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I have just got done reading an article on the 1925 through 1933 Willys Knight Great Six Sleeve Engined Car.

The break in procedure of a new sleeve valve Willy's engine was as follows according to the article.

Willys-Knight recommended that the dealer fill the crankcase with 14 quarts of light oil and let the engine idle for five to 10 hours. Then the new owner was instructed to drive no faster than 25 mph in high gear for the first 1000 miles


John F. Shireman

14 quarts is a lot of oil--then and now. Wonder if that the normal capacity or something special just for break in. Always heard those sleeve valve engines were supposed to be better than "ordinary" ones. Sure doesn't sound like it if they have to be babied like that. Packard, in their 1928 manual, says prolonged high or low speed should be avoided for first 500 miles. On the Packard, wonder what is worse--lower oil pressure & splash from the idle & low speeds or the babbitt bearings suffering from high speed.

Since sleeve-valve engines are extremely tolerance-specific engines I would imagine that this was done so the engine could be properly broken in. Too much heat and too little clearance and I would imagine that it would seize the sleeves and break the cranks.

I've always wondered how well these engines would do if one was made out of completely modern materials with modern methods. Ceramic sleeves and high nickel cylinders come to mind here. Personally, I'd like to have one of the Knight V8 engines to play with, but those seem to be more rare than Packard V8 manual trans setups!

The sleeve valve engine was a very long lived engine, at its best when most engines were worn out, but not at its best when brand new.

In full power tests against a Cadillac V8 in the 1920s, on the dyno test stand, the sleeve valve engine was running perfectly and producing more power after 100 hours at full throttle than at the start of the test.

The Cadillac was a smoking clattering ruin, producing about 70% of its original power.

Sleeve valve engines have a lot of friction. Over time the parts get polished smooth and the friction is reduced, while carbon buildup actually improves the seal.

I would think the long idling breakin would polish the parts and encourage carbon buildup where it was needed. Basically accomplishing overnight, what would take 250 miles of driving at 25 MPH.

Another thing about sleeve valve engines, they are not at their best until completely warmed up and this can take a long time.

An old timer I knew used a Willys Knight as a tour car in the 60s and 70s. He told me that it would burn a quart of oil in the first 60 miles, the rest of the day, nothing. The next day it would burn a quart in the first 60 miles, the rest of the day, nothing, no matter how many miles he drove.

The big advantage of the sleeve valve was not just the silent running, but that it would keep running perfectly far longer than a poppet valve engine.

In addition to the higher mileage between overhauls there was the reliability factor of no burned valves or broken valve springs which were a common breakdown in those days.

For the high mileage driver this was ideal, and worth putting up with the problems of starting, and higher initial cost. But for most owners it was a waste of money.

The last new sleeve valve engines were the English Bristol aircraft engines of the late 40s. They produced some eye popping horsepower but never reached production as the first jet engines were coming in at the time.

This is the same firm that produces the Bristol sports cars with Chrysler engines.

If someone wanted to make a sleeve valve engine today they could make it with an aluminum block, chrome steel sleeves running on the aluminum, and aluminum pistons inside the sleeves.

It would be interesting to see how it worked. Unfortunately the weight of the sleeves would limit the rpms. But breathing and combustion chamber shape could be optimized over what poppet valves allow.

It might work better as a diesel than a gas engine.

The normal crankcase capacity was probably 10 or 12 quarts. A lot of engines held that much back then.

Friends

I've heard that the life of a sleeve valve engine could be in excess of 300,000 miles. One may have to open it up to put new rings in but must never touch the sleeves. I'm not sure what you do when the sleeves finally do go, I presume it's fatal


Gabriel Voisin in France was a proponent. Sleeve valve engines weren't supposed to be hot performers, but he made the observation that you could make the intake port larger that the bore and small numbers of sports and racing cars were built. He made aob ut 40-50 V12 sleeve valve cars, and I think 2 or 3 straight 12 sleeve valves..


There was a series of articles about Charles Knight in the Horseless Carriage [/[i]i]Gazette about 8 years back. I'm fascinated by sleeve valves but OH, that friction....


Regards


John Harley

Here is a little movie of a sleeve-valve lawn mower engine:

youtube.com/watch?v=q8XPuolEZ6Q

Voisin also found out you could run a much higher compression ratio in a sleeve valve engine because you could make the combustion chamber the perfect shape, and perfectly smooth.

He made his sleeves as thin and light as possible too.

One of the results of making the ports bigger, was that he reduced low speed power, like a ported 2 stroke. His engines would run up to 4500 RPM very high for a sleeve valve in fact, higher than most engines of the 30s. But low speed power was poor.