clocknut

My Feedback: (6)

Just picked up what I hope to be is a new project its a 77cc engine made by Chrysler I think for a trolling motor.A friend of mine went to a sale and bought this for me he said they had several but didn't know for sure if I could use it.The engine is double ringed and has a domed piston it weighs about 5 pounds.The only problem I see is that the threads are left hand threads? I check the rotation by the pull starter before i disassembled it and it goes in a counter clock wise direction.Does anyone recognize this engine ,has anyone converted this engine and what about the left handed thread?Do I turn the shaft down and re tap it?I measured the engine with out taking it apart so the 77cc is just a close call.
I would be thankful for any help you could give me.
Thanks
clocknut

Scota4570

The threads on the flywheel side are left hand? I see left hand threads on the back side all the time on chainsaws, that does not matter because you will probably cut that off anyway. The left thread on the drive side would screw tighter in to whatever it was spinning. If you have to you can bore left hand the threads using a lathe. Actually left hand threads are easiar when working in a hole because you don't have to guess where to stop. You start in the hole and the tool emerges. You will be using a CDI ignition? In that case the flywheel goes in the trash and the threads will be right hand, normally. If they were backward the hub would not be self tightning. That might be a problem. Looks like a fun project.

tkg

My Feedback: (1)

This thing is pre internet so there may not be much on it.
Try King Bee, Power Bee and West Bend

clocknut

My Feedback: (6)

I will be using the fly wheel side as that is the side that turns in the correct direction and cutting off the other side so I do have to deal with the left handed threads. And yes I will be using electronic ignition or could go with gas /glow,as I have had good luck with that on some of my other engines and I need to cut down some of the weight.
Also I don't know if you noticed or not but there is a plate on the other side of engine to move the carb to the other side if need be.What if anything would happen if you did this?
tips and suggestions are all welcome.
Thanks
clocknut

clocknut

My Feedback: (6)

had I posted the picture that shows the plate you might have noticed
So do you think this engine would be a good candidate for conversion?

arobatx

The weight doesn't sound bad for a 77cc engine, if that's what it is. There's not a lot of unnecessary metal for you to cut off, and it looks like a mount would be a snap to whip up. Already has a two needle carb with a choke...it has peaked my curiosity

Did I understand you correctly? You are going to use the threaded shaft at the exhaust end of the cylinder for your hub? I'd certainly be more inclined to use the tapered shaft on the other side, to keep the exaust located conveniently. Properly timed, the engine should run any direction without trouble.

Ralphbf

My Feedback: (27)

My thinking says Exhaust in the rear Carb. on the side.

Carbs. never go on the front.

clocknut

My Feedback: (6)

Sorry no, I will be using the tapered shaft side which also has the left handed thread.carb on the side exhaust in the rear.Yes the mounting looks like it will be very easy.One of the questions I had was how to deal with the left hand threads?I will be taking it apart and getting a good measurement to get the actual cc's and doing what ever I have to to make a prop hub and deal with the threads and removing any weight that I can.This is a new engine and has never been run so it should make a good conversion if I can get everything figured out.

arobatx

...you could 'key' the shaft and hub. Looks like there is plenty of weight in the OEM ignition. Send a PM to TKG, get setup with some EI components. Would make timing easy too when you reverse the rotation. Not sure what you want to invest though.

rangerfredbob

My Feedback: (13)

Av8tor gave me the idea once to cut off the stub that's left hand threaded and drill into the crank (with the crankshaft chucked up in the lathe) and tap the snout and install a stud, this takes care of the issue, I've done this once but haven't ran the engine.

arobatx

I like that idea better!

clocknut

My Feedback: (6)

Yes I can do that cut off the threads and drill and tap it.I can also mount my prop hub and true it up while the crank is in the lathe.
Yes my engine is probably heavy but it is a conversion engine and you have to give a Little to get a Little.I could just trash it like the last guy and go out and buy a DA like everyone else but this is more fun and rewarding to me.
Thanks everyone.
clocknut

arobatx

Around 5 lbs with OEM ignition for a 77cc single is NOT BAD at all for weight....especially a conversion. I hope you keep updating this thread, I'm anxious to hear how this one turns out.

clocknut

My Feedback: (6)

Well I took off the fly wheel ,coil, and point bracket,cut off the other shaft and lost 2 1/2 lbs. so the engine is now under the 5 pounds we talked about but then I have to add ign,muffler and prop hub.the tapered shaft on the front is going to work out good as the cam for the points was just a sleeve and came right off of the crank shaft so I have a lot more to work with and I won't be worried about cutting off the threads and drilling it.
Now I have a bigger problem it looks like I'm going to end up with a good engine here and I don't have anything to put it in Unless I put it in my 1/4 scale Waco which now has a G62 in it.One thought the auction here is coming up the 18th of this month Oh what should I buy???
I will post more pictures and up date as soon as possible.
Thanks
clocknut

arobatx

Boy that's a horrible problem to have You're not alone buddy!

clocknut

My Feedback: (6)

Well i took my engine apart and started working on it.I remeasured it and found to my surprise that it is a 82cc not a 77cc it has needle bearings on the crank side and the top side.It has a aluminum rod with a steel insert that the needles lay on.I have removed the left handed threads and started drilling the crank and done some measuring for the prop hub.I will post more as soon as I can get back to it.

clocknut

av8tor1977

My Feedback: (6)

If I am understanding you correctly, the crankshaft has needle bearings both front and rear. If that is true, you will need to come up with a way to deal with the thrust loads. If there is room, or if you can make room, you can use bronze washers to withstand the thrust of the prop pulling, and/or the use of a starter.

AV8TOR

clocknut

My Feedback: (6)

Sorry Av8tor I must have stated that wrong, the crank has ball bearings! The rod is the part that has the needle bearings on the crank and on the piston pin.
clocknut

clocknut

My Feedback: (6)

pictures might help[8D]
clocknut