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Lycoming 4 Cyl engine

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There is another angle I don't think anyone has mentioned. Cars in the twenties didn't rev that fast. First gear was just for getting moving, you got into high as soon as possible and stayed there. Cruising speeds in the early twenties were 30 - 45 MPH. 50 MPH was burning up the roads and 60 was going a mile a minute or going like sixty, very fast indeed.

 

If the vibration does not intrude until you get going 50 or more, it may be characteristic.

 

But if it vibrates to an objectionable degree at 1000 RPM something is wrong. A 4 cylinder car of that day may not be perfectly smooth but it should be capable of normal road speeds without scaring you.

Edited by Rusty_OToole (see edit history)

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A search turned up this information on the Gardner car.

 

"

In 1923 Gardner took the four cylinder engine to a level never seen in the auto industry.  The redesigned Lycoming engine for 1923 had 5 main bearings, and no four cylinder car had it except Gardner.  At 43 BHP it was also the most powerful 4 on the market. 

rs-01_260x207.jpg Best said by Menno Duerksen (Aug '72 Cars & Parts)

... But the builders of the Gardner-Lycoming went even beyond that.  In addition to the five main bearings to reduce vibration, the crankshaft and flywheel were statically and dynamically balanced.  The pistons and connecting rods were carefully weighted and matched.  The engine even included a feature the Willys-Knight sleeve valve engine used to improve lubrication of its intricate sleeve system when operating under heavy loads.  This was a valve connected to the carburetor throttle, which

caused the oil pump to deliver more oil to the bearing, under pressure, as the load on the engine increased.  There is little doubt but that Lycoming and Gardner had indeed come up with one of the most powerful, smoothest and most efficient four cylinder engines ever produced up to 1923....""

 

It seems they went to a lot of trouble to make a high grade 4 cylinder engine. It should be exceptionally smooth for a 4 cylinder, smoother than cheaper cars like Ford and Chevrolet. Contemporary ads quote prices of $1100 to $1200. This would put them in a class with medium priced cars like Studebaker, Hudson, and Nash most of which were going to 6 cylinder engines. You would expect them to go all out for smoothness and power if they wanted to compete.

Edited by Rusty_OToole (see edit history)
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On 18 June 2018 at 11:34 AM, Rusty_OToole said:

A search turned up this information on the Gardner car.

 

"

In 1923 Gardner took the four cylinder engine to a level never seen in the auto industry.  The redesigned Lycoming engine for 1923 had 5 main bearings, and no four cylinder car had it except Gardner.  At 43 BHP it was also the most powerful 4 on the market. 

rs-01_260x207.jpg Best said by Menno Duerksen (Aug '72 Cars & Parts)

... But the builders of the Gardner-Lycoming went even beyond that.  In addition to the five main bearings to reduce vibration, the crankshaft and flywheel were statically and dynamically balanced.  The pistons and connecting rods were carefully weighted and matched.  The engine even included a feature the Willys-Knight sleeve valve engine used to improve lubrication of its intricate sleeve system when operating under heavy loads.  This was a valve connected to the carburetor throttle, which

caused the oil pump to deliver more oil to the bearing, under pressure, as the load on the engine increased.  There is little doubt but that Lycoming and Gardner had indeed come up with one of the most powerful, smoothest and most efficient four cylinder engines ever produced up to 1923....""

 

It seems they went to a lot of trouble to make a high grade 4 cylinder engine. It should be exceptionally smooth for a 4 cylinder, smoother than cheaper cars like Ford and Chevrolet. Contemporary ads quote prices of $1100 to $1200. This would put them in a class with medium priced cars like Studebaker, Hudson, and Nash most of which were going to 6 cylinder engines. You would expect them to go all out for smoothness and power if they wanted to compete.

Like Bud has said in previous reply I have been rowing fairly hard but have only found a few things to try which I will be doing this week. I was hoping that a Lycoming owner may have come forward but not yet I have made a request through the Gardner registery

that may bring up something else.

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On 17 June 2018 at 3:03 AM, Rusty_OToole said:

It is possible to have a 4 cylinder motor perfectly balanced for primary vibration and still have a bad secondary vibration. The manufacturers went into this very carefully back in the day, adjusting the weight of the pistons, connecting rods and crankshaft to get the least vibration. This point is often overlooked at rebuild time. Your pistons may be a "one size fits all" casting of a different weight from the originals. This alone will cause vibration.

 

I suppose these days all the calculations are done by a computer program. There are places that balance motors for race cars, I wonder if they have a way to calculate the balance factor of a long stroke 4 cylinder motor.

Rusty 

Thanks for your reply about secondary balancing I have done a lot of reading in the last weeks but have been un able to find a fix method for the old long stroke engine do you have anything up your sleeve that I can do. It's a bit strange that you mention about the secondary balance because two of our club fellow members talked about the speed of the vibration when looking at the car with me they thought the vibration was faster than engine rpm' that was before you put up your reply . It was also suggested that the exhaust could be causing part of the problem so I fitted a flexible joiner and mounted the rest of the system on rubber straps. But nothing changed.

I still haven't had any contact with a fellow Lycoming owner they must be out there.

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Secondary vibration occurs at twice engine speed so if they felt the vibration was faster than engine speed that would fit. I am not a mathematician, or engineer.

 

Does the crankshaft have counterweights? A lot of early cars didn't. I know that English motorcycles with vertical twin engines, did not have perfectly balanced engines. If they balanced out 100% of the primary vibration they would get a terrible secondary vibration. So they only balanced out 70% to 80%. This meant the engine vibrated but at an acceptable level. Then they damped out that vibration by the way they mounted the engine (not on rubber). I mean where they positioned the engine mounts.

 

If the engine is meant to be mounted rigid it must be rigid. No loose or missing bolts, no missing engine stays. Any mistake here can multiply vibration.

 

All these things have to work together. That is why it is so important that everything weigh the same as original. As the only thing you have changed is the pistons I suspect they are not the same weight. You could make a monkey out of me by weighing one of the old pistons and comparing it to the new ones, if you still have the old pistons. I can't imagine why you haven't bothered to do this, when it would answer your question in minutes.

 

In the meantime you might look on the internet for engine balancing articles. The math is well known and has been since the steam engine days.

Edited by Rusty_OToole (see edit history)

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As for why they stuck with the 4 cylinder. Back then a lot of experts felt the 4 cylinder was the best performing engine as well as the simplest and most practical. 6 cylinders had been around for some time but the first ones were disappointing in power. They were smoother than a 4 but produced less power than a 4 of equal size. They had V8s too but they had little advantage over a big 4 cylinder since they had a 4 cylinder type crankshaft and a vibration period to match. The straight eight was not out yet, the first one in mass production being the 1923 Packard.

 

It is entirely logical that an engineer would figure he could design a really good 4 cylinder that would match the 6s and 8s for power without sacrificing smoothness and have the advantages of simplicity, ease of service, and low cost.

 

Overlooking the point that it would soon be impossible to sell a 4 cylinder car when everyone else had 6 or 8 cylinder engines.

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2 minutes ago, Rusty_OToole said:

As for why they stuck with the 4 cylinder. Back then a lot of experts felt the 4 cylinder was the best performing engine as well as the simplest and most practical. 6 cylinders had been around for some time but the first ones were disappointing in power. They were smoother than a 4 but produced less power than a 4 of equal size. They had V8s too but they had little advantage over a big 4 cylinder since they had a 4 cylinder type crankshaft and a vibration period to match. The straight eight was not out yet, the first one in mass production being the 1923 Packard.

 

It is entirely logical that an engineer would figure he could design a really good 4 cylinder that would match the 6s and 8s for power without sacrificing smoothness and have the advantages of simplicity, ease of service, and low cost.

 

Overlooking the point that it would soon be impossible to sell a 4 cylinder car when everyone else had 6 or 8 cylinder engines.

 

I agree. That was a problem that Stutz, Mercer and several other builders of expensive four cylinder cars found. Also Bentley in the UK.

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A quick search turned up this video explaining secondary vibration. Your engine guy should know this if he builds racing engines.

 

 

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"the crankshaft and flywheel were statically and dynamically balanced" This may be where your vibration problem comes from. It was common practice to fit the flywheel to the crankshaft and machine and balance them together. After that they were a matched set. If you changed either you had to start over to true them and balance them again. This also means if you take the flywheel off you have to put it back on the exact same way. If they are held together by 6 bolts and you don't mark them it is likely they were put together wrong and that is enough to throw the balance off.

 

You may have to strip the engine and balance the crankshaft and flywheel again.

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