My 1973 TVR 2500M : Renew and Restomod

Dusterbd13 said:

Ive had to have custom clutches built. Spec clutch does a good job at a good price and quick.

Cool.  Any special considerations or do you just tell them what flywheel you're using and what transmission?

Pretty much. And throwout bearing if its odd.

So mine is a small block mopar clutch with a ford trans spline and a 4.0 jeep throwout bearing 

I e-mailed SPEC and they already got back to me asking pertinent details.  A+ for customer service so far.

I need to check out the throwout bearing and pilot bushing sizes too.

USERNAMETAKEN said:

I've been conversing with a guy who's doing this swap on an MGB.  He's about a year ahead of me, I'd say.  His car actually runs and drives.  It's really cool.  He's using an NC Miata 5 spd with good success.  That gearbox is so compact.  And light.  The shifter will be just where I want it.  And won't shift like my brother's old Ranger.

And they're cheap in the junkyard.  Did I mention cheap?

Is this Ecoboost-powered MGB on the Internet somewhere us schlubs can peek? Er, with a small amount of self-help, I can update that query to "is this that car?" Looks like that thread hasn't been updated as recently as running and driving...

Alright, more actual developments.  My buddy Kolby came by with an intake tube and a MAP sensor bung to weld.  He's putting a MegaSquirt PNP on his MR2.  So I fired up the TIG for that.  I was actually really pleased with how it turned out, since I've not done any aluminum welding for a while.

We also test-fitted the hood.  I've not had the hood on the car since Day 2 of my ownership.

I really wanted to make sure the engine cleared the hood properly.  Short answer: it does!

It actually looks really good.  I've got a solid 3/4" right as it sits here, and the hood is actually a bit low here.  So I'll have more room.

Good stuff!

Ransom said:

Is this Ecoboost-powered MGB on the Internet somewhere us schlubs can peek? Er, with a small amount of self-help, I can update that query to "is this that car?" Looks like that thread hasn't been updated as recently as running and driving...

Close.  That's one of two threads on that board.

This is the one you're looking for.  It looks really nice.

Been in contact with the guys at Spec Clutches.  They can indeed make me a custom clutch disc that will adapt a Focus ST flywheel/pressure plate to a Miata transmission.  Good guys to deal with so far - fast responses and good info.

I've been trying to do more research on my own, and I almost thought that the Miata 6 spd trans matched the ST clutch.  Looks like not quite, though.  They're both 23 spline input shafts, but the ST gets listed as a 1" and the Miata as a 1-1/32".  So it's probably just a little different.

Was hoping I'd get lucky on that one!

I think I would rather get a used flywheel than a custom clutch. If you burn up your clutch then you need to wait for a bespoke replacement. Stock pieces sit in stock shelves. The Miata flywheel should bolt up... right?

RossD said:

I think I would rather get a used flywheel than a custom clutch. If you burn up your clutch then you need to wait for a bespoke replacement. Stock pieces sit in stock shelves. The Miata flywheel should bolt up... right?

A stock Miata unit should bolt up, yes.  Not sure about the starter. Or the pilot bushing.

Would probably need a Stage 3 or 4 Miata clutch, which would be not off-the-shelf.  The guy from SPEC said the Focus unit would probably have better drivability than the Miata version.  Bigger diameter, more capability perhaps?

Partly I'm just trying to same some money and use what I've already bought.  We'll see if I can sell any of the used stuff and recoup the investment.

Good news!  The guy at SPEC clutches says my ST clutch will interchange with a Miata 6 spd!  He says they use the same input shaft spider on both units.

So I'll stick with the stock unit for now, and upgrade when I need to down the road!

I love those guys.

And i can usually have a custom clutch on my bench within a week of order. They're that quick.

But sooo much better to not need one at all!

In reply to Dusterbd13 :

I was super-impressed with them.  Very knowledgeable and quick to respond.  Had a nice chat with the guy even though it became clear pretty quickly that I wouldn't need to buy anything from him.

Thanks for the tip!

And those guys understand guys like us. We may not be a customer TODAY, but we'll remember their service and be a customer in the future.  

Thats the way its supposed to be if you ask me.

Glad to hear that things seem to be falling into place.   Carry on.

And carry on I shall!

Ran over to one of the auto-wreckers today, and picked up this:

Has about 90K on it.  Hopefully I'll get some good happy miles from it.

Also at the junkyard, I saw an EcoBoost turbo sitting on the floor by the office, and saw this little guy:

This bypass valve was missing on my donor engine, and the new ones are surprisingly expensive.  The counter guy was really busy and asked if I could pull it off myself.  I did, and he ended up just giving it to me.  Score!  Thanks to Javier at Arvada Auto Wrecking for that!

I was actually really happy to learn that I could use my ST clutch with this NC 6 speed.  I was in decision-gridlock between the 5 spd and 6 spd units, and that made for a quick and easy tie-breaker.  Some days a little nudge will help so much.

I'm thinking I'll go for a pretty tall final drive - one where I can hit 60 mph in second.  This motor should have gobs of torque low in the rpm range, so I'm not worried about getting going.  I need to go thru the available options on the R200 and pick something out.  All down the road.

Next up, I want to pull the motor back out and test fit the new trans.  Then I can get back to motor mount fab.

Sounds like you'll be busier than a one armed paper hanger.  What gearing is in it now?

Dirtydog said:

Sounds like you'll be busier than a one armed paper hanger.  What gearing is in it now?

What gearing is in the TVR right now?  TR-6 rear end, though I'm not sure about the actual gearing.  After I made the choice on the EcoBoost I've never planning on keeping the Triumph rear end.  Good Parts does an axle / diff upgrade kit that uses a R200 LSD.  Seems like the smart way to go.

Definitely would do the R200 using the Good Parts CV axles, for your TVR. I am planning the same thing for my V8 TR4A sometime in the near future.

dherr said:

Definitely would do the R200 using the Good Parts CV axles, for your TVR. I am planning the same thing for my V8 TR4A sometime in the near future.

I've been looking at gear ratios this morning, and a 3.54 rear end would make for gearing very similar to my Focus ST.  Which I like a lot.

In reply to USERNAMETAKEN :

How much lighter is the TVR? Light enough that you might want overall taller gearing?

Ransom said:

In reply to USERNAMETAKEN :

How much lighter is the TVR? Light enough that you might want overall taller gearing?

It'll be about 2000 lb, I hope.  That's the stock listed weight for a 2500M, and I think my car will be around that number.  The engine is substantially lighter all by itself.

Stock ST is about 3500 lb.

Oh Boy!  Santa in the purple uniform says I've been good this year:

I’ve been following this but haven’t commented yet since I have no insight to this. But I’m glad things are working out for you. Ready to see this thing come to life

In reply to Papabishop :

Thanks for reading!

Last night I pulled out the engine with the Mustang transmission and got the two separated.  The NC trans did indeed bolt right up, though the hardware is all different now.  I had enough bolts to cinch it up in about 4 spots.

Here's a comparison of the two transmissions.  That MT-82 case is just plain big:

I put the new assembly on the crane-scale and it's not very different.  Only 7 lb lighter with the Miata unit.  For all the noise the internets make, the MT-82 trans really isn't that heavy.

Got the whole thing swung into the car and leveled.  Look really quite nice.  Much more clearance now.

And another view where my exhaust will end up:

Overall a positive step forward, I'd say!

Absolutely.  Keep on keepin on.