Howell V4 Block holding fixture

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HMEM Supporting Member
Oct 9, 2009
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I am building a Howell v4 as my sunset project and dont actually plan on getting it finished but it was the only thing that I looked at that I want to build.
I have built several engines including a Howell V twin and have designed a couple engines but I am self taught and still learning.
For the life of me I couldnt figure out how to hold the block while I machined the oring and water grooves inside the cylinder bores.
I didnt have the angle blocks described in the plans and my little worn out South Bend 9 couldnt swing such and out of balance setup.
I built a fixture to mount in my 4 jaw chuck to hold it and it looks like it is going to work. I am waiting on an internal groove tool so I can start cutting.
Here are plans for what I did if you are having the same issue.
Hope someone finds this useful


V4 Fixture.jpg


  • Howell V4 Fixture.pdf
    1.3 MB · Views: 7
I was concerned when I started to spin my faceplate and angle plate with the V-4…. Angle plate weighed alot more than the block itself…Placed a couple of mill holddown clamps as counterbalance. Your option looks alot less scary !

I struggled with the oring grooves tooling as well. I placed an oring in the groove to test fit , big mistake as I couldnt get it out without using a pin/scribe. So ended up buying a second set of orings for the engine. If you test fit an oring suggest you lay cotton or teeth floss string across the groove so you can easily lift the oring back out of the groove
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