I have a Dynamax fan that it such that I am unalbe to get the fan nut off. Anyone have a good suggestion for locking the piston so that I can get this thing off and repair my fan?

Mike

Fill the cylinder with oil. That's a sure way of making sure you do not scratch the bore with anything stuck in through the exhaust port.

Before I had a fan wrench I would stuff some rags through the fan to hold it.

I use 3/16 cotton rope, works great! Good luck getting that darn thing off!!

Joey.

Most hobby shops that have " car guy" stuff sell a tool that threads into the plug threads and locks the piston. Might work?.

I've tried the bolt in the glow plug hole and it works, but I'm always afraid of bending the conrod. I've got a screwdriver with a small, rubberized flat handled that I stick in the fan.

Find your self an air powered impact wrench! Hold the fan with your hand and bump the air ratchet. It will come off with that, with no doubt about injury to the con rod or piston.
Good luck!
Dustin

Or...treat yourself to the right fan wrench! Cheaper than a piston and cylinder. Been there, done that. I will never stick ANYTHING into the bore again except oil to keep the engine from rotating.
By the way...I learned that trick HERE, so thanks to whoever posted that.
An OS91 p/c set is over $150. Please be careful, whatever way you do it...

Impact wrench from an auto shoppe give them $ 5.00 or get a fan tool $ 12.00 t0 15.00.

Good lock

Carlos

Hi,

What's an impact wrench? Out of fear of ruining the con-rod, I also used rags in the rotor. If there's a better way, I'd sure like to know, too....

This thread might have the answers:

http://www.RCUniverse.com/showthread...304&forumid=26]

Everyone had/has great suggestions however it doesn't deal with the problem of when you have the fan tool, and the right socket and the piston is still moving due to the fan hub slipping on the crankshaft.

However I was finally able to get it free after locking the piston so it wouldn't move. Then had a great conversation with Tom Cook about DF plans.

Mike

Hey Yellow,

An impact wrench is usally used in auto repair. It basically turns the socket with a repeated hammering action. All the force is twisting but can be very great. Some have adjustable torque. Operate in air. Great for loosening sticky/rusty nuts/bolts.
Look at www.Harborfreight.com I think that is correct...they have good cheep stuff!
Hope that helps.
Dustin

Use plenty of penetrating oil before using any of the above. If you can soak it in something like WD40 for a couple of days before, then even better.