Restoring a Tecumseh - another way

[Skipp]

What type tap did you use...bottoming or plug? Thanks for your time....

Thanks

Dave

Now for the last thing, what about drilling/taping the PTO? You know, so you can put on a clutch and bolt it in place (opposed to set screws.) This is pretty easy. The PTO is cast steel, which in reality, is pretty soft (and self lubricating while drilling.) Since we're going to go with a 5/16-24 screw size, you'll need a 5/16-24 tap and tap handle. You'll also need a couple drill bits (1/4" and 17/64", though technically, it's really a letter "I" drill bit, but 17/64" works fine.)

You also need a centering tool. I bought mine from McMasterCar for $15. It works well and is drilled for 1/4". (insert name of tool and part number here.) You just slide the tool into an old clutch, put it on the PTO, and drill 3/4" deep into the PTO shaft. (The clutch is just holding the tool in place, it serves no other purpose in this exercise.) Then remove the clutch and tool, and use the 17/64" bit to enlarge the hole slightly. Then tap it with the 5/16-24 tap. Now your PTO is ready for a clutch. All you need is a 5/16-24 bolt and washer.

 

[cfh]

Sorry forgot to respond on this...
It's called a "drill bushing" and it's available from McMaster Carr.

You want 3/4" outside diameter (so it fits inside the clutch), and 1/4" inside diameter (because that's the size drill bit you want to start with.)
#8493A074 $15.22

Now if you're drilling a PTO that is 1", you'll need a different drill bushing (with a 1" outside diameter, and a 1" clutch as the holding tool.)

 

[Skipp]

thanks made one....using 2- 3/4 inch locking collars instead of the clutch....seems like its going to work ok....just curious about type of tap....maintenance guys at work are telling me to use a starter tap then a bottom tap....i was going to use a plug tap does it really matter? and why 24 thread...can you use 18? Thanks for your time

Dave

 

[cfh]

5/16-24 thread seems to be the general accepted thread size. I use a standard tap. The advantage to a bottom tap is it goes all the way with threads to the bottom of the hole. That would be needed if you drilled a shallow hole. But i go about 1" in. If the threads are only 3/4" deep, that's fine. Also make sure after you do the initial 1/4" drill into the PTO that you follow up with the "I" or appropriate drill size for the tap you are using. (it will be just slightly bigger than 1/4").

 

[Skipp]

Thank you very much...I just grabbed the 17/64 bit so I’ll begin...thanks again

Dave

 

[massacre]

Finer theads are usually less prone to backing out due to vibration. At least in my experience.

 

[cfh]

I was at the powder coater and they had just done an entire race car in white. it's not the total gloss white, but it's what i would call "semi-gloss" (opposed to my stuff which is matt off-white). but you can see there are varying degrees of colors/gloss. you just tell them what you want. Race car guys use it because powder coating is far more durable than paint and 100% resists fuels.

 

[Havasu Dave]

They're using the PC as a primer. Pretty common method now days for race car chassis. The quality isn't there for bodies, as it is too prone to orange peel. It is also very prone to chipping because there is no flex in it.

In this case, I would imagine the car will sport sponsor logos and graphics via a wrap.

 

[massacre]

Wow that is crazy I have never seen a race chassis powder coated like that.
Wonder if there is a weight difference between PC and paint?

 

[Havasu Dave]

Wow that is crazy I have never seen a race chassis powder coated like that.
Wonder if there is a weight difference between PC and paint?

It's very common, and it's much easier than painting as well as more environmentally friendly. Since beautiful bodywork is not a consideration with race cars, this is a viable method of coating for owners, especially because they can use wraps, then campaign the car for a season or two, peel the wrap, and sell it, and move on to the latest technology.

For those interested in powder coating their mini bike, OldMiniBikes Member OND did a beautiful job on this Lil Indian during the build off. He powder coated the engine and small bits himself.

https://www.oldminibikes.com/forum/vbrides.php?do=viewride&rideid=580

 

[massacre]

Yeah the wrap thing makes sense
Whenever I see late models/street stocks, they end up spending more time in the wall than they do on the track. 50 lap race= 30 caution laps lol
Which is why I was wondering but with a wrap it makes more sense

 

[cfh]

Never really wrapped this up, so thought i would...

Here's the 1978 Tecumseh H35 "side popper" all done. I have a youtube video of it running linked below too. Frankly i'm not sure what to do with this motor. It's a nice machine, new points/condenser and carb, 3/4" PTO that is drilled/tapped. Most removable metal is powder coated. The rest is painted. It runs really well but i have no use for it.

Youtube: https://youtu.be/c5zYz17YJ_0

 

[ole4]

Nice job!!

 

[Sunnyknoll]

CFH; I have the 1979 "brother" to that motor. Was used for shop classes in a school up in Vermont. Supposedly has somewhere around 10 hrs. on it. Has one small dent in the fuel bowl. Not sure if all those bowls are the same. Would you happen to know the part# for that? Thanks.

 

[cfh]

I do not have the part number for the carb float bowl. Frankly i don't mess around with carbs, i just buy new ones, as they are really inexpensive on ebay.

Here's the 1978 HS40 Tecumseh motor, also shown in this thread, now finished. If we all remember, the PTO shaft was originally 1" diameter. Turned it down to 3/4" and re-cut the keyway. The shaft is 3" rupp length. I'm kind of thinking i screwed up, and should have colored the motor black! the governor (interally) was removed. Again all removable metal was powder coated, and the other stuff painted with the appliance "epoxy" paint.

 

[cfh]

Here's the last motor in the thread to be completed, a 1970 Tecumseh H50 "fat boy" motor.

On this motor i can't really fathom why i should used this on my Gilson/Chalmers bike. I know it's the original motor, but this thing is a pain in the ass. An Hs50 would be a lot nicer me thinks (though not original.) Is there any clear reason to use the "fat boy" H50 on the Gilson?

Note i have adapted the more modern Tecumseh 730136A mini-bike throttle assembly to this motor. I had *most* of the original mini bike throttle parts for the H50, but not all of them. And i don't think there was any hope of finding replacements. So i went with this throttle system. It works very well, but it does require the internal governor to be removed.