Another flywheel question

[JoshJ]

Lad's,

Just an enquire with regards to cast iron flywheels, from 1933 through to 1935 the flywheel part numbers for 350's (Except NH's) were as follows;

Timing side 1066-33 (Casting No: A8-152)
Drive side 1071-33 (Casting No: A8-153)

From 1936 and onwards the timing side flywheel Prt number remained the same however the drive side changed to Prt No: 1072-36 (Casting No: A7-566)

Does anyone know why there was a change in part numbers, what was the difference?

Cheers

Josh

[Simon.Gardiner]

By the late '40s the drive-side mainshaft number for all models seems to have had a 35 number, so possibly the change was standardise the mainshaft?

SG

[dave.owen]

Was it the year they went to two bearings on the drive side

[nevhunter]

They went to a bigger dia taper there somewhere. Nev

[Roger Gwynn]

The 1933 flywheel has a 3/16x32 tapped hole in the 12 o'clock position on the outside face of the crank pin hole (crank pin at top), this was only used in 1933 and is dropped from the later drawing. This was to lock the crank pin nut in place. The bigger change was in the diameter of the tapered hole for the spindle, from .872 to .996/.997 on the outer face, still with a 1 in 6 taper. This would move the same spindle .828" further in but the spindle did change, I hadn't realized that the size of tape must have changed as well as the length in order to accommodate the extra main bearing. Interestingly the only spindle listed in the 1936 parts book says 'VH only' , somebody forgot to alter the text from the previous year when only the VH had 3 mains. The early 2 bearing spindle 1140-26 has a shoulder, the later spindle 1140-35 does not. The re-design of the taper of the spindle to remove the pointless shoulder would be the reason for the change.

[JoshJ]

Thanks Rog,

The reason i asked this is because the flywheels i have are as per the numbers i gave above (Drive side: 1071-33/Casting No: A8-153 and Timing side: 1066-33/Casting No: A8-152).
The shafts in these flywheels weren't the best (Bearings slid on/off to easily) so i obtained some identical good/better shafts from a shop here in Perth. After a thorough cleanup of the flywheels including the sludge trap i installed these new shafts into the tapers and torqued them up to 60ft/lb however the key on the drive side shaft still protruded from the flywheel - it hadn't been pulled right in. On the old shafts the key had been "Cut" so it wouldn't protrude..i should have clicked when i spotted this.

So i think its safe to say that i have the wrong drive side flywheel for the drive side shaft that i have. I have the large taper (.996/.997) shaft however have the smaller taper 1071-33/Casting No: A8-153 flywheel when i should have Prt No: 1072-36/Casting No: A7-566

Here is a pic of how the key protrudes after installing the shafts to the flywheels and torquing them up, the shaft clearly isn't locating far enough inside the flywheel...looks like I'm on the hunt now for the correct drive side flywheel..!!

Thanks for your help

Josh