Crankcase gasket on my 1981 2pg, not sure why, any ideas?

[sbklf]

I have not made it as far as splitting the case but I can see excess gasket material around the seam so am sure there is currently a gasket between the case halves. Thanks to your replies to my previous post, I know it is not supposed to be there. I am wondering if maybe it was common golf course maintenance to rebuild these engines and they put gaskets in them to ensure a good seal. The gasket looks pretty thick so I am also wondering if they might have machined one of the case faces to accommodate for it, hopefully I can see some signs of why and how once I split the case. Any insight on what might have happened here?

[TheGDFP]

Unless some one pried it apart and mangled the surface, or just thought it needed one, or rebuilt the crank too wide, or... lol

Get it apart, measure every thing.

[sbklf]

Originally Posted by TheGDFP

Unless some one pried it apart and mangled the surface

Get it apart, measure every thing.

Exactly correct three areas on one of the halves were mangled pretty well. I know it is not the best way to measure but I took the averages of about 30 measurements with my dial caliper after a little surfacing (should have taken before measurements) and I have 104.9mm ID between the bearing stops on the case halves and 105.89mm OD to the outside surfaces on the bearings on the old crank (.98mm wider than the ID). The gasket I removed from between the case halves was about .75mm. I quite possibly could have taken .25mm off while surfacing but by this it looks like fit between the case halves was pretty tight.

Is there a tolerance listed somewhere for this?

What should the measurements be?

I know it sounds cheesy but it was either sell my rebuild kit and scrap the cart or try this and I decided to give it a shot. I surfaced the faces best I could on a machined flat surface with 800 paper (wet) and very carefully until I had good flat surfaces. I will press the new bearings on the new crank and measure it and re-measure the case ID to determine the spacer or gasket thickness I need. I might consider a piece of aluminum for a spacer since I have good flat surfaces now.

[TheGDFP]

Been there... I typically use a whetstone to knock the high spots down.
JBWeld if the scars are deep. Yamabond fills small gaps.
Stock, they had two shims on the crank before the bearing, not needed now of course.
Worst case, you can swap one of the 6206 bearings for a 6007, 14mm wide vs 16mm, and shim.
You'll need to be sure the crank webs don't hit the case, shim or clearance to suit.

[sbklf]

Great thanks for the bearing tip, I will probably go that route. When pressing apart, I noticed that the single bearing practically fell out of the case (double was more of a challenge). Because of this I feel the ending clearance after assembled is critical. I am surprised they dont use one of those wavy washers on one side to take up slack.

What should the endplay clearance be?

Can I buy shims for the bearings? For the case?

Should I ding the single bearing OD to create a tight fit in the case?

[TheGDFP]

Ideally there would be zero clearance, but in reality, as long as there is no binding, you're ok. The factory uses the two thin shims. Loose is better than tight.

I wouldn't peen the race or case, but there are Loctite sleeve/bearing retaining compounds for that exact task. If the new bearing for that side falls in, then you may want to use the retaining stuff.

Some thing like this would work fine:

INA AS3047 Thrust Roller Bearing Washer, Metric, 30mm ID, 47mm OD, 1mm Width: Needle Bear Thrust Washers: Amazon.com: Industrial & Scientific

INA AS3047 Thrust Roller Bearing Washer, Metric, 30mm ID, 47mm OD, 1mm Width: Needle Bear Thrust Washers: Amazon.com: Industrial & Scientific

http://www.ebay.com/itm/INA-AS3047-T...item58bcff319c

[TheGDFP]

Or, 2x14 plus:

INA WS81106 Thrust Roller Bearing Shaft Washer, Metric, 30mm ID, 47mm OD, 3mm Width: Shaft Hub Locking Devices: Amazon.com: Industrial & Scientific

INA WS81106 Thrust Roller Bearing Shaft Washer, Metric, 30mm ID, 47mm OD, 3mm Width: Shaft Hub Locking Devices: Amazon.com: Industrial & Scientific