Technical Narrowing Rear End Question

I'm going to re check the total offset tomorrow. And Go over all measurement's again.
I would just run tires out side but trying to keep a stock look to it so that's a no go haha.
No big power plant just a \ 120hp 4cyl with 5spd trans.
Plus keeping weight down. Anyone cut there tubes with a pipe cutter? I was told it make a heck of a lot more precise and clean cut.

 

uuuuuhhh....you have a few 'typos' in the last post......I think you MEANT to type."......just a 1962 Chevy II 153 4 cyl with a 4 speed" (trust me)

 

yeah that's about right

 

Need more evidence that we should "trust" you. 1999 S10 pickup base powertrain was a 120 HP 2.2 liter inline 4, with 5 speed stick shift. This engine is totally unrelated to the Chevy ll, Iron Duke, or later Citation/Fiero cross-flow head version.

 

Perhaps you entirely missed the point of my post..........that being what the OP posted was off topic here (later than 1965) and risked being deleted.........it was a 'wink' 'wink' reply ........not to be taken completely literally.

As for trusting me.....that is a given.....I am, after all, Honest Ray

 

My apologies. What you're saying dawned on me as soon as I posted, which made the OP's condescending response more understandable. Hope I didn't blow it!

 

I was surprised by your comments as I read your posts and knew you are pretty astute guy...figured you had a tough day or were just distracted......no harm done.....

 

I'm okay on the technical stuff, but somewhat challenged on social issues.

 

Well did some re measuring (Vega) rear is 54.375 Wide Crosley (41.5)
(Vega) Rear axle flange to pinion center is 26.75 on one side other is 27.5 so that's .750 offset?
Some reason my math ends up being 6.0625 off one side and 6.8125 off the other?

 

That sounds about right, but you really can measure it like that. The numbers will give you an approximation. To do it proper you have to reverse engineer where you want the wheels, presumably they'll be back in the same location? There is a measurement, the 'B' dimension, you need to know for your discbrake 'offset'. That is the distance from the axle bearing flange to the face of the axle - they're generally a little over 2" but will not be the same as your drum brake offset on the original rear. The other thing you need to know is the thickness of the bearing housing, lots of them are about 1 1/2ish. You figure them out and that will tell you where you need to cut the axle tube. There is a bearing housing on your new rear, you'll need to resure it so it'll be cut off and then re-welded back on or you can buy a new one but either way you need to include it in your cut calculations. Ask your disc brake mfgr how much of an offset he needs - lots of time the caliper mounting bracket is also the plate that retains the bearing an dhold the axle in place, the rotor is on the face of the axle flange so the distance from the face of the axle flange and the bearing housing is fixed so you need to know that too before you whack the axle tube.
Let us know what those numbers are and we'll go back thru the math to figure out where to cut the axle tube.

 

The brake offset on the Vega rear is 2 1/4 I'm running the original Vega drum brakes back on it.
I was going to go about 4" from the axle housing flange cut then once cut remove the needed amount on the remaining tube.

 

Given the information you have provided, and processing that through my simple minded reasoning, here is what it suggest to me. First, the pinion offset is less than an inch, so why bother trying to correct it. It will have no ill effect on anything if it remains. That means you deal only with the total width and cut each side equally.

I agree with OJ, above, that the place to start is with wheels and tires you wish to use, set at the distance apart they need to be to fit the body as you wish. Measure the distance from the wheel mounting surfaces side to side and that is what your axle width will need to be. Compare that to the existing width and .....bingo.....you know total to be narrowed and take half from each side. Would that not work?

And, I agree with your choice of 'cut points', providing the axle housing is same diameter thought the area to be cut.

 

Which side is which, is the 26.750 the p***enger side?

 

I believe Crosley original track width is 40" The wheels i want to run are 4.5" wide and have 0 offset. Tires i'm not sure of yet.
I always though that pinion needed to be aligned with trans. If not then i won't worry about centering and just do even cut off both sides.

 

I kind of trust @Hnstray myself. He is kind of opinionated unlike myself who is not opinionated at all but he has been around cars for a minute.

So got to ask @Desmodromic. You own a desmorooter? Is it a round case?

When you say zero offset you mean center set wheels? 2.25" on the front and the rear? or are you referring to zero back space as in a reversed wheel or??? I ask because while we are all motor heads we don't always use the same language.

And if you are cutting it anyway you may as well center the pinion or at least set your pinion so that you have driveshaft tunnel clearance.

You asked about cutting the axle tubes with a tubing cotter. I have cut them with a tubing cutter, as well as a chop saw a torch and a hack saw. The tubing cutter works well of your axle tube is round. Not all of them are. It is not going to matter much as you are going to have to use a fixture to weld it anyway or at least you should.

I am not sure what your plan is for cutting and welding. I have found that I have my best luck removing the bearing end from the tube and then cutting the tube to length and re-welding the end to the tube. Most (not all ) factory bearing ends or housing ends if you prefer have a sleeve that is inserted into the tube.

Not telling you what to do just telling you how I would do it if it were me.

 

Ok, using your numbers:
the GM rear is a total of 54.250 w/.750 offset, then each tube is 27.125 +/- 1/2 of .750 or
27.125 - .375 = 26.750
27.125 + .375 = 27.500, to test:
26.750 + 27.500 = 54.250 your overall width and
27.500 - 26.750 = .750, your pinion offset, this is what your GM rear is right now
they each should be 20.750, then:
26.750 - 20.750 = 6" shorter
27.500 - 20.750 = 6.75" shorter
Remember, this is your finished length, you'll need to add your bearing housing because you'll be cutting it off the 'drop' and welding it back on.
Hope I did this right, my brain is gobbledlygoop from trying to put a 70year old hand made Italian grille back together using miniscrews from a Rolex and theres multiple sets of holes where they couldn't figure it out either.

 

It does not matter what the original Crosley track was. What matters is what the maximum width, outside of one tire to outside of opposite tire, has to be to fit the tires and wheels you want to use on build into the space available in the body. Once the tires/wheels are mocked up, as though they are on the car, at that width, you measure the inside of the wheel mounting surface, across to the inside of the opposite wheel mounting surface, and that is your needed axle width measured at the drum mounting surface. That number, compared to the present width measured at that point, indicates how much the axle ***embly has to be narrowed. It's really that simple.

Regarding the pinion offset, the pinion does not have 'to be aligned with the transmission', the term 'aligned' meaning, for this purpose, as in the same place side to side and/or top to bottom, as the transmission. What the pinion axial center line has to be is parallel to the engine / transmission center line. Those center lines can be beside, above or below one another, they just have to be parallel. The driveshaft U-joints really don't care if they are angled in any direction, so long as their working angle isn't exceeded. The majority of rear drive vehicles with a solid axle system have some amount of pinion offset, many as much as 2".

 

My 9" is offset 2". I am not sure what it is out of someone said Bronco but I know its 2" wider than the rear that it is replacing. I doubt it will make much difference width wise but if I had an axle 2" shorter than my long axle I could certainly center it up. Not worth the cost to me to do so. Shortening the housing is nothing but either buying an axle or resplining the axle costs.

Where you run onto a problem is with exceptionally short drive shafts. But most of our builds do not fall into that category.

 

****** makes a good point that I neglected to address directly. I mentioned "not exceeding their working angle" which alludes to that. But, to be more specific, as ****** mentions, the shorter the driveshaft the less tolerance there is for offset in any direction as with a given setup U-joint working angles increase as driveshaft length decreases. With your short wheelbase Crosley that is quite important to consider , though by itself the 3/4" offset of your pinion is not extreme. Even with the pinion centered, it will be necessary to keep an eye on the driveshaft/u-joint angles during mock up.

 

You could cheat on your engine alignment a bit if the pinion is off too much. Mount the engine toward the side the pinion is off centered to. Even if you mount it 1" off of center it's not going to be noticeable that much. I offset mine 2" for steering box clearance.

 

Thanks OJ! But i can't cut the flange off as the tube is same size right about up to 1" of the flange it then tappers down. The flange was pushed onto the tapered part then welded at factory. Did i mention this was c-clip axles?
The only info given on the wheels i were looking only says 0 offset but it's hard as i'm not 100% on what i want to run on rear yet. This car has a 80" wheel base so i will have a shorter drive shaft. I just bought a degree tool for when i do the pinion angle so i can set that right.
Unlike the ford 8.8 and those that i seen online where they make that nice alignment jig this is a odd ball and there's no jig for it. So i was figured seeing the tube is same the whole length i'm going to use 2 piece of c-channel clamped. Hopefully that does it. That's why i figured a pipe cutter will make it easier as the cut will be clean.
Welding wise i'll have to find someone. I only have a 125 Lincoln running .035 flux. I was thinking jig it up run some hefty spot welds then bring it to someone who has a acquitted welder.

 

Mmmm, 'C' clips, mmm, not good at all, I forgot about them when you mentioned GM. I can see you will have too many complications. Do yourself a favor and get a Ford 9", here's why: you will go thru all kinds of nasty hoops and machineing etc to get the GM to work and at the show the very first guy will ask 'You got a 9" under that thing?' And he'll give you a look that you never want to receive when you tell him a narrowed GM 10bolt. The Ford 9" will give the car value and very easy to get the right stuff to narrow it with tons of options.
I do these a lot, don't be afraid to PM me if you have questions.

 

Using a Ford Axle has it's merits, especially regarding axle retention. However, given the light weight of your body/ch***is/power train...I'd suggest you consider an 8" Ford axle. It is (according to some published data) about 29 lbs lighter than a average 9" and is plenty strong for your application. That 29 lbs may not sound like much, but it is about a 20% weight penalty on just the axle ***embly. And it is a significant amount of all unsprung weight. On a 3500 lb car an 8" wouldn't be a benefit, but on your Crosley (probably finished will be under 2000 lb) a significant reduction in unsprung weight does matter in how the vehicle handles and rides.

BTW, 8" Ford axle shafts generally are the same diameter as 28 spline 9" small bearing axle shafts.....and in both models they vary in length by application. The 8" ford diff is approximately equal to, if not better than, the average GM 10 bolt and easier to work on.

For the Lookie Lou's who question you..."does it have a 9" Ford?".......your reply can be, "yes, it is a Ford"...and that's enough to say.

 

As pointed out by Porkn******, it is important to be conversing in the same dialect. To reiterate my earliest post, the "offset " of the pinion is one-half of the difference in lengths of the pinion to either side of the rear end. (Axles themselves are probably of equal length in a production auto, which is what results in the pinions being commonly offset.) Based on the latest dimensions you have provided, the offset is not 3/4", but 3/8" (see attached sketch). When contemplating the hostile environment for the U-joint, it's the 3/8" dimension that is applicable. In comparison to the U-joint deflection in the vertical plane, maybe +/- 1.5 inches (?), it is negligible. However, the Chevy ll engine is somewhat longer than a Crosley, and the ****** way more so, resulting I think in a pretty short driveshaft. I'd suggest that you try to set rear end and engine angles (in the vertical plane) so that U-joints are not under any deflection with normal p***enger & fuel loading. (I know it's a pain, since how do you know the normal spring deflection before you finish the build!) You might want to determine the drive shaft length and provide that and expected deflection to a U-joint supplier, who may tell you it's a non-issue.

If you have your heart set on "zero pinion offset", cut the short side 3/8" longer, and the long side 3/8" shorter.

I strongly recommend the you make a scale drawing showing lateral dimensions on everything, including local body with fender lip, ch***is, wheels/tires, brakes, rear suspension (Crosley spring is outside of the rails, if you're using that), etc.

 

Not sure what I said to earn your distrust, but I can live with that.

In response to your inquiry - no, I have an R80ST. I guess it would be considered an oval case, but it does not go by that appellation. But I am in the market for an MB W196 GP car, if you run across one for a low price.

 

Regarding axle selection, the heaviest Crosley made weighs 1400 lbs. ***uming 200 lbs max for the heavier engine/******, and in view of the low 120 HP expected, I think there is no reason to avoid C-clips, as in a GM rear. Also, you would be sacrificing the matching 4x4" bolt circle. I'm not sure if it's feasible to predrill a 5-lug Ford to this pattern, or if there is enough room on a new axle's flanges to provide it. I'd guess you could use and redrill a Ford 6.75 or 7.5" 4x4.25" lug rear (Falcon. early Mustang) to match the Crosley pattern, which would be amply stout. However, I note that these are C-clip designs. So, I see no reason to abandon the GM 7.5" set-up.

By the way, you've referred to resplining the axles. Many axles are larger in diameter at the splines, which would mean you'll need new axles. I ***ume you've checked this out; would like to know what you've found.

 

My reference to axle retention was not related to strength of ’C’ clip style. It was related to the seemingly more critical accuracy of axle length and positioning of the ‘C’ clip groove, especially the groove to axle end dimension. Any competent machinist could do that provided they were supplied with accurate measurements.

But the Ford axle style wherein the outer bearing retains the axle does not demand the same precision. Only that the axle not be too long and bear against the spider gear pin before the outer bearing is fully seated. If the axle is a bit short, it seems to me that is inconsequential.

Further, and of more useful concern, the ease with which the Ford style axle ***emblies can be worked on, for any purpose, trumps the Salisbury style integral carrier housing for ring and pinion setup and necessity of opening the diff case for ‘C’ clips when only servicing an axle shaft. Also, the GM axles ride directly on the axle bearing rollers, serving as the bearing’s inner race and subject to direct wear of the shaft. As compared to the fully self contained axle bearing ***embly used by 8 & 9 inch Ford, I think the Ford clearly is more user friendly.

I acknowledge most of this is moot in this application because once set up, the vehicle in question will be capable of running a loooong time with out much wear to what is, in this light weight vehicle, a Super Duty axle.

 

Maybe a Dana 44 or smaller would be a better rear end to start with.

 

LOL I do not distrust you at all.

one of these?



I almost bought a 750CC round case new. Hind sight is 20/20 of course but today I wish I owned it.

GM axles are not easily resplined. Generally speaking the 12 bolt rear axle or the corporate rear come the closest in a car style rear or the floater axle of the 3/4-1 ton trucks are your best bet.

You can use the large diameter Ford axles and have the C clip cut into them. Then have the drilled for your bolt pattern. A common upgrade (?) is to cut the for axles and use a Ford style housing end eliminating the C clip.

I am running things through my head now and cannot come up with an axle that is already the correct with. The Crosley is pretty narrow.

If it was the early banger with the sheet metal block it would make a fun bike motor. Actually I imagine that the later motor is pretty light too. Sorry just making things in my head.

 

That is a design feature that never sat well in my head. It sort of makes no sense, it obviously works though provided the relatively huge axle gets the same attention that a small bearing race would