Super Jet Cases

BruceSki

Formerly Motoman25
Location
Long Island
they are a matched set. They are machined for the bearings as a set. Mix and match might work, or it might not. It's a gamble.
 
my problem is that the bottom half of my 61x case is cracked and just want to replace lower half to save work or will i have to replace the two
 
^ i agree, i think it was over on pwctoday, there's a lengthy 25 page thread of a guy trying to diagnose an engine problem. he fried a top end and rebuilt it and got it ported. Went back out and immediately fried another top end. so he tore the motor down, etc... couldn't figure out what was going and eventually realized his cases weren't a pair. Nonetheless, wasted tons of money. and i think it took a full year or two to figure out what the problem was.
 
Location
HB
^ i agree, i think it was over on pwctoday, there's a lengthy 25 page thread of a guy trying to diagnose an engine problem. he fried a top end and rebuilt it and got it ported. Went back out and immediately fried another top end. so he tore the motor down, etc... couldn't figure out what was going and eventually realized his cases weren't a pair. Nonetheless, wasted tons of money. and i think it took a full year or two to figure out what the problem was.

How do mis-matched cases which would potentially bind your crank bearings cause a top end problem?
 
Location
HB
How do mis-matched cases which would potentially bind your crank bearings cause a top end problem?

I guess if they didn't seal up properly you could be frying top ends, but I would assume someone building an engine, particularly with mismatched cases, would verify that they were sealed up with a leak test prior to running the engine
 

tor*p*do

Squarenose FTW
Site Supporter
Location
NW NC
I purchased a newly rebuilt motor with mis-matched cases
it spit out the cank seal pretty quickly
went back with matched cases
 
Location
dfw
I guess if they didn't seal up properly you could be frying top ends, but I would assume someone building an engine, particularly with mismatched cases, would verify that they were sealed up with a leak test prior to running the engine

If he was too careless to check his cases then he probably missed what was actually causing his melted pistons.
 
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