76 MGB E Modified Build

Congrats on the build

Very Interesting. What carb, intake, dizzy and headers are you running?

In reply to Dusterbd13:

The process is pretty hard to describe but I have seen my dad do this before. We started with a lot of sketching and measuring. I drew a few variations and we experimented with what we wanted and what would look the best. We used the center of the hubs at ride height as a reference point and drew an arch on the fenders with a sharpie, similar to using a compass to draw a circle. Then we made the arch for the wheel opening out of a piece of steel rod. We cut out the fender that could rub on the tires with a plasma cutter and cutoff wheel. Then while I was teaching for the week my dad did pretty much the rest, but the process involves using scrap metal to temporarily mount the wheel arch to the body where you want it and forming sheet metal between the arch and the line in sharpie, hammering it to fit and tacking it in place. When you get it as close to the shape you want, you use plastic filler to smooth it out and paint it.

I think thats the best I can describe it but basically we planned it and looked at the body for a while to make sure it looked good aesthetically, then traced the outline where we wanted the flair to meet the body, my dad built the wheel archs, mocked them in place and filled the area in between with sheet metal.

In reply to fasted58:

The carb is an oddball, I wanted vacuum secondaries, felt a 390 cfm was too small and a 600 two big so I searched summit to figure out what was in between. I have read that Edelbrock carbs dont deal well with hard cornering so I elimnated them and ended up with thishttps://www.holley.com/products/fuel_systems/carburetors/classic_holley/parts/0-1848-1 but in order to clear the distributor it needed a 1 inch carb spacer. The intake manifold is a Edelbrock Performer. The Distributor is a Proform HEI for an even fire 4.3, I think you can search it for a 4.3 chevy astro with a carb and get the distributor.

The headers started as Novak Jeep 4.3 conversion headers. We got the rear exit model, then cut them apart and tilted them so that instead of exiting down below the engine where there was no room, they went out the fenderwells. At the time I think it was cheaper to do this than buy the parts to build a custom set of headers and was a lot less work.

Initially I thought about keeping the stock TBI setup, but after some research it looked as though the system would have difficulty delivering more fuel if I ever started making big upgrades to the engine. Right now that seems like a moot point as I intend to transplant a supercharged Buick 3.8 into the car once I round up all the parts.

Will the 3.8 transplant incorporate a firewall massage to facilitate 50/50 weight distribution?

In reply to 759NRNG:

I think so, not having a distributor in the back of the engine will make it easier to have access to everything so I might move it back and to the passengers side of the car. If I can help it I dont want to change the drivers side of the transmission tunnel because its close to the throttle pedal, and at that point the easiest route might be mounting a wilwood pedal box.

A lot of that will be determined by how I tackle the throttle body being at the back of the engine, I have seen people weld a U bend in but I am hesitant to add length between the throttle and the supercharger.

I am debating running moving the radiator to the trunk as well for weight distribution, but I am worried about airflow while the car is moving. Part of me thinks its not a problem as the runs are short and I can idle the car to cool it off in between and run a huge radiator so there is always excess capacity, the other part wonders what might happen if I get waived around and do several back to back runs on a hot day.

The radiator in the rear doesn't seem to affect Loose C's ride.....he's making gobs of power at ONLY half throttle.

FWIW the L67s in Holdens came with a U-bend from the factory:

759NRNG wrote: The radiator in the rear doesn't seem to affect Loose C's ride.....he's making gobs of power at ONLY half throttle.

Right, it doesn't seem like it should work but when I research it I see people cooling Big Block A/FX type cars like that. It seems to be all they do is cut out the floor, attach electric fans and give the hot air somewhere to go.

Homework said:

FWIW the L67s in Holdens came with a U-bend from the factory:

Yeh, radiator in the back hasn't given me a cooling problem. I even went to a smaller rad and single fan for this year because the rad and dual fan I had last year had zero issues. Well, maybe zero issues isn't accurate, bleeding the air out of a cooling system with really long hoses is time consuming.

loosecannon wrote: Yeh, radiator in the back hasn't given me a cooling problem. I even went to a smaller rad and single fan for this year because the rad and dual fan I had last year had zero issues. Well, maybe zero issues isn't accurate, bleeding the air out of a cooling system with really long hoses is time consuming.

Looking at the pictures on your car I couldn't tell where the inlet was, I saw the outlet at the back of the trunk. Does the air come in through the trunk floor or somewhere else?

Im getting ready for a regional even, a Montana Challenge race. Tomorrow should be a few hours of thrashing before I load the trailer and drive for a few hours.

My dad found that the vacuum secondary connecting rod wasn't opening all the way, which should explain why the car hasn't been pulling the way it feels like it should. A couple weeks ago it felt like it pulled to about 4000-4200 and then just didn't want to accelerate, we suspected valve float or fuel starvation but now we know the answer.

We are going to put in a lower temperature thermostat. The temperature has been creeping up, this is mostly help the car cool more in between runs so it isn't as hot by the end of the run. Last year this wasn't an issue, the only changes are a different splitter to fit the fenderwells, endplates and the splitter seals better against the airdam. Im guessing that a ton of air is getting in and it cant get out, so it builds pressure and doesnt make it through the radiator. There are now bigger holes in the fenderwells so we will see how things work.

The tires are rotated and fluids look good, so once thats done I should see how the car stacks up.

In reply to MGS10:

The air goes in between the drivers seat and the rear deck lid but some also flows in from rear wheel openings

One of my runs from this weekend, fastest course I have every run. I think at times I was doing a bit over 70.

https://www.youtube.com/watch?v=-iQ9Gd7CyOs&t=129s

I let one of the guys I normally run against take my car around the course, he said he thought the brake bias was off and we spent some time on that. Then we both took a run and things were better but the fronts still lock up too soon. The insides of the front tires and middle were warmer than the outside so I think I can run a little less negative camber but the car already tends to oversteer, so I think I need to make more rear grip. My rear swaybar was full soft so I plan to lengthen the arm about 3 inches and see if the car has tendency toward understeer. If thats the case I will drop to about 1.2 degrees negative camber and see if I go faster.

I might have found a transmission for my L67, a Camaro might donate its auto and all I have to do is haul it off, take what I want and pull the parts the guy giving to me wants. Seems like a pretty sweet deal.

Holy cow, photobucket just broke everything it appears. This is a test/update on the car and my ability to post pictures. It may be a while before I am able to get all the pictures fixed from before.

Here it goes <img src="" /> This is the L67 Buick that will be going in the engine by of the MGB at some point. Last night I picked up a Camaro that will donate its wiring, transmission and whatever makes the swap easier. I will have the computer programmed to run the L67 and adapt the connectors on the fuel injectors.

A thing of beauty and a joy to behold.....your bell housing choice will be?

759NRNG wrote: A thing of beauty and a joy to behold.....your bell housing choice will be?

I feel like a sell out, but I have a 2000 Camaro with a 4L60E automatic transmission that should bolt right up. I think I will fit that with a Hurst Quarter Stick or other gated automatic shifter so I can hold it in the gear I want so I dont have to deal with getting a balanced flywheel. The Camaro also has a NA 3.8 and if I fitted the Supercharger and Heads from the Buick engine I could bump up to a 9:1 compression ration, but then down the road I couldnt run as much boost.

No sell out, just curious cuz LooseC found a source for his LHU...

In reply to 759NRNG:

I didn't think you were calling me a sell out, thats just how a small part of myself feels. The other part sees a cheap drivetrain and PCM with a good power boost and thinks sourcing the flywheel, getting it properly balanced and tracing through the Buick wiring just isn't worth it.

On the other side, its always interesting to see what engines have a plethora of options and which dont. Im not as surprised that Loose Cannon found the bellhousing, as much as I am that he found one to mate that up to a T10. I wouldn't imagine overlap there, much like I wouldn't expect GM to balance the L67 differently from the L36 3.8s.

I knew nothing about the L67 but a quick search reveals that it uses the GM Metric bellhousing pattern, also shared with several other engines like the 5.3 litre V8. This might open up some bellhousing/transmission possibilities. The Chevy S10 pickup transmission would work, as an example. https://en.wikipedia.org/wiki/List_of_GM_bellhousing_patterns#GM_metric_pattern

MGS10...my apologies your effort on this is way beyond what I'm capable of lately. Please proceed however you see fit and we'll all be the better for it.....because what you're pursuing is as equally as interesting as what LooseC has done with the LHU....keep on keepin' on....

loosecannon wrote: I knew nothing about the L67 but a quick search reveals that it uses the GM Metric bellhousing pattern, also shared with several other engines like the 5.3 litre V8. This might open up some bellhousing/transmission possibilities. The Chevy S10 pickup transmission would work, as an example. https://en.wikipedia.org/wiki/List_of_GM_bellhousing_patterns#GM_metric_pattern

The Bellhousings are easy to come by, a specially balanced flywheel is where it gets tricky. I dont know if anyone locally can balance the 3.8 one for the supercharged one and the ones online were more than I would like to pay. I guess I am in a differeent position from most as my current transmission has a bell housing cast into the case, so regardless I need to switch transmissions as it has the V8 pattern.

Went to a local autocross yesterday. Starting to learn the setup better. The first run group my times closer than usually, within two seconds of each other from first run on cold tires to best run with 3 runs within a couple tenths of each other. I noticed the car had a little understeer on entry, about the middle of the corner I could control the balance with gas pedal but I was swinging wide unless I trail braked and doing that I have a tendency to lock up the inside front tire so I made adjustments for the second run group.

I put the rear sway bar one setting harder which is only about 20 pounds stiffer and dropped the air pressure one pound to get a little more, it seems like this helps me get more bite out of the corner and it worked. The first run on cold tires the car didn't feel great, a little jerky but it was less than a second off my fastest time so I kept the adjustment and took four more runs. The car felt better and I ended up about half a second faster than my morning run on on a 90 degree day.

I also put a phone mount on the dash and used the G monitor on my phone. Not entirely accurate but I figured it would give me some idea of what was happening. Braking the car did about .8 Gs, Accelerating about .58 Gs and turning 1.24 to the left and 1.26 to the right. I have been fighting brake bias since I started running the car and I think this highlights that I still need to work on it.

The braking system is really a mismatched beast and I need to fix it before the engine swap. I have Porterfield R4S shoes in the rear, Hawk HPS pads in the front and an adjustable proportioning valve to the rear brakes. Before the adjustable proportioning valve the rear brakes locked up first, after even with the valve turned all the way out the front brakes lock up first by quite a bit. Lines have been bled, the pedal feels right and its not always one side so I think something has to change.

I could get Porterfield front pads to match the rears and hope that this drops the front braking force enough to balance the front and rear so that it brakes like it turns. If I do that I am still stuck with rear brakes that honestly I hate to work on. Bleeding them is a pain because the bleeder is not on the highest part of the wheel cylinder.

I could spend the winter working on a rear disk brake conversion and add rear braking force that I can then back off with a proportioning valve. It looks like Ford Festiva front disks would work the best, small light and about an inch smaller in diameter than the front brakes so they would fit under the 13 inch wheels. Then I might not had bleeding the brakes when I need to but I am having trouble finding any kind of pad with good compounds on them for the 90ish Ford Festiva.

Third option, I buy a wilwood pedal with two master cylinders and a balance bar and use what I already have. At this point I am not sure which rout I want to go.