rcutclif's 1974 MGB-GT

Another update, I finally got my rear in gear to finish pulling the motor. Haha. Forgot it had been two years not one. Yikes.

Anyway, also plunked down $40 for a vendor space at the upcoming Chicagoland British car swap meet (March 19 I think). Have to load all my drivetrain stuff in the truck.

I'll be bringing two short blocks, one head, one od transmission, a bunch of engine ancillaries, and probably some wheels.

If it doesn't sell at the meet it's going to the metal recycler on the way home. Woohoo space in the garage!

As someone who has removed nearly every MGB part from his "Ultimate" MGB, you may be surprised to see me recommend keeping your old mill and fixing it up. There is a guy locally that has fit a small Roots style supercharger to his and it scoots along pretty good. I chopped up my MGB-GT but your car looks really nice and maybe should be kept that way. http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=111407

If you are going to go with the Miata drivetrain, there are some pertinent threads on the subject:

http://www.mgexp.com/phorum/read.php?40,3107418 it's going into an MGA, but pretty much the same challenges

There is an MGB GT thread also,http://www.mgexp.com/phorum/read.php?40,2419629

The B series engine is nice enough if you just want to potter around town, but it's pretty obvious that the designers were not aware of interstate travel when they spec'd the engine for this car; while it will do the job, it does not sound happy to be doing it. The OD does help a bit.

The MOSS supercharger has its fans who shelter in the shadowy belief that it is more "Original" than and engine swap. What they don't mention is that it is more expensive than an engine swap and not without some tuning and cooling challenges of its own.

A friend of mine did a 2.8 V6 swap into his BGT. He pulled the engine & 5 spd trans from a junkyard Camaro and then added MegaSquirt for fuel & spark management. Otherwise the engine is stock, although he suspects the engine was rebuilt shortly before the car was wrecked because the inside of the engine looked perfect when he scoped it.

The original B axle was replaced with something else as well (that he had shortened), but what model escapes me. I think it was out of an S-10. Oddly enough, while he has documented the hell out of most of his car projects, the V6 swap into the BGT doesn't seem to be anywhere on his web page for the car (so I won't bother linking it).

While an essentially stock GM V6 might not make a ton of power, it is still twice as much as the B lump and is a lot smoother (and I think it weighs less). The car scoots along pretty well. It's one of his daily drivers around the Baltimore area.

Thanks for the input all!

I have basically been waffling about this decision for 8-9 years, I have another thread on the topic I will dig up from a year or two ago.

I've already purchased the Miata drivetrain (and pedals, hydraulics, entire wiring harness, etc) and that is what I will be going with.

I think the Miata engine embodies the original character of the car, but is better in basically every way.

Now that I saw that kmiata swap though, I might have to look at the k24 + Miata trans.

You will love the 1.6 you have in hand. I've built or driven and dyno'd them all, from stock (65RWHP) to hot street (80-95RWHP) to race (120+RWHP, but no torque) to crossflow (70-95RWHP) to supercharged (85-120RWHP) to Miata (110RWHP+) to V6 (80-200+RWHP) to V8 (100-300+RWHP). Bottom line for me is that anything near 100HP at the wheels is pretty fun and anything more than 150 needs a lot more traction and other improvements.

There may be better swaps on paper or messageboards, but the 1.6 checks a lot of boxes. It makes a big difference in power and gives you a great EFI and an even better 5-speed with nearly the same ratios as your OD. It's challenging enough to be fun, but not so hard to be discouraging.

I see from the other thread that you've got the GRM stories I've written about the swap--feel free to contact me for more info or swing up to SW Michigan sometime for a drive in my Miata-powered B/GT or my supercharged B. Maybe I can help motivate you to start this build...it needs to happen!

In reply to Carl Heideman:

Thanks!

Yes, your stories and advice have helped push me toward the Miata solution.

And I would love to swing up the other side of Lake Michigan here soon and take a look at what you have done!

rcutclifs, just found this, a friend has a sister to your car with the built ('boat anchor- nohome) B motor. My B-GT (73) awaits a total resto, following Loose and his Pink Panther has brought me to the LHU bullet as the desired replacement, check it. Great looking B

BUMP.

Indy-Guy said:

BUMP.

I really should get this back in gear! Here's the current status:

engine is out, all my b series stuff is sold, Miata drivetrain sourced, some assembly required. Haha

Since the last pic is almost exactly 1 year old, here's the today!

It may not look like it from this pic, but the garage is getting cleaned out and the MGB moved today.

Here's the bigger view that does prove the shop is cleaner, mgb is moving closer to the lift. I think I'm going to fix the brake master on my jag first, but then the mgb moves into the lift bay.

Nice work man!  You moved a ton of stuff...not far...but still a grand task.

Since no one has said it, I'll be that guy...LS swap it!

I saw the first pics of your old garage and had a lot of questions, but then I saw the time stamp, and I now no longer have any questions.

In reply to RACEC4R :

You know I've been "all talk and no action" on this project for a LONG time! Last time this car was on the road at all was 2013, running, but barely. Last summer that I put more than 300 miles on this car was 2004. 

2021 is the year to start to change all that. 

I had the engine sitting on this poor old HF dolly. Yeah, it didn't roll well. 

So I harvested the wheels, grabbed some scrap dimensional lumber, and hit it with some 3 inch screws.

Much better!

I also noticed that the harbor freight engine hoist I've had for ten? years no longer holds pressure in the hydraulic cylinder. It lifts, but the load slowly falls. I need to see if the seals are replaceable or if I just need to swap out the entire cylinder.

With some other projects out of the way (jaguar brakes, building a standing desk for wife, building the closet barn door in the background, shoveling the driveway a zillion times, etc) I finally swept the shop today about 4 times and got the next patient on the table.

​​​​​​

Let's talk goals for a minute. I want to drive the snot out of this car when it is done. Like, not worry about taking it to a rallyx if I feel like it. Or not worry about tossing the keys to a friend if they are in town for the weekend. I want to wind it out frequently. 

I also want something that is daily driveable. So heat and interior at a minimum. I'd love it to be quiet ish inside and comfortable. Functional. 

I've already got the 1.6 miata motor and barring any significant issues that's what I'm going with for engine/transmission. I've also got a lot of other miata stuff that will probably find its way into the car. Pedals for example. Wiring harness (yes, I think I want to replace the mgb harness entirely). Fuel tank. Stuff like that.

Anyways. The car is dusty. Apply broom, then a couple rounds of water from a squirt bottle and rags. I thought I remembered paint under there...

Here's where I was under the hood.

Measure carefully:

I confirmed for myself that it should fit. The steering rack is going to be tight on the crank pulley. Then parts started flying.

If you're wondering what this stuff is, it is a home depot mismash of stuff I used a long time ago to make the mgb shoot a stomp rocket out of the grille. I fully plan to keep it (but maybe improve the system a little bit).

Next up, make a plan! (I'm already re-reading the grm stories on this swap, again).

I do intend to do similar to what I did last year with f-dat and spend the first hour each day working on this. I've mostly continued to do the first hour thing and it is awesome for getting projects moved forward as well as good for the soul. Maybe I'll keep track of time, we will see. Did about 4 hours today. I'll keep track of budget too, but this would only ever be a backup challenge car. I'd want to have no issues jumping in and driving it to the challenge and back, however.

I'll just leave these here to help motivate you...

In reply to Carl Heideman :

OOOOOoooooo

In reply to Carl Heideman :

Uh, I think we’re gonna need a separate thread with details on that.  I have questions.

...

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Also, we may need a cleanup on Aisle 3.  

In reply to Carl Heideman :

THANKS! That car looks awesome. 

Are those triumph 15inch steelies? I happen to have 8 of those in the garage and it is my plan to use them on this build. I am starting to think I should look at grabbing a donor rubber bumper car and maybe consider the crossmember and radiator situation. Power brakes wouldn't be an awful idea either...

jerrysarcastic (Forum Supporter) said:

In reply to Carl Heideman :

Uh, I think we’re gonna need a separate thread with details on that.  I have questions.

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Also, we may need a cleanup on Aisle 3.  

check out the following GRM issues:

June, August, October 2007

May, June, August, November 2015

February, May, November 2016

May, November 2017

In other news today I started looking at the pedals. I didn't have much time this morning or any yesterday since snow's been coming in fast the last few days. 

I have all 3 pedals and their assemblies from the miata, and of course I've got the MGB stuff. I can modify the MGB stuff following Carl's approach, or I also had the thought of just swapping in all the miata pedals. Dunno which path I will take quite yet. Plenty of time to decide. 

I'm also not sure how much I will be stripping this car at the moment. do I pull just the minimum to get the swap done? or do I go full blitz right now?

So many questions...

Very cool project.  I've always loved the profile on the B-GT.  I long had daydreams about doing a "factory hotrod" Rover V8 swap.  I'm looking forward to seeing what you do here!

Robbie (Forum Supporter) said:

jerrysarcastic (Forum Supporter) said:

In reply to Carl Heideman :

Uh, I think we’re gonna need a separate thread with details on that.  I have questions.

...

..

.

Also, we may need a cleanup on Aisle 3.  

check out the following GRM issues:

June, August, October 2007

May, June, August, November 2015

February, May, November 2016

May, November 2017

Of course, most of you probably have all of those issues and can go back to them.  If you don't, most of the stories about that car are the GRM website.  Search for "Swap Science MGB" and you should find at least 7 stories--I think there are more.

The car is pretty much done, but there are still stories that haven't been printed yet.  You'll likely see one about the wiring, one about the gauges, one about the stuff we had to re-do during the sorting phase, and maybe a feature on the finished car.

Robbie (Forum Supporter) said:

In reply to Carl Heideman :

THANKS! That car looks awesome. 

Are those triumph 15inch steelies? I happen to have 8 of those in the garage and it is my plan to use them on this build. I am starting to think I should look at grabbing a donor rubber bumper car and maybe consider the crossmember and radiator situation. Power brakes wouldn't be an awful idea either...

Those wheels are expensive (and heavy) Jag D-Type knock-off replicas that came out of the UK.  Triumph 15in steelies (or MGB 14in steelies) look quite similar, but don't have the knockoffs.  They're also usually bent and not very wide.  Since doing that car, we've seriously considered cutting the centers out of Triumph and MG wheels and re-hooping them for the right width and offset for modern tires and looks (and not being bent).  I know Diamond Racing wheels in Wisconsin will do that for people who don't have the tools.  I think they charge about $100/wheel, so they're not exactly challenge-priced for a set.

While I put the green car up to "motivate," I'll add a cautionary tale about it.  It started as a simple build like you're planning, but our customer (who's a great great guy) kept growing the scope--supercharger, full Vintage Air HVAC, cruise control, heated seats, front and rear coilover conversions, etc..  Each of those additions would have been pretty straightforward by themselves, but combined they have made the car very complicated with tight packaging and much harder servicing.  We probably had over 100 hours in the HVAC alone--building mounts, modifying the dash, moving the wiper motor to fit the evaporator, plumbing, etc..  The supercharger probably added 30-50 hours to the packaging.   I doubt you'll go that far, but you'll be really happy with a simple build.  

So, my unsolicited advice to help you keep it simple is:

1. Use the rubber bumper crossmember with your 1.6 motor and you'll have great packaging space--the 1.6 is 1" shorter than the 1.8 and will give 99.5% of the fun of the 1.8 for less money and less hassle.  
2. Use lowering springs to get the front end ride height correct.  They work well, are cheap, and are super easy.
3. If you're in the mood to bend up new brake lines, use a boosted setup from a rubber bumper car like we did on this one and others.  The car won't stop any better, just less pedal effort.  If you stick with the stock setup, you'll have a little more effort (but still very reasonable) with a firmer pedal feel.  You'll also gain a little packaging space and save some time bending up new lines.  I haven't done the math on using a Miata booster/MC, but it would be important to look at the MC bore and the pedal ratio if you're going to use stock MGB calipers and rear wheel cylinders.   And of course you've got to fabricate and package it into the engine bay.  I don't see a lot of gain there as the MGB MCs are robust and long-lasting.
4. Parting out a rubber bumper car may make sense, but it's a distraction.  Especially if you don't change the brakes, it would be faster/easier to just buy a crossmember from someone or get one for free from someone in an MG club.
5. The rubber bumper radiator setup works well if you go the part-out route.  Make the mounts like we did, cut them off the parts car, or just buy new ones as they're available from suppliers.  As you'll recall, one of our major goals for this swap was to use MGB parts or Miata parts.  If that's not one of your goals, you could just use a universal aluminum radiator from a mail-order supplier and probably save some money.
6. Don't tear into it too far--swap the engine in, drive it, and enjoy it.  You can always tear it apart later and you'll have a better vision for the build if you've driven it.
7. One more plug for simple:  My personal MGB/GT has a 1.8 Miata swap and is otherwise stock.  I've been driving it that way for over 10 years.  If I had to do it again, the only thing I'd do differently is use a rubber bumper crossmember (less work) and a 1.6 engine (easier to find, cheaper, less work).  Oh, maybe a turbo...

Keep going! 

Here's an underbody shot of the green car:

And a couple of glamour shots a photographer friend took when he wanted to try his new equipment: