80" scraper

[Gone Looney]

I have a 1945 set of chief cases with t&o 80" flywheels. Question: has anyone done this type of set up and what did you use for a flywheel scraper or oil pickup? Thanks

[tfburke3]

You can modify your cases to accept the 47 scraper.Cases must be notched out to fit,or can run the stock earlier pick up tube sump valve set up but not as good as the 47 scraper.(at least the factory seemed to think so)
Tom

[Gone Looney]

Doesn't the factory scraper hit the flywheels though?

[1950Panhead]

No, .010" clearance, skimming, not scraping.

[Gone Looney]

Right I just thought because the flywheels we're bigger it would actually hit on the scraper and I thought they were made out of aluminum so they couldn't be bent,is that right?

[tfburke3]

The factory 80 and 74 wheels are the same diameter.The scraper is steel,and doesnt need to be nor do you want to bend it.
All your work will be to modify cases.
Tom

[Gone Looney]

Ok cool,are the t&o flywheels bigger around than stock?

[Chris Haynes]

T&O should bolt in to your cases.

[hairynob24]

as far as i recall its the rods are set at a different height ,flywheels are the same

[Gone Looney]

That's what I was thinking,the pin hight was different but I didn't have a stock set to compare to,thanks

[kitabel]

The crank-pin offset (center of the driveshaft to center of the crank-pin hole) will always be 1/2 of the stroke length.
Chief 74: 2.219"
Chief 80: 2.406"

[cdf6333]

Just in case nobody told you, the inside tops of the cases have to be cut to allow for the larger swing of the rods for the longer stroke. The best way to do this is assemble the flywheels and then insert them in 1 case and put a piston and cylinder on. Remove enough so they can turn plus about .020". Then just match the other case to that one.
Do not forget to do this or the motor will turn once and lock up.
I just found the instructions I used to send out for this.

To modify 74” cases to accept 80” flywheels and/or special rods:

1. Put the drive and pinion shafts in each 80 flywheel. They don’t have to be tight or true.

2. Put the crank pin in a flywheel, again, snug is OK.

3. Put the rods and rollers and cages on the crankpin

4. Put some roller and cages on the drive or pinion shaft and place the flywheel into the case
half you’re working on.

4. Put a 80” piston, which is shorter than a 74 piston, on either rod. Put a cylinder over the
piston and finger tighten the 2 base nuts.

5. Turn the flywheel and look at the front/rear and center of the case, below the cylinder mounting area for rod clearance. Remove the corner which hits the rod with a rough file until the rods have about 1/16” clearance to the case. See the picture below of where to look.

6. Then put the piston and a cylinder on the other 2 studs and check the other side.
Repeat with the other case half and you’re ready to go.

[Gone Looney]

Thanks,I've already got the bottom end together and did all the clearancing