flywheel holder or piston stop

[NAMBA860]

im looking for a piston stop for a turbo plug head or a flywheel holder for use on the cmb that has the pancake style flywheel.i need to tighten down a collett.

 

[Michael Costanzo]

hey bro, go to any auto part store or sears and buy a adjustable rubber "band" wrench that the use for oil filter or when you do not want to scratch like a chrome pipe.

i just used one last night for my cmb 91 with that same flywheel.also can use a piece of solid metal rod or welding wire of correct size and form a "v" shape about 6-7" long and bend the ends in about 1/4" works great for me. good luck. mikie.

 

[Kez]

I always wonder if it is a good idea to use a piston stop to tighten a flywheel nut. Wouldn't it put a lot of compressive stress on the rod, and the crank pin, wrist pin and the piston itself?

 

[Tom Foley]

You can also use a piece of 1/4 X 3/4 " basswood or some other wood that is not too hard, to install the collet which should , in my opinion, be blue loctited on any way . Just stick the wood pice , usually 6 " long for handling , through the exhaust port and don't stupidly tighten it and all is well . Wood leaves no debris and I have been using this method for many years . I may get crucified for this but it works fine with no ill effects on the motor .

 

[RaceMechaniX]

The best way is to use a pin spanner wrench on the flywheel. That is what those holes are for. McMaster has them or its is simple to use some steel or stainless wire are bend yourself a pair. Look at the pic attached. Letter D.

O.S. also makes a very nice Delrin piston stock tool which locks the con rod in place via a slot in the fixture which fits through the rear of the case.

look here:http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMW34&P=7

 

[Eric Gadoury]

I do not use the piston locking tool anymore...it costed me a piston once.

I use a rubber strap and it works greats. Plus the flywheel don't get damaged either.

Eric

 

[Martin Hamilton]

Been useing type B for years never had a fly wheel or coupling come loose, And also very easy to tighten or loosen. I would never tighten or undo with any thing through the exhaust with even wood or plastic simply because its only stopping the piston from going up on the exhaust side, Their for when you tighten or loosen the flywheel your trying to tilt the piston and putting a lot of strain on the piston. This is also why fly wheels probably come undone because you cannot get the same level of tightness as with the proper tool. Also if you need to put loctite on to stop it coming undone then their is something wrong with the matching tapers on the collet and fly wheel. I know a lot of commercial collets and fly wheel tapers simply dont match each other, These tapers have to be exactly the same angles and i mean the same. When they are the same taper even after removing the coupling or nut they are unbelievably tight just through the perfectly matched tapers. Ive always made my own collets and fly wheels not just to have correct tapers but i also need particular sizes to fit in my models. When i make a fly wheel i always make the collet for that particular fly wheel at the same time so that i know the angle is right for the two ( top slide angle set and unaltered so you have the perfect angle for the two) Regards Martin.

 

[jetpack]

One piece crankcases are harder to deal with than two-piece housings.

If it was a two-piece case, a large crescent wrench over the counterweight cutout to hold the crank still while you bring in the collet works great.

If you wanted to stop the crank on a one piece case, a bar has to be made with dowel pins. A large center dowel to go into the hollow of the crank and another smaller dowel located to fit the cutout.

The bar you put upright in a vise and the case down over it to capture the pins.

If you're trying to do this with the motor still in the hull, I would definetly go buy a strap wrench like mentioned above and go look for the longest handle open end wrench on the rack for the least effort and best control as it slips and rips a channel through your deck.

Just dont get crazy tight with it. Only tighten it untill the dang thing dont slip on you anymore. Any past that you'll never get it off easy.

 

[Tom Foley]

Been useing type B for years never had a fly wheel or coupling come loose, And also very easy to tighten or loosen. I would never tighten or undo with any thing through the exhaust with even wood or plastic simply because its only stopping the piston from going up on the exhaust side, Their for when you tighten or loosen the flywheel your trying to tilt the piston and putting a lot of strain on the piston. This is also why fly wheels probably come undone because you cannot get the same level of tightness as with the proper tool. Also if you need to put loctite on to stop it coming undone then their is something wrong with the matching tapers on the collet and fly wheel. I know a lot of commercial collets and fly wheel tapers simply dont match each other, These tapers have to be exactly the same angles and i mean the same. When they are the same taper even after removing the coupling or nut they are unbelievably tight just through the perfectly matched tapers. Ive always made my own collets and fly wheels not just to have correct tapers but i also need particular sizes to fit in my models. When i make a fly wheel i always make the collet for that particular fly wheel at the same time so that i know the angle is right for the two ( top slide angle set and unaltered so you have the perfect angle for the two) Regards Martin.

Although I fully realize the pin - spanner is the proper way to tighten / loosen the collet , I have never , ever had a flywheel come loose , or damaged a piston or rod . Most times you can also use the proper number drill blank in a conventional flywheel configuration to accomplish this task . I will be making a proper spanner for my EVOS ..I have 7 of the darn things !!!!! :lol: :lol: :lol:

 

[NAMBA860]

The best way is to use a pin spanner wrench on the flywheel. That is what those holes are for. McMaster has them or its is simple to use some steel or stainless wire are bend yourself a pair. Look at the pic attached. Letter D.

O.S. also makes a very nice Delrin piston stock tool which locks the con rod in place via a slot in the fixture which fits through the rear of the case.

look here:http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMW34&P=7

thank you tyler i will try the spanner wrench,shane