IN AN article on combustion chamber design in the June '54 issue of MOTOR Life, I pointed out that Chrysler's hemispherical chamber would likely be more limited on compression ratio in the future than the wedge-type chambers of G.M., Ford, and Studebaker. This is because of the very wide flame-front angle around the spark plug, with its attendant fast combustion pressure rise and high peak pressure; on paper-and according to some published test data-the fuel octane requirement at a given compression ratio is higher.
In view of Chrysler's jump from 7 1/2 to 8 1/2:1 compression for '55, I contacted their engineering department on the matter. It looked to me like they would be on thin ice, especially after sonic carbon build-up. Their reply was interesting and significant. They admit that pressure rise and peak pressure are high, but introduce an entirely new angle: With present gasolines and engine designs, it is likely that pre-ignition will limit compression ratios before detonation. (Preignition is self-ignition of the fuel-air mixture before the arrival of the normal flame front; detonation is an uncontrolled explosion of the unburned portion of the mixture.)
In the case of pre-ignition Chrysler claims they'll be in a better position than the wedge-chamber devotees. This is primarily because there is less tendency for the intake fuel-air mixture to pick up beat by scrubbing against hot spots in the cylinder oil the intake and compression strokes. The mixture has a more direct path into the cylinder with inclined overhead valves, and there is less surface area per cu. in. of volume to scrub against. Makes sense.|
Time will tell the story.
CHEVROLET makes a big point in the literature on their new V-8 that the exhaust cross-over pipe passes under the engine instead of over it, like Ford. This does much to hold down the underhood air temperature, which, in turn raises the effective power and torque of the engine on the road. This makes a lot of sense. Engine output is a function of the density (lbs. per cu. ft.) of the intake air, and raising temperature reduces the density. From this angle it's not inconceivable that the hot exhaust cross-over pipe right in front of the carburetor on the new Ford V-8 could cost them 8 or 10 hp on the road! It would be interesting to run some tests.
THE recent adoption of ball-joint front suspension throughout the Ford organization-and now the use of it on the '55 Chevrolet -- focuses attention on this interesting new trend. In an SAE talk by Archie Colwell. V.P. of Thompson Products. he predicted that ball-joint f.s. would sweep the entire industry within four or five years! (Thompson makes the joints for Ford Motor.)
I can't see why not. Functionally. they're far and away superior to the usual knuckle layout. There's no suspension bind, less friction, automatic take-up for wear, more usable space at the front end, lighter weight, and there are fewer lubrication points. Furthermore -- and I think this is really the clincher -- you just about have to use ball joints if you set your front suspension up to give an "antibrake-dive" effect . . . that is, lay out the suspension geometry to give a resisting moment to the pitching of the front of the car on hard braking. (This is much too complicated to go into here, but I'll discuss it in MOTOR Life soon.) Anyway, Chevrolet is featuring anti-brake-dive for '55 with their ball joints, and I think you'll see a heavy swing this way on other makes.
The main objection to ball joints up to now has been cost. It was rumored that Ford had $20 more in their new front end than with the old knuckles. That's not good. They were a hot sales point, though, and this might have compensated. But I have a lot of faith in the Chevrolet cost department; if they've passed on ball joints you can bet your life they've pretty well licked the cost problem! (Incidentally, it will be interesting to compare Chev's new joint with Ford's Thompson unit.)
Speculation on Packard's new V-8 engine design is running wild. Rumors and counter-rumors have gotten all tangled up so John Q. -- and even some industry bigwigs -- are hardly even sure Packard will have a V-8 ready for '55. The fact that the Packard organization has tried harder than ever before to keep this new model a deep, dark secret hasn't helped any. They may even have tossed out some counter-rumors to foul things up. One thing is certain: If even haIf the rumors on the new engine are true, it will rock the industry.
In the face of all this the editors of Motor Life have asked me to dig out all I can on it and get it to you -- fact or rumor -- as soon as possible. Which puts me on a spot, because I don't have any guaranteed pipeline to the inside either! I call only piece the story together from unofficial contacts and hope for the best! Anyway, this is it -- and I hope nothing I say will be used against me:
In the first place, there will definitely be two engines. They will actually be the same basic engine, but with variation in bore, stroke, carburetion, and compression ratio to give a "small" one and a big job for the senior car models. The small Packard V-8 will rate 175 hp and is scheduled to be used in the junior Packard models, Hudson DeLuxe Hornet (and Possibly some smaller Hudsons), Nash Statesman, and possibly the Kaiser. I don't have any details on this engine. However, I can't help but wonder if maybe this rumored "small" Packard engine isn't actually the newly announced 175 hp Studebaker President. (This is the same basic engine as brought out in 1951, but with the bore increased 3/16" -- 259 cu. in. -- a 4-barrel carb, and larger valves and ports.) Studebaker has the capacity to produce this engine in considerably greater quantity than they're using it, so it seems possible that this may actually be the small V-8 that will be peddled to some of the other "independents."
And there's the big engine. The kingsize puzzler here, of course, is that aluminum block business. There's been a very persistent rumor floating for many months on this. I've heard it from several what I consider quite reliable sources. One is tempted to hope that where there's smoke there's fire! But the Packard factory denies the aluminum block rumor emphatically . . . definitely not, they say. The fact that they've been working a couple of years on big wet-sleeve aluminum block diesel engines for the Navy would seem to suggest that maybe it's just a rumor after all. So, as of right now, I guess the weight of evidence is on the side of the conventional cast iron block . . and I'm afraid I'll have to back down off my limb of two months ago (Oct. '54 Motor Life) and call it cast iron for '55!
On the side, though, it's a well-established fact that development on aluminum cylinder blocks for passenger cars on a production basis has come a long way in the last year or two. Alcoa is experimenting with a process whereby the block and heads are die-cast, or permanent mold cast, in sections, after which the sections are furnace-brazed together. As this is written the Doehler-Jarvis machine builders are just completing the construction of a huge 72 inch die-casting machine that can turn out complete aluminum engine blocks on a production line. They admit they're shooting at Detroit with it!
Well, even if we forget the aluminum business, the new Packard V-8 still shapes up as a pretty shattering piece of machinery. They tell me the Packard engineers have designed the thing specifically for a potential 400 hp in a production version on pump gas! Bore and stroke of the big engine are rumored a square 4 x 4" or 402 cubic inches! (The factory admits it's big, considerably bigger than Cadillac and Chrysler's present 331 cu. in., but won't give a hint as to just how big.) In this day of inflated advertised power ratings and power-consuming accessories, inches are the only thing you can really bank on to give that kick on the road that the slide rule says you should get. The new Packard will have 'em . . . with corresponding peak torque probably in the neighborhood of 375-400 lb.-ft. Advertised horsepower will be de-rated down to a "loafing" 275 for the '55 models.
The statements I made in the Oct. '54 Motor Life about the rumored valve layout have been substantiated from another Source. I look for two camshafts set high in the V, operating inclined valves through very short pushrods and rockers. Roller lifters are a possibility!
As I said, Packard is knocking itself out to keep this engine covered up. There's a lot at stake. Coupled with their torsion bar suspension, the '55 Packards bid fair to upset the industry overnight -- and maybe put them back up with the big boys again. In line with this they will hold off introducing the new models until after the first of the year, when the announcement can drop like a bombshell, after most of the rest of the makers have made their splash. Since the big engine will also be supplied to several other makers, this will probably mean holding them back too. The latest dope is that the big Packard V-8 will go into a new Hudson Super Hornet series, the Nash Ambassador, and a special line of Studebaker coupes to compete in the "sports car" market with the Chev Corvette and Ford Thunderbird. That should be a goin' bunch! (Ed. Note: See, "Small Bend's Secret Speedster" Dec. ML)
And that about bleeds me dry on the Packard rumors. Take it for what it's worth!
AFTER all the speculation that the Kaiser-Willys combine wouldn't show with 1955 models or, if they did, the introduction dates would be late, K-W just announced 1955 models. Or at least they're telling their sales force about the '55s. Plans for first view of the cars call for small conventions (of sales personnel around the country and introduction of those models by a special, international closed-circuit television presentation. The show, first of its kind for this type of promotion, will originate in New York, go out to 22 cities here and in Canada. All of this news comes as such a surprise (new models are generally talked about months before their introduction up here) that I'm betting on minor facelifts and some chrome gadgets to comprise the change for '55 in these models. But K-W has done some surprising things, could prove me wrong.