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Yes, I built an engine that with the right headers and intake tuning should peak around 10500.....and would last at least a 1/2 dozen 10 sec drag runs. I had a road race bike years ago with an 82mm stroke that redlined at 9200. If I shifted at 9200 I got maybe 2 hours of track time out of it. But shifting at 7500 it could run all season. This engine is 78mm stroke...so 8kish will give decent life, 9500 once and a while just to hear it but5 honestly in normal street use I'll be shifting at 3000 it will accelerate plenty fast and that's about 75mph on the highway, it should live a good long time at that rpm.

Decision made, 4340 ordered

You called that one, the clutch beating was full of shit. Some it looks like it could be left from the machining...I like to think I cleaned it well but I know me



Speaking of knowing me, it looks like I never properly torqued one side of the intake and #6 had started leaking

Good to hear you got all that extra shit out of there. Would have hated to have it all go back together and then have to come back apart again.


On towards steels..... I used to do tool and die work, mostly running a collection of manual lathes.

9310 and 4340 are both likely good choices. Out of those two, I would have also chosen 4340. The other two options I'd maybe consider if there is a next time would be 8620 or S7.

4340 you can through harden and it'll remain fairly damn tough, but in sudden high stress applications like draw bars and some PTO shaft style stuff, S7 seemed to hold and last when nothing else would. 50-52 rockwell. Corrosion resistance of S7 not as good, but if its half flooded in oil, does it matter?

The other option if all else fails is 8620, carb and harden and hope it doesn't move for shit during heat treat.

Whatever you end up making it out of, you could always leave the OD a bit heavy, 5-8 thou, make an arbor out of 1018 mild shit with a dowel-pin as a dog to drive it, and OD grind the OD either on an OD grinder or a tool-post grinder on your lathe.

I made the cams from 8620, and yes the shaft will get hardened to RC 50-52 when its done.

Today was filled with delays. Started cleaning up the bellhousing, off to the store for more spray cleaner. Need to pull the bearing, off to the store for a new puller which need some modification to the arms to engage and I had to make a piece to lock it at the OD I needed.



Then dig out my notes from when I worked on gears last time....not very good notes it turns out so I remeasured




Then cut out the old bearing boss



and cut out part of the bellhousing so I can get in to weld a new boss in place.



Tomorrow I need to make boss and get it welded. I found some metal I think is left over from way back when I had a blower and needed pulleys to adjust the boost.

This morning I made the new boss I was worried that chuck of metal was not long enough but I had at least 1/16" to spare. yay.




Then start setting up to weld remember I'd been nursing the argon tank and its empty empty. Off to the welding store. Then lunch, then finish replanting a hedge row that "we" decided would look better 10" closer to the walkway, then time to weld. I like to preheat bigger stuff


Then...why no arc?.....oh....


Ok, I'll use the other torch (wp-24). It will probably make welding the indie easier anyway


.....not sure why I believed it was 250A troch, clearly its not.


I got the top mostly welded before it blew. The replacement for the bigger torch (wp-20) will be here Saturday.


The steel for the shaft arrived. I've already broke enough stuff for 1 day so I'll maybe get going on the shaft tomorrow, although I don't think I have the nut to measure so I can't finish the design on that end and I'm honestly don't have much more than a vague concept of how I'm going to cut the internal spline on the other end....I guess I'll play with that next.

Internal splines?

I feel like you're either going to need a sinker EDM, or a custom ground fancy-pants broach or a sorceror.

Thats way above my pay grade.

Have you tried karate chopping it while recording? Seems to work for ThisOldTony on youtube....

I'm getting ready mentally to make the new shaft. My lathe doesn't cut real straight so I think I'll ream the spline bore. The splines are 6mm so I can buy a broach and make an indexing bushing so I can cut the pattern but I may have a line on an EDM source so I'm going to hold off ordering for a little. I also need to get a clutch gear nut so I know what thread to cut so that is a little stalled. I could move on the fixing the valve on #12 but I'd really prefer to get the dirty work done before starting clean work. I guess I'll plant bushes today.

Edit - post came in while I was typing so adding a little more detail. I can make the spline bore 3/4 or maybe 1" deeper than the spline (I want to do that anyway so I can call it a light weight race part) so they don't need to dead end exactly, that will help. then the plan would be broach all 6, the cut the end of the broach. it will mean using smaller shims than normal so more passes than normal but I'm pretty sure I could make good splines. I'll hold a little to hear numbers from the EDM guy...but a broach is $50 and an afternoon of work.

Square splines use the ID as a locating feature, which is why I'm thinking reamer. I could extend the shaft a little and use the old now not used bearing location for axial alignment, but that puts the spline even deeper in the shaft so back to the reamer...$85 at msdiscounttool.com seems worth it.

This would be an easy job on a shaper and I am very much in the lookout for an Eberhardt or Gould&Eberhardt shaper if anyone knows of one.

As impressive as the home improvement stuff is, I am really glad to see you back to designing and fabricating custom parts again.

Good luck with all of it, can't wait to see more!