Thanks guys.

This weekend I'm going to take some measurements. I plan to measure runout on the driveshaft, rear axles, and pinion. I'll also try and check the rear end position/alignment if I can figure out a proper way to do it.

Daniel

Runout measurements
 

I took a few runout measurements yesterday evening.

Driveshaft yoke- .002
Front of driveshaft (about 4" behind weld)- .015
Rear of driveshaft (about 4" forward of weld)- .017
Rear end pinion- .001
Driver side rotor (face/lateral)- .003
Driver side rotor (edge/radial)- .005
Driver side wheel lip (lateral)- .030
Passenger side rotor (face/lateral)- .005
Passenger side rotor (edge/radial)- .005
Passenger side wheel lip (lateral)- .025

Anything stand out as alarming?

Daniel

Update
 

So, through some help from multiple sources, I've narrowed down my vibration to a worn out tailshaft bushing in my Muncie.

I'm trying to replace that bushing with the transmission in the car by using an old Snap On bushing removal tool. Snap On made a few different sizes and I thought I scored the correct one today from a local trans shop. But, I tried it tonight and it's *just* to big to work for my 1.5" bushing.

I've read they show up on Ebay occasionally, so I hope one pops up soon so I don't have to pull the trans to replace a $4 bushing.

Here's the tool I'm looking for in case anyone has any leads. It's Snap On part # S8672D.

Daniel

Update
 

I "rented" the correct Snap On tool from a guy on a Corvette forum. It took all of 3 minutes to pull the bushing with the correct tool.

I installed the new tail shaft bushing, seal, and new yoke on the driveshaft. Finally, got some dry weather the other day and went for a drive. The vibration is still there... It may be very slightly reduced around the 2000 rpm range, but the 4000+ rpm vibration felt the same.

So...……..I pulled the trans out this morning. It went smoothly.

Here's a short video of the play in the input shaft.

https://youtu.be/cbggep6tDu0

Axial play is .007"
Radial play is .065" (measured about 1/2" from pilot end of shaft)
I'm pretty sure that's not within spec. Any input?

The pilot bushing, throw-out bearing, etc, look normal too me.

**Not sure why the top two photos are 90* off**

Daniel

Update
 

I measured the bellhousing runout and pilot bushing ID to input shaft pilot "tab" OD and all was within spec. So, nothing abnormal was found with the clutch, pressure plate, throwout bearing, pilot bushing, bellhousing, or clutch fork.

My existing Muncie M21 has had weld repair performed on the mounting ears of the case. So, instead of rebuilding this unit, I'm leaning towards starting completely fresh.

I spoke with the folks at Auto Gear (https://www.autogear.net/motorsports/) and should be ordering a Muncie M20 from them in the next few days.

Here's the specs on their Muncie:

BRAND NEW Auto Gear "Syracuse" four-speed manual shift transmission/gearbox with Auto Gear/Antonio Masiero 'Muncie' M20 gearset (2.52 / 1.88 / 1.46 / 1.00 ratios), ONLY with 10-spline input, 27-spline output, and passenger side speedometer.
Choice of 7 or 8 tooth speedometer drive (typically 7-tooth for 3.55-4.10, 8-tooth for 3.08-3.42s).
It uses the following:
Auto Gear American-made "Supercase"
Auto Gear American-made C355 aluminum midplate
Auto Gear American-made heavy duty tailhousing
Auto Gear American-made, Oilite(tm) Bronze-bushed sidecover
Auto Gear American-made cast STEEL shift forks
Antonio Masiero (Italy) M20 gears (2.52 / 1.88 / 1.46 / 1.00) w/ 1-inch cluster gear
Antonio Masiero (Italy) Auto Gear-designed synchronizer hub & lightweight 27-spline mainshaft (tighter fitting hub-to-mainshaft fit [40-spline press fit and zero lash])
Antonio Masiero (Italy) forged synchronizer sliding clutches
Forged high-silicon bronze synchronizer "blocker" rings
Auto Gear-designed, Antonio Masiero (Italy) produced T10-syle reverse gears (no more chipped up reverse gears!)

Hopefully, this will do the trick...

Daniel

Nice!

The guys at Autogear are knowledge and helpful when I rebuilt my M20 Muncie for the parts I needed.
Not trying to sway your decision in trans selection but maybe you'd be better off with a TKO600 albeit a few bucks more. Higher 1st gear than the M20 plus with the cam it might be better for you, cruising as well. Plus the 600 bolts up to the stock bellhousing and utilizes the stock Z bar.
Shop builds are nice but kudo's to you on your home build, car's looking really good!

Thanks Wayne.

Simon- Yes, they seemed very knowledgeable.

Trust me, I've spent a lot of time debating Muncie vs TKO600 vs T56, in my head, over the couple of weeks.

T56- didn't want to mod the trans tunnel at this point among the other small changes needed. I've had an BMW E46 330i with a 6 speed and wasn't a huge fan. To be fair, I've never driven a T56 though.

TKO600- thought real hard on this one, but decided against it because of cost, weight, clutch change, etc.

Muncie- ultimately a 4 speed will meet my needs (street and occasional autocross). It will bolt right back in with no changes, same weight, less than half the cost of the TKO or T56 (a trans swap was not in the build budget). The wider M20 gear ratios will be an improvement over the close ratio M21 I had with my 3.42 rear end gear. I will never take this car on a road course, so an overdrive wasn't a "have to have."

Who knows, maybe down the road I'll swap it out for a 5/6 speed. They're never *really* finished right? :confused18:

Thanks for the compliment.

Daniel

Or just add a Gear Vendors OD unit .. That's my plan anyway

I actually did take a look at that. But with the cost of the Gear Vendors unit, I would've rather added a few hundred dollars more to get a TKO600.

Daniel