Jemal updates 5-speed shift-linkage issues
Orig. Posting Date | User Name | Edit Date |
Mar 23, 2015 10:22AM | jchealey | |
Mar 22, 2015 11:45AM | Air2air | Edited: Mar 22, 2015 11:47AM |
Mar 22, 2015 06:43AM | jchealey | |
Mar 21, 2015 11:28AM | Air2air | |
Mar 19, 2015 12:23PM | Jemal | Edited: Mar 19, 2015 12:36PM |
Feb 6, 2015 07:42PM | Air2air | |
Feb 6, 2015 05:14PM | Jemal | Edited: Feb 6, 2015 05:18PM |
Jan 30, 2015 01:24PM | Alex | |
Jan 30, 2015 01:03PM | Jemal | Edited: Jan 30, 2015 01:15PM |
Jan 23, 2015 12:45PM | Jemal | |
Jan 23, 2015 08:06AM | jeg | |
Jan 23, 2015 07:56AM | jimfai | |
Jan 23, 2015 06:30AM | Alex | |
Jan 22, 2015 02:40PM | Jemal | |
Jan 22, 2015 02:29PM | mur | |
Jan 22, 2015 02:08PM | Jemal | |
Jan 22, 2015 01:09PM | CA2SBL1275 | |
Jan 22, 2015 12:02PM | jimfai | |
Jan 22, 2015 11:29AM | Jemal | Edited: Jan 22, 2015 11:30AM |
Jan 22, 2015 10:31AM | mur |
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Jerry
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Sorry Jerry, didn't mean to say I have that 5-speed. Jemal just did a great job on my 4.
Pitched your Dixon show yesterday to these guys at Alice's restaurant on my first test drive. Only one had heard of it which seems weird, but maybe these guys are not into shows so much. I should have had your flyer with me...
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Jerry
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Todd here, and to follow up Jemal is a transmission magician. First day now after I put it in I don't even think when shifting. Before, despite endless adjustments, new hydraulics etc etc it grinded like a ... grinder... and this was a new build.
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Well, well, after a few distractions and side projects... like building an engine for Todd.... I HAVE been making progress on the 5-speed! Last night I test-assembled all the shift linkage, including the brass forks that operate the synchro-hubs on the main-shaft to verify all the gear positions. I spent a great deal of time trying different configurations of shimming the stack of the little 'cranks' on the stud at the bottom of the box. I measured the thickness of more than 100 of the spacer shims that fit between the 'cranks' to come up with a range of sizes to make sure the stack does not bind, but most importantly that there isn't TOO MUCH slop! Remember, when I disassembled, there seemd to be 20 thou or more of freeplay in the stack! The added in stud for the 5th gear linkage also had wobble, so I have spaced it up on it's stud such that I have only 2-3 thousandths of slop. The modified original stack is now shimmed very different to give EVEN gates for all the gear positions, AND less than .005" of clearance between all the 'cranks'.
I still feel that the original modification of the 4 speed case was rushed.... the reverse crank sits too low in the case, giving poor engagement to the shift lug at the end of the stub-shaft that connects to the shifter.... and with the collar that prevents selecting two gears at once That allows enough slop in the reverse linkage such that the gear itself can vibrate itself into slight engagement (or at least very ugly contact) with the teeth around the 1st-2nd slider hub when in 1st gear. The gears will crash HARD if that happens.... it's turning the wrong way to engage reverse when in first!
Well onto the Video.... In this first clip I show how everything fits together and explain the mods to the 1st-2nd 4-speed shift fork to make it as good as a brand-new one for our 5-speed:
In this short clip, I show the assembled linkage in the box, and 'try' to shift through all the gear positions while holding the camera in one hand! It clearly works now... and I intend to reposition one of my shims to raise up the reverse 'crank' at the bottom to keep it better engaged with the lockout collar on the final assembly:
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Another progress report... I've begun to reassemble the 5-speed, paying very close attention to the internal shift linkage at the very bottom of the gearbox. I showed how sticky and hard to shift it was in an earlier video. Here I've carefully shimmed and positioned all the shift forks to create more reliable 'gates' for the shift mechanism. You can already see big improvement in the precision of the linkage: (sorry, once again can't embed video... here's the youtube link)
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Spoke to Chris last weekend - this is almost certainly a development box.
MSport do keep spares for them, not many, but they do have spares.
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OK, just a short update as I get ready to reassemble the box.... I show side by side comparisons of the shafts and gears in a standard rod-change, vs the custom ones in the five speed:
...Can't seem to embed right now! Here's the link to youtube:
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"...The shift crank for 5th looks like it needs to move up a touch, as if there is a missing shim underneath it...
You are exactly right Alex.... I think that would loosen up the 3rd-4th gate, giving some separation and alleviating the tendency to go 2nd to 5th. Don't worry, I won't go nuts with a die-grinder! I've grabbed a bin full of those fork-stacks for the hardened shims, and plan to reassemble with careful attention to smooth operation in all gates. I'll modify perfect brass forks to replace the worn out ones, using a late model 1st-2nd for the extra contact around the collar radius. I will deburr and chamfer as I see fit to get those dual lugs on the shift-shaft to operate without interference.
Again, I do not mean to pick on Mini Sport. You see the number 003 in that last video. It could very well be a very early 'development' box. I only know that my customer got no response from them for repeated requests for help before involving me. That doesn't surprise me! It would be a real headache for them to have to chase down obscure old bits....
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Don't forget that Issigonis also built a racecar. So, I'd venture to guess that had he been allowed, the mini could have had some serious nads. Possibly also why the press went bananas at its initial unveiling.
The peasants are revolting...
"Gone with the Wind" - a brief yet moving vignette concerning lactose intolerance
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That looks like a development box that escaped to me.
The shift crank for 5th looks like it needs to move up a touch, as if there is a missing shim underneath it, and I'd be trying that before filing or grinding anything.
I ought to be seeing Chris Harper this weekend, so I'll ask him.
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Ah, I think the one I mentioned was stolen from Chuck!! Well, attempted anyway!
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Rob Walker described his Colotti gearbox and Shorrock Supercharger equipped mini wagon in a series on cars he owned printed in Road & Track decades ago. That is the only car of his up to that time that had been stolen and since it was a sequential pattern he said that he often wondered how the thief got on with the box. I don't recall any mention of it going only a few hundred feet.
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Yes I talked to Chuck yesterday about his, and his experience is very similar to the difficulties my customer experienced. The way 'mine' came apart, I do not believe anyone else had disassembled it since it was built. Usually one finds "scars" from disassembly, as these do not come apart intuitively!
We also talked about the 5-speeds built in the 60s.... they were small bore only modified from 3-synchro boxes, and had very goofy shift patterns. It seems a car so equipped was stolen for a few hundred feet... until the thief gave up and ran away after finding reverse and breaking it!
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Jimfai:
My comment about 'if a Mini was ment to have a 5speed it would have been built that way' is satire.
If you know any details of the original design, the car was loaded with problems from the beginning.
My comments about making or selling junk parts just to get the customer's money was not satire.
Since Jemal has posted what he knows of the history of this particular 5speed, given the "pay your money and take your chances" reputation of what is for sale on Ebay, anybody could have been playing around inside that gearbox after it was sold as new and may it not have been built that way.
If you are happy with your gearbox, bought it new or know its history, and take care of it, great. Yours is from a different source than the one Jemal is working on.
It will be interesting to see what Cheleker finds when he opens up his Mini Sport 5speed.
The gearbox Jemal is working on may be just a one-time thing but Cheleker seems to think "lot of people frustrated with" the Mini Sport 5speed.
We shall see.
Russ
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i have a minispares 5 speed box in my wagon and i have not driven it extensively yet but the amount i have used it i have been happy with the way it shifts and performs. since i knew very little about these i did talk with them several times about the boxes and parts and from what i gather they manufacture and build theirs from new, not a cobbled set of used parts?
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"...Pardon us for hijacking your post...."
No worries, and lots of good questions Russ.... I view this forum as an ongoing conversation taking whatever direction the participants wish! In previous posts I told the story of this 5-speed. It was no more of a "con" than much of what is offered up on fleabay! It was bought by a customer- building an outrageous Austin America show car with a crossflow Arden twin DCOE head- yes, this box is from ebay. Not my business what he paid! I've been helping the shop that built the car with the 5-speed after it went together and could not be shifted. I did not know it was a Mini Sport unit until I got it here, but I offered to try to "gunsmith" it, guessing all along at the exact problem within.... Poor attention to detail!
Oh, my view on Sir Alec (and I've said this before here) is that in hindsight (before he became an icon of Mini-ness!) he was an engineer following his employer's directives, the top two being 'small' and 'cheap' when it came to the Mini. All the talk of "the way Sir Alec intended" is fine for the huge contingent of enthusiasts that place originality above all else. I've also said that's NOT me! I'm more from the 'resto-mod' camp, not having anything against using performance and safety enhancements that we humans have come up with in the last 50 or 60 years!
I've also said that I don't justify the cost or complexity of a 5-speed for most people or most Minis. If you must go 80 with your engine barely above idle, take the Corvette! Too many people think the 5-speed can be "raced", when in fact they are way more delicate than a standard box, filled with unobtanium parts that were farmed out to machine shops that likely didn't know a Mini from a weedwacker! , And yes, MOST were and are still built from USED late rod change boxes to 'harvest' parts. Go ahead and call KAD or Mini Spares (not sure if Mini Sport has a current 5-speed, and I don't mean to pick on them, this one may be a very early version, I just don't know!) and ask them point blank what's in their 5-speeds!!
Here then is my attempt to take back the topic with this update:
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Colotti was an Italian motorcycle transmission company who made five speeds for minis in the sixties, I think there was one other. Someone on the board has one. There are no reports of an anger crazed Issigonis tearing out what remaining hair he had on their doorstep in protest. I have only worked with a Jack Knight 5 speed and it was a delight to work on and to use. I think they built their own case. All the same I am pretty sure that other rod change 5 speed suppliers were clear in their marketing that their unit was built from modified original parts. It is also possible that the box Jemal has was assembled by someone who totally phoned it in on that day and did not do the proper work, among many possible explanations low volume inadvertent manufacturers ship product out the door that is not right.
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