- Joined
- Dec 10, 2002
- Messages
- 3,327
Friends, I would like to pass on some advice...one of the consistant problems I see as used motors come through here is worn cases and scared crankshafts from guys running their bearings too long. This is the easist way to shorten the life of an engine, but is also one of the easiest to prevent. What happens when you run a set of bearing to long is that they get enough play in them to let the crank start rubbing away the seal area in the front of the case and once this seal is gone the performance and consistency fall off and the engine is not rebuildable (it is if you don't mind buying a new case and crank shaft). It is important that you change the bearings BEFORE they go bad!!! If you use them until they don't feel good any more chances are the seal in the front of the case is already damaged and there is nothing you can do to get it back. I recommend changing the bearings twice a year if you live in a location where you can run all year and at least once a year if you run only in the summer.
I know you are thinking "Yeah, Glenn just wants to sell more bearings". Well not really, it would be easier for me just to sell you a new motor every year or two as you wore out the cases. But because I believe what I am saying I have lowered the price on the bearings! The cost was $60 a set but I have lowered them to $46 a set for the .21 bearings.
Another bit of info on bearings...they are not all created equal! And I am not talking just about what "class" of fit they come in. Things like where they fit in each class, runout, roundness, etc. I have recenty met a gentleman that knows more about bearings in model engines than I ever thought possible. He has built engines for control line speed, RC on-road cars and drag racing, tether cars and has just started building boat motors. One of the things he always does when rebuilding an engine is rebuild the bearings. He has many years of research on these kinds of motors and has figured out exactly how much internal clearance both the front and rear bearings need to provide maximum performance and long life. He can measure and build a bearing down to the .0001" of the perfect fit. I was surprised to hear that many of the new bearings he gets to rebuild are too tight, not to loose. The problems with a tight bearing show up both in loss of performance and reduced life. He has many thousands of dollars worth of ceramic balls in MANY sizes so he can build bearings very precisely. I have been very impressed to say the least and the engine he built for me is the best feeling and running engine I have ever owned.
I have sent several set of Novarossi bearings for him to rebuild and I will try to keep some in stock at all time for those of you looking for another step up. The cost is $45/set in addition to the cost of the bearings. Thant is really a good deal when you think about how much works it takes to rebuild one perfectly and you end up with a ceramic/steel bearing that should run longer (you only have wear on the races now instead of both the balls and races) than the stock ones.
Anyway I hope this doesn't sound too much like a commercial to buy more stuff, but I though it might be helpful information to pass on.
Glenn
I know you are thinking "Yeah, Glenn just wants to sell more bearings". Well not really, it would be easier for me just to sell you a new motor every year or two as you wore out the cases. But because I believe what I am saying I have lowered the price on the bearings! The cost was $60 a set but I have lowered them to $46 a set for the .21 bearings.
Another bit of info on bearings...they are not all created equal! And I am not talking just about what "class" of fit they come in. Things like where they fit in each class, runout, roundness, etc. I have recenty met a gentleman that knows more about bearings in model engines than I ever thought possible. He has built engines for control line speed, RC on-road cars and drag racing, tether cars and has just started building boat motors. One of the things he always does when rebuilding an engine is rebuild the bearings. He has many years of research on these kinds of motors and has figured out exactly how much internal clearance both the front and rear bearings need to provide maximum performance and long life. He can measure and build a bearing down to the .0001" of the perfect fit. I was surprised to hear that many of the new bearings he gets to rebuild are too tight, not to loose. The problems with a tight bearing show up both in loss of performance and reduced life. He has many thousands of dollars worth of ceramic balls in MANY sizes so he can build bearings very precisely. I have been very impressed to say the least and the engine he built for me is the best feeling and running engine I have ever owned.
I have sent several set of Novarossi bearings for him to rebuild and I will try to keep some in stock at all time for those of you looking for another step up. The cost is $45/set in addition to the cost of the bearings. Thant is really a good deal when you think about how much works it takes to rebuild one perfectly and you end up with a ceramic/steel bearing that should run longer (you only have wear on the races now instead of both the balls and races) than the stock ones.
Anyway I hope this doesn't sound too much like a commercial to buy more stuff, but I though it might be helpful information to pass on.
Glenn
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