| THE MG |
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 | |  | October 31, 2010 - I've been learning about MG tachometers.
It's fairly normal to have trouble with older tachometers and LS conversions due to the signal from the GM computer. The usual problem is a voltage one, and the solution is a pull-up resistor. That didn't work.
So I asked the folks on the Grassroots Motorsports forum, and it turns out it's the tach used in the MG. Up until sometime in 1972, they used an inductive loop inside the tach to measure the ignition pulses - that's it with the white wire and the copper winding. Well, this works well with points but not with newer ignitions, it would seem. And of course, our 1972 MG has the old style, identifiable by an RVI part number on the face.
One piece of information I found suggested that dropping the number of loops of the white wire would help, but that didn't work. I suspect that's for when you change from points to an electronic ignition, and the distributorless setup from the GM computer is just too different. I guess this problem is well known in MG circles.
Luckily, there's no shortage of MGBs that have been turned into parts cars. There's an "RVC" tach on eBay right now with an identical face design, and it'll play nicely with the GM computer. I may still need the pull-up resistor, but we'll see when it gets here.
An interesting little side trip into gauge electronics, I have to say. And one that can be sorted out fairly inexpensively.
entry 418 - tags: tach, instruments, wiring | | |  | November 1, 2010 - I didn't feel much like working on the car tonight, but I figured I'd wander into the shop and just do one thing.
Like bolt up that lower control arm that was next on the list before I had to stop yesterday. Arm bolted up, mission accomplished. Then I decided to trace out the cut line for that fender. And then I decided to pop the stainless steel trim off the side of the car to get an idea of how hard it would be (answer: easy). Then I saw the bumpstop targets on the workbench and decided to work on them for a bit.
This is how stuff gets done. By accident!
The bumpstop "targets" are the flat plates on the rear axle that the bumpstop bangs into. I took them off the MG axle. I'm sure they have a better name. Anyhow, I know I need to raise them up a bit for the new suspension. The AFCO shocks can damage their seals if they're allowed to bottom out, so I need to make sure I get this right. But unfortunately I can't tell exactly how much those bumpstops will compress. So the solution is to make them adjustable.
First, I welded a nut to the bottom, underneath the hole that MG thoughtfully left here for this purpose. This gives me the ability to bolt on spacers of various thicknesses. I'm going to start with a 1" pedestal. That's a bit conservative, but I can use a travel indicator to tell how close I'm getting to full shock compression and adjust from there.
entry 419 - tags: suspension, rear axle | | |  | November 1, 2010 - Here's an image of how the bumpstop target sits on the axle.
The middle of the bumpstop is nicely hollow to allow for the bolt head to fit inside. Notice how clean the 39-year-old bumpstop target is? The bead blaster strikes again!
entry 420 - tags: rear axle, suspension | | |  | November 3, 2010 - Time to make some room in the fenders!
For some reason, this cut filled me with a certain amount of trepidation. It's not like I'm dealing with a pristine automobile here, it's undergone massive reconstructive surgery. But this is the first cut that's visible from outside.
Sure didn't take long. Both front fenders are cut now.
entry 421 - tags: fenders, body | | |  | November 3, 2010 - Here's a peek at the front wheel at full compression.
I have clearance for full lock and full bump, so that's good. It looks pretty cool like this. In fact, it almost looks as if I could have just stretched the fenders slightly. Not really, but it looks that way.
entry 422 - tags: body, fenders | | | November 3, 2010 - Today was a frustrating day.
I had the day off, so I planned to do lots and lots of work on the MG.
Last night, after chopping the fenders, I was playing with the rear axle and realized it was time to install the driveshaft. First problem: it's too long. At normal ride height, it's fully seated in the transmission with no room to compress. I suspect the Camaro ring and pinion has a slightly longer pinion yoke than the S10 part that was on the car when I made my measurements. Whoops. Well, at least it's easier to shorter a driveshaft than it is to make it longer. I dropped it off at the driveshaft shop to have an inch taken out.
While the driveshaft was in, I also discovered that the fuel line and main power line also rub against the driveshaft slightly. So they'll have to be moved.
Then I went out to my Toyota truck and discovered that it had developed an oddball ailment of trying to run the starter all the time. Of course, today was the day the "for sale" ad for the truck showed up in the paper. So I spent the entire day trying to chase down a weird wiring problem without any wiring diagrams. I haven't found it yet, but I did manage to chew up my entire day.
Like I said, frustrating. Today, entropy won.
entry 423 | | | November 6, 2010 - Progress has been resumed!
The recalcitrant Tundra has been vanquished. The driveshaft is an inch shorter. The fuel line and main power line have been rerouted to give more clearance for the shaft.
They might fight, but they don't win.
entry 424 | | |  | November 7, 2010 - A giant package arrived from the UK.
This is a complete interior for the GT! What makes it special is the fact that it's "biscuit", a color that's not offered for the GT from Moss Motors and thus not from anyone else in the US. I don't know if it was a factory color for the GT or not, but it's what we have (well, it's the color of our seats and the rest of the interior was spray painted to match) and we like it. I bought it off eBay from Chase MG, and it looks really good.
Basically, it will replace every panel below window level including seat upholstery. All for around the price of one seat from Moss. Nice.
entry 425 - tags: interior | | |  | November 7, 2010 - The braking system is all buttoned up.
The Camaro's vacuum line for the brakes was larger than that of the MG, but a 90 degree elbow with a couple of hose barbs took care of that. It's not the prettiest setup, but I'll sort that out later.
You can also see the convoluted rear line routine - out from the rear fitting on the bottom of the master cylinder, around the master, into the brake pressure switch, into the proportioning valve, then up and over the pedal box to disappear under the fender. Convoluted perhaps, but well anchored and it works.
entry 426 - tags: brakes | | |  | November 7, 2010 - With the brakes all plumbed in, it's time to bleed them.
Unfortunately, I still have a mismatch of front brake pads (1994 Miata), brake rotors (1994 Miata) and caliper brackets (1990 Miata, which uses smaller brakes). I have a set of the later brackets on the way, but with Janel available to help me bleed I wanted to do something. Well, the Seven was just sitting there with an engine problem awaiting my attentions, and it uses the 1990 size brakes. So I grabbed the rotors and pads from that car and voila! Front brakes.
I've also cut the rear arches away to clear the tires on full bump. There's a double skin to the body here so some black duct tape was used to seal it up until I weld in an insert to join the gap. It was gratifying to see how clean the metal inside that cut section is. That's a rust spot for the cars, and mine was pristine inside. Was.
Time to bleed the brakes! All the suspension pivots have been torqued up and the springs are in place. Does it seem as if I'm working towards something here? Perhaps.
entry 427 - tags: brakes, suspension, body, fenders | | |  | November 7, 2010 - The brakes proved problematic to bleed.
I think I have one bad flare which will have to be sorted out, and it took forever to get the rears working. But I got them to the point where they'd stop the car, so it was time.
I bolted on the wheels, checked tire pressures, attached the hood and dropped the car to the floor. It's always fun how much smaller they get when they're sitting on their feet. This car's been on jackstands in the garage for a long, long time. The springs are 8" 375 lb in the front and 10" 250 in the rear, mostly because that's what I have. I snugged the spring perches up to the springs at full droop and nailed the ride height almost perfectly.
After a lot of shuffling around and shoving of bits and pieces into handy corners, I was able to free the MG and point it towards freedom.
entry 428 - tags: first drive, brakes, suspension, springs | | |  | November 7, 2010 - The first drive!
You can watch it on YouTube.
Overall, the first drive was a big success. Nothing broke. Nothing (unexpected) leaked. The car worked as expected. Cue the big celebration!
The car does feel very, very powerful and very light. The Miatas with a similar engine feel a bit beefier, possibly due to much fatter tires. The brakes were definitely not up to snuff - you can see me check them as I leave the garage. They were good enough for this little tour though.
The suspension was not noticeable, which means it was working! Obviously, tougher tests will come. No noises, clunks or anything worrisome. The clutch worked well once we both got used to where it engaged - the bigger problem was the gas pedal which is currently sitting much too high. The sound is excellent. The transmission did try to pop out of reverse, which is a trick it had been doing in the Camaro. There, I thought it was a matter of shifter adjustment and I spent some time fine-tuning that. But I was wrong. I'll look into that.
It wasn't a long drive, just a proof of function. And it did just that!
entry 429 - tags: first drive, video | | |  | November 7, 2010 - Well, you have to don't you?
I gave the car a bit of throttle and both rear tires immediately lit on fire. They're not great tires - Azenis 215s from 2006 or so - but it was still pretty spectacular. I don't have the rear seat in the car or the panel that covers the old battery boxes, so the inside of the car immediately filled with blue smoke. Very entertaining.
We did not get this on video, unfortunately. And we'd attracted enough attention the first time! There will be opportunity enough in the future.
entry 430 - tags: burnout, first drive | | |  | November 7, 2010 - Finally, a chance to take a few steps back and see how the car looks.
Well, it'll look a lot better with the fender flares on it. Right now, it looks as if someone went after the fenders with a Sawzall. But the overall stance is good, the ride height is where I wanted it and the mufflers are nicely tucked into place. We'll call this a success.
I should note that it's been almost exactly two years since we bought the Camaro that provided the drivetrain, and the MG came apart two weeks after that. So this is the culmination of a long, long process. I suspect some people doubted it would ever more.
entry 431 - tags: first drive | | |  | November 7, 2010 - Without any grille on the front or any lower bodywork, you can really see how ridiculously oversize the radiator is!
It'll all be covered once the MG Special Tuning front air dam is installed, and the chrome on the bumper and grille will finish off the car well. I may fog the radiator with black paint to make it a bit more subtle.
It doesn't look much like an MG here, but it does still somehow manage to look British.
entry 432 - tags: first drive, radiator, body | | |  | November 8, 2010 - I posted about the first drive on a few forums, and the responses have been interesting.
A few people who didn't understand that it was a first drive of an unfinished car and who had comments on the cut fenders. Not everyone can look at a project in process and see the final result! A few votes for the factory Sebring fender flares, but they just don't suit the style of the body to my eyes. Maybe if I'd grown up watching MGs duke it out on the race circuit. I personally think the stock Pininfarina body is beautiful, and the Sebring flares just look like slapped-on blobs. It's going to be a challenge to fit the Rabbit flares gracefully (and symmetrically!) but their overall shape complements the car to me.
One of the most common comments was about how low the radiator sits. Granted, when the car is viewed from the front with no bodywork it's an imposing piece! But it's still 5" off the ground, which is about the same as the oil pan on a Miata. Also, as you can see in the picture, it's not unprotected. That bar underneath is 1"x2" with a fairly hefty wall thickness, supported by an extension of the frame rails. I could probably use it to jack up the car.
But it does have me thinking. Flyin' Miata recently came out with a much smaller radiator for the V8 Miatas. It's got all the correct fittings on it and there's even a high-quality shroud and fan kit available that I could just drop in. I'd have to buy new fans for this one anyhow. I might grab the dimensions and see what making the change would imply. I would like to have the option to run the stock nose instead of the Special Tuning airdam. Hmm.
entry 433 - tags: radiator, first drive, protection | | |  | November 8, 2010 - Before moving the MG back into the build area to continue work, I had to spend some time cleaning out the garage.
The two "front" cars got moved out so I had room to bustle about. This left me with an all-British garage, a first! Well, mostly British. The Seven runs a Miata drivetrain and we all know what's hidden inside that black thing.
What struck me is how close the MG is in size to the Seven. When I think about it, they both use the track width of the Miata so their overall width (defined by the wheels in both cases!) is identical. The wheelbase of the MG is about 1" shorter but it has more bodywork on each end. Still, it was surprising.
entry 434 - tags: other cars, size | | |  | November 8, 2010 - Before moving the MG back into its home - I use a moving dolly under each wheel so I can easily slide it into place - I decided to drop it on the scales again.
No surprise, it's gained weight since last time. It's up to 2168 lbs, but it's pretty close to fully loaded at this point. A few pieces of front bodywork, the dashboard and other interior parts and, well, that's about it. Last time I estimated the final weight at 2400 lbs. I think that's a pessimistic number, but we'll see what happens. It's no wonder it felt lively on the test drive, it's currently over 400 lbs lighter than most V8 Miatas.
The car is nose-heavy right now, though. It has about 54% of the weight on the nose. Not terrible, but I'll have to see if there's any way I can shuffle a bit more weight back. Throwing the spare in the trunk will help.
entry 435 - tags: weight | | |  | November 8, 2010 - Amongst all the excitement of the first drive, the new tach showed up.
I'll wire this into the car in the next couple of days and hopefully have a functioning tach. Fingers crossed!
It's in excellent shape, can't complain there.
entry 436 - tags: tach | | |  | November 10, 2010 - One step forward, one step back.
Good news - the new tach works! Well, it works once you remember to actually connect the GM tach wire to the MG harness. Interestingly, it seems to read accurately. I didn't have an OBD-II scanner plugged in to read the exact engine speed to confirm, but the car seemed to be idling right around 1000 rpm cold and that's reasonable. I checked the idle at right around 900 after the drive the other day. Interesting - I'd heard the LS engines put out a "four-cylinder" signal, but I figured that was just because a lot of new fours use a waste-spark ignition and thus look more like an 8. Regardless, I'm not going to complain about it! That was easy.
I also spent some time on the brakes. A bit of fooling around and I managed to get rid of a big air bubble in the front of the master cylinder. Voila, a hard pedal! Nice and hard. But the front fitting on the master was still leaking. This will not do. So I pulled it off and yup, the flare looks deformed.
I figured this was probably the case on Sunday when I was bleeding the brakes, but I was hoping that tightening the joint would solve the problem. Of course it didn't, and in doing this I also damaged the seat in the master cylinder - that's it in the picture. No surprise here. Luckily, the seats can be removed so I'll just call Wilwood and order a replacement.
At the same time, I noticed that the master had a big F and R on the outlets. Now, from my understanding, there shouldn't be any difference between them. I did read a blurb in Hot Rod or Car Craft a while back claiming there was and that swapping the F and R lines around solved a soft pedal problem. I still don't understand how - but since I had to rebuild one of the lines to fix that flare anyhow, I figured I'd swap them. This means new lines for both the front and rear outlet, both pretty short but relatively complex. So now I'm back to no brakes at all. Still, I have a clear vision of the way ahead.
entry 437 - tags: brakes, tach, wiring | | |
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