2 days ago in Articles
The physics behind load transfer are crucial to performance driving.
In October 2011, I bought a V8-powered 1976 Triumph Spitfire off of eBay.
Yep, I'm de-powering a 5.0 V8 Spitfire. Why, you ask? Short story, the V8 is too big and I'm not willing to live with the compromises that were made to fit that engine. It may have worked okay for a dedicated drag racer, but I want a road/track car. For the long story, go HERE. It's really too bad because a V8 Spitfire is a pretty awesome concept.
So what is going in that engine bay instead? This is GRM, so the answer is Miata. The Mazda BP engine, as found in the NA/NB Miata, is a versatile little power plant that will fit nicely under the low hood line of the Spitfire.
Earlier this year I picked up a 1994 1.8, 5-speed, and wiring/miscellaneous bits from a local racer/Miata breaker called SR Enterprises. Austin is a good guy... if you're in need of Miata parts, let me know and I'll put you in touch. Anyway, a big plus is that I got to see and hear the engine run before he pulled it all for me. A little lifter tick, but overall it seemed to be a sound engine. The car it came out of was a rear hit purchased at auction by SR E., but Austin drove it a little up and down the highway and said that it shifted well and the engine ran just fine. Excellent.
The V8 Spit was set up for drag racing, so it has a custom (beefy) ladder chassis that incorporates some of the original Spitfire attachment points. An '85 Mustang GT was the donor for the project, and the 7.5 Traction Lock differential was narrowed and used. The drag Spit was fitted with a 5-link adjustable rear end setup. The shocks are Konis and are stamped "adjustable." Where is the knob? Maybe I just haven't found the word "not" on them yet. The springs brand is unknown, but they appear to be made of granite. They will be changed out for something in the 200 lb/in range (comments?).
The good thing about a car with a front clamshell is all of the engine access you get. The bad thing is that it has to come off in order to remove the engine, and that is a two-person job. I had a neighbor help me lift the bonnet off last weekend, so that I could begin the teardown in earnest.
Everything is so crammed in, a few things had to come off in order to be able to pull the engine. Besides the normal disconnection of electrics, fuel line, coolant system, and various bolts, I had to pull off the exhaust manifolds.
Seems like they weren't sealing too well...
Also, the steering shaft had to be removed, which required the steering rack to be unbolted. How many flexible joints are there between the steering wheel and steering rack (including the stock rag joint)?
Finally, it's ready to pull.
That brings us up to today.
Pretty cool that you're de-powering a spitfire. Honestly the Miata engine probably would have been a good start. I'll have to remember that.
Well, I found out why there is no knob on my adjustable Konis. You have to remove the shock to adjust it. Here's a good video for anyone that needs the same info:
Had shocks like that on my Mk1 Focus. Once installed I adjusted them exactly zero times.
Looks like a cool project.
I hope to "set it and forget it" when it comes to the shocks. It's a hassle having to remove one to adjust it, since its a coil-over. The more I think about it, the more I wonder if the shocks are set on full hard. Maybe that's the reason for the hard rear suspension, not the springs. In a drag car you want hard damping in the rear, right?
Anyway, more progress made today. Out come the seats, so that the carpet can come out, so that the trans tunnel can be removed, so that the shifter can be removed from the transmission, so that the transmission is more easily pulled from the car.
Who needs a welder?! Sheet metal screws, pop rivets and duct tape are good enough! Oh yeah, and black spray paint to make it look professional.
Looks like a job for Super Boy!
Duct tape and (some) sheet metal screws removed.
Good enough to commence with the engine pull.
I then proceed to (mostly) pull the engine/transmission package, but the weight distribution is all wrong and the shop crane is not liking it. Solution: Get friendly neighbor to help you pull the transmission and reposition the chains on the engine block. Skeleton pirate keeps watch while we do the dirty work. Success!
Obligatory empy engine bay shot:
And the blank canvas:
There are things about that bare engine bay that look kind of scary. I'm a bit surprised that the car didn't rip itself apart during hard launches.
Well, it's basically a ladder chassis made from 2"x3" 12ga. tubing with a Spitfire body dropped on top. The same idea the original Spit chassis, but wider and with much beefier metal. That being said, it could certainly use an x-brace. Despite the beefy frame material, there was probably some twisting during launches. The Spit body functions as an x-brace, but as you can see this one is not exactly structurally rigid.
We sold an incomplete 5.0 spitfire project after seeing just how much it would take to try to finish it. So what are you doing with the 5.0/T-5?
Greg Voth wrote: So what are you doing with the 5.0/T-5?
Selling it. For a GRM'er, I'd take $500 for the package. I don't think that you can beat that with a stick. I drove this car into the garage, so I know that the engine and transmission are good. You will need a new dizzy cap though, because I broke off one of the contacts when pulling the engine.
Sounds like a deal. The only problem is shipping or pickup. Any specs on the motor/trans? (Year, aftermarket stuff etc?)
I'll have to talk to a friend of mine about that. Apparently he can get pretty good deals on things if they can be put on a pallet and freighted.
The drivetrain is out of an '85 Mustang GT, so the T5 is the "World Class" type. The accessory brackets are custom made from aluminum stock. I suppose that was done for fitment reasons. It has a remote oil filter setup, which I assume isn't stock but I don't know offhand. It may have come off of another Ford vehicle? Tubular headers as seen in the pics, but they need some work on the sealing surfaces. Carb is a 4bbl off of a '79 truck according to the tag, and I would call it "usable but suspect." One of the float bowls was leaking when I got the car (due to a stripped screw), but I think that I fixed that issue. EGR stuff has been removed. Cooling system shows a little corrosion at the hose connection points, but the coolant that came out looked good (Except for what was in the very bottom of the radiator. Yuck!) Ignition is the stock Duraspark system. All of the wiring is getting old and should be gone over, but it still worked since the car was running. Top end is sealed well but it probably has a front main seal leak based on the oil/crud accumulation below the crank pulley.
That's all I know and can think of about the engine.
Transmission seemed fine. It shifted well and the fluid that came out looked fresh. The shifter was well-greased when I pulled it and the clutch pressure plate looks new. Nothing to report here, really.
I'm not really up for palletizing and shipping this. For now, it's pick-up only. Sorry :( Maybe there's a Challenger headed through Houston, and you could meet them in Gainesville?
looks like it's going to be awesome... hit me up if you need some help... I always need an excuse to get away from the books and school work (and apparently my own project isn't a good enough reason for me :-/ lol)
Looks like a fun project. What do you plan to do with the front suspension? Considering how much everything was hacked up, this may be a good opportunity to fix some things.
I'm not sure if you're familiar with Spitfires, but the front shock towers are meant to be tied together through the motor mounts via a large front plate bolted to the front of the engine. It looks like the 5.0 motor mounts were serving this purpose as well to a certain extent, but keep this in mind when you're figuring out the Miata engine mounts.
Thanks for the insight on the stock setup. I only know what I've seen in pictures, and I hadn't noticed that. Although it looks like the 5.0 motor mounts were reinforcing the towers in some of the pictures, they aren't. The towers are totally on their own
I'll definitely be reinforcing them. My intent is to tie them together with tubing much like you describe the stock setup being (but without being bolted to the engine), and then tie them down into the chassis. The trick will be preserving the ability to easily pull the engine and maintaining that lovely access that a Spitfire has when you lift the bonnet. I imagine that at least the cross-tower brace will need to be removable. I've been in the mental planning stage on this since pulling the engine, with more thinking to do. Expect some MS Paint sketches for critique at some point
IIRC, that's more or less what GRM did with the Roto-Spit car, since the engine was well behind the front suspension. In your last pic, you can see the original motor mount tab on the passenger side tower (plate with two holes). The driver's side seems to have been trimmed off.
If you can get the engine back far enough, you may want to consider reconstructing the towers intirely so you can relocate the steering rack. The OE position is prone to bump-steer. Send a message to Curmudgeon. He did the relocation and can explain it better. Plus, if you redo the towers and suspension you can use Miata spindles and get better brakes and a much easier 4x100 bolt circle. Definitely worth considering since you have to redo the rear suspension anyway...
One of my distant dream builds is a Spitfire with a modified Miata suspension and a turbo rotory, but more as a pro-touring car than as any sort of all-out performance car..
I hadn't really gotten into it yet in this build thread (I think I mentioned it in the other thread), but I am swapping to Miata spindles and steering rack (and possibly steering column as well). I'm hoping to not have to reconstruct the towers, though.
I'm mainly doing it for the bigger brakes and to get rid of the trunion setup, but the more common 4x100 bolt pattern is a bonus. The rear wheels are currently 4x95, but I pulled a drum and was pleased to discover that the factory 4x108 holes are still there.
4x108 has a much wider wheel selection, and I'll even be able to get a set of wheels that are drilled for both 4x100 and 4x108 if I want.
The stock Spitfire front motor plate attaches to the suspension turrets through rubber motor mounts that can flex as much as 1/4", so it doesn't really contribute much to stiffness.
The stock frame has a large boxed cross member connecting the rails that does stiffen the chassis (a bit anyway).
It wouldn't take much to add a 'robust' tubular steel hoop with brackets that bolt to the turrets. The hoop should clear the front of the motor, but still fit under the hood.
erohslc wrote: It wouldn't take much to add a 'robust' tubular steel hoop with brackets that bolt to the turrets. The hoop should clear the front of the motor, but still fit under the hood.
Yeah, that's the plan. Now I'm trying to decide whether to scrap the stock turrets/towers and go 100% tubular, or try to use the towers.
Bad things about the towers: 1. The driver's side gets in the way (slightly) of the Miata steering rack pinion, and will need to be clearanced;
They both get in the way of optimal steering rack positioning;
They are weaker, I feel, than a scratch-designed and fabricated tubular setup would be; and
They're a bit beat up, hacked up, and ugly.
Good things about the towers:
Hack the current (already hacked) towers as needed. Once everything is working and debugged, fab the replacements.
erohslc wrote: Hack the current (already hacked) towers as needed. Once everything is working and debugged, fab the replacements. Carter
I think you're right. I wanna drive this flipping thing sooner rather than later. If I keep the towers, I only have to fabricate a new LCA and do some cutting/bracing. Much less chance for headaches and error than fabbing a completely new front suspension. I can always go back later after the rest of the car is sorted. They drove the stock Spitfires with much worse Anti-Ackerman.
I'll still end up with a touch of anti-Ackerman, but here is where the rack will be located if I don't remove the shock towers:
Here is my initial thought on what the front suspension hoop will look like. It will be bolt-in to allow the engine to be more easily removed if need be. Those curved lines near the engine are gussets.
Please excuse the M.C. Escher-like quality of the MS Paint drawing, but here's the side view:
In reply to Winston:Very nice,any more updates
Winston, if you have not already seen Curmudgeon's 'GT6 Project' thread:
He's converting to Miata front Spindles, but with Spitfire/GT6 suspension pieces and mounting points.
Not much in the way of progress, but I've decided to 86 the stock shock towers and fab up my own. I have the steel and the drawings, now I need to do the cutting and welding.
My lovely wife got me the Wilwood pedal set with master cylinders for Christmas
(Though I think that I may have told her the wrong size for the brake masters. Knowing that the stock Miata brake MC is 7/8" and the stock Mustang brake MC is 15/16", I probably should have gotten two 3/4" MC's since I'm depowering them... right? I asked for and received two 1" MC's.)
I would post pics but my computer is once again having issue with my camera.
Oh, and I have been watching 'Mudgeon's thread. Thanks :)
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