Starting my engine

[Brian Rupnow]

Make the included angle of the valve seat 90 degrees. Make the included angle of the valve faces at 91 degrees. That way you will have a theoretical line contact all the way around between the valve and the seat. What I do now is set my compound rest for 45 1/2 degrees when machining the valve. I don't put any angle on the seat with a machine process. I have a dedicated seat cutting tool with a 45 degree angle and a guide on the end which fits into the hole where the valve stem would normally fit. I rotate it very lightly by hand to cut the valve seats.

[Maryak]

I was pretty careful in making them to the exact same angle as the seat in the cages

You may have more success more quickly if you have around 1⁰ difference between the seat and the lid. This makes for a narrower contact area.

Hope this helps and good luck.

Best Regards
Bob

How do I accurately measure an angle of 1 degree of a seat 0.280" in diameter, with a width of 0.060"?
Mosey

Hi Mosey,

It's not critical, just needs to be slightly different. i.e. a gentle tap on the compound so it moves a couple of bees wings. 

Best Regards
Bob

[Mosey]

Bob and everyone,
I'm working thru the valve/seat sealing issue, and thank you all for the several great suggestions. Soon, I will have them kissing like teenagers! Then, I'll post my results for all to see.
Mosey

[philjoe5]

Good luck Mosey.  Having just gone through this I sympathize.  I'm sure you'll get it.

Bob,

bees wings

Any chance I can find a micrometer with those divisions on it?  I'd add it to my collection

Cheers,
Phil

[Mosey]

Thanks, Phil.
Yes, I will get it.
Those tiny divisions are on your micrometer, you just can't see them, ha.
Actually, the problem with these little valves is seeing them and the seats well enough to make them fit tightly. I'm working on that too. I am looking for my old loupe, as the Magnivisors aren't very clear.
Mosey

[Mosey]

I bought a jewelers loupe, inspected the valves and seats, and discovered that they were very rough. I will recut the seats and make new valves, trying to get a seal before putting the engine back together.
Then, I hope I can get it to run.
Doesn't pay to poorly make pieces, does it?
Mosey

[philjoe5]

Mosey,

Doesn't pay to poorly make pieces, does it?

We all pay for that in the end, don't we?  If only I could make a poorly built engine with all my poorly built parts in the scrap bin, that would run, though poorly, I'd be happy. 

Good luck with those new valves and seats.

Cheers,
Phil

[Mosey]

And while I'm at it, how about the right material for the valves, a new, sharp, honed HSS cutting insert?
Wonder if there is an inexpensive, small telescope for the tool post, so I could see what I am doing? Maybe even put that 1degree angle in between the seat and the valve face?
Mosey   

[philjoe5]

Mosey,
I bought these a while ago

http://www.ebay.com/itm/new-Dental-2-5X-Loupe-binocular-magnifier-lens-glasses-Surgical-Medical-Use-a-/200723804418?pt=LH_DefaultDomain_0&hash=item2ebc123102

I haven't had a chance to use them.  If you ever get out my way (west of Philly) you're welcome to try them.  Seems like they'd do the job.  PM me if interested

Cheers,
Phil

[Mosey]

Thanks, Phil. I think I need something of 10x, so I am looking.
Mosey

[Roger B]

How big are the valves? this isn't an engine I am familiar with.

I made some valves with 6mm heads and 2.5mm stems from some M4 stainless steel caphead screws. On one I left the head and filled some slots to act as a cutter for the aluminium cylinder head. This was one of the few engine parts that worked first time 

[Mosey]

Valve Heads are (.281" )7 mm and stems are ( .112" )3 mm.
Mosey

[Roger B]

This is the seat cutter I made. It was turned at the same settings as the valves and then the cutting edges were made with a triangular swiss file.  Two or three turns with a 'T' head hex key produced a good seat in the aluminium head.

[Mosey]

I am making a seat cutting tool from plans furnished graciously by George Britnell. I looked at my new HSS cutting insert under the magnifier, and found it was as rough as a ploughed field, so I will hone it. Then, we'll see what I can do.
Right now I am waiting on some water-hardening rod to make it from.
Mosey

[Tonyr]

Mosey.

I started making a valve seat cutter when making the valve cages for my Snow build.
I don't really enjoy making tools.
Half way through making the cutter I had an idea.
I purchased a cheap carbon steel 45 degree countersink cutter.
I heat treated it to soften it and ground off the point.
I then put it in the collet chuck and faced off the end .
I drilled and reamed a hole the same size as the valve guide 1/8", then re hardened it.
I used a length of 1/8 silver steel as a pilot.
It only took a hour to make and worked well.
I used a carbon steel cutter so it could be heat treated to soften it so it could be machined.

Tony