30 model A motor mount posistion (no body yet)

[Bruce Lancaster]

Several things: You MUST get hold of a radiator as that is a barrier you can't really mess with.
If engine is still to be rebuilt or get a new cam...swap to 1948 type cam, giving a couple of inches more room and a good cheap ignition. The space savings are very significant in an A chamber.
If cutting a torque tube to fit, build to the radiator, get close up there. Figure out your fan etc. BEFORE you nail things down...again early front parts with early cam is big advantage.
If using the A rear, build to that...bolt trans to A tube, engine to trans, and that is where it needs to go!

[Lucky77]

If you follow the book to a T like I did you end up with several problems. The edition I have says you need a 32 wishbone. So after finding one for $500 and $100 to ship it I ended up with a wishbone that was too long. So I had to spend another $100 on a Model A wishbone and $200 on a set of 33/34 split bones in order to make a hybrid wishbone that fit the chassis.

I also ended up using a 32 K-member $500 that has to be heavily modified. I paid over $400 for 32 pedals that also have to be modified and rebuilt. There are plenty of AV8 cars out there with F1 cross members and pedals that probably cost 1/3 of what I have tied up in parts. The book doesn't mention any of that.

If you step the frame in the rear, then bolt the body back in the stock location the rear wheels are too far back. So you either have to put your body in a different position, that screws with your hood length. Or move the rear crossmember foreward a few inches. I really wish I would have known about that before I finish welded everything. Here's a shot of the car so you can see the wheel placement if you follow the book exactly.

Its still a great guide, probably the best around. Just don't fall into the trap like I did of thinking everything in the book would transfer to my car.

[Vergil]

I have two av8's, one a coupe with recessed firewall and a pickup without recess on the firewall. I am so happy I didn't recess the pickup firewall, there is not much room in them as it is and after recessing even less. If I had it to do again on the coupe I wouldn't recess it either. Again my 2¢.

Vergil

[Koz]

These things are hot rods, not some kit car. Anybody who is building a car from scratch needs to think things through a bit. I usually don't have the whole car on hand when I start but there are basic measurements that stay fairly constant. Anybody that is building a car can get the measurements of just about anything and think it through pretty easily. If we all waited until we had all the parts, most cars would never get started let alone finished.

Just about every dimension you could need is published here or in some of the aftermarket catalogs. I gain inspiration from seeing what I've got done, not what I might do when I get more money.

Admittidly, in an ideal situation everything would be setting there ready to go. We all know that doesn't happen.

In other words, just use your head and it will work out. It's a hot rod not some nuclear project. They ain't that complicated! Get the dimensions you need and lay it out on the floor or some sheet of something.

[jimbousman]

The TD book is great but their build uses a lot of stuff most guys don;t have. As KOZ states Hot Rodding is not a plug N play hobby. That's what I like about it. Hell, even when I built model cars I used to throw out the instructions. Get a radiator and a body (of at least a cowl), bolt them up, drop in a block and tranny and see where you're at. I've mocked mine up at least five times before I was set on mount locations. I lucked out because I only had to bump the toe boards back a bit to clear my heads. No book was going to be able to tell me how and what to do there.

[Koz]

I don't know if this will help but I've built at least 15 frames with this combination now and I stretch the Model A frame 2 3/4" and set my motor mounts 6 1/4" behind the radiator core using the pickup wide belt pumps, ( Speedway 910-15592 ), on the 8ba using a mechanical fan. Most radiators use a 2 1/4" thick core, which puts you centerline of the mounts 8 1/2" back from the center of the radiator holes. The mount holes on the frame brackets are 1 1/8" in diameter and are 20" apart, (across the frame), center to center.

If your running a 39 style box let me know and I'll shoot you the dimensions of where the trans mount goes and the details of building the K member. This setup gives you a chassis with a wheelbase of 106 1/4", 1/4" longer than a deuce. You wont have to cut the firewall in a stock A cowl except for minor clearance around the bell if your using the truck, cast, bell. The steel passenger bells work as is. And yes, you need to stretch the hood if your using one. If you want to spend the bucks Walker makes a radiator just for this combination. I have the part# around here someplace or just call them. The blue car I posted in frame 17 of this thread is set up this way and I think it looks sweet. I can post some side shoots if it helps.

There, I ran my big mouth. Now ten guys will tell me it won't work!

[Koz]

I forgot to mention, I set the frame mounts flush with the top of the rails. For the guys who didn't read post 17, the car is set up for the flatty but i ran the 283 until my flatty was together.

A side pic.....

[Nevala]

Originally Posted by Lucky77

If you step the frame in the rear, then bolt the body back in the stock location the rear wheels are too far back.

How can they be further back? If the step is frame height above it's original position and you do spring-over mounts on the rear, how does that translate to fore/aft movement?

Originally Posted by Koz

I forgot to mention, I set the frame mounts flush with the top of the rails. For the guys who didn't read post 17, the car is set up for the flatty but i ran the 283 until my flatty was together.

But it's also a 30-31 with split wishbones. Is the distance between radiator and firewall the same on 30-31 as 28-29?

[Koz]

Originally Posted by Nevala

How can they be further back? If the step is frame height above it's original position and you do spring-over mounts on the rear, how does that translate to fore/aft movement?

My bet is when he did the rear he didn't follow the plan and laid the Z in like you typiclly do when yoou build a box tube frame. This puts the wheels aproximatly 2" back from where it should be. I've had another one in here that the owner did the same thing. Easy fix. I'm little surprised Lucky77 had trouble with the 'bones an crossmember as the setup described in the B/T book is flawless. I'd be intersested in hearing more from Lucky77.


But it's also a 30-31 with split wishbones. Is the distance between radiator and firewall the same on 30-31 as 28-29?

It is. BigVinny asked about a '30 so that's what I posted. I've done a few '28/'29s with the same results. I just wanted to make sure I didn't piss off anybody named BigVinny. Like I mentioned above building any rod is just a little head work and it'll come out just fine. On my '30 I split the deuce 'bones just cause I thought they looked cool like that. They could have just as easily gone under the car to the crossmember. Remember when you stretch the frame the lenght is picked up at the firewall but the trans crossmember stays at the same place in relation to the front crossmember/axle so a stock deuce 'bone will drop right in. Sounds tougher than it is.

[Tank]

If you build Mounts out of rect. tubing like the B/T book you can damn near butt them right up against the stock front crossmember. I used a '46 engine in my coupe and it fit great with no cutting of the firewall. If you use an early '36 style generator/fan you can run a single belt on the front. There are other hurdles to tackle also.... such as steering, pedal assembly, etc. But with planning, and some inginuity, and lots of trial and error its totally do-able.

[Koz]

I agree with Tank if you have the 59AB you can shorten things up a bit. BigVinny said he was going to use the 8ba which would require a load of changes to run the earlier front setup if I'm correct.

[rpu28]

cayager is correct.

Relocating a radiator on a Model A is not a good idea if you're going to run stock sheet metal and grill. That means the position of the fan on your engine is fixed at roughly 1" behind the rear surface of the radiator. From that point, your engine is either going to clear the firewall or it isn't. So you can recess the firewall or get a shorter engine; sometimes you can find a shorter fan assembly (but please, don't use an electric fan on a period rod).

Recessing the firewall is not a big deal; use half of a large baking pan for the recess. For flathead V8's, the recess is quite low and does not require butchering the whole firewall.