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  335 piston in 340
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   Author  Topic: 335 piston in 340  (Read 787 times)
GaWajn
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335 piston in 340
« on: February 16, 2017, 06:29:19 AM »
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I have a friend who wants to rebuild his 340 single (1971 I think). It needs to be bored 20 over to clean up the mess in there. The cylinder has broken fins and looks terrible. He wants to make it into a driver type engine. Will a first over piston for a 335 work in this application?

What's your take on this Bones?
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1970 Ski Doo TNT 292 Bogie (Restored)
1974 Ski Doo Elan (Habs - custom)
stomper
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how about 20 bucks for it?

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Re:335 piston in 340
« Reply #1 on: February 16, 2017, 07:23:07 AM »
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it will work fine i have a 340 cylinder .80 over with an elko piston regular rings
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1961, 1962,1963,1965,1967, 70 custom, 1973 elan modified, 1988 elan modified,2006 mini z rev,2006 freestyle 300
GaWajn
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Re:335 piston in 340
« Reply #2 on: February 16, 2017, 03:05:32 PM »
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The ports match up?
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1970 Ski Doo TNT 292 Bogie (Restored)
1974 Ski Doo Elan (Habs - custom)
stomper
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how about 20 bucks for it?

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Re:335 piston in 340
« Reply #3 on: February 16, 2017, 06:21:03 PM »
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yup the 340 ports were just bigger same width just deeper
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1961, 1962,1963,1965,1967, 70 custom, 1973 elan modified, 1988 elan modified,2006 mini z rev,2006 freestyle 300
Bones
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Re:335 piston in 340
« Reply #4 on: February 16, 2017, 08:01:35 PM »
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Yes you can use a 335 Oly piston in a 340 TnT engine. The 335 piston is really almost 100% the same as a 70 - 340 TnT piston ( rings are the only difference)
The 71 - 340 piston is also the exact same configuration ie; transfer location, size etc. But the 71 piston has a higher dome/crown and the 71 head is different from a 70 head due to the different dome. If you use a 70 TnT piston or a ( any year) 335 piston with a 71 TnT head your compression will be down slightly, for a daily trail rider it is fine, kinda  good as you can use slightly lower octane fuel.
Bones
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Re:335 piston in 340
« Reply #5 on: February 16, 2017, 08:07:51 PM »
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Quote from: stomper on February 16, 2017, 07:23:07 AM   

it will work fine i have a 340 cylinder .80 over with an elko piston regular rings

Stomper....You are talking about a 340 single cylinder TnT engine here If so some thing is wrong, you can NOT bore a 340 single jug to .080 over size. I doo not think you can find a ELKO piston at .080 over size for the 335/340 engine. If you bore a 335/340 to .040 over the sleeve is getting very thin. If you bore one to .040 and use a 70 crank case the piston will hit in the top of case 
Bones
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stomper
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how about 20 bucks for it?

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Re:335 piston in 340
« Reply #6 on: March 2, 2017, 06:32:13 PM »
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i had a few +80 335 elko pistons yes thin but worked.
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1961, 1962,1963,1965,1967, 70 custom, 1973 elan modified, 1988 elan modified,2006 mini z rev,2006 freestyle 300
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