Hessianben's 521 L16 to L20b Swapperoooo

[0.C.]

haha Yeah, well on Sunday I'll txt you, since it's more convenient for me when hungover.

[hessianben]

haha Yeah, well on Sunday I'll txt you, since it's more convenient for me when hungover.

 

I will laugh through the misspellings...

[hessianben]

I'm feeling good after today...

a friend came up and we got down to see what's what on the driveshaft front.

 

Here's the ground we need to make up on the tranny mount:

needs to be mo shorter.

 

 

I flipped the crossmember, and bolted it flat to get a read on where it needed to be:

hung plumbs from the center of the holes on the tranny and the mount:

 

 

nigh' on 1 7/8"

 

 

[Charlie69]

About 2" :lol: Not bad concidering I modded that trans mount in 1993! Do not forget to drill out the trans mount holes to match the holes in the trans. Looking good.

Edited September 13, 2009 by Charlie69
Added more info

[hessianben]

We got really lucky today....

things fit a little better than I could have hoped for.

 

I test fit the front short-shaft from the 620 into the output of the tranny.

 

 

I will use the front half and carrier bearing from the 620, with the back half and slip yoke from the 521

 

[hessianben]

here's where it sits now:

 

 

I should have ground off those tabs to make it easier to access the torsion bar bolts, but oh well...

 

Slid the front half of the 620 driveshaft all the way home into the tranny. It has more than 4" of spline to slide back and forth on.

this is at full stop

 

 

AND LOOK HOW CLOSE THE CARRIER BEARING IS TO THE STOCK MOUNT!!! :fu:

 

 

it is only about 1.5" shy of lining up dead over the top of the holes!

The 620 carrier bearing is a little wider than the 521, so...

 

I took 2 steel plates that used to be the 620's rear leaf shackles

and drilled holes to relocate the carrier bearing about 1" forward of the stock holes.

 

this also gives the output shaft room to move if it needs to

 

 

 

there's about 3.75" of spline engaged

 

 

 

 

As good as anyone could ask for!

 

 

The rear flange sits just under 1" forward of the stock location-

the rear slip-yoke has about 4.5" of slide in it, so when bolted up, it will have about 3.5" of spline engaged as well.... plenty.

good stuff.

now sleeps....

[hessianben]

About 2" :lol: Not bad concidering I modded that trans mount in 1993! Do not forget to drill out the trans mount holes to match the holes in the trans. Looking good.

 

you did all the hard stuff first! we're just copying!! heehee...

thanks C!

[Farmer Joe]

hell yeah!! i always wondered if there was a bolt in driveshaft for swappin a 5 speed into a 521. cool deal man!!

[fisch]

Niiiice! Could you have used the 521 carrier bearing Ben? Was it just that the 620 one was in better shape?

 

So it does look like the long tail 5-speed and the shorter dogleg 5-speed both need about 1 7/8" -2" taken out of the stock transmount. Which is cool cause once the transmount has been cut, you can use either length 5-speed if you have the proper driveshaft parts in the shed. Awesome! (Unless I am missing something?)

[hessianben]

Niiiice! Could you have used the 521 carrier bearing Ben? Was it just that the 620 one was in better shape?

 

So it does look like the long tail 5-speed and the shorter dogleg 5-speed both need about 1 7/8" -2" taken out of the stock transmount. Which is cool cause once the transmount has been cut, you can use either length 5-speed if you have the proper driveshaft parts in the shed. Awesome! (Unless I am missing something?)

 

i thought about using the carrier from the 521... but after looking closely at it, decided the 620 one was less worn. Also, the large nut on the end of the 620 carrier had a huge punch mark across the end of the shaft and the nut- as not to allow the nut to turn and come loose... looked like more trouble to try to get it off of there!

[datzenmike]

OK. For a long 4 or 5 spd (71B) into a 521, you use the 521 rear drive shaft mated to a 620 front drive shaft and relocate the carrier bearing mount forward 1 1/2". Awesome! Always wondered about this. It's not 'drop in' but you make it look easy.

[hessianben]

OK. For a long 4 or 5 spd (71B) into a 521, you use the 521 rear drive shaft mated to a 620 front drive shaft and relocate the carrier bearing mount forward 1 1/2". Awesome! Always wondered about this. It's not 'drop in' but you make it look easy.

 

I don't know if it makes any difference, but the 620 donor was a kingcab...

 

I'll have to drive it for a little while and make sure there are no driveline issues to let you all know about.:rolleyes:

[datzenmike]

The drive shafts are all 2 piece. All 620 are the same frame wise under the cab so even a KC will bolt to a reg cab frame. The frame length difference is behind the cab so I expect the rear drive shaft lengths are different between a reg cab and a KC/long wheelbase truck. I know this is an assumption but probably safe to say all 620 front driveshafts with the carrier bearing are the same length.

[Charlie69]

Hey Ben, I just remembered pay close attention to the hieghth of the trans mount and keep it the same when you cut & weld the mount bact together. You do not want to put you motor mounts in a twist and cause early failure of the mounts. Also if they are in a twist in is hell to line back up if you have to pull the motor and put it back in.

[hessianben]

Hey Ben, I just remembered pay close attention to the hieghth of the trans mount and keep it the same when you cut & weld the mount bact together. You do not want to put you motor mounts in a twist and cause early failure of the mounts. Also if they are in a twist in is hell to line back up if you have to pull the motor and put it back in.

 

for sure! the holes just need to move back 2".

 

 

Here's a trans question...

 

I hooked up the clutch slave that came with the 5 speed to the stock clutch line and stock 521 clutch master cylinder. Bled it out and topped it off, but still got no pedal.

Looking at the 4 speed, the arm that pushes the throwout bearing has a return spring on it, whereas the 5 speed does not.

 

I'm wondering if the 5 speed is too heavy for the 521 4spd clutch master cyl.

the design of the two slaves is different.

I have the master from the 620 and will mock it up, but will need to bend new lines for it.

[sdsurf]

the M/C should be fine on the 5spd. I have never heard of anyone with this problem. Maybe you have the wrong throwout bearing.

 

I hooked up the clutch slave that came with the 5 speed to the stock clutch line and stock 521 clutch master cylinder. Bled it out and topped it off, but still got no pedal.

Looking at the 4 speed, the arm that pushes the throwout bearing has a return spring on it, whereas the 5 speed does not.

 

I'm wondering if the 5 speed is too heavy for the 521 4spd clutch master cyl.

the design of the two slaves is different.

I have the master from the 620 and will mock it up, but will need to bend new lines for it.

[hessianben]

the M/C should be fine on the 5spd. I have never heard of anyone with this problem. Maybe you have the wrong throwout bearing.

 

I haven't hooked up the 5 spd master. I've been using the 4 spd to no avail.

I won't know if I have throwout bearing problems until I have enough pedal to move the throwout arm. right now, there's just not enough pressure to the slave to push it. I'm gonna mock up the other master today and see if that makes a diff

[fisch]

I had a blown slave that would bleed fine but wouldn't push anything. Pedal right to floor. Drove me crazy till I just rebuilt the slave and suddenly had pressure.

 

Do you know if this slave was working fine? Anyway to use the 521 slave and just switch out the push rod?

[hessianben]

I had a blown slave that would bleed fine but wouldn't push anything. Pedal right to floor. Drove me crazy till I just rebuilt the slave and suddenly had pressure.

 

Do you know if this slave was working fine? Anyway to use the 521 slave and just switch out the push rod?

 

that's my first option today... gonna try that before i make any irreparable changes. thanks!

[hessianben]

:fu:

 

fired it up today!!! banged right to life- I warmed it up, timed it, and revved it till fire spit out the manifold! sounds strong!

 

Question: why would it continue to run when I turn the key off??? I had to pull the coil wire to kill it. I'm thinking I crossed something...? anyone have this issue?

 

PICS AND VIDEO WHEN I GET OFF WORK TONITE!

[motavated]

Must of not connected the wires right from the alt? Maybe dead volt reg? I just had the wires connected wrong...

[hessianben]

IT LIVES!!!

 

 

 

If someone can embed this from youtube, please do! I couldn't get it to work.

Edited September 15, 2009 by hessianben

[fisch]

AWESOME!!! Great video Ben! Rock on with your bad self.

[Farmer Joe]

holy hot damn!! that sounds good!!

 

get that shizz done and drive it!!

[zetozeto99]

Love your truck, Ben! Sounds mean!