TT Pro 40 bearings
03-13-2009, 09:36 AM
#52
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RE: TT Pro 40 bearings
ORIGINAL: GSJames
Would a "Full Complement Bearing" be legal in 424? We have had the same problem with bearing failures in CL Combat engines for many years. We tried various bearing types with various retainer designs and materials. They still failed. The solution that worked best was to remove the retainer completely, machine a small "access hole" in the space between the races, just big enough for the balls to go through and add balls until the race was essentially filled. Hence "full complement". Now there can't be any failures of the retainers, because there isn't one. No, the balls don't fall back out when you are running, because you install it with the access port facing forward.
Would a "Full Complement Bearing" be legal in 424? We have had the same problem with bearing failures in CL Combat engines for many years. We tried various bearing types with various retainer designs and materials. They still failed. The solution that worked best was to remove the retainer completely, machine a small "access hole" in the space between the races, just big enough for the balls to go through and add balls until the race was essentially filled. Hence "full complement". Now there can't be any failures of the retainers, because there isn't one. No, the balls don't fall back out when you are running, because you install it with the access port facing forward.
03-13-2009, 09:40 AM
#53
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RE: TT Pro 40 bearings
ORIGINAL: gsimclair
Scott Smith, Vicman, and Chris,
It's funny when I show the humor in Muffler bearings and you take offense to it, but when someone else says the exact same thing, its OK. I guess you guys realize now that Shadel has humor that only a few understand. It's just a funny thought on his site cause that is just that kind of a guy.
I'm OK with you not liking or understanding what I have to say, I am just direct. nothing personal
G
Scott Smith, Vicman, and Chris,
It's funny when I show the humor in Muffler bearings and you take offense to it, but when someone else says the exact same thing, its OK. I guess you guys realize now that Shadel has humor that only a few understand. It's just a funny thought on his site cause that is just that kind of a guy.
I'm OK with you not liking or understanding what I have to say, I am just direct. nothing personal
G
I just thought you didn't know that the statement he made was an exact quote of the wording on the PSPEC website; that was all. I am not one to try to piss people off, I prefer to have fun.
After all, this is my hobby, sport and my relaxation therapy!By the way, what was the original topic here??
03-13-2009, 09:54 AM
#54
RE: TT Pro 40 bearings
Taken from AMA RCR-1 about engine replacement parts
Engine: A two-stroke cycle, glow
ignition, reciprocating-piston internal
combustion engine. For purposes of events
requiring stock or commercially available
engines and parts, the “engine†is defined as the
complete unit, ready to run, needing only
propeller, fuel, and starting voltage; except that
the following parts may be substituted for the
original parts and may come from any source:
Backplate mount
Bearings
Gaskets
Glow plug
Head and crankcase bolts
Propeller nut
Propeller washer
Remote needle valve assembly
Shutoff mechanism
Engine: A two-stroke cycle, glow
ignition, reciprocating-piston internal
combustion engine. For purposes of events
requiring stock or commercially available
engines and parts, the “engine†is defined as the
complete unit, ready to run, needing only
propeller, fuel, and starting voltage; except that
the following parts may be substituted for the
original parts and may come from any source:
Backplate mount
Bearings
Gaskets
Glow plug
Head and crankcase bolts
Propeller nut
Propeller washer
Remote needle valve assembly
Shutoff mechanism
03-13-2009, 03:12 PM
#58
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RE: TT Pro 40 bearings
Taken from AMA RCR-1 about engine replacement parts
Engine: A two-stroke cycle, glow
ignition, reciprocating-piston internal
combustion engine. For purposes of events
requiring stock or commercially available
engines and parts, the “engine†is defined as the
complete unit, ready to run, needing only
propeller, fuel, and starting voltage; except that
the following parts may be substituted for the
original parts and may come from any source:
Backplate mount
Bearings
Gaskets
Glow plug
Head and crankcase bolts
Propeller nut
Propeller washer
Remote needle valve assembly
Shutoff mechanism
I know this might upset some people and that is NOT my intention here.
I just wondered about the shims. My Engines ( i have 3 TTpro 40's) did NOT come with ANY head shims or "gaskets" as they have been referred too. By adding head shims, is the engine now "stock" or has it been altered? and if we can add head shims, why not go for broke and start adding shims under the sleeve?
If I stirred the pot or ruffled any feathers, I sincerely appologise, I am just trying to make sence of the rules for future question and maybe eliminate the "interpretation" of rulesas they are written.
Engine: A two-stroke cycle, glow
ignition, reciprocating-piston internal
combustion engine. For purposes of events
requiring stock or commercially available
engines and parts, the “engine†is defined as the
complete unit, ready to run, needing only
propeller, fuel, and starting voltage; except that
the following parts may be substituted for the
original parts and may come from any source:
Backplate mount
Bearings
Gaskets
Glow plug
Head and crankcase bolts
Propeller nut
Propeller washer
Remote needle valve assembly
Shutoff mechanism
I know this might upset some people and that is NOT my intention here.
I just wondered about the shims. My Engines ( i have 3 TTpro 40's) did NOT come with ANY head shims or "gaskets" as they have been referred too. By adding head shims, is the engine now "stock" or has it been altered? and if we can add head shims, why not go for broke and start adding shims under the sleeve?
If I stirred the pot or ruffled any feathers, I sincerely appologise, I am just trying to make sence of the rules for future question and maybe eliminate the "interpretation" of rulesas they are written.
03-13-2009, 03:18 PM
#59
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RE: TT Pro 40 bearings
I have 6 TT40 Pro's and all came with a .015 shim( gasket). The shims are silver in color and could look like part of the head. Check again to see if they are not there.
03-13-2009, 03:43 PM
#62
RE: TT Pro 40 bearings
All 8 of mine have them.
If you look at the little manual sheet that came with your engine it will show where they go. (not under the sleeve)
Scott, not only did I read your book I also questioned AMA about it for clarification since the trend is to replace the shims with thinner ones.
If you look at the little manual sheet that came with your engine it will show where they go. (not under the sleeve
)Scott, not only did I read your book I also questioned AMA about it for clarification since the trend is to replace the shims with thinner ones.
03-13-2009, 05:15 PM
#64
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RE: TT Pro 40 bearings
As far as Club 40 goes, the intention of the rules is to use the AMA R/C Pylon Racing General rules for engines. Any engine legal for 424 is legal for Club 40. And when Q-40 Sport gets going, same thing there.
I have a Thunder Tiger Pro 40 with the RC-Bearings.com ceramic and stainless steel set in it. I don't know that it has any performance advantage, but I know it runs well and I don't have to worry about corrosion.
I have a Thunder Tiger Pro 40 with the RC-Bearings.com ceramic and stainless steel set in it. I don't know that it has any performance advantage, but I know it runs well and I don't have to worry about corrosion.
03-13-2009, 06:24 PM
#65
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RE: TT Pro 40 bearings
Left Turn, if you have a new engine, look at the parts paper that is packed with the instruction manual or review the replacement parts list at Thunder Tiger. In the parts list you will see an exploded view and part #12 is called a gasket set (PN0020). When you take the head off, you will need to use a dental pick or the tip of your exacto knife blade to get under it. I use the dental pick and get under it at a bolt hole location and slowly work it loose by going around it till it comes off. It is a "gasket", so it is a VERY tight fit and blends in well. Mine was 0.0145~0.015 thick.
I just took my brand new engine apart to replace the bearings, head shim (I mean "gasket"), remove the throttle barrel spring, glue the low end needle in place and get it ready to break in. I do all of this prior to ever running it, and NEVER turn it over by hand; that will destroy it before you even get a chance to run it. Lots of lube and an APC 8x6 for break-in tomorrow for sure!!
I run at about 100' above sea level in muggy Florida, so it does seem to help some. When it gets hotter I have to go thicker, but I try to keep it as thin as I can by using a very cold plug and only add shims if it starts to pre-ignite the fuel or blow plugs. By lowering the head you actually decrease volume, but you increase compression. It's all a balancing act trying not to go too far! I have beaten myself with engine tuning more than I like to admit.
You aren't ruffling any feathers here man, I think everyone should have all the information available so that there are no "secrets".
I just took my brand new engine apart to replace the bearings, head shim (I mean "gasket"
), remove the throttle barrel spring, glue the low end needle in place and get it ready to break in. I do all of this prior to ever running it, and NEVER turn it over by hand; that will destroy it before you even get a chance to run it. Lots of lube and an APC 8x6 for break-in tomorrow for sure!! I run at about 100' above sea level in muggy Florida, so it does seem to help some. When it gets hotter I have to go thicker, but I try to keep it as thin as I can by using a very cold plug and only add shims if it starts to pre-ignite the fuel or blow plugs. By lowering the head you actually decrease volume, but you increase compression. It's all a balancing act trying not to go too far! I have beaten myself with engine tuning more than I like to admit.
You aren't ruffling any feathers here man, I think everyone should have all the information available so that there are no "secrets".
03-14-2009, 09:33 AM
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RE: TT Pro 40 bearings
ORIGINAL: At the low RPMs combat engines turn, there really shouldn't be a retainer problem.
Perhaps you misread my posting and thought I was referring to RC Combat engines... which do typically turn at relatively low rpms. Although slightly off topic, be advised that .36 ABC Schneurle-ported C/L Combat engines are essentially identical to, and are the predecessor of most of the .40 ABC Schneurle-ported RC Pylon racing engines that exist today. Did you think that Henry Nelson only made RC engines... Heck, I think they even use the SAME case casting. Yep, we had a retainer problem with 40-50% nitro fuels and 8 1/2 x 6 1/2 pylon racing props turning high rpm's. BTW, I never heard of a Nelson CL Combat engine bearing breaking, Henry Nelson and Dub Jett both make gooooood stuff. The full complement bearings solved the breaking retainer problem with the earlier CL Combat engines. We tried riveted steel, ceramic, etc. etc. I can't speak for the possible increase in friction although I can recognize that there may be that possibility. I'm an aero-guy, not an engine man, and do not necessarily recommend the use of full complement bearings in RC Pylon engines, I'm just offering up a little side information and letting everyone know that CL Combat fliers had a similar problem and that we found a workable solution. Best Wishes and good luck.