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Post by goines2 on Feb 18, 2013 2:30:12 GMT -5
You can run 30 over pistons in a 40 over engine. My suggestion is if you are using hypertech pistons to not do it, but of you are running a cast piston they will expand an you will still have clearance so they don't scuff. You ring gap will be larger and you will lose some compression due to blow by. So if its high compression high hp high torque you are wanting not the best idea but can help on derby situations, with some of the right components with it. You can also pull into an arena with 4 flat tires, but people dont for a reason! .30 over pistons in a .40 over hole simply does not compute. You will have minimal compression, mega blowby, and many broken rings in your futire if you do it.
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Post by huhn137 on Feb 18, 2013 3:19:52 GMT -5
I like world, I know there's a guy around here with world heads, sounds pretty darn good Mine? Love them never have had a problem with them sound great make good power on a 355
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Post by shr283r on Feb 18, 2013 9:44:14 GMT -5
Can't run .010 over? Do some checking on piston sewell and check what a piston to wall spec is good for our sport. I said you will lose a little compression and you will have some blowby, hypertech pistons will only sewell 0.001 to 0.002 and a cast piston is much more then that. Forged piston sewell more yet. Once again we are not talking about dirt mod cars or drag cars, or daily drivers for that matter.
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Post by Comet Cyclone on Feb 18, 2013 14:09:44 GMT -5
So in my motor I have forged pistons. engine guys made the bore .005 clearance for forged pistons. Should .005 be enough to have the piston rock? From what i understand the clearance should be .004-.006 for these pistons.Also from what I understand they expand more (to a point) than stop(expanding). I'm thinking about opening up the clearance another .002 Not sure if I should bother if it's not cost effective.Motor is assembled and ran it last year.But I started it (to warm it up)and for the heck of it put a breaker bar on it and seems to turn with quite a bit of effort when warmed up.I had the heads off a month ago and the bores didn't have any obvious scuffing either.I'm not using a high torque starter and seems to turn over easily with the stock starter when hot.Rand the motor last year with warped heads and no radiator for 15 mins but had problems with motor stalling.Eventually wouldn't start to what I believe a dead battery or possibly the heat seizing / weak battery combination. I just ordered a high torque starter this year though.
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Post by shr283r on Feb 18, 2013 18:48:12 GMT -5
With cast or forged, pistons like to run .008 to .010, and don't have any problems. Forged do expand to a point then stop and are a stronger piston. However the do expand more then cast and hypertech, if you give yourself .008 to .010 to expand you shouldn't have much trouble with heat seize. Also remember other areas are going to get hot too bearings and so on. So choose you other parts carefully.
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Post by derbydriver27 on Feb 18, 2013 19:29:46 GMT -5
how would it turn out to put world heads....a lunati cam 468 lift...roller rockers....new intake and new carb....and put it on a stock lower end. Would it hurt the motor at all? And what would be the benefits of it?
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429
Heat Winner
Posts: 356
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Post by 429 on Feb 19, 2013 19:09:15 GMT -5
im wanting to build one of these motors. im goin to change out the heads and cam for sure but not sure what to do bout the bottom end. any tips or suggestions thanks
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lincoln
Feature Winner
Posts: 3,176
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Post by lincoln on Feb 19, 2013 20:30:07 GMT -5
If you're not going to use the heads then save your money and get a non Vortec motor. Itll be cheaper and the bottom ends are the same.
If you want a factory roller almost any SBC with centerline valve covers is factory roller.
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Post by 0cents on Feb 19, 2013 21:06:46 GMT -5
not all centerbolts are roller, some of the roadmasters had them, otherwise it had to be a vortec.
all depends on how much money you want to spend
they run good stock, or with upgrades
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Post by mudmaster on Feb 21, 2013 4:52:34 GMT -5
shr, .030 pistons in a .040 bore is terrible advice. just run the right size bore and open up your ring gap to allow clearances when it swells. Also post above was dead on,hyper pistons swell less under heat. look at your oil system and over compensate for oil flow and coolant passages to be clean and promote good coolant flow from both. Then simply improve any areas there is friction. mark
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Deleted
Deleted Member
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Post by Deleted on Feb 21, 2013 16:35:29 GMT -5
arent the hyperu pistons a little tighter to begin with too?
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Post by farmer33f on Feb 22, 2013 11:43:35 GMT -5
anyone used a set up like this to increase there cooling,? does it work Attachments:
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Post by rhull1977 on Feb 22, 2013 15:55:36 GMT -5
not all centerbolts are roller, some of the roadmasters had them, otherwise it had to be a vortec. all depends on how much money you want to spend they run good stock, or with upgrades This is not exact almost all car one piece seal engines are roller and most truck engines after 92 the vortec started in 96. The one piece seal engines work fine to build not really any different then other sbcs
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noser23x
Feature Winner
R.W.C.
Posts: 1,970
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Post by noser23x on Feb 22, 2013 20:06:31 GMT -5
I like world, I know there's a guy around here with world heads, sounds pretty darn good Mine? Love them never have had a problem with them sound great make good power on a 355 Yes, sounds pretty wicked if I do say so myself
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Post by huhn137 on Feb 23, 2013 2:56:52 GMT -5
Wait until you hear the new one!
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