I tried that in the UK a few years ago and just ended up with a bunch of knackerd or dented kit and others just never made it home again. With the best will in the world, especially with inexperienced mechanics, kit gets dropped and knocked about. You will also find when lending stuff out it always takes a lot of chasing to get it back again.
I had wondered about the effect of a hot cover, and how all the fasteners would need to be done up pronto. I guess the cover could be re-heated after the fasteners were tightened. Heating the cover will add an unknown amount/direction of distortion... The pics I've seen of solder in position show six pieces to crush. Being a reasonable distance from the crushing force (fasteners) there's bound to be resiudual of distortion. That amount of distortion may well be calculable. With repeated experience with multiple trannies, the solder method would become workable and reliable. All imo, and ready for a flaming where and when required.
The factory book gives the clearance as 2 thou to the inner race, Haynes and Clymer give four thou, without stating where, but presumably at the outer. The oilhead crowd had a bunch of dud, over preloaded rear drives, and had a field day devising methods of measurement for resetting them, without the factory tool. A jig and dial gauge set up was devised which proved accurate. Solder checked against the jig was 8 thou too tight, back to what started their problem in the first place. Epoxy ribbon, tank sealant or whatever, proved to give an accurate reading, matching the jig. So if we carry these results over to a box you should be aiming for around 12 thou clearance if you measure by crushing solder at the outer race, or 4 thou if you use epoxy at the same place. The big C3 bearing in the final drive runs fine at either zero or 2 thou preload at the outer race, depending on the type of bearing on the other side, so I think that 2 thou clearance is a safety setting rather than the optimum figure. I stripped a box where the output shaft was overloaded by around 15 thou due to someone crushing in oversized aftermarket gears without checking the shimming. While it ran and changed fine this way for over 60,000 km (Mobil1 synth) it always felt hotter than the engine, and both bearings were eventually destroyed and turning on the shaft. So it appears that even with a major sort of error in the set up you will still get a decent run before the box craps out - but the more preload you have the sooner that day will come. The box will change better and last longer with synth oil too.
I'm afraid this is the way it would be here also. People intend to always be on time. When they are two mins late you should understand. When they are 5 mins late it was only two mins. People think that their intentions are what matters and the fact that they are late was a one time thing that you should understand. It is pretty much the same thing. People have no innate concept of time. People who don't own tools do not know what they cost. They do not have any respect for things they do not understand. If you want to rebuild your own transmission then buy your own tools. The first transmission you rebuild will not be a money maker or a money saver. It may actually cost you more than it might cost if you had a pro rebuild it for you. Learning mechanics is a painful experience. You will make mistakes that cost you money. Transmissions can and do blow up. They break big time and are more expensive to repair the second time because the mechanic to be is learning. Now about this solder thing. I like the idea and intend to try it the next time I put a transmission together. But I also have a beat up shim plate and I have some old parallels so I'm going to compare the two. Trouble is the transmission I have is not perfect but I can bang it through all the gears and I know where the downshifts are hiding and I rarely leave it in a neutral in between anything other than 1 & 2. All in all it's a pretty good Airhead trans. I've had worse.
Hi disston. If you're going to do a comparison test, could you also throw in some Plastiguage, and see how it holds up? http://www.advrider.com/forums/showpost.php?p=20102336&postcount=66 Jeff
Do they make Plastigauge thick enough for this application ? Never mind just answered my own question. http://www.plastigaugeusa.com/pricelist.html They do recommend tho that to check endfloat that a shim of a known thickness be inserted at the measured area. ________________________________________________________________________________________________ Shaft end-float lends itself to direct measurement by PLASTIGAUGE. Flatness and clearance in pipe-flanges and cylinder heads are readily checked and measured with standard PLASTIGAUGE. It is recommended that the surfaces be separated by a ground spacing washer or shim of (typically) 0.002". PLASTIGAUGE is positioned in those regions where distortion is suspected and any variations of flatness will be shown, after the assembly is dismantled, by variations in the width of the compressed PLASTIGAUGE strip. For large bearings, multiple measurements are recommended by inserting two or more gauges around the bearing. ________________________________________________________________________________________________
I thought the factory spec was .002 to no play? Then there's the re-shim and new bearing specs? Something like that. I always just look them up but . . . . I bet I could do it with solder. I have just never done it that way. The solder or your hand moving the cover .002"? Sure! Reminds me of fork alignment. If you had a magnetic V block you would see that just holding the dial gauge against the fork tubes moves them at least .002. How the cover goes on and is tapped makes all the difference. Then, of course, what it does after going through a few work cycles is another thing. The important thing to understand is that too tight is too tight and too loose is too loose.
Seems to me that Plastigauge is not a good idea with a spit-hot cover. I went to a gearbox tech day. Everybody had a helluva hard time fitting covers even with all the tools on hand. My box was repeatedly too tight. I finally concluded that guys were just guessing in order to get it done and get out of there at the end of the day. I took my box home and did the solder trick and it worked out perfect on the first try. Tips: use the smallest solder that will work. Get the hot cover on and tightened quickly. Then heat it again and run the box up and down the gears for a while. Pull the cover back off and measure. Subtract 2 or 3 thou and find the right shims.
The problem with depending on the heated cover to soften the solder is that low temp solders have only a melting point , that is, they turn to liquid at that temperature without softening. Try a bit on the end of the soldering bolt and see. The harder solders which do soften a little before melting do so at a much higher temp than you will sensibly raise the cover too. It is easy to check what effect crushing solder has if you have a shop press and measuring equipment. The shaft, complete with both bearings, can be stood vertical in the press, supported on the outer race of the lower bearing, and the height measured between the outer races. Solder of a known thickness can then be placed on top of the top race and the stack compressed with a suitable spacer until the solder is deformed, and the height of the shaft remeasured. to find out how much the shaft has shortened under the load The spacer can be heated to sizzlle , if required. It would be prudent to check the length at various degrees of solder deformation, as the reduction in stack height at , say , 10% deformation will probably not be the same if the solder is crushed by 30 %. You can then replace the cover with solder in place and apply the appropriate correction factor depending on the degree of compaction of the solder. Test were done on oilhead final drives and it was found that 500 lb pressure was required to deform three pieces of solder 30 % , and that translated to around 8 thou error in the preload setting. However when a few dots of soft 'Kneed it " ,"Tank repair "or similar epoxy ribbon were used in place of the solder there was no measurable difference between the reading made using the correct measuring gear and the epoxy thickness. So just quite why anyone would want crush down the stack with solder is beyond me, and I look forward to seeing the results of Disstons tests. Maybe he can check two shafts with solder and one with epoxy for a true comparison relevant to airhead gearboxes. The oilhead guys found that plastigauge or similar would not stand up to the heat required to fit the covers.
Now the solder stuff is getting interesting! The solder I use to measure stuff is not hard enough to be an issue.
I recently experimented with 1mm resin cored solder to see what sort of pressure was required to crush it. I used an old bearing, and found that although the pressure required was not overly significant, multiplying it by 6 times would become an issue. My shim stacks measured in the high .8's so 1mm solder would have been difficult to take a measure from. 2mm solder would have had to crush approx 1.1mm which is a fair bit, so a 1.5mm solder would have been the go. If they make 1.5mm. Then a vernier with a dial gauge is needed to measure the solder, or a caliper able to measure in .001" grads. I think the vernier option would be best to measure the relatively narrow imprint of a bearing. Buy a shim plate and find new friends! Imagine your popularity if you had a output flange removal tool as well. I officially got older today so I'm wondering whether to get the Cycle Works flange removal tool, or a mitutoyo 0-50 depth gauge (so I can properly use my Cycle Works parallel bars) or a mitutoyo 0-25mm micrometer for measuring shims. Don't believe what is written on the packet as a shim thickness! measure them all. Hmmm, maybe I should just go for the usual boifday present of a new back tyre.
You know, I hadn't thought about how big some of the solder needs to be. I have a BMW shim plate and a BMW flange puller. I have a Kukko bar puller and some Kukko bearing separators too. A bunch of Kukko blind bearing pullers too. I have friends! Vernier is without a gauge. You know, like most micrometers. They are vernier micrometers.
You may have to split hairs to get the proper clearance I'll be getting my rear cover machined tomorrow, just waiting on bearings. Already picked up the new sleeve and washer at my local dealer on Saturday. BTW, is there any value in replacing the detent lever roller with a bearing ? I seem to heard something along those lines. I noticed that the stock roller does not fit the detents of the shift plate correctly. It's actually slightly too large and when I contacted my bearing supplier I found out that an MR158 bearing would have the proper OD of 15 mm while the roller measures 15.75 mm. Any thoughts ?
I was going to change the nylon roller for a bearing until SS mentioned 'feel' through (I assume) the shift lever. I for one have become very accustomed to my shifting and did not want to change. My old nylon roller also was larger than the cam radius. Actually at 13 years old it was the same diameter as the new one. Is there a reason for the roller not being a perfect fit at the bottom of the cam? How does a machine shop machine an alloy cover........that opens up yet more cans of worms. As for using glass to do it......I bet the glass is out more than .002" and as for the bench the glass is sitting on...
Lots of people put K bike solid metal rollers in them. I don't like how it feels on my foot. It makes me think I am on a K bike and if you are really hauling ass in the curves thinking you are on a K bike could be dangerous!