45 Engine Rebuild, Could Use Some Guidance

[Rex]

Starting this thread to seek help on my final project, rebuilding a 45 engine.

Page 18 in TM 9-1879 specifies the valve springs shall be at least 2 19/32” and provide 95 to 105 LB resistance when compressed to 1 7/8”.
My springs:
#1: 2 22/32” 117LB
#2: 2 22/32” 115LB
#3: 2 22/32” 115LB
#4: 2 22/32” 118LB
According to the specs they’re all 3/32” too long and 10 to 13 LB too strong.
valve stem length.JPG

My valve stem lengths when measured as shown here are as follows:
Front Intake: 2 23/32”
Front Exhaust: 2 26/32”
Rear Intake: 2 23/32”
Rear Exhaust: 2 25/32”
Can anyone tell me what the distance as shown would be for stock new valves and cylinders that haven’t had the seats reground would be? I don’t know how much my seats have been ground so I can’t tell if I should leave the extra spring length to compensate for the stems hanging out longer than stock, grind these springs down to spec or get new ones.

Is it possible these are just the wrong springs?

[Rubone]

What year engine? Early and late springs are different.

[Rex]

1937 cases, 1963 cylinders, single shoulder guides.

[BigLakeBob]

I checked 4 used '41-'73 springs and get 2 11/16 free length and 115lbs @ 1 7/8 compressed. Checked new '41-'73 springs 'Made in USA' from Eastern and get 2 11/16 free length and 110lbs @ 1 7/8 compressed. So about the same as you. Coil bind happens about 1 3/4".

[T. Cotten]

Valve stem heights themselves tell you little, Rex!

Please find a light spring, such as from a hydraulic wheel brake cylinder kit, and assemble it upon each valve with its collars in order to measure the actual installed spring height for each assembly.

Then measure the spring pressures at those heights.

Normally they need shimmed up to equal preferred a pressure, but you may need the option of grinding the springs shorter.

....Cotten

[Rex]

Valve stem heights themselves tell you little, Rex!

Please find a light spring, such as from a hydraulic wheel brake cylinder kit, and assemble it upon each valve with its collars in order to measure the actual installed spring height for each assembly.

Then measure the spring pressures at those heights.

Normally they need shimmed up to equal preferred a pressure, but you may need the option of grinding the springs shorter.

....Cotten

That sounds like a good method & something I'd like to do. I have a drawer full of miscellaneous springs for hit and miss engine governors that will be perfect for this.

Will post results upon completion.

[T. Cotten]

Meanwhile, Folks,...

What is the 'preferred' spring pressure upon the seat for an HD 45" with stock cams?

Can we back-calculate from service specs?

....Cotten