Restoring a Tecumseh - another way

cfh

Well-Known Member
#61
The orange HS40 tecumseh with the 1" PTO shaft needs to be turned down to 3/4". In order to do this, the crankshaft needs to be removed. And while we're at it, we'll remove the tecumseh governor. All the internal parts that is, per the suggestions by others above.

Since the block is already stripped of parts, including removing the flywheel, this is pretty straightforward stuff.

1. drain the oil! I guess if you're just removing the governor, you could skip this step (and just have the motor angled so the oil is towards the flywheel side case.) But since we're removing the crank too, the oil needs to come out.

2. If you have a 1" PTO, it's not a bad idea to clean up the entire length of the PTO. The side cover will come off easier. I used some 100 grit sandpaper to get the rust and crap off my 1" pto shaft.

3. with the engine angled towards the flywheel at about 45 degrees, remove the eight 3/8" size bolts that hold the PTO side cover. The angle will keep what oil is in the block towards the flywheel side, instead of dripping on you!

4. I use a rubber mallet and hit the sides of the block cover near the oil input holes, to break the seal and split the case. Usually that knocks the cover loose enough so you can wiggle the cover off, and slide it off. Like i said, if you have a 1" PTO, the side case cover will come off harder, than say a 5/8" or 3/4" PTO engine.



5. With the side cover off, you can see the plastic governor gears on the side cover. Mentioned above, the plastic gears can get hot and melt, especially if you're like me and sub'ed the governor spring with a straight wire. There are two small C clips holding the plastic governor assembly to the side case. Remove the clips and remove all the governor parts.



Below is a picture of the removed governor parts.



6. The metal shaft (which held the plastic governor gears) can stay in the side case. My guess is some people will cut it clean to the side of the case. But i don't really see the need for that. Likewise, the "L" bracket on the right wall of the block (which connects to the exterior governor arm) can also stay. These things are just "hanging in the wind" now, and don't touch anything. I guess if you want to go to a more simplified throttle system, you could remove the "L" bracket, and plug the block hole. But i don't really see a need for that personally. I'm sure others may have a reason for removing these two items though (feel free to chime in.)



The purpose the L bracket was to ride on the governor gears (which are now removed). So again, you can remove it, but they you'll have to modify your throttle system and plug the block hole. Not that this is a terrible thing to do, but i'm not sure there's really a big upside to it.

In the above picture you can see the connecting rod is unbolted, the cam and lifters removed, and the crankshaft removed. That's because we are now ready to put the crankshaft in a lathe, and turn the PTO side down from 1" to 3/4", and re-cut the key way.

 
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cfh

Well-Known Member
#62
Instead of trying to find a 3/4" PTO crankshaft, just went with cutting the original crankshaft down from 1". Won't be any confusion on part numbers that way! Here's the original crankshaft in the lathe getting cut down:





Here's the finished product, with the PTO trimmed from 1" down to 3/4". We're ready to put it back in the block and tighten it all up.

 
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#63
I like your work... However, as one that also rebuilds to period correct restore on these motors. I just can't get over the powder coating! BITD if you asked to see Tecumseh powder coating line they would have looked at you like your from back to the furture.
 

cfh

Well-Known Member
#64
I understand but powdercoat gives a very nice look and is extremely durable. Paint to me is temporary. Powder coating is much more robust. If I didn’t tell you what was powder coated you wouldn’t of been able to figure it out. trust me. It looks just like Paint and is it available in about as many colors and textures and glosses. It is more futuristic but again, if I didn’t tell you was powder coated, I seriously doubt you would’ve been able to figure it out

To that point also, I think a lot of people are being rather hypocritical here. No motors were painted from the factory with basecoat clearcoat. They certainly were not using clearcoat urethane on any motor. Yet some guys think that’s all great. I would call that hypocritical because there’s no way in hell that that’s original either.

To be "original" i guess you need to use a spray and baked enamel. No one is using that. So to that point, nothing is really "original" here.
 
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cfh

Well-Known Member
#66
I played around with some different spray can paints and their resistance to gas. I sprayed these and let them dry 24 hours. Then a put some gas on the tin, used a rag to spread it. The epoxy on the right has the best resistance to gas (for a rattle can). I did not try basecoat/urethane clearcoat. I bet that is better still. What i wanted was something from a spray can that has decent gas resistance. I thought the hammered white would work well, but frankly it did not.

Obviously powdercoat is probably the winner to gas resistance, followed by urethane basecoat/clearcoat. But again, i wanted something from a spray can that had some sort of gas resistance. I should say that nothing from a rattle can will be totally gas resistant, not even the epoxy used here. But of the rattle can paints, the epoxy is a decent compromise, compared to mixing a 2-part urethane or doing powder coat.

 
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pomfish

Well-Known Member
#67
First off, great work on the lathe.

However, When you can buy Comet clone 1" torque converters for the same price as 3/4" or less, why go to all the trouble to turn one down to 3/4" ?
It's still not going to be factory correct and you spent a lot of time=money doing this.

I used to not buy engines with 1" shafts because the clutches cost $85-$100, but then the clone belt drives came out and have gotten cheaper and generally work very well if you use a better belt, I am all about 1"engines.
Thanks,
Later,

Keith
 
#68
How about acrylic enamel? Different than what was originally used, because you're chemically curing the enamel instead of curing it in an oven? This is a single stage coating used by many of us here and in other disciplines. Nearly fuel proof, or highly fuel resistant.

How about urethane? Also single stage, also highly fuel resistant.

The appliance "epoxy" above is an enamel, not an epoxy- despite what is on the can. Kinda like the words "fuel resistant" which also don't mean anything.

If you want to powder coat, powder coat. Your earlier statements concerning paint being a thing of the past flies in the face of the very large, multi-billion dollar industry that uses it from aviation to custom car building. Yes, frames have been powder coated for decades. So what? Paint fumes kill? Don't use it, or use the proper respirator. A two stage job too shiny? Add dulling agent to the urethane clear. Still too shiny? Use one of the several available "hot rod" matte finishes.

And finally, we DO weld on our tins. It isn't difficult.

Stop lecturing please. Many of us enjoy doing our own work, our own way.
 

cfh

Well-Known Member
#69
I’m not lecturing I take offense to that. As stated at the very first post, this is an alternative way of redoing a motor. Again as stated in the first post, I’m not an expert on these things, this is just how I’m doing it. Is it different than what you guys do? Probably. But as stated, it’s an alternative way. The title of the post even says it's an alternative way. If you can't deal with it, then don't read the thread.

I’m just making observations about Paint. Paint provides a chemical adhesion to the metal. Powder coat gives both a mechanical and chemical adhesion. That’s why it’s more durable. If you don’t like it, that’s fine. Use paint. More and more things are moving to powder coat though. It is environmentally much more friendly and more durable. It basically looks the same as Paint, unless you don’t want it to

If you take the solids from Paint and add some metal to it, that is more or less what powder coating puts on the electrically charged metal. It is then baked at 400 to 500°, melting the plastic onto the freshly sandblasted metal. Really it’s not that much different than Paint except for the heat process and lack of solvents. In the end, you’re putting plastic on metal. Just one uses a solvent and the other melts it on.
 
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cfh

Well-Known Member
#70
Got the metals back from the powder coat guy. i have some assembly work to do now. Note i don't use gloss and i don't use bright white. i like the look of off-white, especially when putting a motor on a "survivor". Bright white is too new looking (after all these are 30-45 year old motors.) And gloss finishes on motors don't wear well, and get easily damages (making all that work for naught, if you're using/riding these things.)

 
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#71
Didn't go through this whole thread...but using 2k Clear Coat helps ALOT. Gives it the shine it needs and hardens very nicely and keeps it 'mostly' fuel resistant. It's the only thing I use nowadays. I also use Dupli-color. The other thing is to SODA BLAST your block and head fins etc...Then you get a PERFECT finish, YES the paint sticks. If you want to really do them right, then the prep work is everything. I also use screen printed decals as they were in the 1960's/1970's. IMG_1611.JPG Aspera for TX-3 Dad (1).JPG
 

cfh

Well-Known Member
#73
Jeff one of the things about this thread is to minimize the use of paint. I choose powder coating. It 100% resists gas and is far more resistant to scratches then paint. Also i don't like gloss finishes nor bright white on motors. But that's me. You can get white done bright and glossy in powdercoat. i just choose to not do that. It costs the same in a gloss finish.

The problem with gloss finishes is they show every defect in the metal, and they also scratch easy too. Basically it's not a very durable finish choice. That's why i go with an off-white matt finish. It just doesn't show scratches and dirt as much. Now if you're doing a show finish bike, then yea do that gloss finish. But i ride my bikes, i don't show them. i just want them to be durable and look good for the long haul, and minimize the maintenance.
 
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cfh

Well-Known Member
#75
I don't powdercoat the head bolts. i use paint for that. anything on the head i use paint (easy to touchup with a small paint brush). I could try powdercoating the head bolts. maybe that would be a good test. but i think anything you put a wrench on is going to scratch, probably no way around that. the torque from the wrench will comprise pretty much anything. but next time i powdercoat though i'll try it and see how it goes. I will test it for worst case scenario with a socket with many points
 
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#77
One option to welding is low temp brazing. A larger patch on the back, braze, filling with brass. Less heat, less warpage. Even solder, lead or silver would work. A lot of people I know that weld a lot ignore brazing. Not sure why as it does some things better than welding. But I also like your quick, easy fix of a sticker. We are not restoring a Stutz Bearcat for some elite car show. Thanks for the write up!
 
#79
I love powder coating and use it ALL the time...in fact many of my mini bike frames are powder coated...but its much tougher for an engine due to the process and thickness as well, esp for the fins/block. Plus it's harder to match the block color after the shroud has been powder coated. I try to go as close to the original color as I can get...
 

cfh

Well-Known Member
#80
Jeff are you powder coating the engine itself? I have not tried to do that. I just do the removable metal pieces. And then I paint the fins. I have a good paint color match to my powder coater’s color.

My powder coat guy will not do gas tanks because he says the solder can melt and ruin the tank. I will ask him about brazing. but I think that melt temperature is higher than 500°, which is the maximum the powder coat guys use. I’m not sure the melt temperature of silver solder.
 
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