Muncie Swap Botch Job Manual Clutch

[atvjoey]

Hello fellow square body owners,

I recently bought my first squarebody (1987 gmc) and it was swapped from an sm465 to a Muncie m20 but it was done extremely poorly. First of all I pulled the transmission shortly after purchasing because it wouldn't shift right (couldn't even find the right gears) and would pop out of gear. First I found that they used the original truck bellhousing without an adapter ring or a larger bearing retainer on the trans but they also cobbled together a manual clutch linkage that seems wrong. First the zbar I think is bent but the springs and adjustment linkage also seem out of place. I will include some pictures but if anybody could tell me if anything is obviously not set up correctly or provide pictures of a correctly set up manual linkage that would be great. I have a new muncie to put in but I am waiting on an adapter ring for it. The clutch worked before but it was very stiff and made lots of weird noises when being depressed. I tried to get some clear pictures but the linkage is hard to get to for me. Thanks in advance.

 

[Snoots]

Z-Bar bushings are shot. No fix. Must replace and ADD GREASE!

 

[bucket]

That angle does indeed look terrible. Are the engine mounts shot?

 

[atvjoey]

That angle does indeed look terrible. Are the engine mounts shot?

The engine mounts are fine. On closer inspection it looks as if the frame bracket is actually bent. Does anyone know where to by another one or is it easy to bend. If you look at one of the pics it seems the angle of the bracket is bad.

 

[atvjoey]

Z-Bar bushings are shot. No fix. Must replace and ADD GREASE!

Where can I buy the bushings I've had no luck so far on Google.

 

[wanderinthru]

Machine shop?

 

[AuroraGirl]

That angle does indeed look terrible. Are the engine mounts shot?

always the killer of those z bars. mine isnt killed somehow but the shot engine mounts definintely played with them. I suspect using the right engine mounts for the engine application will also space the bellhousing to be at the right position. I also think my zbar should be on a stud on the bellhousing instead of the block based on the weird angle it sits at, but i suppose as long as the studs still primarily hold the only disadvantage is not a direct and thus more effort on the pedal..? from the looks. Does an m20 demand a crossmember mounted in such a way to maintain the angle and height of where the sm465 would sit, as well? If they didnt put that effort in, they may have it sitting low which could disrupt the z bar geometry further?

im having issue making heads or tails of the pics but from what it looks like, the stud on the bell housing is utilized but for some reason there is a large difference in elevation to the frame mounted bracket.

also, this truck would have had a hydraulic clutch originally, so maybe there is something being used from that? Thats not playing nice?

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well now I just confused myself maybe I meant the engine may be the intended opposite for the z bar? with where my mounts are twisted and worn, I suspect the engine would sit a little bit forward with good mounts and also sit a tad higher, which may actually be the proper alignment of the Z bar. I guess I dont know what a proper OEM one looks like, I have a sm465 which im pretty sure was hydraulic clutch originally in its 86 or whatever and also with regard to my gpa just kinda cramming **** together to work rather than exact OEM design replication.

I guess a good question too is if that bracket on the driver side of this frame on top of the frame rail is the same pivot bracket used by all the manual linkage clutches on squares or if they were different at all?

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@atvjoey i find it unlikely the motor mount pad bent as much as the bucket that the mount bolts through on the engine itself may be twisted. Mine are twisted and im using the mount buckets from another SBC when I put new mounts on so its all good. If the mounts are good and t case(in my case) otherwise rear mount is just in good shape, they probably dont twist under most use. Mine just probably were the only things keeping the engine from twisting side to side when the t case mount broke and the mounts were just loosey goosey. Worth checking well if you can. I pressure washed my engine one day and tried to hit down by the bellhousing and the amount it cleared up was huge and i also hit the mounts a bit and it helped ascertain what was all kinked outa shape.

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if you see how the bucket which is on the engine is pushed like the driveline pulled backward and the mount stayed on the bracket, it became bent where you see the two parts out of shape Probably just from torque but the engine in the driver rear engine bay would have pushed backward to the firewall and jacked up slighlty with the opposite corner being the opposite and all happening over a small distance, but the result is just bent to junk on those cups and the z bar either being out of proper position or just straight up putting a mild bend. The pedal is not difficult to push so i dont think it was severe, but what im saying is those are probably going to give first before the mount pad itself, thats rather thick steel with the crossmember supporting the side and being mounted to the frame securely. Unless they were loose then maybe?

 

[hoagster]

Yoou can get parts from here! https://www.4speedconversions.com/73-87_truck_parts.html

Although mine is not connected all the way because the cab is still off here are some pictures that might help. Plus mine has a sm465. There are suppossed to have felt on both ends also that keeps the grease in the z bar.

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[hoagster]

Here's a more recent picture.

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[AuroraGirl]

Here's a more recent picture.

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at least we are using the same mounting spot on the bellhousing lol. Is your bracket a factory or aftermarket? your z bar seems almost thinner and longer than the two I own. But it could be picture appearing so

 

[hoagster]

Original equipment. I purchased a new one because as you can see in the picture I repositioned one of the arms to accommodate the exhaust manifold change due to a LS swap. Next thing to do is build a new linkage rod to fix the slop in years of use. The old linkage from z bar to pedal is worn.

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You can purchase these but I already have all the tubing and hardware. Just need to get the cab back on and clutch pedal assembly installed and take some measurements.

 

[atvjoey]

Wow these are awesome pictures. Whoever sent the link to the website with this stuff big thanks to you too. If I could ask for a close-up of the spring by the clutch fork that would be much appreciated. It seems I only have one spring going from the fork to the frame.

 

[AuroraGirl]

Original equipment. I purchased a new one because as you can see in the picture I repositioned one of the arms to accommodate the exhaust manifold change due to a LS swap. Next thing to do is build a new linkage rod to fix the slop in years of use. The old linkage from z bar to pedal is worn.

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You can purchase these but I already have all the tubing and hardware. Just need to get the cab back on and clutch pedal assembly installed and take some measurements.

does your rod need to be custom length because I have a cutlass with that rod sitting in the back. i would probably keep it so i have spare clutch hardware but if you needed a measure of the rod that isnt worn to crap i could help. but i feel yours needs a little custom length because of your slight change?

 

[AuroraGirl]

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mine evidently has two different springs hooked together which my best instinct says that is not factory design but the spring was probably missing and my gpa just found two and made them hook somewhere pulling forward.

Original equipment. I purchased a new one because as you can see in the picture I repositioned one of the arms to accommodate the exhaust manifold change due to a LS swap. Next thing to do is build a new linkage rod to fix the slop in years of use. The old linkage from z bar to pedal is worn.

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You can purchase these but I already have all the tubing and hardware. Just need to get the cab back on and clutch pedal assembly installed and take some measurements.

what does your lower spring by chance do on your setup? just make it pull forward rather than put strain on it?

 

[hoagster]

@AuroraGirl I don't need a replacement, I was talking about the push rod from the pedal to the z bar. The two lower springs one holds the pivot pin to the clutch fork and the other pulls and holds the clutch fork away from the clutch when your not shifting. There should be two one small one and one long one going to the frame.