Webster I.C. Project.

[djberta]

Just an update. I have all the material to start the project. Great thanks to members here for helping me out. My mill will be back together here today. Lathe should be ready to go as well.

 

[djberta]

Started working on making some valves yesterday. I made 3. Each one had major flaws. Trying to use stainless something, most of the metal I have is a mystery. I will keep trying. That’s what this project is for. So I can learn how to be more accurate.

 

[PeterT]

I used 303 for my valves which machined pretty well. This past week I tried a new 'stainless' DCMT insert from Ali that was very good on my 304 that usually causes grief. It was really quite amazing, 0.0005" DOC passes & it just peeled it off, nice finish & no work hardening. I think this pic was a 0.002 - 0.003" DOC pass just messing around.





Anyway back to valves. Mine start ~ post #128

Ohrndorf 5 Cylinder Radial

The heads at this stage were cleaned & the valve cages installed using Loctite 680 HT retainer. Permanent installation is required at this point because the next step is to cross drill the port passages through the aluminum head & into the bronze cage. As you can see, the valve seats are cut. I...

www.homemodelenginemachinist.com

 

[djberta]

Hi Peter. I ran in to those exact issues. Cutting nice then it hardened each time. I have tried a couple different cutting fluids as well. One even grabbed and bent. I will try another set of inserts I have. Maybe I will switch to some of my HSS bits that I have. I don't have a very big amount of cutting bits. But I do have some options. I might switch to cutting some of the aluminum and steel pieces. I wanted to start with the valves as I think they require the highest level of precision.

 

[PeterT]

What I would recommend is get a handle on the hole that the valve stem will be sliding in. Very likely drill & ream job because you want the size & finish. Lets say that's 0.1250". That will become your reference to make the valve stem, meaning both OD & finish. You can probably get away with sanding sticks to work it down the last say 0.002-0.003" as long as lathe turning is good. Lapping is better but another kind of rabbit hole. Anyway just saying hole first, valve second. If you reverse it, not only are you chasing reamer size ($$) but your own batch of valves may vary enough that they don't fit as well. Also make spares while you are in the groove. They may be otherwise perfect except when you get to seat seal & then you wish you had another.

You may want to make that cheapo vacuum tester I copied from another fellow. Then valve seal becomes a very precise yes/no/maybe diagnostic before the engine is ran.

 

[djberta]

Thanks Peter. My logic was not correct. I was looking at valve first then seat and guide. I have a 3mm reamer so that’s what I’m aiming for. I’ll see if I can get the seats and guide made.