Engine in Frame/Shims?

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panz4ever
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Engine in Frame/Shims?

#1

Post by panz4ever » Sat Dec 19, 2009 11:14 pm

Got the motor back together and put it in the frame. Torqued the rear bolts to 35 ft/lbs (the right rear is probably about two ft/lbs over in order to get the hole in the bolt aligned so I can put the cotter pin in). The left front case to frame has a gap of .008; the right front has a gap of .003.

In an ideal world no gap would be nice but....

So the question...is that too great of a gap front to back and is the difference between the two (.005 left front and right front) such that it needs to be shimmed. The last thing I need is the case to break off on the front mounts. If this needs shims where in the heck do you get them. Old days all we did was use beer cans that we cut up. Seems like there must be a more enlightened way to go about it in today's world.

Oh, this is for my 49EL. Tried to take back as close to stock as I could so it is not as though this is going to be some Yakasaki Eater.



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Re: Engine in Frame/Shims?

#2

Post by Bigincher » Sat Dec 19, 2009 11:15 pm

panz4ever wrote: Old days all we did was use beer cans that we cut up. Seems like there must be a more enlightened way to go about it in today's world.
Yeah, these days you have to use Lite Beer cans.

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Re: Engine in Frame/Shims?

#3

Post by FlatHeadSix » Sun Dec 20, 2009 12:01 am

actually Panz that's not too bad, closer than a lot of 'em get. Nothing wrong with beer can shims if you cut them neatly and torque the nuts down correctly. In the old-old days we had to cut the shims out of steel beer cans, aluminum is MUCH easier, and as BigIncher says the Lite cans almost cut themselves.

mike

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Re: Engine in Frame/Shims?

#4

Post by concrete guy » Sun Dec 20, 2009 12:48 am

I use flat steel feeler guages most of the time. Shove it in tight, scribe it, and cut it. I always seem to find feeler guages when digging through boxes at garage sales, so I don't have much guilt cutting up guages :)

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Re: Engine in Frame/Shims?

#5

Post by Cotten » Sun Dec 20, 2009 2:18 am

If the need for shimming is apparent,
I suggest "bedding" the frame as target marksmen used to do with their gun barrels:

First dress the motormounts on both frame and cases scrupulously.
Scrape them of any burrs or misalignment that would affect seating upon the rear mount especially.

Then apply a kneadable two-part epoxy or JB-Weld to the front frame mount.

Install the motor tightening the rear mount only.

After the epoxy has cured, then tighten the other mounts.

This assumes a reasonably straight frame to begin with, of course,


....Cotten

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Re: Engine in Frame/Shims?

#6

Post by panz4ever » Sun Dec 20, 2009 10:37 pm

Ended up going to www.use-enco.com. They carry shim stock in all types of metals. They are in Nevada. There is also www.mcmaster.com based in Indiana for all those on the east coast. Appreciate all the input.

Diluted1
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Re: Engine in Frame/Shims?

#7

Post by Diluted1 » Mon Dec 21, 2009 5:31 am

What is considered a "reasonably" straight frame?

The reason I ask is that I have some "issues" at the front motor mounts. I do not know the actual measurement that is out, as I have not measured it nor paid much attention to it, but I do know it is fairly substantial, enough to know it is out.

Is there anymore information on the "bedding" process as Cotten explained earlier?

Thanks,
Jason

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Re: Engine in Frame/Shims?

#8

Post by concrete guy » Mon Dec 21, 2009 6:09 am

Brownells is a large gun supply store here in Iowa and you can find them on line and they have bedding material. The art of bedding a gun can be found on many target gun articles and forumns.

I have much respect for Tom's knowledge but bedding the front motor mount sounds crazy to me for 5-10 thousandth of air gap. I would just be worried that the wrong person could read this and in turn glue the front of his engine down to his frame. Next time the engine comes out the same person is breaking the engine mounts off.

As far as your front motor mount on the frame being substantially out, I think jigging up the frame correcting/replacing the motor mount would be money well spent.

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Re: Engine in Frame/Shims?

#9

Post by Cotten » Mon Dec 21, 2009 2:46 pm

Many of you will find erosion and wear upon the underside of your engine cases' front motor mounts, and perhaps the rear as well.

This wear will not be nicely parallel and flat.
Early frames can wear especially deep, as the frame mounts are much smaller than the case tabs.
Corrosion erosion can leave a surface that looks like the Moon.

If your cases are disassembled, then welding and millwork is an option.

Otherwise, JB-Weld does wonders!
And it doesn't walk out like a metal shim.

If you are really concerned that your cases may become 'glued' to the frame, then lay a piece of tissue paper across the frame mounts before you set the motor.

On to Jason's question about frame straightness:
The Service Manual gives directions and dimensions for frame inspection. Unfortunately, it requires a stripped frame.

So basically you are at the mercy of your own intuition and careful observation of how the motor sits.
If you can clamp long straightedges crossways upon both motormounts, and then stand back far enough, you may detect if they are no longer parallel, or square to the vertical axis when compared to the fork and wheels.

The circumstance to be avoided is where the frame moves when the front motormounts are finally torqued. This would mean that your motorcases would be under constant stress.

....Cotten

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Re: Engine in Frame/Shims?

#10

Post by panz4ever » Tue Dec 22, 2009 10:26 pm

Ordered my shim material and it should be here on Wednesday. In order to prevent the shims from walking out I am going to drill them first and then cut the shims. Because the shim material is so thin I intend to put it between 2 pieces of quarter-inch plywood that I will clamp together and then drill and then cut to fit Figure if I scribe it I should be able to get a pretty round outside diameter.

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Re: Engine in Frame/Shims?

#11

Post by fourthgear » Wed Dec 23, 2009 2:02 am

Shims would only walk if the bolts loosened . I have shimed alot of refrigeration compressors & elec. motors and never had a problem with them moving. Bedding is a good idea also but I would worry about it cracking or some thing ,under the vibration. If done correctly it should work .

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Re: Engine in Frame/Shims?

#12

Post by Cotten » Wed Dec 23, 2009 3:04 am

With all due respect FourthGear,

Refrigeration compressors & elec. motors don't have to bounce off of potholes or railroad tracks.

....Cotten

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Re: Engine in Frame/Shims?

#13

Post by fourthgear » Wed Dec 23, 2009 11:23 pm

Cotten
You have no idea of the size of motor's & compressors I'm talking about . Rail road tracks & pot holes are nothing compared to the vibration that a large multi piston shaft driven refrigeration compressor puts out or what a ( running 24/7 )large HP elect . motor puts out .Not to mention large motor driven pumps. I have shimed HD motors before & never had a shim come out on its own. You do have to keep an eye on all faseners on HD's , they can come loose even with loc tight on them.

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Re: Engine in Frame/Shims?

#14

Post by pan620 » Sat Dec 26, 2009 2:02 am

There is NOTHING that vibrates like a Harley, not a Top Fuel Car, or a electric motor, nothing...
listen to Cotten. IMO Dave

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Re: Engine in Frame/Shims?

#15

Post by Cotten » Sat Dec 26, 2009 2:43 pm

It's not about vibration.

It's about flex.

And occasionally, its about impact!

....Cotten

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