A local club member has had a triple gear bushing failure for the second time in about 1,000 miles. On the previous replacement the clearance was set about 0.005" on all three pins. The bushings used were bought at one of the T suppliers.
We have checked this failure thru the transmission cover and the sump cover. The gear is very loose and the pins are still in the correct position.
I hate to just fix it again for the same to happen in another 1000 miles. Any ideas?
Does he still have magnets on the flywheel? If they are removed, I think it's important to put a few oil slingers on the flywheel to keep oil mist in the air inside the transmission for oiling of the triple gears.
Here's an old thread about similar troubles as your club member have in a T engine with an experimental full pressure oil system: http://www.mtfca.com/discus/messages/331880/355193.html?1366510858
Apparently in the above thread the transmission didn't get enough oil when there was an oil pump sucking it all from the flywheel region and with only the keepers left on the flywheel for splashing oil. Without magnets you may need oil slingers - I've made mine out of angle iron:
I'm staying out of this one.
We now have the new bushings in stock right from the Ford print, Bob c93200 z bronze
Tony- if you never want to have that problem again, contact me by PM or email. dmcgearsatyahoodotcom.
My 1926 TuDor has recently suffered the same problem. The transmission was re done about 10 years ago, with new bushings. Then about 5 years ago during an inspection one bushing was loose in it's triple gear, and the others had some wide clearances (more than 5-6 thou) so the bushings were replaced again. A week ago when inspecting again, I found one bushing loose again in it's triple gear and one bushing was hogged out more than 0.030". The pins measure OK. Unsure why the bushing failed, don't see anything that is a miss. Thinking that this is a material problem. May try Bob's new bushing this time.
I have a stock transmission. Magnets, stock clutch plates etal. Mike
Maybe the pin when pressed into the flywheel is not as straight as you think. How is it loose, rocking or sliding? What were the signs that lead to the conclusion that the bushing was bad? Were the bushings faced for the proper clearance between the triple gear and flywheel?
Mine, replaced pins and bushings reamed to about the same, slide easily on the pins but have given no issues.
The pins are tight and are close to new diameters. The bushings were faced and honed on a honing machine to proper clearance, don't remember exactly what it was. The triple gears are in very good shape as is the drum gears. The drum assembly fits well once assembled. Mike
Bob - c93200 is NOT z-bronze! It's the common SAE-660 bushing bronze everybody else is using. I thought you said you were having them made from a custom made alloy duplicating "Z-Bronze". (As per Ford spec.) C93200 ain't it!
Sorry, I couldn't help it.
I will try to answer all the points brought up.
Roger, the magnet have been removed and eight oil slingers added and bolts added to hold the magnet side of the pins In place.
Ken, chicken but I wish I could......
Mark, tough to tell from the inspection cover but seems to rock about 3/32 from what we can see. The clearance between the flat on the bushing to the gear surface was about 0.006", I watched the machinist measure it last time.
Mike, I tend to agree that it could be a material problem. Seems like Bob claims his bushing meet the material and dimensional specs.
c93200 ( e-7 ) also these were approved by Steve Coniff and this is off the print
material specifications atsm b505/b505m, qqc-390 b notice 2, type 111,
sae 660, qq-b-691. comp 12. mil b-16261, g6
I just went through this. Transmission rebuilt about 9 years ago. Two bushings / gear were fine, but one had seized to the pin and gear wore the bushing. Got a new bushing and installed and reamed, but may have to check the oil clearance again. All three bushings, I assume were from the same material when rebuilt 9 years ago. Only thing I can guess, is the one that seized may have had a slightly smaller oil clearance.
Some of the pins I have been getting do not have fine enough finish on them. I polish them before installing. Dan
When I finished my engine and transmission, everything was tight - the babbitts were snug, the triple gear bushings at .002"-.003", so I started with 5W-30 synthetic oil. On the first drive, the triple gears started howling. I changed the oil to 15W-40 Rotella and haven't heard a peep out them since. My 2¢ is .005" is too much to retain a film of oil (particularly thin oil), which can be as bad as too little clearance that can lead to binding.
I don't know where the pins were from but some I have bought had a 8 for a smooth finish. I bought some from Roberts sale and they were much better finished.
The quality of the pin finish has been an issue over the years, like Dan I polish them before using, if you ever come across new Ford ones, they had a finish on them as good as a new piston wrist pin!
"ATSM b505/b505m" just means it's a standard alloy. That being SAE-660. What a disappointment.
Z-Bronze it ain't. I hope you refrain from calling it that.
I HOPE BOB MEANT TO SAY 92300,
93200 IS 660 BRONZE, 92300 IS Z BRONZE
COPPER 85-89, TIN 7.5-9, ZINC 2.5-5, LEAD 0.3-1,
FORD LISTS AT LEAST THREE FORMULAS FOR Z BRONZE. THEY ARE ALL VERY CLOSE AND ALL FALL WITHIN THE LIMITS OF THE MODERN 92300 BRONZE. FORD SPEC. COPPER 85-89, TIN 7.5-8.5, ZINC 2.25-4.25, LEAD 0.75-1.5, PHOSPHORUS 0.05-0.10. ANOTHER FORD CHART LISTS LEAD AT 0.75-1.75. 92300 IS AS CLOSE TO THE ORIGINAL FORD Z BRONZE AS YOU WILL EVER GET OR NEED. WHAT WE HAVE TO REMEMBER IS THAT WE DRIVE THE CARS A LOT HARDER AND A LOT FASTER TODAY. THAT IS WHY ADEQUATE CLEARANCE AND LUBRICATION IS SO IMPORTANT.
I concur. But turn off your CAPS-LOCK. No need to scream.
^ Glen is not a young man.
If he requires caps to see what he is doing so be it.
THANK YOU CRAIG. I'M GLAD I HAVE SOMEONE ON MY SIDE. But I will switch to small case. It's not often Ken agrees with me. THANK YOU KEN.
Truly a historic moment to be memorialized in the annals of the MTFCA forum forever.
I can't win. Now my son is picking on me. O happy day.
Otis Clinton made the best replacement triple gear pins. Sadly Otis is no longer with us. A true friend indeed, and a top notch machinist and friend. He is missed. He sold those pins to all the major T parts suppliers.
Hey, don't go overboard. We're not dating yet.
Just trying to glean some accuracy from the post.
Here's what Bob said. He must be reading it from somewhere. ???
material specifications atsm b505/b505m, qqc-390 b notice 2, type 111,
sae 660, qq-b-691. comp 12. mil b-16261, g6
I talked with Bob at length about this problem. He said he was going to use 92300 for the triple gear bushings, not 93200. 93200 (660)is what he use In the past. Snyder's uses 92300 for the triple gear bushings and 93200 for the other bushings. So they are both doing the same thing. Both Steve Coniff and I paid to have the Ford bushings, both NOS and used tested. I also paid to have Snyder's triple gear bushings tested. All bushings tested fell within the specs of 92300. So it is not the bushing material at fault. It is how we clearance them, lubricate them and use them.
I just looked again c923 is material , Bob
There is a lot of load on these bearings, specially because apart from very high precision machining, there is only one bushing taking the full load at a time. And when all gears are mixed during a rebuilt, things are worst. You also need a lot of clearance in the other bearings in the gear box so that more than only a single triple gear takes the full load.
It's amazing to me that the gears can spin on the bushings if the pin clearance is a little tight, considering the amount of force required on the press to install the new bushings into the gears.
They didn't all fit tight. Years ago many of the bushings were too small and could be pressed into the gears by hand. I remember having to knurl a set of bushings to get a press fit. We are blessed with better options now.
I think I would disagree that all the force is on one bushing/pin at a time. All three gears are in contact with the drum gears all the time.
And that leads to another reason why some bushings burn up/seize. A dragging drum can cause the triple gears to spin unnecessarily. Whether a drum is dragging could be caused by too-tight a band or poorly fitted bushings or oil too thick. I don't recall anyone looking beyond the triple gear bushing being the cause. At least that's all any one ever photographs. Bushing failure could be the effect of another cause. YMMV.
I should have said; "And that possibly leads to another reason...". I have not had the opportunity to analyze a bushing failure.
I have seen about 8 or 10 failures. They all had one thing in common . The clearance was too tight. As long as the oil level is up to the top oil cock the triple gear bushings should get ample oil. However,it is imperative that you have either magnets or a good set of oil scoops to throw the oil. The bushing should be knurled if they are not a tight press fit in the gears. But if the bearing seizes on the pin it is going to spin in the gear no matter what. As I said before we drive the cars a lot harder and a lot faster than they did in Fords time. So we have to expect some problems.
In a set of planetary gears such as in the T transmission, the three pins have to be perfectly perpendicular to the flywheel in the correct location, the gears all have to be cut exactly the same, and the bushings have to be machined exactly the same in order for the load to be equally shared by the three gears. If everything is not perfectly true, and it never is, one gear will be carrying the load. As the parts wear, the load will become more evenly distributed among the three gears. That is if the one initially carrying the load lasts that long. This is why it is important to match the parts as close as possible when assembling the transmission, and have the correct and consistant clearance to maintain the oil film between the pins and bushings. I think this is why you often see one of the triple gears fail.
Yesterday we removed the motor from my friends T and disassembled the transmission. Indeed one of the bushings had failed. All three pins look fine and the other two gears spin nicely on all three pins. The failed bushing is on the right and a 30+ year old bushing is on the left.
The new failed bushing looks more "brassy" than the older one, maybe it is age or maybe a slightly different material?
He is giving up on the original design and plans to have modern roller bearings installed.
Have one experience with stuck bushings, but cause wasn't material, just workmanship. The bushings lacked getting faced properly and the face of the bushing galled on the flywheel, causing the bushing to seize on the pin and spin in the gear.
Replaced the bushings in the gears, reamed to .004" and faced each to Ford spec and no issues to date.
Do carefully inspect each pressed, reamed, and faced bushing to be sure the 1/8" wide oil groove in helix shape exits the end and face of the bushings. You want to be sure oil can flow into the grooves. Sometimes cut the groove openings in the face and ends a bit deeper to insure the 1/8" channel is open.
If the transmission drum bushings have sufficient clearance then they can float and find their own center thus balancing the load on the triple gears. If the transmission bushing are tight then the gears have to run in the position they are in, unbalancing the load on the triple gears and forcing the gear teeth to run in new positions so you get a lot of transmission noise. Many times you are better off to run the transmission as is rather than replacing the bushings. You always have to look for cracked drums.
I read these postings about triple gear bushing fits and I scratch my head. For a large number of years I have simply replaced the pins and run the original Ford bushings. Rarely have I found significant wear on the bushings. Yes the pins are always worn a lot. New pins and the clearance is in the .006-.010 range which I find works fine. Just my position on this