Major transmission assembly goof........

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George Andreasen
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Major transmission assembly goof........

Post by George Andreasen » Sun Mar 17, 2019 1:58 pm

This post will be a bit long, but I need to present the information in order to get advice or help.

I've been working on rebuilding my 1918 engine for almost a year, as money and time would permit. It was a mess......everything but the block, flywheel and crankshaft needed replacement. The engine itself was finally assembled and then the transmission rebuild began and that's when trouble started. Oh, I bought the MTFCA transmission book.


When I bolted the flywheel to the crankshaft flange, it wobbled. My dial indicator proved the error in the flange itself.....evidently when the crankshaft was turned at the shop, they missed checking the flange for being true...or they dropped it, not sure. Anyway, .010" was removed in order to true it up and the final assembly was done. Remember that .010".

All three drums were cracked, so I got two good used ones and a brand new brake drum. I transferred the gear shaft from the old drums to the new and riveted them. When I assembled the transmission pack, I discovered that the driven gear would not seat even with the end of the shaft. I disassembled everything and ground enough from the face of the gear below to allow the driven gear to seat properly. About .025"-.030" combined had to be removed from both gear faces below in order to get the driven gear pressed into position. Remember that .025"-.030". All gears rotated smoothly. At this point the engine/transmission was lowered into the crankcase.

Okay, now for assembly. I fought with the hog's head and was finally rewarded to have it slide into place and carefully bolted it up. Then I looked at my brand new wooden bands. Each of them was riding just a bit on the adjacent drum! On top of that, the output shaft (for the u-joint) is recessed almost 1/4" from the end of the ball cap. Say what???

Examination of the whole situation shows that the entire transmission drum assembly is about .030"-.040" too far forward, causing the bands to be too far to the rear.....or just about the amount of material removed before assembly. Not sure why the shaft in the ball cap doesn't come even with the end.

This engine is almost completely assembled after a year's work, so I'm pretty disgusted with myself right now. The only "quick fix" I can think of means taking everything apart and adding a .020" shim between the crankshaft flange and the transmission shaft. That would eliminate a lot of error. OR, I could wait for someone to tell me "There, there........it'll be all right. Just run it like it is."
Last edited by George Andreasen on Sun Mar 17, 2019 2:09 pm, edited 2 times in total.

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Re: Major transmission assembly goof........

Post by Steve Jelf » Sun Mar 17, 2019 2:07 pm

So the reverse band is overlapping onto the low drum and the low band is overlapping onto the brake drum. What could possibly go wrong?
The inevitable often happens.
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Re: Major transmission assembly goof........

Post by George Andreasen » Sun Mar 17, 2019 2:11 pm

Well Steve, remember that sage old advice......"In an emergency, step on all three pedals at once".

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Re: Major transmission assembly goof........

Post by Jim_PTC_GA » Sun Mar 17, 2019 2:25 pm

Very interested in hearing the fix for this. I just assymbled my engine and am fixing to begin on the transmission. I hope I never learn what your feeling right now. It seams everything I've done in the past year has been 2 steps forward 1 step back. When you find the fix please post it so we or at least I can learn from your experience. Don't give up.
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Re: Major transmission assembly goof........

Post by George Andreasen » Sun Mar 17, 2019 2:47 pm

Like you said Jim one step forward, two steps back! The only thing I can think of is that I used parts from at least three transmissions....the decision to grind material from the face of the shafts was mine alone. Mike Bender was nice enough to talk to me at that time and yet neither of us could account for the mismatch. After I assembled the transmission pack I had high hopes, even though I KNEW something wasn't quite right.

I just came in from the shop. No way around it, I'm going to have to pull it all down and find a solution. Despite all the work I put into it, I might be better off to just send the whole thing to Mike and let him rebuild it. At worst, he'd have to install new shafts on the gears and fit everything. In the meantime, I'm just going to stare at it....... :cry:

Edit: Another possible solution would be to remove the bands, grind material from inside one side of the ear and weld material on the other to move the bands over a bit. But that's pretty hoakey...........


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Re: Major transmission assembly goof........

Post by Nv Bob » Sun Mar 17, 2019 2:59 pm

Swapped and mix and matched many trannies
But never rerivited drums
I take a few old drums and measure the center serfaces frome a fixed point the measure your drums
Yes youl have tear it back down atleast you onow for sure and job should be less messy
Keep us pisted

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Re: Major transmission assembly goof........

Post by RichardG » Sun Mar 17, 2019 3:17 pm

GEORGE, don't think you are the only guy that's done something like that. but my advice for you , please take the time now to do it right, your sorry now ,however if you run it that way [if it would run at all] you will end up having to replace .things that are hard to come by, plus ,its much easy'r now where its not all together yet. think hard on it, every thing is clean and not stuck and will come apart the second time way easy'er than the first time. after all, think of the fun, your playing with your favorite toy.


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Re: Major transmission assembly goof........

Post by Dave Frost » Sun Mar 17, 2019 3:34 pm

IMO, the crank shop has some explaining to do. One of the 1st things to be checked should have been the run out on the flange. Best wishes on the build, you'll get it right.


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Re: Major transmission assembly goof........

Post by George Andreasen » Sun Mar 17, 2019 4:35 pm

Thanks for the encouragement guys..........Just came in for a bit of lunch after pulling the hog's head and removing all the crankcase bolts (an air ratchet is your friend here!).

I'm going back out and set up my engine crane and stand, then I'll remove the block from the crankcase. The part that REALLY irks me is that I'll lose most of my gasketing and probably destroy my nice modern crankshaft seal. Darn.......it was so close! :(

After I get everything apart, then I have to decide what to do. I'll contact Mike Bender in Oklahoma and see if I can ship the whole thing to him for a proper rebuild. Of course that's gonna be spendy, shipping wise, so it'll have to wait until funds become available.


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Re: Major transmission assembly goof........

Post by John kuehn » Sun Mar 17, 2019 4:41 pm

After reading about the transmission drum assembly I didn’t see anything about installing the transmission spacer washers. Did I miss that? I think they need to be in the assembly. Maybe. That being said If you have the earlier brake drum the bushing inside the drum has the necessary thickness made on the bushing. And if you added the spacer washers that might move up drums enough so the driven gear couldn’t be pressed down flush.
The Ford service manual might not mention that the earlier drums have the bushing that has the spacing made on to it. Can’t remember if it does or not.
You mentioned that you were using different drums. You may be using the earlier brake drum with the earlier bushing. That might be the assembly issue but maybe part of it?
Hope this can be of some help. Good luck.


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Re: Major transmission assembly goof........

Post by Kerry » Sun Mar 17, 2019 5:09 pm

Trying to give myself a mental picture on this, the whole drum pack too far forward by the removal of .025-30" on crank flange right? doesn't seem much to afect band alignment but if it has to the exstent of the band over lapping by that amount, well being wood bands how about just chamfering a little off the edge on the low and reverse band, the brake wouldn't matter running a few thou on the drive plate.

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Re: Major transmission assembly goof........

Post by Ruxstel24 » Sun Mar 17, 2019 5:19 pm

I'm curious as to where the flywheel and mag ring gap lies... :?:
Also if the crank was machined with the flange off or untrue, wouldn't everything be out of alignment ?


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Re: Major transmission assembly goof........

Post by Kerry » Sun Mar 17, 2019 5:50 pm

Dave,
Over the years I've had to set up mags minus the ford shim and even grinding some off the mag ring but never come across it putting the drum pack that far out of alignment with bands. I've come across cranks that have been set up in block that could be 10-20thou back or forward after a re-babbitt at some stage of it's life and still not worry the band to drum alignment
As for crank grind, the chuck would clamp on the out side of the flange, that wouldn't pick up on a run out on the surface of the flange but should have been checked and corrected before leaving the shop.


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Re: Major transmission assembly goof........

Post by George Andreasen » Sun Mar 17, 2019 6:45 pm

The crank was checked for cracks, welded to bring up the surface and turned/ground between centers to .020" under. The crank flange isn't really the culprit here....the .010 was removed to simply true it up. No, the majority of the error is mine because I ground material from the gear faces on the drum shafts in order to get them further on the shaft....all that so the driven gear would push on flush.

Look at it this way: the driven gear wouldn't press all the way down flush with the shaft, lacking about .035" if I remember (should have taken notes). By grinding the faces of the drum gears, the drums slid on further and I was able to press the gear on all the way, HOWEVER, that allowed the drums to move forward that much, plus the .010" removed from the flange. Quite a compounding error on my part. Even though everything revolved nicely and seemed okay, I had that nagging doubt......

At this point I have the engine out of the pan and back on the stand. My stepson is on the way over to help me turn it vertically so I can begin disassembling the transmission, then I'll start planning a proper repair. I'll keep everyone posted along the way.

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Re: Major transmission assembly goof........

Post by Henry K. Lee » Sun Mar 17, 2019 8:25 pm

George,

Let me know if you need any odd parts for the transmission. I have plenty of cleaned, inspected ready to go parts.

All the Best Buddy and you will win!

Hank in Tin-A-See


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Re: Major transmission assembly goof........

Post by Bill Dizer » Sun Mar 17, 2019 9:20 pm

.040 is less than 1/16" so that shouldn't make it that far off? Sounds like there is something else, like a bent pan?


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Re: Major transmission assembly goof........

Post by George Andreasen » Sun Mar 17, 2019 9:27 pm

Thanks Henry, I'll bear that in mind after I get it apart and see what's what.

The overlap of each band is just about 1/16" + on the adjacent drum. The spacing between the drums is nice and uniform, so I lost some space somewhere!

The pan is a replacement and was straightened on a jig in my presence by Erik Barnett in Auburn....a real T guy.

At this point I'm not exactly sure WHAT'S wrong......but I have the old drums and shafts, so once I get it apart I'll do some measuring.

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Re: Major transmission assembly goof........

Post by Henry K. Lee » Sun Mar 17, 2019 9:37 pm

This may sound totally stupid but I have seen this only one other time. By chance did the machine shop set the thrust at other than the third main? Sounds stupid I know, but I saw something years back that I could not believe either. Just thinking in aid to the problem.

Hank


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Re: Major transmission assembly goof........

Post by George Andreasen » Sun Mar 17, 2019 9:43 pm

I doubt it. Despite the crooked flange (just an oversight I'm sure) everything fit like it was supposed to. Besides, Ed down in Carson City set up the basic block for me and he's done a "few" T engines in the past.


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Re: Major transmission assembly goof........

Post by Norman Kling » Mon Mar 18, 2019 11:21 am

Before you take everything apart, look very carefully at the position of the top ends of the connecting rods with the pistons. If all 4 are not centered, but forward in the block, then I would suspect the crankshaft thrust to be too far forward. If you do need to remove the crankshaft, it would be best to replace with a SCAT new crankshaft. If the bearings were poured undersize, you might be able to save them by boring to standard. You will however need to correct the thrust surfaces of the rear main, perhaps by re-pouring the cap. Once you have the crankshaft correctly installed, place the transmission and flywheel and then fit the crankcase and hogs head and see if the linings are properly aligned with the bands. If so, you could place in the car and try it out to see if it runs OK. If not, you might need to replace all the parts which you ground down in the transmission.

If you find that the thrust is OK and the rods are centered in the pistons, then you could try a shim between the transmission shaft and the crankshaft. I have never tried this so maybe someone else has done so and could comment on the results.
Norm


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Re: Major transmission assembly goof........

Post by George Andreasen » Mon Mar 18, 2019 3:44 pm

Norman Kling wrote:
Mon Mar 18, 2019 11:21 am
Before you take everything apart, look very carefully at the position of the top ends of the connecting rods with the pistons. If all 4 are not centered, but forward in the block, then I would suspect the crankshaft thrust to be too far forward. If you do need to remove the crankshaft, it would be best to replace with a SCAT new crankshaft. If the bearings were poured undersize, you might be able to save them by boring to standard. You will however need to correct the thrust surfaces of the rear main, perhaps by re-pouring the cap. Once you have the crankshaft correctly installed, place the transmission and flywheel and then fit the crankcase and hogs head and see if the linings are properly aligned with the bands. If so, you could place in the car and try it out to see if it runs OK. If not, you might need to replace all the parts which you ground down in the transmission.

If you find that the thrust is OK and the rods are centered in the pistons, then you could try a shim between the transmission shaft and the crankshaft. I have never tried this so maybe someone else has done so and could comment on the results.
Norm
Thanks Norm......you and I think alike. I'm pretty sure the crank is correct, although I'll check as you suggested. The shop that did the work specializes in nothing but crank rebuilding and has done its share of T and A crankshafts.

I just got the entire transmission pulled apart on the bench before lunch and will start doing some measuring in a bit. As I mentioned before, everything fits properly and clearances are correct, the only thing being it's assembled from different parts. If I can't actually find the discrepancy, I may have to place a shim on the crankshaft flange in order to push the entire transmission assembly to the rear a bit. Once that's done I'll do a "dry fit" of the entire block/transmission in to the pan and reinstall the hog's head. If everything looks good I'll gasket it up.

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Re: Major transmission assembly goof........

Post by Jim_PTC_GA » Sun Mar 24, 2019 12:56 pm

George I was wondering if you found out what caused the misalignment?

I was test fitting my flywheel this morning and noticed that if the alignment pins were the wrong size this could pull the drums toward the engine and not let the band's line up. I would think this would cause the magnet holders to hit the magneto though. This is my first T engine rebuild so I could be wrong. Just an observation.
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Re: Major transmission assembly goof........

Post by Scott_Conger » Sun Mar 24, 2019 3:34 pm

In another thread, you mentioned "grinding off gears" to get everything to fit. That was a huge red flag to me and wonder how you are able to ignore this issue as you search for a cause of the transmission being forward? I have NEVER had to do such a thing and cannot imagine a circumstance where this would be necessary. In any event, the transmission assembly sits against the output shaft, via the brake drum main shaft. I would suggest that your main shaft may have been trued up and the flange may be thinner than designed. This will throw both the flywheel and the transmission forward by the amount that was trimmed. Usually this amount is insignificant, though. Personally, I do not see .030" forward being any real issue. I am curious as to how you came up with that value and if it is even real? At final assembly, there is built in float between the transmission drum assembly and the clutch basket, so that's more slop. There's an awful lot of slop in the bands and cannot imagine there being any problem.
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Re: Major transmission assembly goof........

Post by Corey Walker » Sun Mar 24, 2019 11:57 pm

I don’t know the story behind this because all I bought was the transmission but it had had some shins added as was mentioned earlier.
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Re: Major transmission assembly goof........

Post by Sarikatime » Mon Mar 25, 2019 9:13 pm

It seems I have a similar problem with the gap to the magneto coils. Does anyone have any shims like the pictured shims in the above post or know where I can buy some. Need to enlarge the gap between the magneto rings and the magnet clamp plate by roughly twenty five thousand. Should it be out of metal material or can I make shims from gasket material?
It seems in the last rebuild ( before me) the transmission center shaft was cut for some reason and now I have a different problem because of that. All help will be greatly appreciated. Frank

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Re: Major transmission assembly goof........

Post by Henry K. Lee » Mon Mar 25, 2019 9:33 pm

Frank they are not hard to make. Get some shim stock material to the size required with a little extra and use a gasket hole punch(es) and a pair of scissors.

Hank


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Re: Major transmission assembly goof........

Post by George Andreasen » Mon Mar 25, 2019 10:45 pm

Hi everyone.......sorry about no updates lately, but here's the latest scoop:

Okay, first of all, about grinding those gears. This transmission was assembled from parts from several others. Not the way I wanted to do things, but everything except the triple gears was pretty much junk. I got a used low speed and reverse drum from another member, and purchased a new brake drum for safety and had the vendor rivet my old shaft to the new drum. I pressed in new bushings, bored them to size and began to assemble things. That's when I found that the driven gear would not press down completely. Since I was using my original brake drum shaft (on the new drum) the used replacement drum gears were "too long". To solve this, I placed the low speed and reverse drums in my lathe and ground off the ends of the gears until the spacing was correct when assembled. Note that I did NOT remove any material from the brake drum shaft which is what controls the distance of the assembly from the face of the flywheel. In other words, the material removal could not have moved the entire assembly, only moved the two other drums so that they were spaced correctly in relation to the brake drum.

The transmission was assembled with the triple gears and everything lowered on to the brand new triple gear shafts......perfect. Rotated smoothly as it should and the clearances between the transmission gears and triple gears was good.....a bit generous if anything. The Jack Rabbit clutch was installed, along with the steel spacers so that end play was within limits. Clutch spring installed and we're good to go. In other words, it looked completely normal.

I lowered the engine into the pan and put the hog's head on. That's when I found my band/drum alignment problem. It wasn't much, but enough that the band were rubbing their edges on the adjacent drum. So, I removed everything and obtained a piece of 14 gauge black sheet metal (.066" thick). Using a spare transmission shaft as a template, I super glued the sheet metal to the flange and turned it down to the diameter of the flange. I then removed it from the lathe and drilled the six holes, using the flange as a drilling jig. The new spacer was removed from the flange by heating it, then any burrs were removed. Wish I'd have taken a picture......looks absolutely factory perfect. Seeing the post showing identical shims in another flywheel leads me to believe this wasn't the first time the problem has come up! Thanks for posting that.

Knowing that an ordinary stack of magneto shims wouldn't be tall enough, I cut four shims from the 14 gauge metal. At this point the flywheel is back on the engine and I've just finished measuring the clearance between the magnets and coils in order to shim everything to .025" gap. There might be a little variance, but the magneto should operate properly. At this point I'll have to order a new set of magneto shims before I can completely assemble the transmission to the engine, so there'll be a delay of a few days while I wait for the U.S. mail.

So, what have I done here? Well, I never did discover why the drum assembly is too far forward. Again, my removing material from the two gears to make them fit did NOT result in the drum assembly moving. No, something else was at work here. What I HAVE done is shimmed the flywheel/transmission so that the whole shebang will move rearward .066" and hopefully place the bands/drums in proper alignment.

Stay tuned! :mrgreen:


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Re: Major transmission assembly goof........

Post by Scott_Conger » Mon Mar 25, 2019 11:22 pm

If shimming out the transmission shaft (and thus the flywheel) puts the transmission drums in the correct place under the hog's head AND causes you to need additional .066" additional shims under the mag ring to bring it out to correct clearance to flywheel magnets, you may have "fixed" the problem, but something is still wrong.

Is your pan absolutely straight? If it droops to the back, your hog's head will act as though it's "too far back". I'm guessing you're at your wit's end, and your setup may work fine, as it sounds like you have the skills and aptitude to do this, but boy, it would sure bother me.
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Re: Major transmission assembly goof........

Post by George Andreasen » Tue Mar 26, 2019 11:12 am

Scott, Erik Barrett aligned the pan for me while I was visiting so I know it's straight.

Everything should line up when installed this time and yes, I was close to tearing my hair out. When everything looks, smells and feels right, it's usually right. This is one of those screwy things that just doesn't answer to logic.

I'll be checking my magneto clearances today and ordering shims.

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