One of those things I'd never done before. Installed a few but never narrowed one myself. Actually, other than the constant second guessing on the math it wasn't bad at all. Rather than re-post the whole story here, you can catch the complete blow-by-blow at my Tempus Fugit Garage site (personal playground): http://tempusfugitgarage.com/narrowing-ford-88-differential/

The gist is, I needed to get a rear end up under my conversion project and was able to land a nice 8.8 with a Trac-Loc on my doorstep for $250. After looking into the cost of having it done or buying one, I decided to give narrowing it myself a go. While I don't think there's all that much savings to be had after I add the brake package and the axles from Moser, I'm still glad I did it. Wouldn't call it fun, but something I've wanted to do.

Just for comparison sake, I was able to source a narrowed 8.8 for about $1500 complete with rear discs, not including freight. By the time I include the spring perches ($50), the differential itself ($250), the axle/bearing package ($500), the disc brake package ($400), the axle housing ends ($100), the paint, wheel seals, welding rod, and other sundry items, I have around $1300 in the project. Not a ton of savings especially if you want to include the time but enough to keep me in beer for a little while.

Where did you source the narrowed 8.8? Is it narrowed to a stock MG diff or shorter to allow for wider tires? Thanks.

I narrowed mine myself. At one point, Mike Forte of Forte's Parts up in the Boston area was (and may still be) narrowing 8.8 units to whatever specs you want. When I originally priced mine, he was having a special on the few remaining Trac-Locs he had on hand. Don't know if that's still the case but, if you're looking to buy an 8.8 "out of the box" so to speak, he'd be worth a call.

I narrowed my 8.8 to a custom width to accommodate my Preform Resources bodywork and wheel and tire package so, no, it's not stock MG width. Axle flange to axle flange, my differential is 56.5" which is, I believe, about 3.5" wider than a stock rear (53" is the number I frequently see mentioned).

Regards,

DT

Not pickin on ya Kaz, but I see this quite often. Of course, a narrower rearend is not the key to wider tires. Maybe, IF you have particular set wheels you really want to use. The stock wheelwell will dictate how much rubber will fit. A bit of massaging here & there will allow more tire than needed. Match the wheel width to the tire. Match the wheel offset to make it fit. A 225/235 will go in a slighty massaged stock wheelwell with the stock width rearend.

I believe that the stock disk wheel rear is about 52" wide or a shade under.

I guess, I should clarify a bit here. The title of the post says "narrowed" and that is correct—I narrowed the stock 8.8 to fit my application. It might be more accurate to say that I actually widened the stock MGB track width.

In my case, there were two reasons I made the swap 1) I needed a wider track (56.5" flange to flange vs. the stock MGB 52" or so) due to the Preform Resources rear wings that add about 10" to the width (Dave, please correct me if I'm wrong on the number) of the car. My wheel and tire package isn't anything that unique - a set of 70s era BBS 16 x 7 wheels with a pretty normal offset and backspace. And 2), I didn't trust the MGB differential to stand up to the near 400HP the 302 dry sump motor is expected to put out. Additionally, if for some insane reason I elected to keep the stock rear, it would have meant going to 2" spacers and, while I know they're available, not something I wanted to do.

Good job David !!!

David, as many cut rear end housings and I adventure to say about 40% or more (not sure of the %) they have bearing failures regardless of did the job, yes if Moser did it it will not 99% correct.

I like to check the tubes and make sure they are straight. Checking the tubes is easy and straighten them is also easy but time consuming.

Place the axle on good supports, make sure the floor is level. Divide the axle bearing end into 4 pieces marked them with a marker, place a protractor matching the lines on the tube bearing end, it should read 0, rotate the axle and place protractor on the other lines and should read 0.

If they are bent, then take the torched, heat opposite of direction, heat the center of the tube until is red and let cool off. and remeasure, the heat will shrink the tube.
This is a good time to add camber to the rear axle, no more than 1 degree, best is .5 degree. It will no affect bearings or seals.

When you measure, avoid toe out, this is not good, a little toe in is ok. dead straight is also good, meaning no camber and no toe.

---

It is our attitude that will determine the outcome

Other than cutting the tubes too short, probably my biggest concern was the potential to warp the them when welding. To help minimize the chance, after tacking the housing ends at 90 degree spacings, I welded 1/4 of the way around, then rotated the axle 180 degrees and welded the opposite quarter and son on, being careful not to hot spot anything.

Seems to have worked. While I didn't use your protractor method, placing my magnetic angle gauge on the axle tubes showed 0 degrees. I rotated the differential just as you described and measure checked again. All zeros according the angle gauge. If the readings are wrong, I'm sure going to find out in a hurry.

How did you ensure the ends were concentric with the axle centerline and the perpendicularity of the bearing face to the axle centerline? I have seen mandrels that clamp in the carrier bearing saddles but they cost more than having a good shop do the narrowing for you. Not getting it right is what eats up wheel bearings

---

Jim

"If you want me to agree with you then we would both be wrong"

'66 MGB widened 11" with LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108

To keep the new housing concentric with the axle tube, I fabricated a cone out of an exhaust adapter (the inside of the axle tube and the housing were two different diameters) that I then slit lengthwise and inserted into the axle tube, then the housing. It fit sung enough that it wouldn't move in either the axle tube or the housing end. Once the tack welds were complete and the housing wouldn't move, I reached in with a flat blade screw driver and pried an edge of the cone over then finished collapsing and extracting it with a pair of flat-nosed needle pliers. Not very elegant, but it worked. Necessity is, indeed, the mother of invention.

To keep the housing ends perpendicular to the axle tubes, I started by leveling the assembly then, with my magnetic angle gauge on the housing end and reading 0 degrees, I tacked the top and bottom of the housing. Next I rotated the assembly 90 degrees, rechecked for level and repeated the process. Again, not very sophisticated but the result (as far as I can tell from re-checking everything after I finished) was nearly dead on (to the degree that my angle gauge is accurate). One of the ends is off top-to-bottom by less than a half degree which, I am told, should not be of significant consequence.

In any case, the proof will really once the axles are installed and I'm actually rolling and putting miles on. At the rate I'm going, that shouldn't be for another year, maybe longer. In the meantime, I will content myself with the pleasant illusion that everything is within an acceptable tolerance (until/if it proves otherwise



Edited 1 time(s). Last edit at 08/13/2012 01:52PM by dtownsend.

IMHO, while there is some self satisfaction and accomplishment to tackling a job like this, some things are best left to professionals that have all the right equipment (welding/checking fixtures, hydraulic presses to ensure correct camber & toe, spline cutting equipment, etc.
I had my complete 8.8 shortened years ago at Moser for a very reasonable sum.
Hope that everything works out for you!

Can't disagree with you Graham. But, as I said at the beginning, its something I hadn't done before and wanted to try. If it doesn't work out, I'm not really out anything but my time. Have already talked with Moser in that regard and said I could ship the whole thing to them and they would make it right. In any case, car is unlikely to be under its own power until spring so I won't know until then.

The exhaust adapter was a clever approach but it does assume that the I.D.'s of the axle tube and the bearing end are concentric with the axle centerline. That is the reason the professional tooling used an arbor that registers off the carrier bearing bores. If you want to check the parallelism of the bearing flanges you can take a couple long straight edges (4' to be really accurate) and hold one against each side. Measure the distance between the front and back ends like you are measuring toe in - which you are. Do the same in the vertical plane to get the camber. A tape measure will be plenty accurate at those lengths to check your results but you will need at least two extra sets of hands to hold the straight edges in place while you take the measurements. If you find you are off you won't know which side (or both) that needs to move but it is a good final check of your work.

---

Jim

"If you want me to agree with you then we would both be wrong"

'66 MGB widened 11" with LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108



Edited 1 time(s). Last edit at 08/13/2012 03:41PM by Jim Stabe.

Jim,

So what would be the ideal result from the measurements? Amount of tow in? Amount of camber? I don't have anything 4' that
are reliably straight but I do have two 3' squares that are dead on and can easily clamp them to the axle housing flanges. Would that work?

DT

Ideal is zero toe and zero camber. Some of the racers bend camber into their housing but they don't care about changing parts all the time, it is very hard on splines and bearings to have them running at angles. You want the axle splines to be centered in the side gear internal splines and you want the extended centerline of the axle to pass through the center of the wheel bearing and be perpendicular to the axle centerline. You will probably be fine since the production processes and tooling that produce axle housings are very good and the concentricity of the factory assembly is probably right on. All I was suggesting is that you can add an additional check to your welding on of the ends by checking toe and camber of the ends using straight edges. Obviously, the longer the more accurate but use whatever you have available as long as they are straight.

---

Jim

"If you want me to agree with you then we would both be wrong"

'66 MGB widened 11" with LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108

Thanks. I'm going to head out to the garage this evening and see what I have.

I may regret posting this but, earlier in this thread I responded to Graham's comment but I've been thinking about it all afternoon and would like to add to what I had said previously.

As said, I do not disagree with Graham's statement on the surface but, respectfully, strongly disagree with it on several other levels.

If I were take the approach that "some things are best left to professionals" I would have never built my first dry sump motor. I could have easily bought everything I needed from any one of several very fine suppliers and the result would have, undoubtedly, been every bit as good or better than my effort. In doing so, I would have learned absolutely nothing about the intricacies of dry oiling rather simply confirmed that my credit card still has capacity.

Same goes for the tin work I didn't know much about before I started this project that I could shopped out, or the fiberglass work or the electrical work or a thousand other things I had never attempted. Or the front suspension, a kit I could have purchased from Bill Guzman and that would have, hands down, been better than what I finally came up with. But I would have never tested myself, never pushed the boundries of my knowledge, never had the deep and abiding satisfaction that comes from efforts made and successes earned. In short I would have never converted my knowledge into real learning. Something I will always keep with me.

The bottom line is, I hope someone else reading this post, looks at what I did and finds inspiration to try something on their own. Whether he knows it or not, I owe a good deal of my inspiration to guys like Jim Stabe, Jim Blackwood and others against whose efforts mine seem a bit paltry. Not that I'm not proud of what I have accomplished but simply to acknowledge men of greater skill because to me, those people are the essence of hot rodding. And I mean hot rodding as in right after WWII when it really took a grip in this country with young men hungry to build faster cars with whatever resources they could cobble together. There was no "aftermarket", only their energy and eagerness to try things...and to be willing to fail in the process.

Maybe I'm all wet on this, but your statement really struck a nerve with me. I could have outsourced the whole damn thing. It's a popular custom in our country today and the only thing I would have learned is that I have the capacity to buy what I want.

Diatribe over. Thanks for listening.

David

Spoken like a true dark sider, well done! First of all paying for something from a "professional" does not always ensure quality. I have seen numerous examples of really sub standard engineering and workmanship that people have paid dearly for. That said, there are also a lot of professionals that truly are professional and produce well engineered, quality products. For all the time and effort I've put into my car over the years, I could have bought a factory car that would be more comfortable, faster, quicker, got better milage and probably superior in many other aspects BUT all I would have learned was which way the mag stripe goes when I swipe my card and I would have had a car that looked exactly like 10,000 others on the road.. Some people here think I have super car building powers, I don't agree. I think what I have is the willingness and desire to learn and to do something innovative. I am deeply in debt to skilled people on Metalmeet.com, Allmetalshaping.com, the HAMB, Garagejournal.com and others who have shared their knowledge over the past 10 years. Have I made mistakes over the years - heck yea! What I learned from those mistakes is far more valuable that whatever it cost me to correct the mistake. I eventually got to the point that I thought I had something I could give back so I started posting on the various forums. I am proud of what I've done and more proud of what I've learned. I try to share the successes as well as the not so successful in the hope that someone will have the courage to go out on the limb and try making something themself.

My god, I'm starting to rant like Lloyd. I applaud David on his efforts and hope he is an inspiration to others here to follow his lead. His car is coming out beautifully. Hell, anyone can restore a car (or pay to have it restored) but it takes a real man (or woman) to cut one up. These cars of ours are cheap and parts for them are cheap so it's not the end of the world if you try something innovative and it doesn't come out quite right. All you have to do is start over from a smarter place than you started last time. Knowledge and skill are addictive, the more you have the more you realize what you don't know.

---

Jim

"If you want me to agree with you then we would both be wrong"

'66 MGB widened 11" with LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108



Edited 1 time(s). Last edit at 08/13/2012 06:28PM by Jim Stabe.

Whoops! I was a little too quick on the 'post reply". Answer below.



Edited 1 time(s). Last edit at 08/13/2012 06:58PM by dtownsend.

Okay, I don't how this translates to degrees of camber or toe in but here's what I have. At 32" from the center of the axle housings I have 3/16" difference front to rear, the rear track being the wider. This, I believe equates to toe in but I honestly don't know if it's good or bad. Top to bottom at the same distance from center, I have 1/4" more at the bottom than the top.

Give it to me straight. This is mostly a track day car with some street driving from time-to time, maybe an occasional trip thrown in and is unlikely to see more than a 2-3 thousand miles in any given year (keep in mind the driving season where I live is only about 8 months long). I'm not opposed to having to replace the bearings from time-to time or even have another differential built up if I've truly junked this one. Run with it? Re-do it?

I was wondering what 8.8 axle you started with?
Although I don't have an MG, I do have a Super 7 replica I scratch built from nothing and I used an 8.8 out of a Ford Explorer.
The wms to wms is around 59 inches, I paid 75 bucks for this at Pick a Part and did all my own welding as far as the 5 link goes and shock mounts etc.
Cutting the tubes and axles does not seem like a big issue.
I apologize to everyone if my question doesn't sound proper, but where does 1500 bucks come from, that seems like a lot of money?

Al