Re: Oversize 318 poly pistons?
[Re: Dodgem]
#796860
09/09/10 11:22 AM
09/09/10 11:22 AM
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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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depending on how much lift/duration you have, you can probably use LA flat top pistons an not have an issue with piston to valve clearance... what is the cc's of the poly heads? http://www.summitracing.com/parts/STL-H814CP30/http://www.summitracing.com/parts/STL-526P30/
Last edited by patrick; 09/09/10 11:31 AM.
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: Oversize 318 poly pistons?
[Re: patrick]
#796861
09/09/10 11:37 AM
09/09/10 11:37 AM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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Quote:
depending on how much lift/duration you have, you can probably use LA flat top pistons an not have an issue with piston to valve clearance...
Valves are real close on the poly pretty much need the poly piston they all have notches
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Re: Oversize 318 poly pistons?
[Re: Dodgem]
#796862
09/09/10 12:08 PM
09/09/10 12:08 PM
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Anonymous
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Anonymous
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Quote:
Valves are real close on the poly pretty much need the poly piston they all have notches
I looked at the Summit pistons you linked to above, and they don't have notches.
Also dished. Kinda look like low CR truck pistons to me. But 
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Re: Oversize 318 poly pistons?
#796863
09/09/10 01:19 PM
09/09/10 01:19 PM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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does say that but the ones my buddy used were stock and had valve reliefs?? discription of one on Fleabay These pistons are flat top pistons with two eyebrows along the piston edge. When listed, we have +.020", +.030", +.040", and +.060" pistons available. Please contact us for other sizes. We ask that you specify piston/bore size and bearing sizes with payment. Image is for illustrative purposes only. Buyer will receive correct part(s) for application described within listing. http://cgi.ebay.com/ebaymotors/Dodge-Ply...=item2ea38cb8ac
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Re: Oversize 318 poly pistons?
[Re: Dodgem]
#796864
09/09/10 01:39 PM
09/09/10 01:39 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
description of one on Fleabay
These pistons are flat top pistons with two eyebrows along the piston edge. When listed, we have +.020", +.030", +.040", and +.060" pistons available. Please contact us for other sizes. We ask that you specify piston/bore size and bearing sizes with payment. Image is for illustrative purposes only. Buyer will receive correct part(s) for application described within listing.
http://cgi.ebay.com/ebaymotors/Dodge-Ply...=item2ea38cb8ac
I'd bet money those are Egge pistons. Never used them myself, but have read that they don't have the metal anti-expansion inserts like the factory and that they are OK for a parade car, but not for any performance use.
As for the ones Summit offers, maybe they've changed since you bought them, don't know. I'm curious myself because I have an early 318 poly I'm thinking about swapping for the 277 that's in my 56 Plymouth.
Older NOS or NORS 318 poly pistons do show up on ebay now and then. I'm thinking I'll either go that way or, in my case, just hone the cylinders, re-ring and re-use the original pistons. I realize the last is not an option for the OP, given the amount of bore wear he has.
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Re: Oversize 318 poly pistons?
[Re: Dodgem]
#796865
09/09/10 02:10 PM
09/09/10 02:10 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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Quote:
Quote:
depending on how much lift/duration you have, you can probably use LA flat top pistons an not have an issue with piston to valve clearance...
Valves are real close on the poly pretty much need the poly piston they all have notches
best way to truly check that is to pull a head, put clay on top of the piston, rotate it around a few times assembled, then take out and cut the clay with a razor blade to check actual clearance....
both gross lift and duration (timing events) play into v-p clearance...you could have plenty of clearance with .5" lift but short duration, and not enough with .450" lift and long duration.
the F-M poly ones are listed at 1.79" comp height with a .090" deep, 3" dish. the LA/magnum replacements I listed are spec'd at 1.745/1.755" CH flat tops/no valve reliefs. even if you had to add eyebrows into them, they're $80-150 cheaper than the poly replacements, and should give more compression...
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: Oversize 318 poly pistons?
[Re: polkat]
#796866
09/10/10 10:11 PM
09/10/10 10:11 PM
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Joined: Jun 2005
Posts: 1,021
Chesapeake Va
BobK
super stock
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super stock
Joined: Jun 2005
Posts: 1,021
Chesapeake Va
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Contact Gary Pavlovich. glpavlovich@cox.net He is a Poly guru. Got me 40 over pistons, and a wicked grind cam. He is a good person to know!!!!!
1964 Plymouth Fury x 2
1964 Plymouth Sport Fury
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