How to Install the Driveplate on .049

https://sites.google.com/site/coxenginecollection/replacing-a-broken-crankshaft-in-a-post-1959-babe-bee

I use a arbor press and a small dia rod pushing on the back of the crank to push the drive plate back on. So far no problems doing this. I twisted off more than one 5-40 screw in a crank shaft trying to put the drive plates back on.

Harbor Freight has a 1/2 ton arbor press on sale right now for $28.

Jason

Micro,

Make sure the splines in the driveplate engage correctly with the splines on the crank. Use a little grease or oil on the splines and throw on an old prop and just tighten the screw. I have done this numerous times without any issues or broken screws. You say it is wonky? When looking from the front is the end of the crankshaft fully seated against the drive plate?

Keep in mind if you have to use too much force then something is wrong and stop before you break something. This usually isn't that hard. If you have it apart look at the splines on the crank and driveplate and make sure they are not damaged. Also look for any burrs or foreign material between the splines. It does require some effort to press it back on but, not so much that you are bearing down on it and sweating.

Do new drive plates have splines? I had always assumed the drive plate splines were formed by the crank during a press fit on original assembly.
Al

If you drove the new plate on hard and it went on crooked, you have probably pushed a ridge/wave of alum in front of the plate, and as such it probably wont fit correctly once it is reinstalled. A loose plate/prop might occur during running.

As you drive a new one on, you are cutting splines into the plate with the nose of the crank.

I heat the new plates up with a heat gun, get it to expand slighly so that it kind of finds center as it is pressed on. each time I have done it this way the plate is on there perfect.. heat it up, drive it 1/2 way on,,let it cool,,then drive it to the correct depth.

I had the same problem, large brass driveplate would not pull up to the crankcase without excessive endplay. I thought it wasnt fully seated so kept turning, stripped the threads.
Still dont know why. Seems like the back of the driveplate pulls up to the front of the crank journal and stops leaving to much endplay.
I use a prop stud and prop nut the kind that holds a rubber spinner.

Maybe the crank was a little too long so it looked like it was not correctly seated but was in fact on as far as it could go.

I started started checking cranks and cases they all the same. Seems like the driveplate should have a small relief in the back. The small driveplates pull right up.

Ron Cribbs and I recently posted a lenthy discussion on this very subject.

Suggest doing a "search" to find that information for your guidance. A "search" will reveal an entire 'library" of stored information.

Micro, hows it going with that thrustwasher?

I did use the search function, but nothing came up. Guess I used the wrong keywords.

I still cannot get it to work, I think I ruined it.

microflitedude wrote:I did use the search function, but nothing came up. Guess I used the wrong keywords.

I still cannot get it to work, I think I ruined it.

Unlucky there.

In short, I've never had a problem installing one on a crankshaft by doing this:.

Place the thrist washer on the crank while aligning the splines on both.
Install a prop, washer and nut on the crank.
Tighten the prop nut.
As you tighten the prop nut the trust washer/plate will be pressed onto the crankshaft.

EeeZee

microflitedude wrote:I did use the search function, but nothing came up. Guess I used the wrong keywords.

I still cannot get it to work, I think I ruined it.

Micro,

Post a picture of what you have. Let's take a look at the damage and see if it can be salvaged. Even if it started out crooked it should have centered itself when it was fully tightened. If one side is flush and the other is not seated it may only need a couple taps with a small block of wood and a small mallet. Or if you have a rawhide or plastic mallet you can omit the wood if you are careful. Patience and working slow is they key to solving problems.

Jason_WI wrote:I use a arbor press and a small dia rod pushing on the back of the crank to push the drive plate back on. So far no problems doing this. I twisted off more than one 5-40 screw in a crank shaft trying to put the drive plates back on.

Harbor Freight has a 1/2 ton arbor press on sale right now for $28.

Jason

This is the way we assemble all of our engines, with presses.

The 'traditional' way using a screw/hub/stud will also work well, but they will wear out over time.

Matt

MATT:

Come to think of it I have installed studs in my Coxes and did so long ago. I much prefer a prop nut rather than a screw to secure a prop because a screw is very easy to damage more so than a nut.

So this explains the success that I've had installing thrust washers by the method that I have described.

SuperDave wrote:MATT:

Come to think of it I have installed studs in my Coxes and did so long ago. I much prefer a prop nut rather than a screw to secure a prop because a screw is very easy to damage more so than a nut.

So this explains the success that I've had installing thrust washers by the method that I have described.

Yeah, that is very true at least in what I have run it to.

Matt

Matt:

These are the studs that I use in Cox .049 cranks:


Cox 049 Engine Stud (3)
SKU: 490STUD
Our price:
$ 1.95

I have been using a 5-40 hex head prop screw with spinner...

What I use:
http://www.tonysscrews.com/product.sc?productId=308&categoryId=-1
Grade 8 black oxide with a extra deep hex drive. His metric stuff is grade 12.9

Micro,

Send the thing to me and I will install it for you. Shipping one way will be cheap. If I break the crank or driveplate I will foot the bill for a new one. Shoot me a PM if you are interested.

cribbs74 wrote:Micro,

Send the thing to me and I will install it for you. Shipping one way will be cheap. If I break the crank or driveplate I will foot the bill for a new one. Shoot me a PM if you are interested.

Thank you very much Sir. I will do that.

EXModelEngines wrote:

Jason_WI wrote:I use a arbor press and a small dia rod pushing on the back of the crank to push the drive plate back on. So far no problems doing this. I twisted off more than one 5-40 screw in a crank shaft trying to put the drive plates back on.

This is the way we assemble all of our engines, with presses.

Matt

I have found an arbor press to be an almost indespensible item in the shop. As noted, they can be had fairly inexpensively from several of the larger online tool vendors, although shipping can be high due to the weight. I keep an assortment of rods and blocks around to support whatever I'm working on. I also have a hydraulic press, but prefer the hand operated arbor press for smaller work since it gives me a better "feel" for how things are going.