rcutclif's 1974 MGB-GT

Well, this is a new build thread for an old project of mine. I've had this car since high school (going on 12 years I think), and its only really been running for a sliver of that time. I drove it for 2 years before I graduated HS, but then it needed a clutch, so naturally I decided to rebuild the engine.

Long story short that rebuild was not the best work I have done in my life, and now I am re-rebuilding it. ha.

the motor has been bored out from 1800cc to 1950cc, and it does have a nice big cam. I hope to keep both of those things.

during this motor's first 100 miles or so since the first rebuild, the #4 rod end separated and chaos ensued. Upon tearing it down again, I found why: ALL of the rod ends and main bearing caps were hardly tight. Dunno what I was thinking, but torquing those bolts was something I forgot. Frankly I'm surprised it ran as long as it did.

Here's a picture of the damage to the crank. I can get a new rod no problem, but wondering about this crank. Can it be repaired or will I need to use another crank?

Oh, and just for fun, as the car sits now (there are lots of other stories of me and this car, but those are for another day at another time):

with a gouge that size im not sure it can be undercut enough to make it safe. im guessing your going to need to source a crank.

I love my GT but to be honest, after 36 years of mucking with the engine and transmissions, have to say that the drivetrains are not fit to be boat anchors; all noise and no poise. Dont ask me how, but the damn thing would figure out how to fail at that task.

Have you considered that for the price of a good engine rebuild you can do a GM 3.4 V6?

In reply to dropstep:

Yeah, I don't think cutting alone would do. I was kinda wondering if they could be welded and then recut, but I'm no machinist.

In reply to NOHOME:

Yeah, I have thought about the gm swap (Ive spent too much time over on mge, and it seems to be the only solution there other than a numbers matching restore for 95% of those folks).

I guess I'm just not all about the v6. Doesn't really do it for me.

I thought REALLY hard about both a miata swap and a BMW m42 swap, but then I think, "well, if I'm gonna cut, might as well go crazy" and then I never drive the dang thing. I figured if I could get this motor running again for cheap, I might as well do that and then enjoy the car for what it is.

Of course, if I cannot, then all bets are off.

The Miata swap is not one that attracts me: not enough torque to make it worthwhile. But the gearbox is appealing.

Lately I have been thinking about the Honda V6 swap that is meant for the Miata. If they would sell the engine adapter separately and you can figure how to get some traditional engine mounts attached to the engine, it would then give you Japanese V6 with over 250hp and the great Miata gearbox.

Of course, the Ford 302 has become such a commodity swap into the MGB that it is hardly worth the effort to do your own engineering unless you want to.

rcutclif wrote: In reply to dropstep: Yeah, I don't think cutting alone would do. I was kinda wondering if they could be welded and then recut, but I'm no machinist.

A crankshaft can be welded and reground to stock. I had one done many years ago. I've heard that the result is actually tougher than stock but don't actually know that for a fact.

Well, more progress. Figured I'd get some work done grabbing the other engine out of the car (might as well see if that crank is any good).

Up on stands:

First out with the coolant and oil, then pull the two coolers:

Next, disconnect the carb.

And finally disconnect everything on the passenger side, starter, distributor, alternator, etc. Pull the valve cover, and remove the engine mount bolts.

Hopefully tomorrow I will get to disconnect the engine to trans bolts and lift the engine out!

Wow, that's a really nice looking car!

WAY easier to lift the engine and box together rather than try to split and re-mate the two.

The engine has been out of my car so many times that me and a friend have it down to a two hour effort. He specializes on the PS and I do the DS.

We did forget to re-install the throwout bearing once when reassembling, but hey, that was in the middle, so no one to blame!

If it ever warms up, I should pull mine out of storage and drive it around the block a few time.

Thanks Woody, it actually takes pictures better than it looks I'm real life. Its a maaco job over some rusty areas that weren't repaired correctly. I will have to redo it at some point, but for now it is great driver shape.

Thanks for the advise nohome. I have also done mine several times, both with gearbox and without. I actually think it is easier this way, and I don't have to drain out all the trans fluid, but I understand, getting them re mated in the engine bay can suck. Either way, two hours is a great time. I feel like all the bolts on an MGB are fine thread pitch and half an inch too long so they take days of ratcheting each. While cranking today, I was wondering how much lighter the car would be if all of the bolts were cut down to the right length....

Please don't listen to the B series nay sayers. They are full of character and a masterpiece of design for the resources and material available at the time.

Adrian_Thompson wrote: Please don't listen to the B series nay sayers. They are full of character and a masterpiece of design for the resources and material available at the time.

It is nice to know that I am full of character and a masterpiece of design for the resources and materials available at the time. I will thank my parents.

I live about 10min from the Killer B V6 place(www.killerbv6.com) and after hearing the 3900 car... it sounds like a blast. It's a very clean and well done swap too.

I'm not all into the old British stuff too much, but it ALMOST had me wanting to overlook awful wiring and rust and parts availability problems for one.

flatlander937 wrote: I live about 10min from the Killer B V6 place(www.killerbv6.com) and after hearing the 3900 car... it sounds like a blast. It's a very clean and well done swap too. I'm not all into the old British stuff too much, but it ALMOST had me wanting to overlook awful wiring and rust and parts availability problems for one.

"Parts Availability" is hardly one of the MGB's problems. Not only are all parts easy to get, they are relatively cheap compared to most other classics and new cars. Quality, I will concede, can be all over the map.

As to the rust issue: The only reason to get a rusty MGB is because you want one as a project. There are a lot of rust free examples to choose from and the truth is that they never had inherent rust problems. The rust that people associate with the car is due to exposure to salted winter roads and years of use. If you use cars from southern states as a control, you will note that they are actually quite rust resistant even after 40 years.

As to the wiring, I will say that is more fable than truth, certainly no worse than the contemporary cars of its era, and certainly better than anything the Germans are selling today.

Link to clip of the Killer B 3900 conversion.

https://www.youtube.com/watch?v=BAxT-yN7YK4

You mention the "Killer B" shop near your house. I would be curious to know if they are still in business since rumor is that they have closed shop.

NOHOME wrote:

Adrian_Thompson wrote: Please don't listen to the B series nay sayers. They are full of character and a masterpiece of design for the resources and material available at the time.

It is nice to know that I am full of character and a masterpiece of design for the resources and materials available at the time. I will thank my parents.

Touché

In reply to NOHOME:

It was about 2 years ago I went there for something to be machined for my Jeep, you could probably call and find out.

In reply to flatlander937:

Two things: the 3900 car sparked my infatuation with v6 mgbs, and your screenname doesn't happen to be a 90's bmx reference, does it? I hear flatlander and instantly get transported back to newsprint magazines and crupi pedals.

Looking forward to seeing what happens, op. Its always tough to get back to the firs love when new projects beckon. Hence my neglected duster.

Thanks all for the encouragement. Right now, I think I will stick with the stock motor (well stock ish) I do have a block and 4 good pistons to bump from 1800 cc to 1950...

And I thought you were talking about these guys (very close to where I used to live, and they are freaking experts on the MGB). MG Limited / Killer Beez Racing They are a little rough around the edges but they know a ton and always had stuff in stock for me, which was amazing.

In reply to Dusterbd13:

Ha yes actually. I was on the Backlash BMX boards long ago. The i think it was Pedal BMX. I Can't remember half the boards i was on, but i would have been flatlander_14 or flatlander757. I organized a bunch of flatland jams when i lived in Va Beach. I still have my bike, a 99 Hoffman EP that's had literally everything replaced, mostly all parts from flatlandfuel.com. I kept the name but changed the area code when I moved to Dayton, Ohio.

Flatland was my first money pit. Moved to RC cars then 1:1 scale cars :-p

Sorry for the off topic, if you want to reply let's do via messages to keep from a derail. :)

If doing a rebuild, stay away from crane cams and cheap lifters.

Finished disassembling the block today (removed cam and oil pump drive). No photos though.

Will drop the crank by the machine shop early next week, and then get to ordering a new rod and bearings.

Did I mention that you should be replacing the oil cooler after a bearing failure? Or bypass it since it is not really needed. Lots of metallic crap gets parked in that thing when the engine fails.

NOHOME wrote: Did I mention that you should be replacing the oil cooler after a bearing failure? Or bypass it since it is not really needed. Lots of metallic crap gets parked in that thing when the engine fails.

Yeah, good idea. I had a rod failure technically though, the engine slammed to a halt when it failed, so there was actually very few shavings in the oil. Just chunks of rod at the bottom of the pan.

I will have to see what I do about that cooler.

I'm kind of in the zone of 'get it back together so I can drive while I source (and decide) on a more permanent option'.

New direction!

https://grassrootsmotorsports.com/forum/grm/mgb-gt-engine-choices-what-to-do/117137/page1/

the B will be getting a 1.6 from a miata!