MGB Cargo Bay Car

[BlownMGB-V8]

I got more parts!



The axle is an early B WW or possibly MGA. It sure felt lighter than the Salisbury axle but I'll weigh it when I get home. Looks almost dainty so it should be perfect for this build. I don't remember but weren't some of the WW hubs on these axles removable rather than being a one piece hub? That would be convenient if I could just unbolt them. Either way it'll work but I may have to cut the splined section off. It has the fine thread spinners, if that's a clue. The housing will fit in the lathe so narrowing should not be a problem, I just need to find a set of wheels so I can figure out how much. That might take me awhile as I want to see what I can do with the offset. Also I like the looks of the vintage style American Racing spoked wheels, particularly with the silver (Arconite maybe) spokes. and they make those in an inexpensive cast version so that might be a possibility, at least maybe in a skinny front for a bracket racer.

That will let me know what axle width is acceptable which in turn will let me know more about body width and how much I need to narrow the tub.

The bellhousing is pretty compact. I have yet to look at starter mounting provisions and may have to add that on. If I do I'll use the GM mini starter and position it somewhere out of the way if I can. More news after I get home.

Jim

[BlownMGB-V8]

At 124 lbs the banjo axle is 33-1/2 lbs lighter than the Salisbury. Springs and hardware adds another 50 lbs. I will be using a tubular 4 link instead. Maybe 20 lbs or so reducing overall weight by over 50 lbs. So far I have removed about 325 lbs from the car plus 200 more from the engine weight and estimating the difference in transmission weight, roughly 500 lbs removed. I'll get more off the wheels and tires, chunks cut out of the axle, narrowing the body, shortening the hood and trunk lid, etc. The tires I'm looking at are 8 lbs each so I'll be dropping 50 lbs or more there. The wheels are probably going to be around 10 lbs or less each so another 50 there as well. I'll be removing about half the metal of the front fenders and using part of an aluminum hood. A 1500 lb car may be within reach. Possibly, we shall see.

The slug for the engine coupler comes in tomorrow and once that is machined I can start on the housing, although I do need to source some aluminum plate. Guess that's on today's agenda. There won't be room to put the Toyo starter on top in the original location as it will hit the cylinder fins but it should fit at the side either by the oil filter or on the opposite side. Engine side clearances are beginning to be important.

I ordered an early Mazda RX7 space saver spare which used an Enkei spoked wheel that I think will look nice and do the job. Replacement tires are available in a 115/70-15 size which is 21.3" in diameter and that will work. Once it checks out I'll buy 3 more, they aren't scarce. The center hole will have to be enlarged, a simple operation on the mill or possibly in the lathe depending on if it will fit. Some PO did cut the ways so that is a possibility.
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The windshield will be a challenge. Is the curvature of the stock MGB windshield constant from side to side? Seems like it might be and if so I will experiment with the cracked one that originally came off the car. Maybe I can cut down the glass with a diamond blade in the angle grinder and rig cam locks on the side posts, making the whole works removable. If I can do that, cutting down the top is feasible as well.

The exhaust will have to go through the framing members and tuck in tight to the floor. 1-3/4" was recommmended as the exhaust pipe diameter which does make sense considering the primary runners on my headers are 1-5/8". But I won't be able to have anything hanging below the framing members or the crossmember and the suspensions will need to compress enough to let the belly contact the ground or come very close.

Jim

[BlownMGB-V8]

The Mazda spare came in and it looks good. Weight with a 135/70-15 tire is 22 lbs which is 14 lbs lighter than the Rostyle wheel and tire so I'm now at about 400 lbs lighter than stock. Good progress there. The lug pattern matches and I've decided that rather than bore out the wheel center holes I am going to turn down the mating part of the hubs to fit. I have to machine the rear ones anyway so I might as well and the fronts are only about  an eighth inch big. Time to go shopping for 3 more. The diameter is 21.5" but that is not fully inflated so it could grow a little. I dropped a board in the wheelwell and set the tire in to check fit.

[attach id=23893]

The diameter should work, the axle clearance should be very close.

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Side view should be OK and the lug nuts shouldn't project past the bodywork.

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Now I just need to determine the axle width. I may wait to get a second wheel before I do that so I can take an actual physical measurement though.

[attach id=23896]

I've made progress on the engine coupler as well. I've machined a coupler to adapt the compensater to the flexplate and am waiting on some 9mm bolts to finish that. The bellhousing plate is done as is the connecting tube. Once I have the locating pins I can transfer hole locations, bolt it together and check alignment prior to welding up the assembly. Then maybe some final machining to correct warpage and it should be ready for a test fit in the body. Perhaps I can get that ready to do while I have guests here for the Cincy car show.

Jim

[MGBV8]

Should be about 22.5" dia.  

Good luck replacing those tires.   May have to go with a 145/65-15.  Still not much selection.

[BlownMGB-V8]

There is a 115/70-15 that should work and it's a little shorter as well.

Here is a shot of the bell and the matching plate.



And here's one of the big tube and the compensator coupling.



Jim

[MGBV8]

I don't get using a space saver spare that should not be driven more than 50-70 miles.

At least the 145/65-15 is a real tire.

[BlownMGB-V8]

It's a dimensions thing Carl. Overall length is limited to 100" which means wheelbase has to be less than 80" if the tire diameter was 20. What is available is a very narrow window and the smallest space saver available allows the cockpit to be kept almost completely intact except for the footwells. As you know it is possible to ride in the B in a knees-up position so for short trips that is feasible.

Then there is the matter of suspension componentry and I do want to complete this build some time in this decade preferably sooner than later. Compromises must be made, but I'm an old hand at using what's just lying around.

Anyway the car will probably never be driven 70 miles at one go so that puts it under the limit, right?  Seriously though, The tread depth is much better than many an old tire I've driven on, the carcass is strong enough to handle 60 psi, and it is rated for over 1500 lbs. In this application it will never see more than a third of that weight and half that air pressure so I think it'll be fine. Just because it has warnings put on it for insurance purposes doesn't necessarily mean it is unsuitable. Besides I really do like the wheels.

Jim

[MGBV8]

But they are not real tires...

[BlownMGB-V8]

Maybe not in the sense of being compared to your sticky tires Carl. but keep in mind the job they are being asked to do. Which is, to remain in storage indefinitely while holding in high pressure and to then act reliably as a temporary replacement tire while carrying a weight that is all out of proportion to their size. This requires a rugged construction using durable materials while minimizing weight and size, while the tread has to be sufficient to avoid hydroplaning, give adequate traction in adverse conditions, and not cause any issues for the average driver getting home. That is what they do and do pretty well as we have seen.

Now in this application, they will have to remain in storage indefinitely, at a moderate pressure and light load, and occasionally do tire things like carry a light load at moderate speeds usually under good conditions. I really don't see the problem here. Is there something specific they need to do that they can't?

This weekend I hope and expect to be able to finish up the bellhousing and extension, which will require some TIG work and a little more machining. The bolt holes are all drilled, and tapped where needed except one hole that needs a lug welded on beside it as it is too close to the edge. Two bolts on the engine side need cutouts in the tube for clearance to insert them into the flange but I've figured that part out. Harley did NOT use anything even remotely approaching a symmetrical bolt circle, used odd sized locating pins (#1 drill) and two different bolt sizes (1/4 and 5/16 on a metric engine).

This meant that to center the tube on the crankshaft I first had to dial in the alternator rotor and mark the high and low points with the amount of runout. Then prepare two transfer pins to seat in the locating pin holes, then position the tube using four feeler gages to center it on the crankshaft centerline, bang the end of it to transfer the pin locations, take that all off, drill the pin holes, check fit, and then finally position the thick aluminum seal (which comes with a molded in o-ring) on the locating pins and using transfer punches mark the bolt holes and drill them. Pretty involved and plenty of opportunities for mistakes. I got that done yesterday so today first thing I need to make sure the bolts will go in. Final assembly will be after some welding and cutting two windows for bolts and needs to account for concentricity, runout, spacing and weld warpage. So not a particularly simple part. Good news is it's nearing completion and the bolts for the coupler should soon be here.

Jim

[MGBV8]

How many miles do you expect to put on these tires?  I agree, they do seem to hold up very well in  long term storage.

[BlownMGB-V8]

Not sure Carl, I don't expect it to be a lot though, the car will see service as a local runabout, any long distance trips will most likely mean loading up and moving the bus. Tread depth is 5/32" which is probably about what you shave your sticky tires down to. Considering the light loading they will probably get about the same mileage I'd guess.

I cut clearance for a couple of the bolt heads on the crankcase adapter and got set up to add some metal to the two holes that are just too close to the edge. Those two will get bolt access windows cut in the tube, a pretty simple operation. The inside will also get some welds between the bolts for a stronger assembly to avoid any risk of cracking later on. Good chance I'll get that done today. Then it all goes back in the lathe for truing and final assembly, and maybe a final shave after welding the major pieces together.

Jim

[MGBV8]

I did shave my Toyo RA-1 100TW tires to 5/32 to prevent tread squirm & chunking.  I run my Falken Azenis RT615K+ 200TW tires full tread 8/32.

My current set is at 4/32.  They are terrible in the rain.  Coming home from Long Island, NY, I had to slow to 45 mph on the Interstate in the rain to keep from hydroplaning.  Not sure what is more scary, hydroplaning at speed or thinking I may get run over by a big vehicle.

[BlownMGB-V8]

Yeah, I think we will probably try to avoid driving this buggy in the rain if we can. It might not even get windshield wipers. But it will get a windshield and soft top. Tucking the bows down far enough might be something of a challenge but luckily I have a quick-mount solution that I used on my roadster.

Got the welding done yesterday so today a little machine work I hope. Maybe later this week test fit the engine/transmission for the first time.

The plumbing on the bus is completed and leak free. Ordered more wire and propane tubing, so moving along. Might be some chance of having these two driveable by spring time.

Jim

[BlownMGB-V8]

Need to catch up a little...



I'm still waiting for the bolts to complete the compensator coupler but have finished up the bellhousing adapter and bolted the engine and transmission together. Still need to mount a starter but I haven't picked one yet. The Lexus starter is a bit too long. Maybe a SBC mini starter will work.



On initial test fit there was too much interference to get it into the car, primarily with the rotisserie itself. Cutting was required.



After trimming the brake rotor I had enough room and it more or less slipped into place. A different mainshaft yoke is probably needed and some trimming of the tunnel is required to allow the transmission to go up into place. Nothing very drastic though, just clearance for a fitting, a sensor, and the shift selector. The front of the tunnel will need to be bumped up an inch or so.



Clearance around the engine is generally not too bad but this will get much worse when the tub is narrowed. I'll have to get a little creative in mounting the crossmember. I have more photos showing underside clearances and such and will probably post those tomorrow. For now I have pulled the engine back out and chucked it under the bench. I can start on width calculations now. I think I can go up to 8" narrower. Weight of the engine/transmission assembly is 360 lbs on the nose. The starter is the only other accessory needed other than a fan.

Jim

[BlownMGB-V8]

More photos. First the clearance around the tail of the gearbox, clearly a bit of bumping is called for here.



Next the bottom side view, this will be raised up once the above issues are taken care of



And finally, this $h1t is about to get real. 8" removed.



More photos tomorrow, I promise.



Jim

[BlownMGB-V8]

A few more shots.



The panels are fitting back in nicely, some minor trimming is required.



Tunnel looks good, I suspect the transmission clearance issue just requires a setback of the tunnel of 3-4 inches which is easy to do.



Width between the tunnel and the sill is 16" but the seat can sit above the sill.



Jim

[BlownMGB-V8]

Good progress since my last post, I've been quite busy actually. The position of the transmission required the tunnel to be moved rearward 3-3/4 inches and here is the only photo I have of that right now from the bottom, you might be able to see where I shortened the kick plate under the driveshaft and the battery opening is closed up. It is no longer the low point on the body. I sectioned it between the rear bulkhead and the seat belt bolts and moved it back then welded it back in and finished the floor repairs on the passenger's side using metal cannibalized from the footwell side wall. In addition you can see the new bolt-in crossmember and transmission support, and some of the mods to the front crossmember.



Next the crossmember had to be narrowed but only 5-3/4" due to the offset of the RX7 space saver wheels. I actually could have gone an inch or so less than that but didn't want to make things too tight. This meant of course that the crossmember had to be welded to the frame rails but that was always going to be a necessity anyway as the following photos will show. Here is a bottom shot of the narrowed crossmember that also shows a pretty good shot of the cuts required to fit in the engine and transmission. At this point the engine is supported by one mount attached to the rotisserie cross bar.



Next was reducing the thickness of the crossmember to allow the engine to sit low enough and providing an access hole for a drain plug and again I do not have that exact photo but here is one that shows the cutouts in the frame rail needed to accommodate the transmission adapter. It shows the positioning of the crossmember an inch rearwards and the width offset. I used the rear stud tubes to position the crossmember by welding a piece with a 9/16" hole so I could drop the pins in and later cut those off after some welding was done. That angle cut was plated and welded to the crossmember as well as the inner fender, extending the inner wall all the way from the cut to the front of the rail and using 14 ga metal (.075 thick.)



Next another layer of 14 ga was added extending from the transmission tunnel past the end of the frame cut to the crossmember and below the frame rail to the crossmember with a long gusset at the front and a lower gusset at the rear. Although this narrows the front section of the rail, it adds considerable vertical strength and triangulates the section between the passenger compartment and the crossmember as well as making the crossmember now a structural component. Considering the amount of weight removed from the front, I believe it will be quite adequate but may consider additional bracing later on. I also added a closed triangular gusset on both sides of the tunnel under the gas pedal to brace the rail tot he floor where there is a height reduction in the rail. This combined with the tunnel strength will compensate for the abrupt size change caused by the removed section and won't affect foot position.

Jim

[BlownMGB-V8]

WooHoo! My new mini starter came in! It fits the 3.0 and 3.6L GM engine, is 1.4kw and may or may not have the grunt to crank over this engine but at least it is smol and has a usable mounting flange. I will get to do a test fit later today and perhaps even cut the mount.
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So here are the other shots of the most recent work.









I have now completed the engine plate/mount combo aside from the hose connections which I will add after the next test fit of the engine as they will need a couple holes through the frame rail on that side. As a dry sump engine it will need a supply, return and a vent connection. Nothing exotic there for motorcycles.  The return gets the thermostat and oil cooler. The Evo and Twinky engines used the transmission to hold the engine's oil supply, just one step away from unitized construction really, well that and the primary, which of course I am not using. So I will have to provide an oil bag which I may or may not find pre-made. I will post shots of that mount next time.

Jim

[MGBV8]

The Evo and Twinky engines used the transmission to hold the engine's oil supply...

Nope.  Engine, trans, & primary all have completely segregated oil.

[BlownMGB-V8]

Maybe the Evo but the Twinky uses the tranny as the oil bag. The tranny parts are probably the same but the case is very different. It has a removable oil pan and a big front flange that bolts directly to the crankcase. This plate matches the engine side and is marked for the oil and vent passages.



The next two shots show a bit more of the engine mounts.





Jim

[MGBV8]

The Twin Cam also uses segregated oil.  Engine oil & tranny oil do not mix.  The engine oil is stored in the engine oil pan that is bolted to the bottom of the transmission.  There is no tranny oil in that oil pan.  Only engine oil.  The trans oil is stored in the tranny only.  They do not share.

Disclaimer: I have had an Evo Wide Glide for 31 years & my BIL has had a Twin Cam 88 20+ years.  He had a Shovelhead prior to that & a Panhead before that.

[BlownMGB-V8]

I did not know that, Thanks for clearing that up. You are now my go-to source for Twin Cam knowledge. I plan to plumb in a thermostatic valve and oil cooler on the return line. 3-1/2 quarts of 20w50 or 10w40 Harley syn3 oil. I haven't found the oil change intervals yet.

So is it true that the Twin Cam is referred to by the 'great unwashed' as the 'Twinky' or was I misinformed about that too?

I ordered one of the chromed gear reduction 1.4kw starters off Amazon, but don't know how big it is. Hopefully I have room for it. Should be here in a couple days. I will almost certainly have to mod the gear to match the Lexus ring gear. Otherwise mounting should be fairly simple and as the Lexus ring gear is significantly larger it should be easier on the starter. Those two big jugs are a challenge. I saw reference in the manual to an automatic compression release (ACR) but I don't think my 96 has those as I didn't see any electrical connectors for them on the heads.

Now here's a serious question Carl. Has anyone successfully developed a Microsquirt controller and programming for the Harley especially the Twin Cam? I see that in '07 there was some buzz about it but opinion seemed to favor the stock controller and "cert", whatever that is, at a cost of $357. Apparently because it runs so many other functions on the bike. Which I don't need of course. Have you heard anything lately?

Today I get to mod some bolts and weld up a piece to complete the compensator coupler which leaves only the starter mount to machine into the transmission adapter. Steve and I will probably do another test fit and work up the body side of the engine mounts in the next couple of days, maybe with Dan's help when he gets here. Getting ready for my big birthday party, wish you could be here.

Jim

[MGBV8]

Yes, Twinkie is slang for Twin Cam.

No, I have not heard anything about using the Megasquirt/Microsquirt in recent years.  The early EFI Twin Cam wasn't very good.  I think that ship has sailed.  HD improved it.

I am far from an expert on EVO or Twin Cam.  I did buy the HD shop manual when I bought my EVO Wide Gide new in '94.  I did my own 500 mile service & had the store manager sign it off.

[BlownMGB-V8]

Steve and Dan have been helping on the car. We have done several things, added enough of the front suspension, adding enough parts to get the wheels and tires on and check clearances, see what parts are needed and such. We got the compensator coupler completed and mounted, bolted on the flex plate and messed around with 2 or 3 starters trying for something optimal. Still would like to find a really small gear reduction starter rated for about 1.4kw.

We then bolted up the transmission and did another test fit. With the new side plate it is too tight in the front so I will have to take some thin slices out and reweld to get some space but otherwise it looks pretty good.

We also looked at the steering rack to see how hard it would be to narrow and I really don't think that will be very hard to do. The required 5-3/4" can all be removed from the long end of the rack where there are no teeth and I expect I should be anle to turn threads and cut a ball socket and do whatever other turning or milling is required there.

I seem to recall someone saying that the rack really was not the optimal length for the car. This could be a chance to correct that if I knew the details.

Jim

[MGBV8]

Lloyd Faust said it was too long.  Maybe he may know by how much.