Would this be wrong?

There's a beautiful '73 GTV for sale. Nice body, rollcage, Konis, all freshly built and semi-stripped - about the same as the GRM car was. It's just missing an engine and transmission.

Would I be a terrible person if I stuck a Miata engine in it? I'd build a high-compression one with throttle bodies for maximum sparkle. I'd end up with the great Miata transmission, a vintage looking engine (especially if I grind the valve cover smooth), solid reliability and possibly more power than originally.

Yeah, it would be wrong. It really needs a V6 out of a Milano.

Keith: "Would I be a terrible person if I stuck a Miata engine in it?"

Yes. What more reason do you need?

I'd say it depends... if you can swap in the Miata engine/trans into it w/o a lot of cutting, thus allowing installation of a proper Alfa drive train at a later date, then go for it.

Yes it would be wrong.

Do It!!!

Hmmm. I tend not to look at it from an 'ethical' point but a common sense one. It won't be really any more powerful than the Alfa engine (less?). It won't reduce the weight (Alfa is all aluminum engine). It may reduce the initial cost, but Alfas really aren't expensive to maintain from the engine bay...they are pretty well built. Alfa engines aren't hard to get (plenty of rotting Spiders in the world). The trans would arguably be an improvement. However...when you go to sell this thing, unlike a Miata powered MGB, your're not going to find many buyers after doing all the hard work of the swap. Alfa owners are pretty anal about purity. And, the thing would be legal for about...nothing, except a truly uncompetitive autocross class. Simply doesn't sound like a good business plan to me, regardless of the car you'd wind up with from a driving standpoint.

Keith: Wrong? Yes, but only on the CMS site. As a for a Grassroots approach to the car "Go for it".

Ron

From what I could tell, it could be more powerful even in stock form. The 1750 engine was rated at 132 hp, while the Miata 1.8 ranges from 128 to 142 - and is gross vs net HP going to come in to play there? I don't now. If I did pop in some high compression pistons and the set of throttle bodies that are on my desk, I'd definitely have more power than a stock Alfa and the engine would last for a loooong time.

Legality doesn't interest me. My local autocrosses work on the NASA system which makes a lot more sense than the SCCA morass. I don't have the tracks to race wheel-to-wheel. So it would be a fun car. Something with a bit of style but the reliability and manners of a Miatas.

It's probably not going to happen. It's just that this GTV showed up not all that far from here and I have a real weak spot for these cars.

What did the CMS Alfa sell for? Anybody know?

We love Alfas and we love Miatas.

Separately.

:)

-BaT

I'm going to also say wrong! I love both too, and currently have a Miata, but I've owned dozens of Alfas in the past, including GTVs, and the Alfa motor does indeed have more potential for power, and vastly more torque. All of the various sizes interchange fairly easily, it's all aluminum, and it's sleeved, so blocks theoretically never go bad. Pistons usually come with liners, so you simply change it all out.

Until the Miata came out, most transmissions in the sports car world were gauged against the Alfa, it was usually thought to be one of the nicest shifting cars out there, second gear crunch excepted.

Properly engined, GTVs are rising at an extremely fast rate, with a Miata engine, I would imagine it to be almost worthless.

So lets see, heavier motor, less hp potential (unless supercharged), makes the car worth a lot less. :grin:

Oh, and properly maintained, Alfa engines are really very reliable. Electrics on the other hand can have grounding issues...but that's a different story!

So Mazda hasn't figured out yet what Alfa knew in the 1970 when it comes to engine design?

What's different about it that makes it such a powerhouse with vastly more torque? I'd love to see examples and compare it to what's in my garage right now. I'm genuously curious - maybe I can learn something to help my poor Miatas.

With the current rising spirit of hybrid technology, I say go for it.

Keith, I will say a definate yes. This is no different than a Miata powered MGB GT.

The question is, do YOU want to do it? Let's face it, you are a project driven guy. If you are up to another project and would like a car with a roof to go with the roofless sum'bishes in your driveway then you have your answer.

Colorado. A mere 1350 miles from Edmonton :)

The Alfa's safe, I'm not going to go for it. Not from lack of desire (and a strong temptation to stick it to the purists) but from a lack of time and funds. Although I'd certainly enjoy it a lot more than the new pickup my wife wants me to get.

I'm still curious about the Alfa engine in general. What sort of power/torque numbers can it make - realistically, running 91 octane pump gas and with a 100k mile lifespan? Does anyone have dyno numbers? What does it weigh?

Hm... think I have to disagree there. A GTV is worth a lot more than a BGT... but more importantly the Miata drivetrain is a big improvement over the B-series engine... not so much over the sweet Alfa twin cam.

I'm no purist and definitely no opposed from that point of view, but like the others I think you would expend a lot of effort and end up hurting the value of the car...

Bill

Resale value means nothing to me, by the way. It's a car, not an investment. Even if I rendered the car completely unsaleable and had to crush it (obviously an extreme example), it would cost me about the same as buying a soulless new car and driving it for a year.

On some cars I have to agree with you Keith. This would be one. I share that attitude in that it's my car and I'll play if I want to. OTOT, I've no made permanent changes, welding or cutting to my TR3, just in case the next owner wants to build a trailer queen.

Will there be a next owner? Right now it looks like that will be one of my kids, they are ready to fight over it, but only time will tell.

Jack

Jack

I don't have the numbers in front of me, but I'd have to say first off, it has more displacement to start with at 2 liters, and I think the stroke is not nearly as square, with the bulk of their power much lower in the rev range. Torque figures are nearly double the Miata I believe. They can still be made to work very well up high also. The four cylinder range of motors of that vintage are basically adaptations of their former Grand Prix motors. In race trim, it was not uncommon to see them north of the 250hp mark naturally aspirated.

An interesting side note, Mazda used the Alfa motor as one of its "copy" designs when building theirs for the Miata, Protoge, etc, or so I've read.

In any event, the Alfa motor was greatly ahead of its competition back in the day, when the British were using what basically amounted to tractor blocks in their sports cars. By comparison, Alfa was using all aluminum, double overhead cam motors derived from Grand Prix cars. You simply don't have as much to gain from a motor swap.

Another interesting side note; the first manufacturer to use variable cam timing in a production car: Alfa.

Now if you were to take a less than stellar example and restore it with a 13b turbocharged rotary, I'd be a lot more interested!

Boy, if I had a dollar for every time I'd read that Mazda copied someone else for the Miata :nice: The engine was basically a development of the old GLC engine. Not quite 1960's Grand Prix, I'll admit. The valve cover was definitely Alfa-inspired though. Anyhow...

According to the CMS website, the 2l engine in their GTV was rated at 134 ft/lb at 3000 rpm along with 130 hp at 5500. I'm assuming those are the 1974 numbers, so I don't know if they're gross or net or how they compare to modern ones.

A 1999 Miata (1.8) is rated at 119 ft/lb at 5000 rpm and 140 hp at 6500. I know the Miata doesn't have a reputation of making a lot of torque, but I think "nearly double" might be overstating the case somewhat :) A set of cams from a Protege would bring the torque down lower.

Of course, I have a Miata engine in my garage right now that makes significantly more than that, probably due to the higher compression and 2.0 displacement I stuffed inside.

250 hp (crank) is plausible and not out of line for a Miata engine, albeit with considerable work. Then again, I doubt the Alfa race motors quoted were stock either.

I just KNOW Per had to have put that Alfa on a dyno at least once.

Get him to 'fess up! Nice round rpm numbers like 3000 and 5500 make me think we're looking at factory quotes.

What was the selling price on that car, anyhow? Or is that confidential? I just want to know to torture myself.

We never got solid numbers for power and torque on the GTV after we fixed things..It started out in the 80s, then was in up in the 90s at the wheels...but we wound up with more than that (110?), our local dyno shop kept having ignition sensing problems. frustrating on many levels.

other than that, IMO, if you're going to do an engine swap, a twin spark is a good option.

15k

We used to have a Dynojet. Those ignition dropouts drove me crazy.

110 hp at the wheels would be in line with a 1999 Miata.

You are kinda asking for an apples to oranges comparison.

First of all, the Alfa motor was state of the art for racing in the mid 50's when introduced in the road car- aluminum head and block, replaceable iron liners, killer crank and oiling system.

Whereas the Miata motor is a derivative of a production motor- Iron block, heavy trans.

But.

The Miata motor WILL last 100k+ miles with virtually no maintenence, and pretty much maintain the power as designed. (I've got 148k+ on my '99)

Wheras the Alfa would have gone through a handful of head gaskets to do the same.(time for rebuild after 20k hard miles on my '74)

Basically, both engines have their strong points- but as far as technology or actual performance potential, there's no real comparison- the Miata is superior.

(note my name, too)

I'd bet it would be pretty hard to install the Miata into the GTV chassis. There's a guy installing an S2000 engine into his GTV- check the alfabb.com and there's a huge thread about it in one of the engine sections.

A better choice in this case would be the TS engine from a 75- they are becoming more plentiful and easy to import. For the cost and effort to install the Miata, you can make a lot more power with the TS motor (they are good to over 200 hp).

Some people will hate you, some will love it. It's your car, do what you will (yea, I know- you mentioned that you are not getting it- it's just my view).

Eric

Thanks, Eric. That link is perfect.

What was once state-of-the-art is now just normal. It's the sad truth for classic cars - and even cars that are just a few years old. EVO magazine has a test of the classic Lancia Delta Integrale Evo vs a bunch of modern hot hatches, and the editorial team has to do some fancy footwork to make the Integrale seem like anything but trounced. Even the legendary Porsche 959 has to bow to the current Porsche Turbo from what I understand.

Heck, the Miata engine is a boat anchor compared to just about anything with HONDA on the valve cover. When I've got some time, I'll read through all 20 pages (!) of that S2000 swap thread. It is a bigger engine than the Miata one physically.

One comment got my interest - what's the weight of an Alfa transmission? A Miata trans is right around 75 lbs which I always thought was pretty good.

I guess I shouldn't tell anyone about my deep desire to build a Hawk Stratos with an NSX engine, should I? :twisted: