Thumper--a 1 3/8" bore i.c. engine

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L98fiero

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Brian:
Your stick of bronze appears (to me) to be 660 "bearing bronze". I say that because it looks to have that spiral greyish mark the length of it on the outside.
Aluminum bronze often has a similar finish but is 'whiter'/not as brassy yellow as 660 and being tough to machine is also a good indication it's not 660, if your tool is not sharp, it will just rub if your machine isn't rigid.
 

Brian Rupnow

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Today I made two cams and two tappets and a larger valve seating tool from 01 steel, and flame hardened them, then quenched them in some dirty old motor oil I keep just for that purpose. It certainly doesn't look like much, but I spent most of the day doing it. The two cams are positioned on the cam-shaft, in the cam box, and the two lifters are "posed" in the top of the bronze lifter bushings. You are not going to see the larger valve seating tool because it is really, really ugly.--but it does the job I needed it for.
 

Brian Rupnow

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I spent this morning working on things that mostly don't show. I lapped the valves into their seats in the valve cages, and cut off the "handles" so that the valves are now finished. I opened up a bit more clearance on the inside floor of the cam box to let both cams fully rotate without hitting something. It doesn't show in the picture, but I realized that I needed to make a shaft collar for the far end of the camshaft to keep it from floating longitudinally. I drilled and tapped both gears for set screws. I had painted the gas tank and the rocker pivot support with "semi-gloss" black paint for a little contrast, and reassembled them. I have enough brass to make a pair of nice rocker arms. I was going to drive across town and buy some 1/2" brass bar to make the large elbows that screw into the sides of the cylinder head, but I may rethink that. I may just make them out of steel.
 

Brian Rupnow

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Todays offering is a set of valve springs and keepers in place, as well as two brass rocker arms. The sharpie pen is just wedged in there to hold the rocker arms up. They are slightly "tail heavy" and I haven't yet made the connecting link that fits between the tappets and the end of the rocker arms. Don't be afraid to say Hi people. I know you are looking, because my post count keeps going up. I like to hear from you. This "social distancing" thing is starting to make me feel like Rapunzel locked in her stone tower, and I don't have any hair to let down.---Brian
 

awake

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Hi! I'm watching with interest. I hear you on the social isolation distancing ....
 

cheepo45

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Thanks, Brian for keeping us entertained!
I look forward to every new posting.
Can't wait to see it run! (take your time, though - I'm stuck in the house until May 15th)
Scott
 

a41capt

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“This "social distancing" thing is starting to make me feel like Rapunzel locked in her stone tower, and I don't have any hair to let down.---Brian”

You keep buildin’ em Brian, we’ll keep watchin’!

John W
 

werowance

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Watching along Brian. on the paint on the tank - is it fuel resistant?
 

Bighoss

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Enjoy reading your posts. And watching your videos keep going it will get better.
Thanks for posting
 

Brian Rupnow

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Fuel resistant---I don't know. The Naptha gas I use for fuel doesn't seem to affect the paint at all. I'm pretty sure that ordinary pump gasoline would wash the paint right off.
 

Peter Twissell

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Watching with interest here.
Wish I had time to build as quickly as you are, I've been working on my radial for 7 years now.
Retirement in 3 years!
 

Brian Rupnow

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Hello Peter---I am more or less retired. I don't really have much else to do, so my engines get built relatively quickly. If you can convince yourself to make at least one part per day, they come together quite fast.
 

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