So are the ones Bruce T sells a littel undersize, and I need to stretch
them, or should I Ebay these and get smaller ones? I haven't assebled

the

motor yet, but it was a bad (stock) Oring that caused the motor to die

in

the first place.

Mike Harrington

How much under size is the over all diameter of the O-ring Mike?
If it is less than about 5% it is best to stretch them slightly.
The exact dimension is not important as long as you can stretch them
slightly.

The very important dimension is the section diameter.

Going on Bill's recommendations to not completely fill the slot
what is the section diameter of the ones Bruce T sent?
I measure the outer slot width at .130 inch and 0.070 inch deep.

What do your outer O-ring section diameter measure Don?

Looking at the Creavey catalog I just uploaded it looks like
a 0.098 or 0.093 section diameter is called for.
Note this is not a 3/32 section diameter O-ring. A 3/32 O-ring is
actually well over .11 and may be too large. McMaster Carr only sells
the 3/32 section diameter which may be too large for the outer slot.
I know that was the case for the oil scraper O-rings.
Best to order the exact size directly from Creavey.

The outer slot dimensions are 305 mm ( 12 inches) top to bottom and
248 mm (9.76 inches) side to side. These measurements are inner
slot wall to inner slot wall.

The inner slot is 191 mm (7.52 inches) across and 248 mm (9.76 inches)
top to bottom. Interesting.

These measurements are inner slot wall to inner slot wall.
In other words it is an elongated circle with a radius of
about 95 mm (3.74 inches) at both top and bottom.

The inner slot width is a bit wider at .150 inches.
This could be why the 3/32 section diameter rings work from McMaster Carr.

The depth of the inner slot is about the same at .070 inches.
The same 0.098 or 0.093 section diameter is called for.

Check my measurements carefully on your engine.


Paul Lamar

I'll check the dims this week sometime... I get plenty of grease time now
that classes are over :)

FWIW, I only have the inner TES orings... my outers were in great condition
when the motor was disassembled, so I see no reason to use anything but new
stock. Same with my oil seal orings - lasted 160K miles with no problems, so
I opted for stockers. However, this is an auto engine so not the high duty
cycle that you get from an aircraft motor.
Mike H

Also you can pull over to the side of the road if you engine develops 
a coolant leak and overheats  :-)>

Paul Lamar
 
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