Author Topic: Sachs Dolmar 166 big bore  (Read 467 times)

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Offline EHP

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Re: Sachs Dolmar 166 big bore
« Reply #20 on: November 08, 2014, 10:23:35 am »
Adam, my first pistons I made were out of 4032 , I found i had no problems of any kind until I tried to really high rpm the big bores , the 60 mm piston worked perfect and I still have that piston here . I put it in a real used 3120 and put it to work cutting big firewood and ran it for a solid week then took it out to see how it looked , I figured if the thing blew up I was not out alot of money . If you phone Wiseco and need just 1 or 2 pistons of a bore they donot do they use 4032 or a different number alum. but I cannot remember it now  maybe 4031 something like that. I seen the alum. sitting on the floor last time I went threw the piston plant . There are other guys making pistons and I have tried them but they may work great in a snowmobile engine but broke all to hell in a nitro motor , When you got chainoil all over your boots and the piston pin goes out the pipe its not a good day  ;D

Offline aclarke

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Re: Sachs Dolmar 166 big bore
« Reply #21 on: November 08, 2014, 04:56:14 pm »
Thanks for the info.  That opposed twin looks like sweet motor. Looks like the crank is forged with an added machined center section.  Great idea.

Adam

Offline aclarke

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Re: Sachs Dolmar 166 big bore
« Reply #22 on: November 08, 2014, 05:12:03 pm »
Ed, I think I remember seeing a picture of one of your pistons many years ago. I may try another with the 4032 for fun. Spent a ton of time machining them and got frustrated after seizing a few motors.  I'll see if I have any pictures

Offline 660magnum

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Re: Sachs Dolmar 166 big bore
« Reply #23 on: November 08, 2014, 05:12:19 pm »
That is correct about the crank. There were two cranks turned end for end with new longer crank pins pressed into a circular connector plate. There was a big decision about the plate to make it a "Dog Bone" or circular shape. Finally for crankcase volume considerations it was made circular. The back crankshaft was cut off and the bearing sets in a blind pocket. The original single cylinder engine (doner Parts)was a cantilever design with a read valve and carb at the rear.
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Offline Eccentric

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Re: Sachs Dolmar 166 big bore
« Reply #24 on: November 08, 2014, 05:21:13 pm »
Great info guys.  What's the minimum # of units (of a custom piston) that Wiseco will do?  About what do they charge per unit?

Offline aclarke

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Re: Sachs Dolmar 166 big bore
« Reply #25 on: November 08, 2014, 05:46:11 pm »
Thats a neat idea of putting the bearing in a blind hole in the crank as the shaft isnt needed with your application.   

Offline aclarke

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Re: Sachs Dolmar 166 big bore
« Reply #26 on: November 08, 2014, 05:49:32 pm »
 These are 62mm that i never used after seizing the 60mm version...


Offline aclarke

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Re: Sachs Dolmar 166 big bore
« Reply #27 on: November 08, 2014, 05:51:52 pm »
heavy compared to Eds 62mm wiseco pistons



Offline EHP

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Re: Sachs Dolmar 166 big bore
« Reply #28 on: November 08, 2014, 07:43:48 pm »
your pretty thick on the piston skirts , that causes seizing cause the thicker grows more in size than a thinner skirt . I keep mine as thin as the stock piston from the factory and have never seized a piston but I never put a piston in without coating the hell out of it either and pay very close attection on piston clearance , A couple 1/10's of a thou makes a huge difference , If its a race motor run it abit loose and if on gas run it looser again. As far as Wiseco goes you need to design your piston and it is not to be the same as anyone elses but Wiseco is pretty much just like a Hooker on the street corner , if you got the money they will build you anything

Offline aclarke

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Re: Sachs Dolmar 166 big bore
« Reply #29 on: November 08, 2014, 11:15:06 pm »
Ed thanks for the input, probably why I had issues.

 

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