spankrjs's Biloxi, MS '83 Scrambler

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
This is what I am starting with, subject to change:

20200713_172850.jpg

I chose this pulley to start with, think it will work, we will see:

20200713_172855.jpg

On trying to choose an idler pulley, I went through 3 pages of Gates pulleys. I narrowed it down to the following choices:

20200713_172903.jpg

My criteria:

1) price and availability
2) steel (plastic would be fine too, I guess, I just wanted steel)
3) outer diameter, thinking I need something under 3"/90mm
4) not too wide to rub, but wide enough to catch the belt without really having to get a narrow pulley located super precise
5) the 17mm bearing ID uses common reducers for 10mm or 12mm bolts (also, the bearing in this pulley is a common bearing)

I am going to start off with this pulley. If it won't work, I will be able to easily find something that will, i.e bigger OD.

Hard to see, but where my middle finger is pointing to:

20200713_173646.jpg

Directly to the left of the steering stabilizer, on the timing chain cover, two threaded studs. This is where I want to mount my plate that will hold the idler pulley. Perfect location, already there, easily adaptable.

So, let's "RedneckRay" a mounting plate!!!!!!!

20200713_180320.jpg

My "CAD" drawing:

20200713_180326.jpg

I may be a redneck, but I find it easier to use metric when doing this stuff!!!!!!!. Easier to divide 40mm in half vs fractional inches LOL!!!!

My drawing/drilling actually worked out well. The studs are 3/8", I drilled the holes in the plates to 7/16", and either plate slides tight over the two studs, which is what I wanted. Not bad for a block of wood, old Dewalt hand drill, dull drill bits, and "RednecRay" math!!!

20200713_194419.jpg

The lower, smaller plate is 1/8". This might be a hair light.

The larger upper plate is 3/8". I would prefer this for two reasons:

1) Thicker, so I can drill/tap it for the idler mounting bolt, plus a nut, extra secure and strong
2) The larger size gives me more space to offset the idler pulley bolt to where it is needed (center line of the drilled holes might not work due to the OD of my chosen pulley)

The problem with the 3/8" plate: when I place it over the timing chain studs, not enough thread left sticking out for a regular nut, let alone a lock nut. A jamb nut will work. Not the end of the world. If need be, I can pull the OEM studs out, thread in long 3/8" bolts from the back side, gain more threads and fore/aft adjustability. Or, thread lock the jamb nits on. My tight holes mean I do not need washers between the nuts/plate.

This is also why I bought two adapters, one for 17mm bearing ID down to 12mm, one down to 10mm. So, I can use the larger bolt (prefered I guess) or use the smaller bolt IF the hole is closer to the edge of the plate.

This is all just a start, subject to change. I "might" make up some wood plates to test fit. Wood is cheaper, and easier/faster to work with.

Anyway, that is it for now.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
These are some a/c brackets that came off a 258 YJ with factory air, so the factory did not use a ”real” tensioner. Just the arm with the pulley bolted to the mounting plate.

(Excuse the fact the pulley is not mounted, I‘m in the process of replacing a bad bearing.)

DF59126B-E301-4F66-B36D-1BFE640903EC.jpeg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
These are some a/c brackets that came off a 258 YJ with factory air, so the factory did not use a ”real” tensioner. Just the arm with the pulley bolted to the mounting plate.

(Excuse the fact the pulley is not mounted, I‘m in the process of replacing a bad bearing.)

View attachment 85374
Thanks for the pictures :thumbsup:

I was pretty sure it was just a "dummy" arm, not a real tensioner. I couldn't figure out/imagine how it could be a "tensioner", given its size/shape/location/single bolt mounting.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
More "RedneckRay" fab work.

The thinner plate installed:

20200714_174126.jpg

Pic below, where my finger is pointing to, shows a gap/recess between the two mounting studs. This is where the idler attaching bolt/nut needs to go.

20200714_174340.jpg


Idler should bolt to the plate, something like this:

20200714_174404.jpg



I wanted to "offset" the idler bolt location closer to the belt to gain the most deflection from my small diameter idler pulley:

20200714_175912.jpg

Since I am closer to the sedge of the plate, and to ease mock up, went with the smaller diameter 10mm bolt, vs the 12mm bolt:

20200714_175925.jpg

Drilled a hole, mock up, this is what I am looking for:

20200714_182345.jpg

20200714_182351.jpg

And a problem: the bolt head hits the timing chain cover if I offset the mounting location closer to the belt from center line of the plate:

20200714_182511.jpg

20200714_182524.jpg

If I reverse the plate, offset away from the belt/center line, plenty of clearance:

20200714_182654.jpg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
But, the small diameter idler pulley will not even contact the belt at the reversed offset position:

20200714_182822.jpg


20200714_182847.jpg

So, round two, this time with the thicker plate. And of course, clearance issue: this off the shelf/garage floor piece of plate is larger than the thinner plate, so it is fouling on one of the compressor mounting plates.

20200714_183810.jpg

Thought just nipping the corner off would work:

20200714_184512.jpg

Nope, had to trim the overall length down on this side. No big deal, poor Dremel getting a workout cutting 1/4" plate LOL:

20200714_185011.jpg

20200714_185501.jpg


Plate now clears the compressor mounting plate, BUT it is fouling on the face of the timing chain cover, due to it's larger size:

20200714_185813.jpg

20200714_185820.jpg

Good news, I do get full thread engagement with regular nits on the studs with the thicker plate:

20200714_190135.jpg



Easy enough fix, pull out the studs, one at a time, add two washers behind the hex, space it out, plate will clear timing chain cover:

20200714_190606.jpg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Spacing the studs out will allow for mounting bolt head, or nut, clearance between the back of my plate and the timing chain cover:

20200714_190752.jpg

But, I would have to space the studs out really far to get clearance IF I offset the idler pulley mounting stud offset toward the belt. So, I made the executive decision just to mount the idler in the center of the plate, in line with the mounting holes. I did not want to start trying to space the studs way out. That is an option , I just decided not to pursue this avenue, at this time.

Drilled and tapped the idler pulley mounting bolt hole:

20200714_200513.jpg

Loose mock up:

20200714_200720.jpg

Two nuts behind the pulley, on the pulley bolt, to clear the plate/plate mounting nuts:

20200714_200726.jpg

Installed, loosely:

20200714_201007.jpg

20200714_201026.jpg

Unfortunately, my small OD idler pulley is not putting enough tension on the belt. I can turn the pulley with my hand, belt stays stationary. No big deal, I will just install a larger OD pulley, to get more tension on the belt.

One other issue to note in the two pictures below, the pulley is not perfectly aligned with the belt, it is offset some:

20200714_201042.jpg

20200714_201127.jpg

Remember the stud I pictured earlier? Well, I have two different sized hex studs in this engine for some reason. One hex is 11/16", one is 5/8". The 5/8" hex is thinner than the 11/16" hex, causing the plate to run not perfectly aligned, at a slight angle. No big deal. I will pull a stud out of red Scrambler, or put a washer on the 5/8" stud outboard of the hex to get the plate running true.

So, I will install a bigger OD pulley, realign the hex studs, and report back.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
I went with a 90mm OD pulley. The reason being, you only gain half the increase in OD toward the belt. So, only increasing upwards from 65mm to 76 mm would only have gained me approximately 5.5mm in OD. I wanted a bit more then 10mm, so the increase from 65mm to 90mm gave me a15mm increase where I wanted it.

20200715_161928.jpg

20200715_161934.jpg

Quick mock up, much better. Hard to see, but look between the small tensioner pulley on the right, and the AC compressor pulley on the left, you can see the new idler pulley down there. Belt hits pretty close to center, too.

20200715_164135.jpg

I removed the thinner hex stud, replaced it with a thicker hex stud, because that is what I had in the spares box.

20200715_165152.jpg

20200715_165156.jpg

Besides the hex thickness difference, I noticed that my small piece of 1/4" plate was slightly bent. So, I put it on a flat piece of steel, beat on it with a sledge hammer, straightened it back out to flat. Feels good to beat the crap out of stuff sometimes.

Anyway, with matching thickness hex heads, and a flat plate, plate/pulley/alignment are a true.

I went ahead and re-drilled/tapped the idler pulley mounting hole out to 12mm. The 12mm bolt is a hair bigger then a 1/2", the 10mm is closer to 3/8". I figured the bigger bolt would resist bending more.

Mock up on the mounting plate, the pulley completely hides my mounting plate.

20200715_174035.jpg

On the rear of the plate, I allowed for 10mm stick out, just as a starting point:

20200715_174043.jpg

20200715_174938.jpg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
I reinstalled/removed all this stuff about 10 times, getting the pulley centered up with the belt. Changing the rear spacer stack, the front washers, rear nuts, etc:

20200715_175655.jpg 20200715_175707.jpg 20200715_180510.jpg 20200715_180515.jpg 20200715_180520.jpg 20200715_180720.jpg 20200715_180726.jpg
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Quick mock up, the belt looks good, BUT I can not install a nut on the back of the steel plate, it fouls on the timing chain cover.

20200715_181133.jpg

20200715_181145.jpg

20200715_181232.jpg

I am going to revisit this soon. I do NOT want only a 1/4" of thread engagement holding this pulley assembly to the plate. I am going to swap out the hex head bolt for a 12mm allen head cap screw, installed from the rear of the plate. A 12mm cap screw head has an OD of 18mm, so 3mm to either side of the bolt. I have 3mm clearance. A 12mm hex nut is closer to 22mm from point to point, 19mm flat to flat, not enough room back there.

When I do this, the pulley bearing bushing will be riding on threads, NOT a smooth shoulder. I was concerned about this, until I thought about it. The bushing is held stationary to the bearing inner race/bolt, once the attaching bolts/nut are tightened down. So, the bushing/inner race do NOT turn. The balls/outer race spin around the stationary center. So, no problem, AND it will be easier to assemble the plate to the engine, without the pulley in the way.

Once I redo this, I will take some pictures to better explain it all.

Anyway, tightened plate down, snugged up the idler pulley assembly to the plate, everything looks great:

20200715_181855.jpg

20200715_181919.jpg

20200715_181927.jpg

In all of the above pictures, it looks like the plate is cocked. It is NOT, just hard to get good pictures down here.

I started it up, WITHOUT the tensioner spacer installed. Squealed non-stop. Reinstalled the tensioner spacer washer:

20200715_182727.jpg

Started up the engine, no squeal. Engaged the AC clutch, no squeal. Turned the AC off/on about 20 times at idle, not a peep :woot:

20200715_182909.jpg

So, besides fine tuning/changing out my idler pulley attaching bolt to a allen headed cap screw, this is good to go, and it works.

Very happy!!!!!!!!!

That's it for now!!!!!

20200715_182920.jpg

Poor Red in the background itching to hit the dunes!!!!!!!!!!!!!!!!!!!!!!!!!
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
I also plan on revisiting my tensioner pulley adjustment. The spacer thing works, kind of butch, not very user friendly. More on this later, after SandBlast:fingerscrossed::fingerscrossed::thumbsup::wave:
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
Rather than the socket head bolt from the back, what about grinding down the side of a nut to sit against the timing chain cover in a way that also locks the nut from spinning? Use it to help get everything good and tight without needing a wrench on it, make a spare to throw in your box? Could also just weld the modified nut to the back of the plate.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Rather than the socket head bolt from the back, what about grinding down the side of a nut to sit against the timing chain cover in a way that also locks the nut from spinning? Use it to help get everything good and tight without needing a wrench on it, make a spare to throw in your box? Could also just weld the modified nut to the back of the plate.
I could, but I threaded the steel plate, and want to keep the threads in the steel plate, since they keep the bolt exactly where I want it. If I drill out the threads now, the bolt would be a hair loose in the hole, possibly allowing a wobble. I want the bolt to thread into the steel plate, and be secured by a nut/head on both sides of the plate. So, the socket headed bolt will thread into the plate from the back side, it's head will press against the plate, and a nut will be threaded down from the other side against the plate, Triple protection. Overkill probably, but I don't want this idler pulley flying off under load and taking out the radiator :eek:

And besides, I already decided to go this route and ordered a few bolts :thumbsup::rotfl::cheers:

Note I said few, as in I will have some spares of this "not common at hardware stores across the country" bolt :thumbsup:
 
City
Halifax
State
UK
Rather than the socket head bolt from the back, what about grinding down the side of a nut to sit against the timing chain cover in a way that also locks the nut from spinning? Use it to help get everything good and tight without needing a wrench on it, make a spare to throw in your box? Could also just weld the modified nut to the back of the plate.
Or use a half nut?
 
City
Halifax
State
UK
Is a half nut a different thing in the States?. i meant one of these, looked like there was room for one on your photo and made for the job.
Let me get out of the way now and you can carry on the way you were, you seem to be managing fine without me. :thumbsup:

 
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