MGB Cargo Bay Car

[BlownMGB-V8]

As some of you know I have a little project in the works, a cargo bay car for an intercity bus. After many suggestions I've come around to the idea of cutting down the Chump Car candidate to suit. The finished car will have to be not more than 100" OAL, 29" high, and 50" wide at the widest point, less than that towards the top of the fenders. I think it's possible to meet those requirements using the MGB tub and I just happen to have an early RB tub to try it with. It's really less a question of what to remove as what to keep but the zip blade and the sawzall will see significant use and the air hammer and plasma cutter may even come out to play.

I like the idea of retaining the MGB title and VIN while much of the car is just... smaller. And in some places just not even the same.

Should be fun. Have to remove the v6 drivetrain first.

Jim

[BlownMGB-V8]

I've been thinking about this project for a long time now so I have some idea of how to go about it. Been taking some measurements and such to map things out as well. The bodywork needs to curve inwards towards the top, which the MGB tin already does. The critical point is at 2 ft up and needs to be no more than 48" wide at that point. This is to clear the hinge mechanism of the bay door.

We already know the rack is a bit short for the B so I'm not too concerned about that. The crossmember and front suspension is most easily narrowed by sectioning the center, the rear axles and housing do not pose a challenge, just effort.

If I retain the stock wheel and tire size the wheelbase should be 75".  That leaves 5" above the tires which is acceptable. Moving the front crossmember rearward looks like a valid approach to shortening the wheelbase. 16" has to be removed. Bringing the wheelwell back to the door post can achieve most of that.

Converting the rear suspension to quarter elliptical should be fairly easy. A 3rd link and a pair of coil-overs should do it. Possibly the stock swaybar with stiffer pivot points would do the trick or maybe Mikes trick of slicing out the center section to make it a modified 4 link.

Riding position is likely to be 'knees up' but that is OK for short trips. The car will never be driven on a long haul.

This fall I will begin visiting the pick-n-pull to look for a suitable engine. Something like a Japanese 1 liter v-twin that can be coupled to the Toyota 5 speed automatic I have.

I need to come up with a method to drop the suspension for storage in the bay. I think I might start with the old air bag spares and work from there. I'm sure that can be done.

It'll end up being a bit heavier than I'd like, but a lot of things will be deleted in the process so maybe I can get the weight down around  1500lbs. We shall see.

Jim

[MGBV8]

"We already know the rack is a bit short for the B "

It is actually the opposite, Jim.  A number of people have shortened them because it it too wide.

[BlownMGB-V8]

OK. Well that shouldn't present any real problems I wouldn't think.

I have to put brake pads on Edith's car in the next day or two and then I can get the tub up on the lift to remove the drivetrain. After that's out I'll drop it back down on the cart and begin cutting I think.

First thing I'll remove the section between the door posts and the removable splash shields. That will shorten the wheelbase by 15" and if I use a 185-60/14 tire that gets me the other inch I need. It should also be possible to move the crossmember back another inch or more on the frame rails to get more and I may want to do that.

So, make those cuts and weld it back together, then work on either the height or the width and get an engine for it.

Jim

In the meantime, I'm finishing up the tray for the shower in the bus and should have the enclosure done within days. As soon as I have made a vanity cabinet for the bathroom sink I can finish up the plumbing and the bus becomes nominally usable as a bunkhouse. Wiring and AC to follow.

[MGBV8]

I will make my reservation.  

[BlownMGB-V8]

Works for me. The bus can sleep 2 or 3 without resorting to camping gear. Not likely to have AC by then but you know, it's amazing how we don't get bugs (mosquitoes) here. Must be because of all the birds.

Jim

[BlownMGB-V8]

Yesterday I removed the drivetrain and suspension from the tub and set it back on the mill cart. At a glance, I will need to remove no less than 15" from the wheelbase and no more than 18". This is possible mainly by removing the footwells. Anyone who has ridden in Tom Cienza's BBC MGB knows this is feasible for a car that will not be asked to make long distance trips.

I may be able to use 13" wheels, it depends on the wheel. If so it should be possible to use 21" tires instead of 24", saving 3" and making that part of the job easier.

The width will have to be reduced by 10". This probably means a bench seat and may mean cutting down the tunnel to get more room. Certainly the hand brake lever will have to be moved.

The cowl is 28" above the bottom of the car, leaving only 1-1/2" above and below that. I will probably need to section the body to reduce the height.

This morning I cut off the rear part of the leaf springs, converting them to quarter elliptic. I have left over air bags from the air suspension project that I can mount at the bump stop location and get the same suspension travel as stock or better. Original Armstrong shocks can be used on both the front and rear. Swaybars may be out. Airbags at front and rear will let me drop the suspension for loading.

That's all for now, once I start cutting I will post some pictures. It'll be wheelbase first, then width, then height. Bobbing the front and rear may happen at any time, there is a scheme for making the nose and tail pieces re-attachable so it makes sense to do that part last.

A liter bike engine is seen as the powerplant and a trip to the junkyard is planned. I may find FWD alternatives to look at, although that is sacrilege in an MGB.

Jim

[BlownMGB-V8]

At present I'm looking at the possibility of using the 1200cc Triumph motorcycle T120 vertical twin engine as the power plant. 80hp, 79 ft/lbs of torque.Possible weight around 1500 or so. It's a light and compact engine, the weight is most likely somewhere between 150 and 200lbs but I've been unable to find that specification. Still for a runabout it doesn't sound bad.

One of the benefits of the Triumph twin is the chain driven primary drive which raises the possibility of direct coupling the crankshaft to the torque converter on the Toyota 5 speed automatic I have. What to do about the 6 speed bike transmission is a question I don't have to deal with right away but removing it would make fitting the engine into place pretty simple I believe, and modifying the case halves is something I should be able to handle.

The Bonneville used a dry sump and an oil bag, not much of a concern. This new version uses liquid cooling and a small radiator. I may have something suitable.

I also found out today that a 115-70r15 tire exists which has a 21.3" diameter. This is a donut tire, but would give me another 3" in the wheelbase which would help considerably. They don't have to be performance tires.

Jim

[BlownMGB-V8]

Found out today there's a 115-70r14 that's 20.3" diameter. I could cut 14-15" out of the wheelwell very easily and be just fine. I think that's the new plan. There is also a 105-70D14 used on the Aveo but hard to find and may only be available overseas. Not a great choice and not needed anyway. If I happen across a source I'll consider those, otherwise it looks like the 115's

My focus is now on the engine. I'm planning a trip to the yard tomorrow to see what's what. Then I need to evaluate intake options. The stock efi is likely to cost about as much as the engine, I have a set of '74 SUs, and a Rochester 2GC is at hand. I will have to decide how to feed it.

At some point after that I will start cutting metal. I'd like to get my mig situation resolved first though.

Jim

[BlownMGB-V8]

Today I bought this engine:

https://www.ebay.com/itm/177228631303

In case that post drops, it's a "07 Harley Dyna Super Glide Custom FXDC OEM EFI Twin Cam 96 Engine Motor 13K 1283" which translates as a 1573cc 45 degree V-twin Harley Evo engine with 13k miles on it. Includes the throttle body and air cleaner. Seems like a pretty fair deal to me.

I may use the Microsquirt as a controller. If memory serves it was developed specifically for bikes in the first place so it should be able to run the Harley engine. It comes in a sealed housing with an automotive grade gas sealed multi-pin connector which meets my requirements. About $375 with the harness. This is less than a used factory ecm and the main bike harness. I will have to come up with connectors for the throttle body, sensors, etc.

The engine height is about 24" which leaves me with 5-1/2" to spare. That is acceptable. The width and length should be workable. I will have to get a primary sprocket that can be cut down to mate with the torque converter on the Toyota automatic. It will need a controller also.

The microsquirt can also be used as a transmission controller apparently. I will be looking into that but I do already have a fully built Megashift controller that I will probably use instead. It was the one I built for the 8 speed so it will have unneeded functions but should serve the purpose. Once again, I will need to come up with connectors. I may consider selling that controller and buying a second micro if there are any advantages to doing that.

I should be picking up the engine from the depot in a few days. After uncrating it the first thing I will do is set it in the tub and see how it fits. Photos to follow.

Jim

[MGBV8]

That engine would make a great upgrade for my 80 ci Wide Glide.  

[BlownMGB-V8]

Mmm.... maybe not. Lots of changes between 1980 and 2007, many of which you would not like. But on we go. I brought in the Toy tranny and found an old V6-60 flywheel and stole the ring gear off it. Just a bit smaller than the torque converter so a plan is forming. It's a narrow pan tranny so that helps. I will eliminate the compensator since the converter will handle that but I'm thinking of elastomer bushings to couple the converter to the flex plate, which right now I don't have. I'm not happy that the output shaft is not hollow at the end like some of the earlier motors appear to have been, that will cost me about an inch. I may have a line on a custom converter but it probably won't be cheap. I will know a lot more once I can do a test fit.

Jim

[MGBV8]

My Wide Glide is a '94.  I would definitely stay with a carb if I upgraded.  EFI motorcycles seem to have a different throttle response.

[BlownMGB-V8]

Been reading up on it, so not an Evo but a Twin Cam. Probably helps to know what it's supposed to be called.

Jim

[MGBV8]

Yes, it is.  My brother-in-law has an earlier 88 ci Twin Cam.

[BlownMGB-V8]

Had a quick look at the Toy transmission. It is an Aisin 35-50LS also known as a Toyota A650E, some speculation online says the LS extension means a V8 version with a bit stronger internals. In any case it's plenty stout for this job. Its weight is 175 according to my grain scales. That's with the converter and estimating the weight of the bell based on a V6 one I weighed so should be within a pound or so. There goes my weight loss from the engine, or at least some of it. Shipping weight for that was 200, we'll see what actual is when it gets here. Strange to have a transmission weighing as much as the engine. Oddly enough it has a total of FOUR planetary gearsets, the gear spreads are reasonable and the OD is around .75 or so. I think this one had 40k miles on it. It's a bit of a chunk, but having an automatic in the bay car will be a plus.

I don't think the length of the engine is going to be a problem.

Jim

[BlownMGB-V8]

They put a thing on the output shaft that they called a Compensator. It's nothing but a rotational accumulator designed to absorb the power pulses and reduce breakage and such. This engine didn't come with one and I'm not planning to add it. But I do need a hub to fit the output spline. It may be a common size so once I have taken measurements I will check with my local power specialists CB&T and see if they have anything that matches. Ideally it would be a Browning tapered bushing. That would give me a lot of freedom fabricating the flex plate. Looks like the Lexus flexplate goes for about $60 which might be a good starting point.

If I put 6 elastomer bushings at the bolt holes for the converter it'd do about the same thing as the compensator. Maybe not as well but then again the fluid coupling of the converter would do a similar job up to the point where the OD clutch locks up.

Jim

[MGBV8]

A motorcycle Cush drive does similar as the Compensator.

[BlownMGB-V8]

Right. I guess some people rely on a belt drive to do that. I think the converter would work but wonder if the lock-up clutch would cause vibrations. It should only come into play at cruising speed. Maybe those 6 elastomer bushings between the flexplate and converter would be a good idea. They would also allow for some misalignment between the crank and the input bearing of the transmission so probably a good thing.

At this point I'm thinking I might be able to shove the engine and transmission forward a few inches and take some width out of the tunnel. That would help with seating. As it is I will likely have to use a bench seat and position it above the door sills. Don't know if I can take any off the top of the tunnel or not. Also the output of the tranny uses a big rubber donut instead of a u-joint and slip yoke. That may have to change, but it probably means putting a slip joint in the drive shaft and finding a matching flange to bolt to the output shaft.

Meanwhile I need to come up with a better mig welder. Brothers Dan and Andy each have one I can borrow. I may just have to do some testing.

Jim

[MGBV8]

Will there be any issues tagging this creation?

[BlownMGB-V8]

Shouldn't be, I have the title for it.

[MGBV8]

No inspection, I take it.

[BlownMGB-V8]

You think the Deputy that does the inspection is going to have any clue about what an MGB is? Or what it's supposed to look like? I think as long as it doesn't have any obvious deficiencies (and for 1974 that's pretty wide open) I figure it'll get pencil whipped.

Supposed to go pick up the engine tomorrow. WooHoo!

Jim

[MGBV8]

Depends how old he is.

Bring it down here & register it in TN.  

[BlownMGB-V8]

You don't fool me Carl, You just want the engine. ;-)

Jim