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

Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
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.
 
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.
w4O7Xd.jpg
 
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.
mvGutz.jpg
 
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
Jc5ppx.jpg
 
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
 
“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
 
Enjoy reading your posts. And watching your videos keep going it will get better.
Thanks for posting
 
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.
 
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.
 
Something really weird has happened. I have an icon on my desk top that always took me to this site. It doesn't work any more. I thought maybe the site was down because of the virus. It seems that the site is still there, but my icon doesn't work anymore. Can somebody help me please.---Brian
 
Brian, I don't quite know why it has stopped working, but probably the quickest fix is to delete it and create a new icon. To do that, first right click on the icon and choose Delete, then right click on the desktop and choose Create Shortcut. Copy the url to the site into the shortcut.

That was the quick version, and may have told you what you already know ... or may have been too brief. I will be happy to follow up as needed, or others may chip in with a better solution.
 
I had the HMEM app on my android phone. It stopped working also. I deleted it thinking I would reinstall it and solve the problem. I can't find the app in the app store now. Wondering what has happened??
 
I was wondering what happened to you Brian and told myself to come back here and read to see if you were taking off.

After their software update, I had to login every day. Reading that thread Ghosty links to, it said to delete cookies for HMEM. That seems to have worked. I think Awake's suggestion should get your desktop icon working again.
 
Okay--I just did what Awake suggested, and it seems to have worked. Thank you very much. Now I have to copy and post a bunch of progress.---Brian
 
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.
ik7fmI.jpg
 

Latest posts

Back
Top