|04-17-2012, 01:21 AM||#1|
DIY Short throw shifter by modifying stock shifter *WARNING* This is long
This one is for all the guys/gals with tools at their disposal, or at least access to them, and know how to use them, or know someone else that knows how to use them SAFELY!!!
So, you bought yourself a fancy new Camaro with a manual transmission, and you're not happy with the feel of the shifter... Me too! You started shopping around for a short throw shifter, and you thought that everyone was charging quite a bit for an 8" piece of metal... Hey, me too...
What you are going to be creating is basically a less fancy version of the factory "Hurst" short throw shifter. I will update this later with pics of the factory Hurst shifter, so you can see the difference between the Hurst and the base shifter. If you're ever looked at pictures of the factory shifter, or even the stock one for that matter, you'll notice that it is actually 2 pieces, molded together with some kind of rubber to prevent vibration, and excess noise. Many aftermarket shifters do not offer this, and can potentially be noisy. From what I can see the factory "Hurst" shift lever is just a different bottom, with the same base model shifter top molded onto it via the same molded rubber method. What I'm about to give you the instructions to make, will probably shift almost, if not exactly the same as the factory "Hurst" option shifter.
I'm not going to try getting real technical in this write up but, but lets talk about shifters for a moment. How does a short throw shifter work, you ask? Well, the pivot point on the shift lever is known as the fulcrum point. The most effective, and proper way to shorten the shift throw is to raise the fulcrum point on the shifter, therefore giving the mechanical throw to the shift linkage more travel engaging the gears sooner with less movement of your hand/arm.
The other way to essentially "fake" a short throw shifter is to simply cut down the shifter on top of the fulcrum point. While this does not increase the mechanical throw to the shift linkage on the shifter, it still does reduce the actual movement of your hand/arm.
Any time you raise the fulcrum point, or cut the shifter above the fulcrum point, you are reducing the mechanical advantage of the shifter... This is what makes your shifting experience feel more "positive" or if you go too far, notchy. For example if you take a shifter that has a 4" upper movement of the hand/arm, to give the shift linkage a 1" movement to engage the next gear, this would be a 4:1 ratio... For easy math sake, let's say that this 4:1 ratio takes 10 lbs of force from your hand/arm to shift gears. Say you want a 25% reduction of shift throw (movement in your hand/arm), you would need a 3:1 ratio, your hand now moves 3" to make the linkage move that 1" to engage the next gear... That's great, nice quick shifts now, right? But since you have lost 25% of the mechanical advantage, it now takes approximately 25% more hand/arm force to shift gears.
Anyway, I think you guys get the basic ideal. Keep in mind this is very rough math, to explain shifter theory.
So, what you will be doing to your stock shifter is a little of both of the above mentioned methods of making the throw shorter... From what I've calculated, 1/16" (.0625") of change to the fulcrum point equals about a 4% change in the throw... So for instance, the shifter I modified today, I raised the fulcrum point 5/16", meaning I reduced the throw by about 20%... I have not tested exactly how far you can go with the factory shifter at this time, but I believe you can probably go up to about a 32% shorter throw by modifying the factory shifter in the factory shift lever housing.
There is a "limit" to how far you can raise the throw while retaining the stock shifter housing, without some magical spacer on the top of the shifter housing allowing the mounting point of the shift lever to be raised. The factory Hurst shifter has this magical spacer, but I'm not exactly sure why, because it's only a 22% reduction in throw. Many of the other aftermarket shifters have this magical spacer also, and different pivot ball bushings . What happens is, if you raise the fulcrum point too much and try to retain the factory mounting point in the OE shift lever housing, the extended mechanical throw on the bottom of the shift lever will actually hit the housing at some point, not allowing you to be able to engage some or all gears. So remember that more is not always better, especially when you can't get the car into gear because you went too far...
That said, the first shifter I did I raised the fulcrum point 7/16 (28% shorter throw), so I know it will work up to that point, and I think you can probably go another 1/8 (36% reduction), possibly more, but have not tried it. I will tell you that I did not PERSONALLY like the shifter at a 28% reduction, I'm not a big "super short throw" kinda guy, but I did know that I did not like the factory shifter much, and really feel that about a 20% reduction is the magic number for these cars.
For those of you that are still with me and haven't gotten tired of reading yet, I'm finally getting to the point where I tell you how to do this... Here's a picture of the modified shift lever (20% reduction, left), and stock (right)...
I'm guessing the ball is probably super heated, allowing it to expand, while the shaft may even be cooled to allow it to contract when these 2 pieces are put together from the factory... Either way, the ball is just pressed on somehow, and as I'm sure you may have read, there seems to be no set in stone placement at the factory, what you get is what you get... I started buying a few cores, and was very disappointed to see that out of 4 (including the one from my car) they all ranged within +-6% of each other, the one that came out of my car being the absolute worst... I don't have the measurements of the stock throw off the top of my head, but 6% is really quite a bit. Anyway, the ball is pressed on, and from the looks of it, the bottom is welded on after.
From what I've found there are 2 ways to do this, depending on what tools you have at your disposal, either way, please be safe, wear your PPE, etc, I am not responsible if you injure your self trying this in your own home. Method A requires a press and a torch... Method B (aka the easy way) requires a grinder with a cut off wheel, a welder, and a DA sander.
I do recommend you buy another stock shifter to play with before you commit to trying this so your car isn't down for a couple weeks while you search for a replacement. Or maybe ruining your original is the perfect excuse to spend $300 on a good aftermarket shifter???
You will need: 1) A press 2) A torch 3) Some sort of fixture (a jig, pinion bearing puller, giant sockets, pieces of metal etc) 4) Bucket of water...
TAKE EXTREME CAUTION when using METHOD A, you don't want this shift lever to come flying out of your press and through your face.
It is a good idea to mark how far you want to move the pivot ball before you start attempting to move it. Basically what you are going to do here is to get the shifter set up in the fixture (jig, etc) in your press. This may end up being harder than it sounds because of the 2 piece shift lever assembly with the molded rubber holding the 2 pieces together... If the fixture isn't made correctly, when you try to jack the press down to move the pivot ball, it will just press the 2 pieces together compressing the rubber, accomplishing nothing. SO, once you have a proper fixture, what you're going to do is heat the ball with the torch to expand the metal and hopefully be able to use the press to move the ball up on the shift lever. Once you have the ball where you want it, dump it in the bucket of water to cool the shifter from the torch head to avoid melting the rubber and separation of the 2 pieces. You will want to all of the above mentioned steps fairly quickly to avoid excess heat to the molded rubber, if the 2 pieces do separate, you better find another shifter as there is very little chance of salvaging it.
Now, with METHOD A, you may or may not be successful no matter what you do... Some balls are just tighter than others... Seriously though, the "knurling" on the shift lever rod may have something to do with it, some come out better than others, who knows?
If you find no matter what you do with METHOD A the ball won't budge, move onto METHOD B aka "the easy way".
So you tried Method A, but had no luck, well I guess it's time to go to your buddy's house because he has a welder
This method requires: 1)A grinder with a cut off wheel 2) a welder 3) Some kind of sanding device (I use a DA sander) 4)bucket of water... You may also need 5) a BFH 6) a chisel.
This is far easier than Method A, but I figure most people won't want to cut the ball... But it is what is is. If you can't figure out a really good fixture for Method A, or your shift lever is an overachiever, this is the next step, or you may just want to skip to this one all together and avoid Method A like the plague; can't say that I blame you.
Again, mark how far you wish to move the ball before you start... Use the grinder to make a relief cut into the pivot ball all the way to the shift lever shaft. Use the BFH and the chisel, or whatever you have handy to try to move the ball after it has been cut... If it doesn't want to move, hit the cut you just made on the ball with the chisel, or a big screw driver and a BFH to try to spread the ball a bit to loosen it. After a couple good whacks it should move fairly easy if it doesn't already after you cut it. Get the ball into the desired position and fire up your trusty welder... MIG or TIG seem to work equally well, I have done one each way, and notice little difference in the end result. Put a tack weld on either end of the ball holding it into place, and proceed to quickly weld the cut up to complete the ball again... Do this quickly and dunk the shift lever into your bucket of water as to not melt the rubber. Remember when you are welding this, it's not structural, all it does is ride around in a plastic bushing, try to weld it as "flat" as possible that way there is less sanding to make it a finished ball again. Once welded, fire up your DA or other sanding device and sand the weld to the contour of the ball... I have been using 120 grit sand paper on my DA for the 2 I have done like this, and have had no issues...
Before you completely reinstall the shifter in the car, get it in and bolted in with the retainer, and "run it through the gears"... Don't worry if it seems like the throw is "extra long" as you won't be able to feel the actual throw until the linkage to the trans is hooked up. What you're checking for right now is just that the motions seem smooth, and it doesn't seem to hang up on anything if you shortened it too much.... If it seems a little rough, take it back out and do some more sanding.
Get it in, try it, you'll like it... Your wallet will like it even better.
So that's how it's done... I will edit this the next time I do one of these with some pictures, etc, but I think you guys all get the idea... Really think hard about this though, shifters all do the same thing, with the exception of the MGW which has a self centering apparatus (which I'm working on making a spring assisted centering addition to work with the stock shifter housing), some have the same 2 piece rubber mount construction, some have 2 pieces with a piece of rubber in between, and some have nothing and are potentially super noisy.
If you have the means/tools, and you think you want a short shifter, give this a shot, all it will cost you is a bit of your time. Don't have the tools, or time? We are currently working up the cost to offer this short throw conversion service on a core exchange basis through our shop, at a fraction of the cost of even the cheapest aftermarket short throw shifter. We try to do them all using Method A as the final product is a bit cleaner not requiring welding etc, but in the end, I can't tell Method A from Method B in the car personally.
Please excuse any spelling and/or grammar errors, I've been working on this for 2 days, and it's over 5 pages long in MS Word and I'd like to get some feedback on this. For all the super techy guru guys out there, please excuse the lack of scientific terminology, just trying to make it easy and less boring to read, I'm no genius, but I can build stuff. Some of the terminology or theories may not be typed out quite correctly, but it does work, which is more important to me.
If you made it all the way through this, please post your thoughts, or better yet, if you actually went through with building one, please feel free to review your results.
As for my review, the first one I built for myself was a 28% reduction, I felt it was too far, "too notchy", and really felt 20% was the magic number... I built the 20% shorter throw shifter this last Saturday before heading out to the first drag race of the season here, and I think it performed absolutely amazing, not a single missed shift all day or a single 3rd gear grind. I am a happy camper.
Last edited by Jason@JacFab; 04-17-2012 at 02:00 AM.
|04-17-2012, 10:57 AM||#2|
Drives: 2012 45th Anniversary 2SS
Join Date: Mar 2012
Location: West Chester Ohio
This is great stuff man. I would try it myself but my 12 came surge the hurst short throw so I'm set for now.
But I would Definitly try this if not!
Your leading the way for DIY'ers
|04-28-2012, 07:19 PM||#4|
Join Date: Apr 2012
Location: NEW YORK
Method B works great, cut, weld, 3M abrasive disc to polish and done. Excellent mod. The bottom of the ball to the top of the tube with the bushing in it measured 0.60 stock. I moved the pivot ball up the shaft .330 and it seems to work perfect, not to notchy, but alot shorter of a throw. Excellent write-up and am so glad I did not go the hurst route. Seems the stock shifters don't have the 1" of side play while in gear!!
2004 Ford F150 Roush
|05-22-2012, 05:32 PM||#5|
Drives: Camaro LS M6, Fiero, Ford F100
Join Date: May 2010
Great Job! Thanks for posting. I might try this mod myself, as I don't want to install a short throw that is going to vibrate and make noise.
|05-24-2012, 05:56 PM||#6|
BTW this WILL NOT work on the factory Hurst short throw shifter if you think you wan't to modify the one in your car. The bottom piece of the hurst is machine from one piece, and you can not move the pivot ball like a stock shifter.
|09-25-2012, 10:07 AM||#7|
I decided to update this with some info on the OE Hurst shifter. As I mentioned before the the top of the OE Hurst shifter is the same as the stock shifter, and it appears to be joined in the same manner as the stock shifter. However you can't do the "move the ball" trick as I described in the first post on the hurst shifter because the bottom section is machined out of one solid piece.
Not the best picture, but you can see what I'm talking about here. It can not be modified. Also note the deeper "retaining ring" keeping the shifter in.
Below is a picture showing the topside of the OE Hurst assembly.
Note the piece on the top of the shifter mount/housing. This is most likely needed because of the (I assume) longer fulcrum point length to keep the bottom of the shifter from hitting the housing. Some aftermarket shifters also utilize a piece similar to this. Another potential reason for this piece is that the bottom section of the shifter is positioned farther inside the top section resulting in a shorter stick (from the center of the fulcrum point to the top), which would make the throw "act" shorter, but I suspect GM wanted to retain a close to stock shifter height inside the cabin.
Because the fulcrum point is raised in the shifter assembly itself, a deeper "retaining ring" (as noted above) must be used to retain the shifter in the assembly...
The shifter mount/housing appears to be the same as all of the SS shifter housings, and 1 ZL1 shifter assembly I have here, with the same SS8 number cast on it. I suspect there is no difference, aside from the holes on the top side are possibly tapped to accept the top piece of the Hurst.
I believe IF you can get the OE Hurst shift lever, the top piece, and the longer lower retaining ring, that the Hurst stuff can easily be transfered into a factory non Hurst car with little to no modification. However, none of these items can be purcahsed individually from GM, and you have to buy a complete shifter assembly. But if you could catch a person with a factory hurst going to a different stick, perhaps you could get the parts at a reasonable cost and make it work.
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