Author Topic: Dolmar 7900 piston choices  (Read 7000 times)

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Offline EHP

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Re: Dolmar 7900 piston choices
« Reply #30 on: May 07, 2012, 09:04:43 pm »
when you get a jug replated you can ask for whatever clearance between the piston and bore you want , On my 52mm jugs I had replated I went with 52.01 mm bore size so that gives me .0025 of a inch clearance and that is not counting on the coating so they are a touch tighter than that , once you get up to say .004 that is getting pretty loose and 99.9% of the time you are loose material on the intake skirt so you have to watch you donot get to much clearance and drop that skirt off your piston cause when that happens , lets just say its not a good thing  ;D
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Offline Cut4fun .

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Re: Dolmar 7900 piston choices
« Reply #31 on: May 07, 2012, 09:21:23 pm »
when you get a jug replated you can ask for whatever clearance between the piston and bore you want ,

Thanks Ed.

I know one guy that tried to make his 5cu build so tight he kept scuffing brand new pistons.  Couldnt have happened to a  :-X :-X :-X :-X :-X :-X guy  ;D
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Offline Playinwood

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Re: Dolmar 7900 piston choices
« Reply #32 on: May 07, 2012, 09:30:09 pm »
Okay plate the jug... I thought he meant plate the piston... I didnt understand that...the piston already has a heat resistant "slippery" coating and now you want to plate it... brain fart on my behalf sorry

Kevin those WORK saws will flat out fly if ported to the pistons potential, might get a little hot in the wood pile though ;D ;D
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Offline Playinwood

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Re: Dolmar 7900 piston choices
« Reply #33 on: May 07, 2012, 09:32:35 pm »
Quick everybody, you've got 2 weeks to Webster.... :D :D

One will be there for sure....

Offline EHP

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Re: Dolmar 7900 piston choices
« Reply #34 on: May 07, 2012, 11:10:07 pm »
I'm not sure how many will be at Webster but figure a couple should be there but I know 1 that will not be and that is me , I need to get the foot infection taken care of first , I figure keeping  my foot is a little more important than a contest

Offline EHP

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Re: Dolmar 7900 piston choices
« Reply #35 on: May 07, 2012, 11:14:36 pm »
Kevin, I'm not sure what he had for clearance but my first 60mm were at .0015 and had no problem but found that a touch more clearance you got full power alot faster instead of waiting until the piston loosen up abit , now those were on alcohol but the very first piston that went into a racesaw was in Chopwoods 3120 and I first took that piston and put it in a stock 3120 and took the saw to the wood pile and ran it as hard as I could for 3 or 4 hours just to make sure no problems , I honestly think that turned out the best way to do a saw

Offline EHP

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Re: Dolmar 7900 piston choices
« Reply #36 on: May 08, 2012, 11:37:34 am »
pretty sure we are sold out of pistons at this moment , if everyone comes threw with the coin we are sold out thanks Ed

Offline Cut4fun .

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Re: Dolmar 7900 piston choices
« Reply #37 on: May 08, 2012, 12:30:39 pm »
I just seen a guy showing off his alky 7900 with a wide skirt piston he called it. I just had to laugh to myself because all it looked like  inside the exhaust port was a 1.5mm ring 272 piston.
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Offline EHP

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Re: Dolmar 7900 piston choices
« Reply #38 on: May 08, 2012, 09:24:10 pm »
some guys are putting the stock 272 piston in these but the race piston would gain alot more wide the far wider skirt and being coated the heat does not seek to bother the piston , I have put a couple of the 60mm race pistons in gas racesaw and so far no problem

Offline Playinwood

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Re: Dolmar 7900 piston choices
« Reply #39 on: May 08, 2012, 10:03:20 pm »
I just seen a guy showing off his alky 7900 with a wide skirt piston he called it. I just had to laugh to myself because all it looked like  inside the exhaust port was a 1.5mm ring 272 piston.

You could tell just by taking a muffler off and peering inside it was a 272 1.5 mm ring piston? dayuuuuum!!!

Btw my 7900 ,vintage about 2005, is the 272 piston. Its works fine...

 

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