'm going to be using these smaller rings, I hope there is some power as well as and good sealing with them


IMO, the 1.5mm isn't that small. 1.5/25.4=0.0591" which is close to the typical 1/16"=0.0625. Small to me would be the 0.043" rings.

The oil ring is smaller than the typical 3/16"=0.1875", 3.00/25.4=0.1181"

Quote:

The piston information sheet shows the compression hieght as 1.150


OK. I run the shorter rod, 6.535 long and use 1.300-1.320" CH pistons. These leave room for the rings.

Out of curiousity, how far is the top ring from the top of the piston (not the dome)?
And how long is the skirt from the top of the piston?
Posted By: jyrki

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 07:15 PM

Off the shelf Mahle pistons have 1.5/1.5/3mm rings, no problem. Donät remeber the weight, bit they were in thh "eagle 4.5" stroker kit" for a 440. I remeper hte pistons were under 600 grams each, shich in my opinion was great for an off ahlef piston. Coated too. Personally I don't like the oil ring in the pin hole, have had problems with that once, nut that was in a street engine. Something got to the ring roove and locked the oil ring.
Posted By: Quicktree

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 08:49 PM

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Quote:

how much hp are expecting out of this one Cab?


At least 400 It depends on which heads, intake, carb and the dyno More than anyone in Florida can make with the same parts


thats what I am talking about. you are the man Cab good luck with the build . the pistons look nice. I will be ordering a light weight set soon.
Posted By: Cab_Burge

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 09:19 PM

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Out of curiousity, how far is the top ring from the top of the piston (not the dome)?And how long is the skirt from the top of the piston?


I was going to measure and post the length of the skirts and forgot to The pistons and rods are in the block now, sorry I would guess around 2.500 skirt length from the deck to the bottom based on measuring one of my old ross pistons for my pump gas 512 motor, they measure 2.550, they also have a 22 cc dish, the rings on them are .190 from the deck to the top of the top ringland, which has a 1/16 top and 2nd ring.The Ross pistons weighed 556 grams without pins, rings and oil ring spacer, the Diamonds weigh 521 grams bare with the dome The Diamond wrist pins are thicker, longer and heavier than the Ross wrist pins, the Ross pins are tapered and the Diamonds are not :shruggy Next time I will step up to a tool steel lightweight race wrist pins IHTHs
Posted By: Performance Only

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 09:26 PM

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Quote:

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Out of curiousity, how far is the top ring from the top of the piston (not the dome)?And how long is the skirt from the top of the piston?


I was going to measure and post the length of the skirts and forgot to The pistons and rods are in the block now, sorry I would guess around 2.500 skirt length from the deck to the bottom based on measuring one of my old ross pistons for my pump gas 512 motor, they measure 2.550, they also have a 22 cc dish, the rings on them are .190 from the deck to the top of the top ringland, which has a 1/16 top and 2nd ring.The Ross pistons weighed 556 grams without pins, rings and oil ring spacer, the Diamonds weigh 521 grams bare with the dome The Diamond wrist pins are thicker, longer and heavier than the Ross wrist pins, the Ross pins are tapered and the Diamonds are not :shruggy Next time I will step up to a tool steel lightweight race wrist pins IHTHs




Quote:

The deck hieght is -.009 on one number 1 and right at +.003 on number 6




so your going to assemble the engine like that?, really?
Posted By: Cab_Burge

Re: Stroker pistons, AKA "hockey pucks" - 06/10/11 09:31 PM

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The deck hieght is -.009 on one number 1 and right at +.003 on number 6




so your going to assemble the engine like that?, really?


It is assemble now, am I going to run it that way, I don't know I haven't made that decision yet, I will decide after measuring the rest of the deck hieghts and see if the machine shop cut the block wrong or if it caused by the rod , piston or stroke differences If it is the block I will probally try and use a different thickness head gasket, if it is a rod or piston I will fix it, if it is the stroke, I don't know yet
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