John Deere Model D engine compression

Tnbshr · Jun 24, 2020

Does anyone know what the engine compression should be on a 47 model D? Also the flywheel is cracked and has been repaired can a flywheel from another tractor be used or would that cause a balance problem?

buickanddeere · Jun 24, 2020

Certainly get rid of the cracked flywheel before somebody is crippled or killed .
Factory All Fuel compression was a feeble 3.91 to 1 and made 42HP at the pulley .
With High Compression Gas pistons and a cold intake/dual exhaust and a few other tweaks . It will approach 60HP.

buickanddeere · Jun 24, 2020

https://www.tractordata.com/farm-tractors/005/6/8/5683-john-deere-d.html

Tnbshr · Jun 24, 2020

Thank you. If I were to do a compression test on the engine want would be the acceptable range?

GreenEnvy · Jun 24, 2020

Gas equipped Ds according to JD gave them more horsepower then the R.

WeirdDeere · Jun 24, 2020

Deere service bulletin 181S lists for the D:

Cranking at 105 RPM
Pressure of 62.5 PSI

Hope yours is electric start! Hand start, you aren't going to check it!

You can substitute flywheels no problem as long as it's the same part number. Make sure to line up the marks for proper balance and timing. Some flywheels have a bigger spline to match a screw in the crankshaft that sticks out slightly. Make sure that the pin used to drive the oil slinger (it's on the crank behind the flywheel) is good. Check your flywheel splines and your crank splines to make sure they're all good. Consider new bolts, and don't be afraid to crank on em, I would normally say torque them but that's hard to do on a D!

Brandon

Tnbshr · Jun 25, 2020

(quoted from post at 19:56:04 06/24/20) Deere service bulletin 181S lists for the D:

Cranking at 105 RPM
Pressure of 62.5 PSI

Hope yours is electric start! Hand start, you aren't going to check it!

You can substitute flywheels no problem as long as it's the same part number. Make sure to line up the marks for proper balance and timing. Some flywheels have a bigger spline to match a screw in the crankshaft that sticks out slightly. Make sure that the pin used to drive the oil slinger (it's on the crank behind the flywheel) is good. Check your flywheel splines and your crank splines to make sure they're all good. Consider new bolts, and don't be afraid to crank on em, I would normally say torque them but that's hard to do on a D!

Brandon

Thanks Brandon

John Deere Model D engine compression

Tnbshr

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buickanddeere

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buickanddeere

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GreenEnvy

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Tnbshr

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