AMC history (Buick/Jeep V-6)

[farna@xxxxxxx]

The GM V-6 has the "AMCish" oil pump because the Buick V-8, from which the V-6 was derived, is made that way. So it would be more correct to say AMC has a "Buickish" oil pump. 

Jeep was using the even fire V-6 under 231 inches (226??). Kaiser-Jeep continued the engine as it was when they got the tooling from Buick with no changes. I'm not sure AMC cast ANY new blocks -- they used up the stock of parts in a special model CJ (the first Wrangler, maybe??) for 1971, and may have used it in the 72 Commando as well (don't have my Jeep books handy for exact dates/models). In any case, once the stock was used up they didn't make any more, and made no changes. When Buick got the tooling back they made the changes, more cubes and that awful odd fire crank to begin with. My ex wife had a Pontiac Sunbird (78 or 79) when we met with that shaking odd fire in it! Timng chain noise and vibration were always a problem with it. Don't know when GM wised up and started making a new crank for even firing and smoother running. I still don't knwo the theory behind the odd firing order to begin with! 

As for the rotary... as John Mahoney mentioned AMC signed a licensing agreement with Curtiss-Wright in 1973. CW had exclusive north american (or was it just US?) rights to the rotary engine, so GM had to buy a license from them also. As you know AMC was always short on funds in the late 60s through the 70s. They couldn't afford to tool up for a new engine and new body at the same time, especially not with double digit inflation starting in the late 70s. So they signed an agreement with GM to purchase rotary engines for at least a few years ( I don't knwo how long). This benefitted GM because they could start building a high number of engines from the start, bringing down their per unit costs. GM had problems getting the rotary to meet upcoming emission standards and asked congress for a temporary stay on emissions for the rotary until they could solve the issues. Congress said no, GM said screw it and wrote the whole billion dollar project off, leaving AMC hanging with a car!
  designed around the compact rotary and no engine. Mazda solved the immediate emissions problem by mounting a chamber that burned up excess emissions inside the exhaust, right behind the manifold. Just inject some air and the stuff will burn in the chamber before it gets pushed out. Simple and effective. I don't think the newer rotaries have that chamber though. 

The rotary had only two real advantages: compact size and fewer moving parts. In theory it would be cheaper to build than a reciprocating V-8 as long as production numbers were high. It also fit in a smaller space for the same amount of power, and had a bit of a weight advantage. Other than higher emissions it had another disadvantage -- it burned the same amount of fuel for the same amount of power as a V-8. Only the weight advantage helped mileage any, and that was no more than 1 mpg, certainly not enough to retool. The production savings wasn't that great in the short term because of all the new tooling. Long term it would be, but the engine was so different few of the existing tools could be modified to work -- almost all new equipment was required. This is why many engines, like the AMC V-8s and sixes, share common bore centers over different models and years -- the same machining equipment can be used with slight modifications to fixtures. The only way to really take a!
 dvantage of the rotary was to design a car around it, like AMC did with the Pacer. Put the rotary in a standard front engine car and the only difference was you might be able to get by without power steering because of less weight on the front wheels. Power felt different, as the rotary has a steady thrust rather than a surge,but that was all. GM wasn't ready to redesign the fleet for an unproven engine, and they weren't ready to build another Corvair (unique engine and parts for one or two models is very expensive, compared to many platforms sharing a few common parts, the main reason the Corvair was discontinued). 


From: "Geoff Harrison" <geoff_h@xxxxxxxxxxxxxxxx>
To: mail@xxxxxxxxxxxx
Subject: AMC history
Date: Fri, 25 Feb 2005 08:26:48 +1100

Hi all, in a recent post there was mention of AMCs dealings with GM in 
regard to Buick V6. (and also Mazda rotary)
Does any one know what AMC did in the way of development of the V6. I 
understand when GM took it back it was different. The oil pump looks very 
AMCish for one. And I believe the engine grew a few cubes. Some reference I 
have seen states the balance shaft in Mitsubishi 4s in under licence to 
Chrysler. So did AMC put the balance shaft in? I don't know if the 225 V6 
had the balance shaft.

If AMC did do some mods, we could say AMC has been living under our noses in 
disguise.

Regards to all,
Geoff

Geoff Harrison IT Services.
Port Macquarie  NSW.
Tel 65827181



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