Healey Sports Cars

For many years there has been a very straight Mk-I Sprite Body hanging from my ceiling! The wheel wells are flared and all of the good intentions are finally coming to a point where "it's time to get 'er done"!

Recently, we saw a TR6 with the GM V-6 conversion. The rear end had been changed to a solid axle. Fair enough...but as nice as it looked, I am not sure about the value @ $10K for the "hot rod"!

So...here is what we have been thinking. Perhaps those of you who have been there before can guide us a little.

The German Ford 2.8 V6 looks narrow enough. The engine also appears to be installed in some older Broncos, etc. This being the first-ever project of this kind, the thought is to make it simple: V-6, automatic trans, rear end from the donor. There is also a GM 2.7 (I think that is the one that is the subject of many posts.) That one looks like it was used in some early Jeeps and maybe even the Isuzu Rodeo. The Bronco and Rangers have a more narrow rear end than the Jeep/Rodeo. Is this right???

Personally, I don't mind the thought of tires coming out of the back...but I would want the fronts under the fenders.

Front suspension would maintain the Armstrong geometry, with the "WeRace" type tube conversion. I might convert the levers to MG that has a dual wishbone. Coils are nice...but I am not sure that is the look I want for this one...maybe.

Rear end and suspension would depend on the axle; I see full length leaf springs back there with a panhard and maybe even "mini traction bars"! This is a "cruiser" and not designed for anything but to rumble and roar a little!!! (We have had plenty of competition experience...time for a little fun of a different kind.)

The frame would be reinforced front and back from a main hoop. It would probably be 1.75" seamless steel. (By the way, where can I learn how to make bends?) Strengthing to the front shock towers through the fire wall in the front; strengthening to the rear springs, axle along the floor boards. One nice thing about the Mk-I...it is open with lots of room (relatively, speaking)!

Exhaust would be dual, exiting though the wheel wells into side pipes. (Anyone suggest long and thin [motorcycle] that do not sound like they are grinding rice?)

OK...all of that said: I know that Bill Young has put some kind of V-6 in a Midget. Can I also ask The Forums' suggestions regarding engine-trans-rear ends? 100 hp in one of these things will get your undivided attention...so anything that is 125-150 is what we are thinking.

We love Rotary engines...race them regularly...but this one needs to be a V-6 with side pipes!!


Thanks!


ed

Welcome to the forum Ed!

The little Ford "Cologne" 2.8L V6 would probably work quite nicely for you - but its becoming less popular with age. It would give your car sort of a late-seventies flavor.

Would you be willing to consider a newer Ford engine? Here's a brand new write-up that's not quite ready for publication - it needs some editing and some new photo captions yet - but I think it does a very good job of making a case for the Ford Zetec inline-four engine in a Sprite: Rick Bondy's Zetec Powered 1961 Austin Healey Sprite



If you really want a V6, the GM 60-degree V6 engines would offer some big advantages over the older Ford V6 engines. You can buy them in crate form, or find them in lots of running donor cars. There's a lot of great vendor support available for them. If you're willing to consider fuel injection (and I certainly would!), then give this new write-up a look because I think it does a very good job of explaining the case for later GM V6's from front wheel drive donor cars: Scott Costanzo's GM 3100 installation in an MGB

Bill Guzman has a Ford 2.8 he's trying to give away.

[www.mgexperience.net]

Jim

Hello Ed, welcome to the world of modified LBCs. As you already know I have some experience with the Spridget chassis and engine swaps. The choice of power plant is wide open, but the modifications to the chassis get quite involved with some selections. If you consider the bellhousing diameter, engine length, and height and look at the limitations imposed by the footwells and steering rack there aren't a lot of choices which won't require a lot of cutting and welding. It's been a while since I saw the Ford V6, but I measured a lot of engines before I settled on my GM 60 degree V6 and if I remember correctly the Ford was a bit long to fit between the footwells and the steering rack. How much modification you can stand to the footwells really depends on how tall you are and what size feet you have, for me at 6'4" and size 12s I didn't want to reduce the footwell size at all if possible and I managed to do that with my swap. I like to keep the tires tucked into the body if possible with just minimal flares. For a Spridget you will have to have a rear axle narrowed, there just isn't anything that narrow that will work well in stock form. I chose a Chevy 10bolt from a Monza as the lug pattern was the same as the Midget and I could continue to use the wheels I already had for the car. I'm no longer a fan of tube shock conversions, although I built my own for the rear of my car if I had it to do over again I'd stick with the lever arms front and rear. A good set of rebuilt levers from Peter Caldwell (World Wide Auto Parts) along with the stiffer TR6 valves should be just fine for a little sprinter.

Making bends for a roll bar requires special tooling which isn't cheap. Probably better to farm that part out to a local race car shop. Let them bend and fit the main bar and any others requiring bends and then you can fit up the straight bars at home. I used a main hoop I picked up at a local swap meet, the rest of the bracing is just straight sections of DOM tubing.

I can't see any benefit in making the rear suspension into the later half eliptical spring arrangement. That would require additional reinforcement on the rear side of the axle that really isn't needed. Instead you could probably build a nice 4 link arrangement using the stock spring perches and upper bar mounts along with some coil over shocks. Something along the lines of the 4 link kit developed for the MGB by Bill Guzman (Classic Conversion Engineering). You could easily tie the rear braces for the main hoop into the crossmember where the coil over shocks would mount and have a really nice solid package.

Don't let the rear be too high like the red Midget with the blown Chevy in the Newsletter, Spridgets don't have any adjustment for caster so if you get the rear too high the car will be really squirrely.

I'm not a fan of automatic transmissions in Spridgets. Nothing against the auto box, it's just that most of them are pretty wide and the Spridget chassis derives quite a bit of it's strength from the section between the firewall and the center crossmember. With an automatic I think you'd have to move the main rails out quite a bit and that would require both substansial reinforcement as well as reduce your leg room in an area where most really don't have any to spare. Do some careful measurments before you decide. Most of the time a manual 5 speed just makes sense from the size standpoint.

By the way, the little V6 used in the Jeeps and Isuzu is from GM and basically the same as that used in the Camaro and S-10. The best of the lot would be the 3.4 liter from a later model Camaro. Largest displacement, good rear oil seal, and good heads and cam. Hard to beat and usually available at a reasonable price or as Curtis said as crate engines from GM.



Edited 1 time(s). Last edit at 12/31/2008 12:30PM by Bill Young.

Welcome and all great advise came before me. Let me add just one thing: TO keep it inexpensive, or at least as much as it can be when retrofitting something, you can purchase an S10 with auto or stick, TBI or carb and start to fit everything out of a 2.8L V6 pickup. I agree, just about any auto is wide. The shifter may or may not be wrong from an S10 in a Midget. Its wrong for an MGB but it all depends on your engine location and what sheetmetal will be altered.

The Ford engine was a great choice but they were not nearly as common as the GM RWD 2.8, 3.1 and 3.4L V6 ever were and since the GM versions are newer, this makes it an even larger gap between the two. There are plenty of other issues that make the GM a better conversion tool in my opinion as well but the Ford can be a nice conversion when you find all the pieces.

No axle is narrow enough but there are a few guys here that can say more about that subject. I have heard of RX7 axles, Ford, Vega and GM 7.5" axles being used for Spridgets.

-BMC.

Ed, I found an interesting item in my latest catalog from Speedway Motors, a realitivly inexpensive tube bender that you could use to bend up a roll bar and cage if you want to do your own. [www.speedwaymotors.com]
This is the least expensive unit I have seen so far and appears to be pretty well made.

Thanks for the "welcome"...but mostly thanks for helping us head in the right direction!

For years we have farmed out tasks like bending bars...the Speedway unit is reasonable and we run many products we buy from these guys. Thank you, Bill.

There are numerous 2.7 GM engines: I think that being a little "old school" I would prefer a carb. There was mention of the automatic trans being too wide: will it fit in the Midget/Sprite engine bay without compromising the wheel wells?

I saw Bill Guzman's Ford...what was epecicially amazing were the headers! Can you please discuss headers on the 2.7 in a Midget/Sprite engine bay?


Thanks...Happy New Year to All!


ed

Ed, the GM V6 clears the fender wells and foot wells in a Spridget very well unless you set the engine back and down to clear the hood. Your choice. It's been done both ways, I chose to leave the engine a little forward and high and modifiy the hood instead of the chassis or footwells. Headers will have to be fabricated. Because of the steering shaft I couldn't find any combination of stock manifold that would clear and from the looks of the headers such as the ones sold by Bill Guzman for the MGB swap they wouldn't clear either. It's not hard to fab up the headers though, these were my first attempt and I think they worked out pretty well. One of the nice things about the GM V6 is that the exhaust ports are round and the bolt pattern is so simple, I found two hole flanges in the JC Whitney catalog along with some U bends and that and some sheet metal to form the collectors from was all it took.
If you want to keep the engine simple, carb and ignition,then I'd say look for a 3.4 RWD engine, an early 2.8 intake manifold, and then you can use an early S10 non-computer distributor and a Holley carb adaptor from Bill Guzman. Makes a real nice high torque package that would make a Spridget fly.
As far as the various types of GM 60 degree V6s there are really only two types, either one designed for a rear wheel drive installation or one for a front wheel drive. The difference is in the motor mounts and starter locations. Either would work, but I think it's easier to work with one designed for RWD. There were three basic displacements 2.8 liters, 3.1, and 3.4 liters, although I believe that only the 2.8 and 3.4 were made in RWD configuration, the 3.1 was only a FWD engine. Early engines before 1987 had a slightly less advanced rear main seal, so for that reason the later engines are prefered. Also from 1987 on all of the RWD engines had the larger valve heads, so there's really no good reason to use an early engine.
As far as the automatic trans, it's not clearance with the foot wells or fender wells that I worry about, but interference with the front main frame rails. These are only about 18" apart and most automatics are wider in the pan area than that, so the rails would have to be modified. That area winds up being between the foot well box section and the center crossmember and that area of the chassis does handle a lot of the stress. If you start cutting in that area make sure you reinforce it well. It's also just about the area of most drivers thighs and knees so making the transmission tunnel any wider at that point can severly impact driver comfort.
I made up a quick drawing of the area I'm talking about.





Edited 3 time(s). Last edit at 01/02/2009 05:31PM by Bill Young.

The litttle Ford Zetec will make from 135 to 250 hp. The weigh remains almost the same as the 948cc so off the shelf suspension componets can be used. The only cutting to the tub is notching the frame rails for the bell housing, removing and replacing the front crossmember and enlarging the shifter hole. The foot wells and the trans tunnel remain intact. I'm at 180 hp, switch the cams if you want, the next step up is 210hp. This thing runs with my Porsche 997 C-2 until 80mph.

If you are sold on a GM V6 there are actually man choices depending on what exactly you are looking for and what you want to spend. My first choice would be a 4.3 but you would have fitment issues. as mentioned above you have the 2.8 and 3.4 motors. There are also some Buick v6 motors that I have been told are really good for taking modifications. All these would be great carb motors.

If you want to get into more money and fuel injection there are only 2 I would choose from, not because they are bad engines just for these being the best choices for power. Again the 4.3 is he first choice. It would be a good amount of power and readily available. They are easily modified as well but again fitment issues. My second choice would be the 3.6 that is used in the new CTS. It is a aluminum motor so it would be lighter than most others. If you can get the direct injection motor you would be looking at 300 hp. The issue I would see is the 6 spd auto. I have never actually seen one but I am guessing it is big. The cost of finding one of these would be high as well if you can find one. I have found one and it was $6k for the motor, tranny, computer and wiring.

If you are willing to go to a 4 cyl there are many choices. You can find these as back as the '60s in the Chevy II up to the S10, these would all be carb motors and lower hp. Then you can get into the Ecotec motors that can be adapted to rwd and can be found in Cavaliers and many of the mid size cars.

As far as transmissions go the smallest ones I know are the powerglide and the TH200 if you need the auto. I have a TH200, I can grab some measurements off of it if you need me to. I picked it up as a package deal but I have no idea what they would have come in.

Jason, good ideas but with any OHC engine such as an I4 or V6, its going to be taller. This is why the OHV 2.8, 3.1, and 3.4 look so good. Less top end room needed. The I4 can look good this way because the fuel system is off to the side, but sometimes the top of a OHC/DOHC I4 can be taller from the top of the cam cover to the centreline of the crankshaft. All these idiosyncrasies are what determines lots of factors in a conversion. If outer sheetmetal is of little concern, HEMI may be the answer, and believe it or not, there is a Bugeye somewhere out there with one it it!

BTW: I like the idea of the 2010 Camaro V6. 3.6L DOHC 300 BHP stock. The issue of course will be the size and adapting the PCM.

-BMC.

The Camaro/CTS 3.6 motor is fairly decent sized as far as I can remember. I am sure once you loose the a/c and power steering pump that will help with space concerns a little.