steve J06

I've never rebuilt one so only going from picture and book knowledge.

What exactly is happening when i'm shifting my C6/MN6 without the clutch? I've gotten pretty good (ok just decent) at matching revs up and down but then read in one of the Smith books that this was a waste of time on a synchromesh type. Am I just wearing the synchro rings faster even though it slips into gear just fine? What does it take to convert a trans to dog-ring? or even sequential? I see that sequentials use a 'drum' instead of levers and rods to actuate the forks. Not interested in buying one of the 24K emco trans but want to understand it all. What technique does is take to drive a dog-ring or sequential and can it be done on the street? Is it that much different that how one would manage the trans on a cycle?

Happy new year to all.

steve

davidfarmer

I'm not a trans guy either, but I play on on the internet........ Seriously, here is the manual so you can dig for yourself. http://www.davidfarmerstuff.com/T-56_Service_Manual.pdf

I DO know that you can seriously damage a trans with synchros by trying to rev match and double clutch.

wallyman424

Thats a new one to me. I've never heard that rev matching/ double clutching on downshifts can cause damage.

Care to elaborate?

errance

steve J06

Thanks for the link Dave. Having now looked it over, let's see if I understand....

It looks like when shifting T56 without the clutch, the disadvantage is possibly faster wear in the synchro mechanism. Specifically, it looks like the friction cones will be the ones to suffer. (Assuming the match is close enough to avoid grinding the keys out of the synchro ring itself). I suppose that Carroll Smith's comment about a waste of time is related to the time/efficiency in operation and care of the transmission. It seems that you could shift a synchro trans just a fast as a dog-ring (dr) type but with the friction cones taking the abuse and not learning how to really match gears. It seems that in order to convert synchromesh to dr type you need to insert dr type gears and the dogs substitute for the whole synchro mechanism. Yes?
So to the other point, How are dr and sequential type trans to drive?

steve

mgarfias

You cannot hurt a transmission by correctly rev matching and not using the clutch. Thats because when you do it right, there is zero torque running through the driveline. No torque = no wear.

Now, if you don't match the revs right, or force it into gear, yeah, you're going to break something someday. Its a skill you should have, as I have lost clutch actuation in a pickup a number of years ago, and a friend lost clutch actuation in his 02Z while at the track without a tow rig (he drove it home anyway). Practice it in a beater to learn, that way you can junk the thing instead of fixing the trans.

mgarfias

Oh, and Carroll Smith was talking about doing the shift-with-out-the-clutch thing and not being a good idea on a syncromesh box cuz its slow, not cuz you'll blow it up, thus no point to doing it. He also went on to say that a good race driver will use the clutch, but only a slight dab at it to cushion the driveline on the shift (this is with the dog box), and not use a full pedal stroke.

rustyguns

You guys push in the clutch?

steve J06

been there done that. had several escorts with bad synchros or clutches so already had the hang of it.

mgarfias

Then do it, if you're comfortable. One thing to remember, unless you're revs are matched perfectly, in the c5/c6 you're going to put more stress on the syncros as it has to spin up/slow down the drive shaft, not a little input shaft. 'course, it has to do that with a normal shift, so wtf.

Webz

Not if I had this.

http://www.pro-touring.com/forum/sho...308#post613308

mgarfias

want

gkmccready

I'm curious about this one, too. I can't see what it would matter and it seems like it should actually wear the synchros less.

wallyman424

if I had to guess I think he was implying on clutchless shifts, however you can't double clutch without a clutch. Thats where he lost me.

steve J06

Thanks for the replies so far.

RE: keisler dog box t56:

Looks like the conversion from synchro to dog-ring is exactly what I thought. It seems like in the video, it is not being driven correctly as the tires chirp on each downshift. should've gave a little throttle blip me thinks.

Why can he bang the upshifts like that while in my current stock setup it takes so damn long for the engine revs to drop enough for the next gear? Is it the computer map holding up the rev drop? Or is it because of the heavy factory FW & clutch?

Can anyone explain why the dog box can take this abuse better than a synchromesh? I'm guessing because synch cones are being worn by friction while dogs just grab the next gear no matter what. Wouldn't the corners of the dogs get ground down if the match wasn't perfect? as it seems in the video.

steve

rustyguns

get an aluminum flywheel and the engine rpm's drop fast! i luv it for rev matching!

0Randy@DRM

The biggest difference is the rings. The standard trans has many teeth for gear engagment. The sycro also has many teeth. The teeth have points on the end of them to make it easier to put into a gear. Once those teeth start wearing, hear comes the grinds. It only gets worse also.

A "dog" or "crash box" Has 4-8 teeth on the gear, it is very slam, bam, thank you man way about it. The teeth are strong and take much abuse but isn't forever. Most roadracers will look at the gears everyweek for damage.

Randy

mgarfias

More than just the # of teeth randy. The syncro box is designed to use friction to equalize the rotating speeds of the two shafts, because it uses friction (the cones) it takes a bit for the shafts to sync and let you into gear.

A dog box doesn't have the friction cones, and the teeth are under cut, so that they "grab" when you get close to in (and also stay engaged when in gear). You pay for this by having to replace the dogs often unless you're matching revs well, and also for shocking the driveline.

Wonder how much those guys would charge to replace the dogs?

0Randy@DRM

I was paying something like 250 for the gear and slider thingy for my iceracer. But they were able to machine them, never had to replace or weld a new dog ring on.

Big money transmissions equals big money replacement parts.

Randy

davidfarmer

I probably wasn't clear.......it is pretty much impossibly to get it right 100% of the time, so the damage you do when you DON'T get it right isn't worth the risk. I know people who've learned this the hard way.