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Simplest modern MGB swap

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BMC Gold Member Brian Mc Cullough
Minneapolis, Minnesota, USA   USA
In reply to # 3716583 by Tremelune Interesting stuff about the bellhousing and flywheel...Good details to be aware of.

In reply to # 3716553 by scotabbott One can change the look from rubber bumper to chrome quite easily in a number of ways

Yes, it simplifies, but it also complicates other things. The rear mount, shifter, and parts change but it leaves the hydraulics external if the rest of the system is correct. My take on this is is you exchange some issues for other issues. I will not call it bad, only different.

In reply to # 3716583 by Tremelune
Is that...true? I found one writeup, and I think there was cutting, fabrication, and paint involved...If it's a bolt on/off affair, that might change things.

If you bolt it on, it leaves spots on the body that show the car is obviously a conversion not complete. If you plan to paint the car in a few years, it can be done. Be aware, Good point products, sand paper and all the various items for paint will run about $2500 for Material. That's if you have the equipment and are not hiring anyone to do it. It can be done for less and it will look like it was done for less. If you strip the body of the average GM, Ford, Healey, MG and turn in a sound, no-rust, very little damage car and all the trim, handles, glass and everything are removed, paint usually starts around $5,000 for something you are likely going to enjoy. Finding a car with good paint is always a step ahead.

-BMC.


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V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
In reply to # 3716338 by jewar
What ratio of rear end would you use to optimize the performance of V8 T5 with 063?

IMO, a 3.5 gear would be great for 70-80mph. Not sure why you would work from that. The .63 has helped my get by with the stock rear for many years, but if I did change the rear that 5th gears would be long gone. The gap between 4th & 5th is huge. I would replace it with a .72.

As for a 3.7 gear vs the stock 3.9, not worth the effort for 200 rpm.

Have fun playing with the numbers:

http://www.crawlpedia.com/rpm_gear_calculator.htm

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BMC Gold Member Brian Mc Cullough
Minneapolis, Minnesota, USA   USA
Carl,

Your point of the large gap (what I refer to as making up for the close ratios down low) between 4-5 in the V8-T5 is very good.

I also agree that the 200 RPM difference between the difference of the 3.9 and a 3.7 is hardly worth it. To pay someone to do this is not usually worth it, but if the factory had done it or if I had a car that we had to get a new set of gears, I would do it in a heartbeat for either a strong stock MGB or a car with a V8-T5 in it but very hard to justify.

-BMC.


Member Services:
Minnesota's only Fully Dedicated British Classic only shop providing Professional Restoration & Services & Specialty Products including- proper L.E.D. tail lights, Wiring looms and Engine and five speed Conversion Kits
scotabbott Avatar
scotabbott Scot Abbott
Pittsburgh, Pa 15216, USA   USA
1974 MG MGB "Bee"
(1) Reply to Brian McCulloch:

1a) 2.8L carb or TBI. They don't fit as-is. Lots of little issues and not a lot of power. It has been done MANY times before but personally I recommend staying away. Trying to not waste time with longs lists at this time.

All the motors of that geometry and mounting details fit in in the same way. Manifolds and accessories make tthe difference. Even the poorest performer (2.8 with automatic) does quite well as a daily driver. It is not glamorous or a hot rod, but it can be a very decent car.

(1b and 2) 2.8L and 3.1L MPFI engines.
Same thing, one says 3.1 and the other one says 2.8 on the badge. Same everything otherwise. Lots of time spent fitting things and the engine height is taller. Fitting this engine IS going to take more time and hundreds more in Cash (only if you buy from certain vendors) for Less power and an older series. For these reasons, plus the average 3.1 and 3.4L go for the same average price, a 2.8/3.1L for a few hundred dollars less than a 3.4L is NOT worth it. There are MANY people who find this out retrospectively even after I preach doom and gloom (a few hundred more dollars for less power AND a more difficult and less supported fit) that still go this route. car-part.com is a great resource to find one and have it shipped to wherever!

Brian's support of the 3.4 is great and works well. It is the refinement of the swap series, and is the route of choice where budget is of no concern.

(3) More complicated- by a few more wires if you are going to find a wiring loom in acceptable shape and rework it yourself. If you are building it yourself and do not like the 3.4L wiring, chances are you will also dislike the 2.8/3.1 wiring and go carburetted. If you have never wired a system previously (sorry everyone!) and are purchasing wiring from us, it's simple. Following a wiring diagram with a bit of bravery and patience gives a result the hobbyist can can brag about. The engine wiring is done, wrapped up and set to go. The fuse/relay station is easy to mount, very small and the wires that leave it are Lucas wire 'coloured'. Lucas white goes to white, white/red tracer goes to white/red tracer, brown goes to brown, so on and so on. We put the time into these to make them easy and do our best for phone support as well.

What one chooses depends so strongly on situation and preferences that people have. There is no one exclusive and only way to do this. The great thing is that all work better than the stock B setup.

One of the things not mentioned is avoiding the HTOB. That is important to do up front so when the slave fails, you dont have to remove the whole drivetrain or butcher the crossmember at the front of the driveshaft.



Edited 1 time(s). Last edit at 2018-04-15 03:09 PM by scotabbott.

scotabbott Avatar
scotabbott Scot Abbott
Pittsburgh, Pa 15216, USA   USA
1974 MG MGB "Bee"
The discussion on rear end and tranny ratios has overlooked the most important element for driveability. Rather than look at how many RPM's at what speed, just look at the ratio of the gear ratios across the range. This defines the "jump" between gears. The more similar these ratios are, the better and smoother the driveability.

By ratio of ratios, I mean

ratio 1 = ratio of 2nd gear/ratio of first gear
ratio 2 = ratio of 3rd gear/ratio of 2nd gear
ratio 2 = ratio of 4th gear/ratio of 3rd gear
ratio 2 = ratio of 5th gear/ratio of 4th gear

The goals are:

(1) Get these values similar so there is no long jump when one shifts gears
(2) Set the overall drivetrain ratio in top gear to match highest torque at desired cruising speed

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V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
In reply to # 3717395 by scotabbott

One of the things not mentioned is avoiding the HTOB. That is important to do up front so when the slave fails, you dont have to remove the whole drivetrain or butcher the crossmember at the front of the driveshaft.

I am going to have to take exception to that one, Scot.

So, what do you do when a regular throwout bearing goes bad? My dad had one go bad on his '63 B. We had to pull the whole drivetrain to repair it. Since we went to all that trouble, we also replaced a perfectly good clutch.

I can R&R my T5 to replace the HTOB without pulling the engine or hacking up the fixed crossmember. I have swapped a broken belhousing, as well, with engine in place. My McCleod HTOB just turned 17 & is still getting it done.

scotabbott Avatar
scotabbott Scot Abbott
Pittsburgh, Pa 15216, USA   USA
1974 MG MGB "Bee"
I am going to have to take exception to that one, Scot.
This is not a surprise.. We have different perspectives and viewpoints.



So, what do you do when a regular throwout bearing goes bad? My dad had one go bad on his '63 B. We had to pull the whole drivetrain to repair it. Since we went to all that trouble, we also replaced a perfectly good clutch.

My comment about HTOB was primarily concerned with the hydraulic side of the HTOB. The experience from several people has been hydraulic failure-not the throwout bearing. They found it either difficult or impossible to do the replacement without removing the drivetrain. If you know how to do that a great service to us to hear the details here. Going with the S10 route provides a lighter flywheel, as well. The S10 route has been less expensive and easier to install than the HTOB, Several posts in the post decry the hassel of adjustment on installation of HTOB's. No such problem exists with the s10 route.


I can R&R my T5 to replace the HTOB without pulling the engine or hacking up the fixed crossmember. I have swapped a broken belhousing, as well, with engine in place. My McCleod HTOB just turned 17 & is still getting it done.

They found it either difficult or impossible to do the replacement without removing the drivetrain. If you know how to do that a great service to us for you to post the details here. Incidently, going with the S10 type route provides a lighter flywheel, as well.



Edited 1 time(s). Last edit at 2018-04-15 07:28 PM by scotabbott.

V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
In reply to # 3717546 by scotabbott

My comment about HTOB was primarily concerned with the hydraulic side of the HTOB. The experience from several people has been hydraulic failure-not the throwout bearing.

It is a component of the same system. Something else that can break besides the hydraulics. Back in the day, I have had several friends with Camaros, Novas, Dusters, etc, that had squealing throwout bearings.


In reply to # 3717546 by scotabbott

They found it either difficult or impossible to do the replacement without removing the drivetrain. If you know how to do that a great service to us for you to post the details here. Incidently, going with the S10 type route provides a lighter flywheel, as well.

I did. I will try to find it in the archives. May not be possible with all swaps, but I am not the only one here that has dropped the tranny with engine in situ.

40indianss don foote
2walla wa, USA   USA
I would suggest that this ne does not need to hack up the crossmember. It is a simple procedure to make it removeable and still retain the structural integrity of the design. If one has the capability to do the modifications to perform a power train transplant then I think they should be able to modify the cossmember, then they would not need to complain about what a pita removing the transmission to get to a throw out bearing is. I think an ounce of prevention may be worth a pound of cure

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1744 Avatar
1744 Gold Member Bill Guzman
CA, USA   USA
1973 MG MGB GT "Renegade I GT"
1974 MG MGB "Renegade"
In reply to # 3716599 by Tremelune General question: Does anyone have any favorite writeups? Comprehensive build logs, etc? I checked the FAQ, but there's no list of links as I would have expected...It's many pages of interspersed discussion that would take a while to get through.

You can visit www.classicconversionseng.com Frequently asked questions
There a few comparisons of gear ratios.



It is our attitude that will determine the outcome


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V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
In reply to # 3717546 by scotabbott

They found it either difficult or impossible to do the replacement without removing the drivetrain. If you know how to do that a great service to us for you to post the details here. Incidently, going with the S10 type route provides a lighter flywheel, as well.

I did. I will try to find it in the archives. May not be possible with all swaps, but I am not the only one here that has dropped the tranny with engine in situ.
[/quote]

Okay, I spent over 30 minutes searching & can't find it. I did this in 2007 before the British V8 Meet because I discovered that I had a severely cracked bellhousing caused by wheel hop from drag racing. That Buick 215 bell with the open bottom & clutch fork opening nearby is not very strong.

This has been done by Jake Voelckers, Chris Gill, myself, & probably more.

Put the car on 4 jackstands with the rearend hanging down. The driveshaft will then be able to go back & up, then forward & down. Support the back of the engine before removing the tranny crossmember. With the shifter & speedo cable removed, the tranny can go back, then down & forward. The bellhousing bolts were removed from underneath the car with a swivel socket wrapped with masking tape & attached to two long extensions. Did this on the concrete, under the car, solo. With a lift & a helper, it's a piece o' cake.

Naturally the T-5 is a bit lighter if you drain it first. Lighter is better when trying to reinstall it. winking smiley Otherwise use a tailshaft plug & secure it with duct tape.

Then, as Haynes or Chilton is famous for, "Installation is the reverse of removal". smiling smiley

jewar Avatar
jewar Silver Member John Warlimont
Abbotsford, BC, Canada   CAN
Re: Bill's comment on designing this conversion to basically install a Camaro drive train in a MGB.
I believe V6 T5 Camaro rear end ratio is 3:23
What ratio did the Camaro's with a V8 T5 come with ?
John

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BMC Gold Member Brian Mc Cullough
Minneapolis, Minnesota, USA   USA
I have never mentioned this previously but I had one or Two bad release bearings- in my S10 pickups! They were very annoying to say the least. When someone calls for diagnostics and asks- could it be the components you manufactured or something else, I always say that Everything man-made is bound to fail. Everything has to be considered and diagnosed and it is nicer if things can be moved and made easier, but not everything can be. Your point about moving things to easier locations to repair is duly noted Scot.

-BMC.


Member Services:
Minnesota's only Fully Dedicated British Classic only shop providing Professional Restoration & Services & Specialty Products including- proper L.E.D. tail lights, Wiring looms and Engine and five speed Conversion Kits
V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
In reply to # 3717881 by jewar Re: Bill's comment on designing this conversion to basically install a Camaro drive train in a MGB.
I believe V6 T5 Camaro rear end ratio is 3:23

Only the 1982 V6 Camaro had a 3.23 & it was a 4 speed car (no T-5 til '83). All Third Gen V6 Camaros with a T-5 sported a 3.42 rear gear.

http://hyperlogos.org/page/Camaro-Technical-Database#engine3rd



In reply to # 3717881 by jewar
What ratio did the Camaro's with a V8 T5 come with ?


Quite a few, 2.73, 3.08, 2.23, 3.42, 3.45, & 3.73

http://hyperlogos.org/page/Camaro-Technical-Database#engine3rdv8

NOHOME P P
O, ON, Canada   CAN
1967 MG MGB GT "Maggie (GT From Hell)"
Based on internet reading I would cross the road to avoid the hydraulic throw-out bearings. While I agree that they are the most elegant solution to the packaging of a throw-out bearing gin a hot-rod, all I ever hear is that they are broke.

Personal experience is one in a Coyote swapped 69 Mustang, when it came time to start and drive the car, neither love nor money would bleed that stupid throw-out bearing. Did not help that Ford does not see fit to put a bleed screw on the slave cylinder. Ended the project and I don't know that it got finished to this day.

If you can fit an external slave, IMHO...it is the wise way to go.

Pete

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