Rebuilding engine
- Thread starter Phineas
- Start date
Man that's harsh.
You shoulda said "Here, before you protest and waste your money, run my tires and see if you pick up speed."
Point taken.
CCZ Racing
Member
Noobie confusion here. My son just finished his first season in junior1 with 27+ races on a clone. At the end of the season we got an animal motor for his other kart. I was told by the rebuilder that the animal will need to be "refreshed" after 10-12 races. The letter from Briggs seems to be saying something different. So how often should a purple plate clone (running pump gas)or a blue plate animal (running alcohol)be "refreshed"?
Alcohol tends to wash oil from cylinder. Also contaminates oil, necessitating more frequent oil changes and rebuilds. Good maintenance practices help extend between rebuilds.
Your engine guy will give you the best idea based on engine setup based on jetting for plate classes and his experience.
Some weekly racers will run until performance drops off. Depends on whether you can get a rebuild in the middle of season. Ymmv.
alvin l nunley
Site Supporter
Of course a 15,000 RPM two cycle is different from a 6000 RPM four cycle, but I would always check the compression pressure after each race. I'm fond of saying "compression is the Holy Grail" and I stand by that.
Get a good compression gauge, Pep Boys doesn't sell one, and keep tabs on the compression pressure of your engine. Sears and Roebuck cells a good one, SNAP ON cells a good one. Plan on spending at least $100. With a clone, you have to back off the exhaust valve clearance to bypass the compression release. I've been told .030" is plenty.
Of course compression is not the only consideration. Bearings are really important. I would put an indicator on the crankshaft and check it for up and down movement over time. No movement is best, and the more movement you get would be an indication of bearings going bad. Both of these, compression and bearings, should be a weekly part of your maintenance routine.
Get a good compression gauge, Pep Boys doesn't sell one, and keep tabs on the compression pressure of your engine. Sears and Roebuck cells a good one, SNAP ON cells a good one. Plan on spending at least $100. With a clone, you have to back off the exhaust valve clearance to bypass the compression release. I've been told .030" is plenty.
Of course compression is not the only consideration. Bearings are really important. I would put an indicator on the crankshaft and check it for up and down movement over time. No movement is best, and the more movement you get would be an indication of bearings going bad. Both of these, compression and bearings, should be a weekly part of your maintenance routine.
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