Chasing some advice on fitting a Milodon gear drive to my LA stroker. Tried fitting the gears to the crank and cam only to find out WAY too tight with approx 0.0018 interference fit. Milodon couldn’t give me an exact answer......”snug fit”. So was wondering what most of you chase when fitting these gears. I was thinking along the lines of 0.0005 - 0.0008.
Thanks again
Macka

I've never had to fit either gear. That seems weird but if you have to hone them a bit you have to hone them.

I don't think .00018 is much more than it should be. Honestly mine have always fit so I've never measured the press fit.

Not used that part exactly, but .001-.002 is common for press fit on crank snout stuff that's not driving a blower or something. Add a little heat and should slide right on. S/F....Ken M

Heat it and it should slide right on. i would rather have it be a little snug than a little loose when the motor heats up.

Last time I fitted one, I popped it in the oven and dropped it on

Silly question .....what’s temp is safe as to not adversely effect the hardness/metallurgy of the material?

just use a emery roll on the inside just a little thats how mick and i done ours

I usually heat bearings or races/etc up to 300 degrees Fahrenheit to achieve a slip fit, or 148 C for you metric guys...

That thought crossed my mind if the oven thing doesn’t work.

Thanks!

Take it to someone who can hone a harmonic balancer. He should be able to get it where you need it.

Just use the appropriate size brake cylinder hone to get proper press fit.If you heat it to press them on then if you have to remove it can be very difficult.It may galled to the crank and you have a real mess.Add antiseize before installing.

This ,also I fill the key slot with bondo or fiberglass resin. after a light smear of vasoline so it dosen't stick. then I save them for future use.

only to find out WAY too tight with approx 0.0018 interference fit. Milodon couldn’t give me an exact answer I was thinking along the lines of 0.0005 - 0.0008.
Thanks again
Macka [/quote]

.0018 is way too tight. I have never ever had to heat any crank gear or cam gear on anything to make it fit. At +.0018, your shearing metal off to get it to fit. Keep in mind, a crank damper is typically a press on fit, at +.0006 to .0008. That is a positive press because of the nature of the part itself and what it does. A cam gear doesnt need a press fit as such, and the crank gear, well, yes tighter to keep harmonics and such in check, but 99% of them STILL are a slip fit, maybe a slight tap with a brass hammer.Where is a crank gear going to go with a keyway in it? If its too loose, then chain whip and harmonics can affect it for sure, bit it never should need heat to install.

Something doesnt sound right here, unless, the crank is a bit oversized on the snout dimension, and the cam is the same?

If you must make an adjustment, a rod hone is the correct way to do it, with a keyway mandrel. Its the only way to properly keep it straight and round, but I am sure some of the other ways here will " get it done" if thats your decision .

Honed to the correct size sounds like the way to go!

We find many aftermarket cranks vary in dementions,snug is better than loose,press fit is idea, interference is not.We have seen crank gears actually split and crack from being forced on and once seen a Milodon gear go out of round from too much heat being applied and crack from becoming too brittle.Too tight or loose can cause metal transfer result in galling and actual weld the gear to the crank snout.

With .0018 you might not even get it on..
might pull the threads out of the crank..
I had to hone 2 of mine.. I set them for
.0007 press and it was still tight with no
warming them.. once its on and off its a
bit easier

I've always felt that nothing negative "starts" to occur on steel until the 400F range.

Hone it until it barely slides on