Valve guide material

A question for APE Jay or maybe Larry C. Just wondering,what specific bronze alloy is used to manufacture valve guides? Seats?
Tom

Sorry that I'm not either of the two members who's opinion you seek, but at least I'll get you a bump. I have seen valve guides made from AMPCO 45 (AMS 4640; ASTM B.150) nickle-aluminum bronze or C63000 nickel bronze. Hope this helps.

Yes, that helps. Thank you. I welcome answers from anyone with information.

I suspected aluminum bronze, but with silicon added. I need to do some more research.

Tom

Planning on machining your own guides? Aluminum bronze is "interesting" stuff to machine.

testarossa wrote:

Planning on machining your own guides? Aluminum bronze is "interesting" stuff to machine.

Thinking about it. I don't even know if I'll need new ones yet. I only know that the old girl smokes on deceleration. Maybe just needs seals. Compression is 130, 140, 150, 160#
with a squirt of oil in the cylinders, not much lower without the oil. I figure it wants a valve job. The valve clearances were very tight before adjusting them last spring.

Machining characteristics of al. bronze = 30% machinabilty compared to 360 brass. Could be exiting. Done much on this stuff?
Tom

Yes, and you are in for a learning experience if you haven't cut it before. Specifically, drilling holes to size is difficult. The stuff is horrible about concentrating heat around the tip of the drill when it's deep in a hole. If you cannot get good coolant to the cutting edge, then your hole gets progressively smaller as the hole gets deeper. See the problem here. When making guides the hole size is very critical. Personally, I work in a machine shop and would purchase guides. Not worth my time unless I couldn't find them for my application. Just my .02

I used to have to make a part with numerous 3" deep holes under 0.250" diameter with intersections. The tolerance was +/- 0.001" and they were a bear to get right. The holes were always running small at the bottom.

I work in a machine shop too. Mine. I was formally trained in gunsmith school. Had a gun shop going for a while and am now retired. My dad was a machinist and got me started pretty young.

I wouldn't try to drill to size. I'd drill to .010-.015" under, then bore to make sure the hole was concentric, then ream to size. I could finish the outside in the same setup or finish on the Sioux pilot between centers. I have to make or buy a pilot anyway.

I have mist coolant on the lathe for the tough jobs.

Tom

testarossa wrote:

Personally, I work in a machine shop and would purchase guides. Not worth my time unless I couldn't find them for my application. Just my .02

If I was working, I'd buy them without an eye blink. I have more time than money. Besides it's a good feeling when you know you can do for yourself. I gotta make that lathe pay for itself, over and over. I figure I'll save about $55 if I make 'em. Money to spend on stuff I can't make, like tires or gasoline.

Tom

I hear you man. I'm currently working 10+ hours of overtime every week, so my time is rather valuable to me at this point, but if the roles were reversed I would probably feel differently. Also, if I had my own equipment, then I might be more inclined to make them myself as well.

You really want more than mist coolant for this material. Think flood coolant, preferably through spindle, and my ultimate preference would be cutting oil, not water soluble. The stuff will give you a hard time with that reamer, but you can make it work. You may need to go a couple of thousandths oversize to get it right, but you'll just have to experiment. That job that I mentioned having a difficult time was being finished with reamers, but I still had to go + 0.002" IIRC with flood coolant (water soluble.) You'll get it, just be patient, and don't try and over speed anything. The chips will start turning brown and then purple if your surface footage gets too high. If you see the drill pulling purple chips, then you know you just drilled a funnel. :laugh:

I would finish hone the guides,and the correct way is to have them a bit smaller, install and then finish hone to fit. the only thing that comes to mind wold be the hardness finish, I am not sure what the correct procedure would be, but if they were soft they would wear too fast.
making them yourself would be cool, but for my money I would buy them might be money ahead in the long run.

just my 10 cents worth

I'll check the Machinery Handbook for speeds and feeds. You make it sound like quite a challenge. Here's hoping I don't need them. I'm building a table to put the bike up on tonight. Tomorrow I'll start the tear down. Thanks for the insight.
Tom

ohh dont forget you will need to regrind the valve seats to match the new guides, and either replace the valves or grind them to the correct angle.
ohh BTW,I spent 10 years as a automotive engine shop, and did a lot of bike heads also