A Few F20 Questions (Mag/Radiator/Fuel Tank)

Hello all.. I know I haven't posted in a while kind of leaving you all in the dark. I've been working little by little on this (these) F20 project(s), and have made quite a bit of headway. After pressure washing the block inside and out, I was able to get it very clean. The main bearings cleaned up real well, and I didn't end up having to pull the flywheel and crank (after thorough oiling, it seems to rotate very smoothly). I did pick up an extra pressure plate and clutch disc (with a couple spark advance linkages) from a gent about 2 hours from me. Other than that I have been working on honing cylinders, polishing the crank, adjusting the shims in the rods, and cleaning up the clutch components (as you can see from the pictures). By the way, if you have ever wondered about Evapo Rust, that stuff works (check out the pressure plate assembly)! Anyhow, here are my questions..

1) What do you typically set the tappet clearance to when cold? I should be ready to do that this weekend I hope. Most all of the parts I need should arrive by the end of the week.

2) When replacing the radiator overflow tube, what do you typically do? Here is my thoughts.. I have already removed and tapped the hole in the upper tank that it threads into. My brain tells me to get some copper tubing and a fitting to fit the hole that has an ID for the tubing to fit into. I'll slide it into the fitting that is threaded into the tank, and stop it about 1/2" from the inside top of the tank. From there, I will solder the tube in place in the fitting. Does this sound feasible to what you all would do?

3) One of the holes in the bottom of the magneto is stripped out. My thought is to drill and tap to the next larger bolt size - but I am concerned about the casing cracking (is there enough material there to support drilling to a large size)?

4) Also, I have to replace the bolts in the fuel tank straps. Any tricks to doing this? I am thinking I will just cut them off so that I can remove them, and then replace them from the bottom up (putting a nut inside the strap itself). Not original, but it will work I think. Thoughts?

Also, here is a link to my latest video in the F20 series. I hope you all enjoy.









1938 F20 Episode 9

A} Tappet hot .15 I go .02 over cold. B} Over flow tube I think I used 5/16" brake line and fitting worked soldered in.
C} you can fuss with the mag if you want plenty of tractor running out there with 3 bolts. D} if you spread the strap a little you can get the bolts out, I bought new bolts and ground the heads square as original were and put them in with new nuts and washers. oldiron29

Thanks for the input, old! You always are quick to help!

(quoted from post at 19:31:53 06/27/17) A} Tappet hot .15 I go .02 over cold. B} Over flow tube I think I used 5/16" brake line and fitting worked soldered in.
C} you can fuss with the mag if you want plenty of tractor running out there with 3 bolts. D} if you spread the strap a little you can get the bolts out, I bought new bolts and ground the heads square as original were and put them in with new nuts and washers. oldiron29

Click to expand...

Valve clearance is .017" hot, I go .019" cold and then re-torque the head when hot and readjust the valves to .017". On the stripped mag hole, I have repaired several of those with a 3/8" helicoil.

Thanks Kirk! And to be honest, I have never used a heli coil. I can imagine they are pretty simple? Just a drill and tap the hole, thread in heli coil, then cut off smooth with the surface... OR something of that nature, I would think...?

Pretty simple, yes. I bought a kit through my local NAPA auto parts store, which includes 8-10 helicoils (3/4" long I think) the special helicoil tap and a helicoil installing tool. You can get different length helicoils for different applications so you don't have to cut off excess length, it can be done but works better if you don't have to.

I had a magneto with bad threads in one of the four holes, so I just had 3 bolts holding it on. No problems so far, it's been 8 years. I reckon you could get away with only using only two of them as long as they are diagonal to each other, this would prevent the mag from moving fore & aft and side to side.

However, to do it correctly, Nebraska Kirk described the correct way to go about it.

Keep posting your updates, I enjoy following along with your project! Good work!