Zenoah Glow fuel eng?

[dwilfong]

Just the fit frank.

 

[Daniel's Racing]

Dwil,, Is there a "stop" between the two front bearings ? Snap ring inside the case ?

What keeps the bearings from walking out of front and back of the housing ?

Between the two bearings at each end there is a ridge so the inside bearings go in from inside case and butt up to it then the outers go in from outside until they butt against the same ridge in bearing bore.

Nothing to retain the outers but the press fit into a well heated case then after it has cooled shrinks on them tight IF the bore is correct size and someone has not made the mistake of pressing cold bearings out or in it ever.

The outers often do get spit out of these engines because the factory skewed up the fit or someone pressed the bearings out cold or reinstalled them cold.

You must heat the case to remove and again to reinstall or you will absolutely loose the interference fit enough that they can come out.

 

[Wasted wages]

Yeah, that was my concern...on the inside,the crank would keep the bearing from walking out, but the outer one if there is nothing to retain it other than the fit, it could start walking it's way out.

Is there enough "meat" around the bearing housing anywhere to drill and tap a setscrew that would help retain the outer bearing ?
Shouldn't take a very big one ... 8-32 maybe ?

I'm just thinking that with the RPM that the motor is going to be turning it's really going to need dual bearings to control crank flex ..

Just my .02...

 

[dwilfong]

You will never control the flex.
The bearings will gust bind up and over heat.
This is the same bearing I used in a CMB 1.01
This is most likely a sign to not use 2 front bearings from the nitro gods...............................LOL

 

[Terry Keeley]

This is when I had the motor solid mounted on my dyno, look how much that solid pillow block moves around!

 

[dwilfong]

Amazing how much thing flex.
I will not get into my theory of undulation.............................

 

[dwilfong]

I will tell you one thing I am very impressed how much seal this ringed eng has.
At 9.2 CR it is still a beast to try and turn over.
You just bump it with the starter no turning it over with any RPM.
A few bumps and it pops right off.
I pulled the plug wire and it popped when I put the glow driver on it.
I bet it will start with out the starter like my other nitro eng do after I get the needle set.

 

[Wasted wages]

This is when I had the motor solid mounted on my dyno, look how much that solid pillow block moves around!

Wow....that's amazing!!

 

[Mike Mooers]

One way to solve the seal problem would be to use an exhaust throttle. Might be a lot less hassle.

 

[Daniel's Racing]

The crank is most likely reduced diameter where it goes through the 3rd and 4th bearings so it doesn't fit or even make contact with the inner race of bearing so very likely it doesn't even turn it. They end up being a stationary steel zero drag seal. Since they don't spin they do not shed water either and rust up. Never leave the inner rubber seal in place on the outer bearings for sure.

A rubber seal is truly the answer. They don't run right when the crankcase isn't sealed up tight.

 

[dwilfong]

When I open it up to remove the outer bearing. I think I will remove the second one on the back side also and only leave the ones next to the crank.
Looks like the first run will be at open water on Friday at the Melbourne race in 2 weeks.
I would enter it but there is no class for it.
Nitro is dead in Dis 3 NAMBA and thy did not make a open Hydro class.

 

[Daniel's Racing]

When I open it up to remove the outer bearing. I think I will remove the second one on the back side also and only leave the ones next to the crank.
Looks like the first run will be at open water on Friday at the Melbourne race in 2 weeks.
I would enter it but there is no class for it.
Nitro is dead in Dis 3 NAMBA and thy did not make a open Hydro class.

Oh for sure it will blow either side out just the same. Fix just one end you know which one will be next.

 

[dwilfong]

The back side is closed on the R254 case.

 

[Daniel's Racing]

The back side is closed on the R254 case.

Oh yes I forgot again that you were using one of those original R cases. You still would not want the increase in crankcase volume up in that dome cover looking cap if that is how it still is.

 

[dwilfong]

Never put much valve in crank case volume one way or the other in terms of pumping action.
The pipe will do the work the case is just along for the ride.
Kind of like the fly wheel helping one way or the other.

 

[Daniel's Racing]

Maybe with the nitro but the same engine with gas the flywheel is everything. You will not launch gas without one unless it at least has full circle crank to replace some of missing flywheel weight and it will still not be easy. That and the vibration a flywheel diminishes is considerable.
Porkchops and TK superlite flywheel is even a little hard to launch. Built electronic ignition engines that didn't require a flywheel but you sure as heck still needed one.

 

[LohringMiller]

I'm pretty sure the crankshaft will flex enough that the outboard bearing will carry some load. On our CMB 35 we added an extra grease lubricated bearing on the output end because we were getting flywheel strikes on the magneto coil. The Quickdraw electronic ignition also saved a lot of weight.

Lohring Miller

 

[dwilfong]

ABC 3019-19-38

First run.

 

[dwilfong]

Well got a gallon threw it almost be for the crank twisted a little on the pin.
Never took a plug.
Pipe works like a charm.
Will line up the crank pin and have it tacked in place.
Had to do this on a few of my .77 cranks.
Piston looks brand new.
Still have not leaned on it all the way.
It will pull any prop we threw at it.
The problem will be finding a prop big enough that will not make the boat act funny.
This fing thing is a BEAST!!!!!!!!!!!!!!!
Takes 36V to a dynatron to crank this thing over.....LOL

 

[julianconde]

Well got a gallon threw it almost be for the crank twisted a little on the pin.
Never took a plug.
Pipe works like a charm.
Will line up the crank pin and have it tacked in place.
Had to do this on a few of my .77 cranks.
Piston looks brand new.
Still have not leaned on it all the way.
It will pull any prop we threw at it.
The problem will be finding a prop big enough that will not make the boat act funny.
This fing thing is a BEAST!!!!!!!!!!!!!!!
Takes 36V to a dynatron to crank this thing over.....LOL

And people said it will never work LOL guess you Proved some people wrong