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#1
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Dishing Ross pistons
I am going to build a pump gas engine. I have a set of ross flat top pistons sitting in the garage. I was wondering if it is feasible to dish these 15cc? Will there be enough material to dish them?
Or should I look at buying new? |
#2
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What size will the bore be at?
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#3
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You need to measure the crown thickness. Might me better to cut the whole top across for maximum loss
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Be carefull of the feet you step on today.They may be attached to the a$$ you kiss tomorrow. |
#4
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Mike,check with Ross?Tom
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The Following 2 Users Say Thank You to tom s For This Useful Post: | ||
#5
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Often also on their spec sheet they send with the pistons it has thickness, But I agree with Tom. Usually they have a job number stamped on the bottom pin boss area they can look up the specs too.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#6
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With a 4.150” bore you would need to mill off the whole top of the piston by .066” according to my math to end up at 15 CCs gain in volume.
If your block has no intake valve notches then putting such in would buy you back 3 CCs and you could then reduce that .066” by .012” to end up at needing only .054” taken off the piston top. I would think that such is livable and you will not melt out the top ring land if your not looking to make more then 600 Hp. Burn wise and power wise I would much sooner mill the needed amount off the whole top of the piston then mill in a dish. You would also be unshrouding the intake valve more above the .400” lift point.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! Last edited by steve25; 10-05-2023 at 10:24 AM. |
#7
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I wouldnt really like cutting the top of the piston off. What thickness head gasket do you have now? I would start with a thicker head gasket and look at opening up the combustion chamber on the head as well. You could always put a shorter rod in it or offset grind the crank to put the piston further in the hole. Many ways to skin that cat if you want to reuse the old pistons.
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#8
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Selling your pistons and buying new ones built to the specs you need would likely end up being the cheapest and easiest route.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
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#9
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I think when H-O cut a dish in TRWs the were .100 deep and 2.800 diameter.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
The Following User Says Thank You to Skip Fix For This Useful Post: | ||
#10
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Quote:
Lightweight Ross flat tops I’m sure are a lot thinner where you’re going to cut a dish, of course as one would expect their dished forgings are designed for the dish.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
The Following User Says Thank You to b-man For This Useful Post: | ||
#11
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Quote:
2.8" diameter by .100" deep with .no radius 10.09 cc's 2.8" diameter by .100" deep with .100" radius 9.78 cc's 3.5" diameter by .100" deep with .100" radius 15.38 cc's Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#12
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Here is a 22 cc dish in a 4.185 bore.Tom
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The Following 2 Users Say Thank You to tom s For This Useful Post: | ||
#13
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On a set of 428 pistons, I milled .156 deep in a D shape, to keep the quench area. Was about 15-18 cc's, don't remember exactly.
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#14
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Ross 4.135" bore 26cc dished 421 piston, note that the valve reliefs for the early 20 degree 421 heads are almost gone.
They ended up measuring 27ccs.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#15
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Send them back to Ross and let them do what's needed. They probably know something about Pistons.
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Be carefull of the feet you step on today.They may be attached to the a$$ you kiss tomorrow. |
#16
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Yes they do, when I was getting info on my pistons ring lands to see exactly what was involved to back cut some gas ported Total Seal rings they had the spec for every inch of that piston. I bought them in 2003 from Butler, they were not in their computer database, but in a room upstairs they still had the info in a file cabinet.
I got a education on pistons-rings from Ross and Total Seal with this experience. Let the experts decide. |
#17
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but in a room upstairs they still had the info in a file cabinet.
Yep, a set I picked up used they had to do the same.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#18
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If the piston casting is XL408, this is what a 14cc dish looks like on one. The dish is .0875" deep.
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Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures Last edited by tekuhn; 10-24-2023 at 11:34 AM. |
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