| Author |
Message |
    
berny
New member
Username: berny
Post Number: 3
Registered: 01-2017
| | Posted on Sunday, February 05, 2017 - 11:45 am: | 
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I'm rebuilding an Acadia 8 hp 2 cyl. and i wonder if somebody new the main bearing tolerance. I plane to adjust the bearing to .002 inches and i need a .010 inches paper gasket to achieve this goal. I wonder if someone knew the tolerance for the bearing and where can i find the gasket sheet. |
robert
Senior Member
Username: robert
Post Number: 831
Registered: 07-2003
| | Posted on Sunday, February 05, 2017 - 12:46 pm: |
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Others can correct me if I'm wrong, but it sounds like what you need is a shim, not a gasket. Copper shim material will make the seal if the surfaces are properly prepared, and will give you the clearance you want. There used to be sheet material you could buy made up of sheets 2 thou or so thick, stacked on each other up to 20 thou or so. You cut out your shape and then peeled off as many sheets as you needed to to get the right clearance. And of course if you needed to adjust for bearing wear later you could peel off more. |
berny
Member
Username: berny
Post Number: 4
Registered: 01-2017
| | Posted on Sunday, February 05, 2017 - 01:56 pm: |
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Thank you for your reply. I thought to used copper shim but i wonder if it's make a good seal, the Acadia is a 2 stroke engine so you've got pression on the crankcase. The existant seal is made out of
fine paper gasket layer about 5 thou. Do you have leaking problem with copper shim ? |
miro
Senior Member
Username: miro
Post Number: 899
Registered: 11-2001
| | Posted on Tuesday, February 07, 2017 - 08:38 pm: |
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The seal around the bearings is made by the grease that you put in with the greasers.
One turn of the greaser will usually last about 20 minutes of running under load.
The internal crankcase pressure is usually in the range of 5 to 8 psi, so once the engine gets warm you may see grease droplets spinning off the crank. But since the internal "atmosphere" inside the case is a mixture of gas and oil, you'll still have lubrication on the bearings.
You've got about the right amount of bearing clearance, but I wouldn't use much more than that.
miro. |
keith
Senior Member
Username: keith
Post Number: 482
Registered: 02-2002
| | Posted on Wednesday, February 08, 2017 - 05:34 pm: |
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I believe a paper gasket is appropriate for sealing the upper and lower crankshaft housing. You just need to find the correct material thickness. Brass laminated stock, copper or steel shims are the required for rod bearings. |
berny
Member
Username: berny
Post Number: 5
Registered: 01-2017
| | Posted on Sunday, March 12, 2017 - 07:08 pm: |
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Here is a video of the first start of my Acadia 8 hp
https://www.youtube.com/watch?v=tLBqkke4veo |
ned_l
Senior Member
Username: ned_l
Post Number: 114
Registered: 08-2012
| | Posted on Sunday, March 12, 2017 - 08:15 pm: |
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Congratulations, it looks and sounds great! |
