T head engine by Brian

[brian Rupnow]

If I'm bored next week, I may make a cooling fan for it. This won't be anything new, it will be very similar to the cooling fan I made for my vertical engine. These fans put out a lot more wind than you would think. When the engine is running at 1000 rpm, the fan is turning at about 5600 rpm.

[Willy]

Congratulations Brian on another good runner, that an the fact it looks absolutely great!
Nice to see that you didn't have to engage in a lot of hand wringing in order to get it running well.

Not sure how much run time you have on it yet but I'm sure you've probably seen it loosen up a bit already.
How's the compression seem now that it's got a bit of time on it?

I gotta ask......
What's next?

[The Artful Bodger]

Another excellent project, thank you Brian.

[brian Rupnow]

Thank you guys. Here is the true story of the cam and valve timing that I use for all of my gasoline engines. This cam is longer than the most cams are, but the profile is exactly the same. I use the same profile for both intake and exhaust valves. I use this profile for flathead, T-head, overhead valve and overhead cam engines. It works fine for all of them. You can see on the drawing that only 120 degrees of this cam has any effect on the lifter or pushrod. Since there is a 2:1 ratio between the camshaft and crankshaft, that means that this cam actually has 240 degrees of influence on the engine. I set my exhaust valve to begin opening 40 degrees before the piston reaches bottom dead center on the power stroke. Due to the cam profile, the exhaust valve will begin closing 20 degrees after top dead center on the intake stroke. The intake valve begins to open 15 degrees before top dead center on the exhaust stroke, remains open throughout the entire intake stroke, and closes 45 degrees after bottom dead center on the compression stroke. The ignition timing is set to spark 12 degrees before top dead center on the power stroke.

[woodenbird]

Sounds great, looks great. Congrats on another engine this time with your own rings.
Thanks tor taking us along for the ride.

[brian Rupnow]

Now, for something a little different----I had trouble cutting the cams for this engine on my manual mill. The main reason for this was the extreme overall length of the cams. I appealed for someone with CNC capabilities to make me a set of cams in exchange for a set of engine plans. Sid stepped up and machined a beautiful pair of cams for me, but doesn't want the plans. He asked that a free set of plans be given to someone else who wanted them. Okay, I'm going to do that. The only stipulation I would ask for, is that whoever gets the free plan set must start a thread on building the engine and post it here for us to follow. So, who will it be?--If you want a complete set of engineering drawings for this engine, and will post a thread on this forum to show us your progress, then let me know. I am going to send a free plan set to whoever speaks up first, as long as they can meet my conditions.----Brian

[sid pileski]

Sound like a great incentive Brian!

Thanks!

Sid

[brian Rupnow]

Tomorrow I am going to try something new. In the attached model, you can see that there is a blue fan shaft support plate setting on top of an existing gear guard. There is no good way to bolt this onto the gear guard. I have modelled a completely new gear guard which has the fan shaft support integrated into it, but I don't have material to make it that way. Tomorrow I am going to buy some "alumiweld" brazing rod and attempt to weld that blue piece to the existing gear guard. I can buy two rods for $10 at Canadian Tire. If I fail, I'm only out $10. It would probably take about $15 worth of material to make a new one piece gear guard combined with fan shaft support. I've been wanting to try this method of welding aluminum, but haven't had any real reason to until now. I will let you know what happens.---Brian

[Sparky_NY]

That aluminum gas welding rod is extremely tricky to use. Nothing beats a tig welder for doing a nice neat job on aluminum. That said, aluminum is a lot different to TIG than steel. TIG on aluminum does require AC though and I don't know if your new TIG has AC capability or is DC only. TIG is the right tool for the job.

[brian Rupnow]

I know that my TIG will weld aluminum, but I have no experience doing that. I remember welding aluminum with oxy-acetylene in high school, with a special set of goggles and a flux that turned color when it was time to add filler rod. I distinctly remember the aluminum getting hotter, and hotter, and then suddenly disappearing because it had melted or vaporized.

[sid pileski]

Wait, didn’t you just buy a TIG welder???
Aluminum it one of the places they shine!!
I’ve never tried aluma weld, but then again I have a TIG.
I think stuff like that is a gimmick, that never really works.
I guess $10, you’ll find out.

Then, fire up that TIG!!

[Sparky_NY]

I know that my TIG will weld aluminum, but I have no experience doing that. I remember welding aluminum with oxy-acetylene in high school, with a special set of goggles and a flux that turned color when it was time to add filler rod. I distinctly remember the aluminum getting hotter, and hotter, and then suddenly disappearing because it had melted or vaporized.

Oxy Acetylene is going be be a real challenge on aluminum, times I have seen it done was with a propane torch. Pure aluminum melts at about 1100F, so your recollection is correct about it disappearing into a glob quickly.

Why not also pick up some 1/16 aluminum tig rod while you are at the welding supply? You won't get experience with the TIG watching it collect dust.

[J Tiers]

Is that a welding rod? Or one of those "rods to solder aluminum"? I have a coil of wire for "soldering aluminum". I can tell you that is not what it does.

I found that it ended up being gas welding, since the aluminum and rod all seemed to melt at about the same point (I was using propane). I am not sure if it alloyed that fast, or really did all melt at once.

I got done what I needed to, but it was really ugly. Uglier than you can imagine, sort of like bird poop mig welds, only the blobs were more fused into the two pieces. I still have the rest of the coil of wire, but have never used it again.

You want to be very careful to avoid having the whole corner of the gear case collapse as you work.

That may be one advantage of the tig... lots of heat right there, which I did not have with the propane torch. Aluminum is a deceptive metal when welding,. My record using a spool gun is 50-50. Half the time it worked acceptably, the other half it really did not at all..

[olf20]

Great job on the engine! Glad you got the CI piston rings working. I know it does not make any
difference on the engine running, but CI rings just seem to be natural. LOL
Great job.
olf20 / Bob

[brian Rupnow]

This is one of the gear guards with the new fan shaft support tab setting in place beside it. I chickened out on using the 'alumiweld' brazing rods and instead went to my welding supply shop and bought some 3/32" aluminum rod to use with my tig welder. I will practice a bit on some scrap aluminum pieces, and then weld the two pieces in the picture together. Tig welding with aluminum is a skill I have to develop, and I might as well start now. I will post the end results of this tig welding.