1/2 be variant

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errolmcgill

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1628009975732.jpeg
Has anyone done this?
Removing front section allows:
1 use of roller bearings
2 integrating PSRU by adding a gear to the crankshaft and adding a stub axle coincident with the camshaft
 

Flyguyeddy

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The camshaft cannot take those loads. Are you wanting to use the standard cam gear and crank gear as a psru on the end and not use the cam as the shaft?
 

TFF

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Continental had an engine like that. They will not acknowledge it was their engine anymore. The Tiera. What happened in practice was the prop, depending on if it was driving or being driven, would throttle the engine because of play on the cam gears. The prop would advance or retard the cam timing like VVT except the wrong way.
 

TiPi

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Worst part is that you would need a 2:1 gear ratio, a big no-no for gearings. They should always be an odd number (fraction) between them to ensure that each tooth is meshing with every tooth on the other gear over time and not stuck with the same ones. That's why every geared reduction drive has quite a few decimals in thhe ratio number. The cam gearing and some other timed events are the exception but none of them transfer any significant loads.
 

Pops

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Where is the oil pump ?
 

errolmcgill

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The cam is not in communication with the stub prop shaft. The crankshaft driving gear is one tooth greater than the standard cam driver and the prop gear is one tooth less.
Not shown is the front cover\bearing plate that also serves as the engine mount with the bearings and thrust surfaces functions.
The smaller oil pump will be driven from the opposite end of the camshaft as is the ignition trigger.
 

Kiwi303

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Worst part is that you would need a 2:1 gear ratio, a big no-no for gearings. They should always be an odd number (fraction) between them to ensure that each tooth is meshing with every tooth on the other gear over time and not stuck with the same ones. That's why every geared reduction drive has quite a few decimals in thhe ratio number. The cam gearing and some other timed events are the exception but none of them transfer any significant loads.
Thats why on the gear drive cam systems you find for smallblock V8's from racing and parts stores come with two intermediate gears between the crank and cam gears. they're not direct mesh, even cam gearings shouldn't be 2:1 even when cam timing needs 2:1

They are generally some ratio like 20 crank/40 cam/17 intermediate.


s-l640.jpg
 

errolmcgill

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To clarify, the crankshaft has the original timing gear and a second PSRU gear.

In the photo, the aluminum disc represents the driven gear.
 

Chris Matheny

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Thats why on the gear drive cam systems you find for smallblock V8's from racing and parts stores come with two intermediate gears between the crank and cam gears. they're not direct mesh, even cam gearings shouldn't be 2:1 even when cam timing needs 2:1

They are generally some ratio like 20 crank/40 cam/17 intermediate.


View attachment 113964
The reason they do not mesh them directly isn't for reliability, its because the gears large enough would not fit in the timing cover and the cam would be turning the wrong way if they did. Look at the Ford 300 inline 6, had a direct gear to gear 2:1 gear drive and was one of the most reliable setups produced.
 

TFF

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The idle gears also are to keep the camshaft rotating in the correct direction. Old Chevy marine engines had two gears and special cams. With picture above, all normal cams on the market should work, and if you are racing, you will be experimenting with cams a lot.
 

Geraldc

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Thats why on the gear drive cam systems you find for smallblock V8's from racing and parts stores come with two intermediate gears between the crank and cam gears. they're not direct mesh, even cam gearings shouldn't be 2:1 even when cam timing needs 2:1
Also they replace a chain drive.
 
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