Author Topic: Thumper--a new 1 3/8" bore i.c. engine  (Read 6578 times)

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #90 on: March 24, 2020, 10:16:57 PM »
Hi Chris, good to hear from you. Admiral--it isn't really a linked connection. It is connected to the tail of the rocker with a pivot pin, but the bottom end of it is "free standing" in the tappet.

Offline Art K

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #91 on: March 25, 2020, 03:00:06 AM »
Brian,
Things are looking good the cam and rockers turned out well. I bet you don't notice a pea under your mattress either. I haven't heard much about Canada & whats going on with the Covid 19 but things are getting pretty serious here. I expect you have to avoid the mall now for your walk.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #92 on: March 25, 2020, 12:38:14 PM »
Art--it is bad here now. Many infected, quite a few dead. Wife and I are "social distancing", (Which isn't a great difference from the way we normally live) but we miss seeing the grand-children. I no longer walk in the mall, just on the roads around the sub division up behind our property. The bush trails are my favourite, but they are 8" deep in solid ice, too slippery for me.

Offline Admiral_dk

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #93 on: March 25, 2020, 10:12:02 PM »
Quote
It is connected to the tail of the rocker with a pivot pin, but the bottom end of it is "free standing" in the tappet.

Ahh that makes perfect sense now - thank you for explaining  :ThumbsUp:

I can see the problem with not being able to do your walks inside now the weather isn't nice for walking outside and being around other people isn't really an option too  :thinking:  I do hope that you find an useable solution to this problem too  :cheers:

Per

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #94 on: March 25, 2020, 11:18:10 PM »
Today I made funky little brass elbows. They are two part construction, silver soldered together. I did give them a soak in my citric acid solution, and scrubbed them with a small brass bristled brush, but I see in the picture that they still have a pinkish glow in spots. I will mix up a fresh batch of solution tomorrow and give them a bit more soak time. Tomorrow I will drill and tap the cylinder head and drill the exhaust and intake ports thru the cylinder head and thru the valve cages which are now loctited and lightly pressed into place. Every day I'm getting closer and closer to crankshaft time.
« Last Edit: April 01, 2020, 01:27:00 AM by Brian Rupnow »

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #95 on: March 26, 2020, 12:29:24 AM »
Today as I was making the brass elbows, I found myself wondering "what keeps the weight of the muffler or carburetor from making the elbows turn down, or "droop" when the engine heats up." There is no way that I can machine threads so that the elbows tighten up and "lock" in exactly the right position.----So--I went back to my 3D model for a closer look this evening. Hot Damn!!! I'm smarter than I thought. I had taken 1/4" thin hex nuts and retapped them for 3/8"-16 to use as lock nuts on the elbows to keep them positioned properly.
« Last Edit: April 01, 2020, 01:27:34 AM by Brian Rupnow »

Offline awake

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #96 on: March 26, 2020, 12:13:07 PM »
Brian, I take it that the thread on those elbows is 3/8-16? Not a tapered thread? I ask because I had wondered about threading these connections, but didn't know how well the intake needed to seal.

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Andy

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #97 on: March 26, 2020, 02:58:51 PM »
I don't use tapered threads. It is very important that the joints don't leak. I coat the threads with green loctite before assembly. This totally stops any leakage, yet is still easily disassembled.

Offline awake

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #98 on: March 26, 2020, 03:13:33 PM »
Thanks!

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Andy

Online crueby

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #99 on: March 26, 2020, 05:19:02 PM »
Brian, does the green loctite you use have a number? There are several that are green.  Thanks!

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #100 on: March 26, 2020, 07:23:23 PM »
Loctite #638--I use it everywhere. It is the only Loctite product that I have. it is wonderful. Today sees the engine completely assembled, except for crankshaft and flywheels. I have to make up some proper pivot pins with circlips for the rocker arms, but after I do that the crankshaft will be next. I am well pleased with things so far.---Brian
« Last Edit: April 01, 2020, 01:28:11 AM by Brian Rupnow »

Offline Art K

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #101 on: March 27, 2020, 02:26:58 AM »
Brian,
Are you going to make a built up crank, or turn it from solid.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #102 on: March 27, 2020, 12:07:11 PM »
Art--I think that I'm going to make a built up crankshaft.---Brian

Offline Craig DeShong

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #103 on: March 27, 2020, 12:48:24 PM »
Art--I think that I'm going to make a built up crankshaft.---Brian

Certainly a lot less ‘excitement’ in a built up crank  :embarassed:

Still following along :popcorn: :popcorn:
Craig

Offline Brian Rupnow

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Re: Thumper--a new 1 3/8" bore i.c. engine
« Reply #104 on: March 27, 2020, 02:45:11 PM »
Yesterday my rings came in from Debolt. They look good. They are exactly 0.094" thick. The grooves I cut in my piston with my 0.094" parting off tool are only 0.088" wide.  Not sure how that happened, but it should be an easy fix. The rings have a staggered lap joint in them, which I didn't know would be there, but I'm sure they will probably work okay. Some horrible economics are involved with these rings. Debolt charges $8 each USA money for these rings. Change that to Canadian dollars, pay tax on it, then pay for shipping. Ends up costing me $56 Canadian. This morning I machined and installed an ignition cam. I went to make proper pivot shafts for the rocker arms, but I'm having an issue with concentricity. I checked my lathe head-shaft and chuck, and it has 0.003 TIR, same as it had when I bought it. The main chuck will only close down to 0.150", so I'm holding an extra smaller chuck in the main chuck. I'm getting crazy concentricity results and I'm not sure why, but will probably figure it out after posting this. As of today, I've been machining on this engine for 30 days straight. I may soon take a break and start setting up my TIG welder.
« Last Edit: April 01, 2020, 01:28:42 AM by Brian Rupnow »