Builds The Clustertruck Rides Again - Refurbishing a 1975 Chevota (1 Viewer)

[RWBeringer4x4]

Some redundany for those helping me on the "V8 gurus" thread but in an effort to keep this build obnoxiously thorough, I'll update here too -

I spend most of this weekend trying to get my transfercase and pinion flanges parallel.

Plumb lines were dropped:

A chalk line was drawn between the two pinion flanges first. Then, a similar line was drawn through the transfercase flange points. The initial results were less than ideal.

Initially, over the ~24" run between the rear transfercase flange and rear pinion, the lines were out of parallel by just over 3/4" (13/16").

Below, the "X" is the plumb line point, the "O" is where it needed to get to be parallel with the pinion line:

Ultimately, I learned quickly why we all mount our V8's to the driver side. Even after 100% maxing out the passenger side rear mount, to the point where welds will need to be ground down, I was still out of parallel by close to 1/2".

The solution? Pull the engine's front mounts toward the driver's side. Ultimately, I wound up with about a 5/8" offset to the driver's side. This is going to make my steering pump and steering shaft a bit close for comfort but I think
I'll have about 1/2" with the belt fully tensioned.

Even better news - I can get to my #3 spark plug (just barely)!

 

[RWBeringer4x4]

Under the truck, it looks like the offset is pretty parallel at about a 1.75" offset between the transfercase flanges and the pinions.

Some quick trigonometry shows that the driveshaft angle will be at about 4-degrees from side to side

The reasoning behind the driver's-side offset becomes increasingly clear! About another half inch or so over, and I'd be within the magic "3-degrees" operating angle. I suspect I'll probably be OK with 4 degrees...not sure how much difference a degree makes in this case...

I'll also need to modify the passenger side transfercase mount - there is a definitely clearance problem with the parking brake backing plate - as it stands, I won't be able to fully mount the backing plate. From there I'll probably need to clearance it a bit further to avoid conflict as things flex.

I might grind out 1/2" or so when I grind down the welds to get the cushion to sit flat.

 

[Cdaniel]

Compliments to your welder

 

[reddingcruiser]

Rick
Before you get to far along, you might consider 'splitting' your steering shaft and raising it. It requires a support bearing (i.e. pillow block or similar), building a stand and adding another Borgeson joint for the 1" DD shaft, but might allow you to raise the shaft enough to get the engine back over to the drivers side. I am about to do the same on mine to move the shaft away from the header about 1/4".

I'm sure there's a fellow 'mud member out there that has a pic of one complete that they can post.

FYI, things aren't as close as they look in the picture and my motor mounts are through-bolted (Advance Adapters), so the engine can't move too much side to side.

Too bad I didn't have more time, I'll be in Greenbelt, MD tomorrow. I'd love to see firsthand what you're up to.

 

[RWBeringer4x4]

Compliments to your welder

Thanks Cliff - That'd be my friend Colin. He's responsible for the monstrosity below, so he has had some practice:

I just bought his Hobart Handler off of him - but I have a lot to learn before I start welding structural stuff!

Rick
Before you get to far along, you might consider 'splitting' your steering shaft and raising it. It requires a support bearing (i.e. pillow block or similar), building a stand and adding another Borgeson joint for the 1" DD shaft, but might allow you to raise the shaft enough to get the engine back over to the drivers side. I am about to do the same on mine to move the shaft away from the header about 1/4".

I'm sure there's a fellow 'mud member out there that has a pic of one complete that they can post.

FYI, things aren't as close as they look in the picture and my motor mounts are through-bolted (Advance Adapters), so the engine can't move too much side to side.

Too bad I didn't have more time, I'll be in Greenbelt, MD tomorrow. I'd love to see firsthand what you're up to.

View attachment 1447575

Wow, too bad, Greenbelt's only about an hour south of me. If you find yourself back this way, stop up for a beer! I'd love to show you around the Clustertruck.

As for raising the steering shaft - I've considered it, and I remember seeing the heim-joint added somewhere. I might investigate further - but I have to wonder if the juice is worth the squeeze...

Honestly, beyond a little concern over the driveshaft angles, virtually everything else lines up pretty phenomenally. I'm sure I'll be kicking myself if 4-degrees side-to-side driveshaft angle results in a gnarly vibration, but I'm also pretty sure once everything is locked down, I'll still have the ability to slide/adjust the engine's side-to-side location in the bay.

Perhaps this is a situation where I can get away with putting it back together, test driving it, and IF i have a problem with belt clearance or drive line vibration, It wouldn't be a monumental task to chop the steering shaft and shift the engine over another inch.

EDIT - here's the Heim Joint setup for future reference:

show your steering shaft with saginaw conversion pics

Looks like that guy just welded it straight to the frame...

 

[RWBeringer4x4]

Alright - here is more comprehensive paint-art of where I stand. I THINK I'm about where I want to be - opinions welcome (unless they're opinions on my artistic talent).

The front driveline makes me quite nervous - wondering how many degrees I'll gain at full droop...

So, I "drooped" the front of the truck, and it looks like I go from about 9 degrees to about 15 degrees of driveshaft angle at droop - which would put my U-joint operating angles at 19 degrees at the transfercase and 16 degrees at the pinion - I think that will WORK, but it's getting awfully close to maxing out the yokes...

Then again, how much time will I spend at full droop?

 

[Cdaniel]

What's going on with your rear pinion? I would think the side view would be more like this in back.

 

[RWBeringer4x4]

What's going on with your rear pinion? I would think the side view would be more like this in back.
View attachment 1447963

Drawing is not to scale

MS Paint has its limitations - just trying to indicate that the pinion is indeed angled slightly "up" toward the transfercase. Here's the actual angle:

As far as I know the springs, etc. are all stock, minus the shackles which are only about 3/4" over stock length. So the rear pinion angle should be pretty close to stock.

 

[Cdaniel]

Okay, reality is much more reasonable.

With full droop at front, look for binding/contact between the u-joint flanges.
Otherwise at slow 4x4 speeds it's probably ok. No AWD rally racing.

 

[RWBeringer4x4]

Okay, reality is much more reasonable.

With full droop at front, look for binding/contact between the u-joint flanges.
Otherwise at slow 4x4 speeds it's probably ok. No AWD rally racing.

Definitely no racing. In fact I've made it 4 years with no front driveshaft at all due to binding...

I fully drooped the suspension last night, and stuck a level in between the pinion flanges up front to roughly simulate a driveshaft (I don't currently have one that fits). At full droop it looks like the operating angle will be about 19 degrees at the transfercase, and 16 degrees at the differential.

When you factor in the compounding angles due to the offset driveline, you get 19.4 and 16.5 degrees, respectively. Those are some ugly angles, but I think the yokes can handle something like 25 degrees before they bind. So, it's ugly, but I think I should be OK...

My bigger concern is the compound angle on the rear driveshaft. with the offset as I have it, the rear pinion will operate at a 4.12 compound angle, and the transfercase U-joint will be running at 5 degrees. This SHOULD be acceptable up to about 3500 RPM (I think I've had the truck over that about twice in 4 years) but it's right on the cusp...

 

[RWBeringer4x4]

A test to confirm as best I could that the driveshaft should run at full droop...

With both front wheels off the ground, I separated one of my driveshafts to get the length close, and installed it to the transfercase. Then I used a jack stand to point it at the pinion:

The downward angle is about 14 degrees at full droop - obviously with an offset and the transfercase tilted up there are compounding affects.

Nonetheless - it appears I have plenty of space at the transfercase:

In fact the driveshaft can drop about another 1.5" before it binds...

Not sure how a future 2-2.5" lift would affect this...but for the time being I think I'm in the clear.

 

[RWBeringer4x4]

Decided to switch gears a bit tonight - I've got the driveline measurements just about as good as they're going to get without making significant changes...I wish I could get them a TOUCH further to the driver's side - but I'd have to spend more money to reconfigure things, and I THINK a 5-degree operating angle, with virtually all else parallel, will be sufficient.

So I fabbed up a new clutch line to relocate the clutch slave over to the pssenger's side:

And refitted the radiator to the stock mounts, and fan to the engine, to see where I stand there.

The radiator will definitely need to move down at least 2.5-3 inches to be centered on the fan:

It also identified my next sticking point - in order to move the radiator down 3 inches, I will need to cut the radiator cradle, and sit the radiator directly on my steering shaft - which is obviously not a solution:

Conveniently that corner of the cradle is already rusted out so I'm not worried about cutting it up - but once again, im concerned about clearances under flex - the last thing I need is the steering shaft obliterating the bottom of my radiator...

Similarly, on the passenger side the lower radiator hose conflicts with the fan - so the radiator has to move...

Compromise might be the name of the game here - cut the radiator cradle and lower the radiator slightly (1.5"??). and maybe move it to the passenger side (1"??) the fan won't be centered, but it will be closer to centered...and I will hopefully still have 1-1.5" of clearance over the steering shaft.

Anyone following running both of these setups?

 

[RWBeringer4x4]

Took a tool and a skill I learned ripping up the lenolium floor in my bathroom and applied it to the Clustertruck today.

I'd been dreading getting rid of the tar heat/sound deadening for a while - but this little multi tool cut through it pretty quickly!

30mins later:

This seems like a prime candidate to get some sheet metal welding practice in once my welding mask arrives. I bought my buddy's Hobart Handler 210 off him.

I can't really make it any worse than it currently is...

 

[waiting for time]

Yes you can, but I hope you won't.
I started my welding practice on the exact same part.
It is now one of the projects I need to tackle and it's going to be a lot of work to undo my previous work.

 

[reddingcruiser]

Pick up bunch of sheet metal scrap and practice, practice, practice. You'll be surprised how quickly adding metal can make even more metal "disappear". When you find that perfect combination of amperage and wire speed make sure to write it down. You'll need it again.

 

[waiting for time]

And remember, take your time. To much heat and you'll have a lot of work getting the warping out.
And keep in mind that grinding your welds introduces heat too.

 

[RWBeringer4x4]

Yes you can, but I hope you won't.
I started my welding practice on the exact same part.
It is now one of the projects I need to tackle and it's going to be a lot of work to undo my previous work.

All ye of little faith yes, I will definitely be picking up some scrap at varying thicknesses to practice on before I move on to things that aren't scrap!

Pick up bunch of sheet metal scrap and practice, practice, practice. You'll be surprised how quickly adding metal can make even more metal "disappear". When you find that perfect combination of amperage and wire speed make sure to write it down. You'll need it again.

And remember, take your time. To much heat and you'll have a lot of work getting the warping out.
And keep in mind that grinding your welds introduces heat too.

Good advice all around - I've watched sheet metal work done a few times - lots and lot of tack welds.

 

[gator25]

That hump is really thin man, just a heads up.

 

[RWBeringer4x4]

That hump is really thin man, just a heads up.

Isn't it 16ga like the rest of the truck? Or do you mean thin as in "rusty" thin? From a rust perspective it actually isn't THAT bad - what you're seeing is the PO's work with a torch...

Bought some sheet and assorted metal bars and whatnot today to start messing around - don't worry, I won't be starting on the hump straight away.

 

[gator25]

Naw man, its like 20ga. if that. If it is like (ours is a 75 and a little rusty) I used 20ga. to repair mine with and I think it was thicker then it was. I ended up putting a support under it just to be on the safe side.