Brian Builds the Kerzel Hit and Miss I.C.

[Brian Rupnow]

So there we have the crankshaft installed. It looks good, but as I had feared, the crankshaft is no good. The fact that my tailstock had moved out of alignment sometime during or before the crankshaft machining operation has given me a crankshaft that has a terrific wobble in it. This is dissapointing, but its not an unfixable disaster. I will use this crank to set everything else up on the engine, and make another crankshaft closer to the end of the game.

 

[Brian Rupnow]

It's coming along nicely Brian - you are waaaay ahead of me. One thing tho', and you've probably picked it up already, Kerzel shows the bore on the small gear as 0.312" - I know you like tight fits but you'll have a jolly old time trying to fit that on the 0.375" crankshaft.

Damn, you're right Tel---I never even caught that one. Somebody down in Pennsylvania stepped up and volunteered to make the gears for me and send them up. They are currently in the mail ---SOMEWHERE!!! I'll have to open the bore on that gear when it gets here. Kerzel made a few mistakes in the drawings. Not real big ones, but ones that show up when I model the drawings in my software----But that 5/16" bore went right over my head. Is this your first I.C. engine?

 

[walnotr]

So there we have the crankshaft installed. It looks good, but as I had feared, the crankshaft is no good. The fact that my tailstock had moved out of alignment sometime during or before the crankshaft machining operation has given me a crankshaft that has a terrific wobble in it. This is dissapointing, but its not an unfixable disaster. I will use this crank to set everything else up on the engine, and make another crankshaft closer to the end of the game.

Brian, this may not be problem, but have you done anything to insure the crank bushings will return to thier exact positions after you line bored them? If the bore is a little off center you have created eccentrics that can cause binding if they are not in the exact alignment they were in when you bored them.

Steve C.

 

[Brian Rupnow]

walnotr--Yes, I have match marked the bushings and the caps rotationally. The problem lies with the crankshaft. If you back up about 10 posts, you will see that I dicovered my tailstock was way out of line with the headstock spindle after I had finished machining the crank.---Brian

 

[tel]

Damn, you're right Tel---I never even caught that one. Somebody down in Pennsylvania stepped up and volunteered to make the gears for me and send them up. They are currently in the mail ---SOMEWHERE!!! I'll have to open the bore on that gear when it gets here. Kerzel made a few mistakes in the drawings. Not real big ones, but ones that show up when I model the drawings in my software----But that 5/16" bore went right over my head. Is this your first I.C. engine?

Yeah, this is my first go at an IC after 20 something steam engines and two locomotives - must be a slow starter

I only found it because I wasn't happy laying out the gear centres from 'cold' as it were - decided to cut them before I got too far into the bearings. As you know, Kerzel gives specs for 32 and 48 dp gears, but all I had cutters for were 40 dp - now a bit of mental calculation told me that as my cutters fell half way between his the outside diameters should stay fairly constant with gears of 50 and 25 t - and so it proved, turns out I could have just done the bearings from the drawings. Oh well, the gears are out of the way now.

 

[cfellows]

So there we have the crankshaft installed. It looks good, but as I had feared, the crankshaft is no good. The fact that my tailstock had moved out of alignment sometime during or before the crankshaft machining operation has given me a crankshaft that has a terrific wobble in it. This is dissapointing, but its not an unfixable disaster. I will use this crank to set everything else up on the engine, and make another crankshaft closer to the end of the game.

Brian, that wobble might just be from stresses in the original piece of metal you used for the crank. I would have thought the tailstock being out of alignment would manifest itself as a taper on one or both sides of the journal. If you have a consistent diameter all the way accross, I would suspect warped metal rather than the tailstock. You might be able to straighten the crank with an arbor press. I've been successful in doing that in the past.

Chuck

 

[Brian Rupnow]

Chuck---There doesn't seem to be any measurable taper. I will try staightening the crank with an arbor press before I go right at it and build another one, but I'm not terribly hopefull.

 

[tel]

.. and here they are!

 

[Brian Rupnow]

Loverly stuff Tel---And now, just to keep things rolling, we have a piston. True, it has no rings yet, but I haven't been across to Hercules O-ring yet to pick up Viton rings and the specs for the grooves. That will come later. I haven't drilled my one side frame on the engine yet for the screw that holds the camshaft stub in position either. I want to wait untill I have the gears, just to be really sure of the center to center distance.

 

[Brian Rupnow]

Believe it or not, there's a connecting rod in there---

 

[Brian Rupnow]

Honest---I wouldn't kid about something like this---

 

[Brian Rupnow]

Son of a gun---I knew it was in there, all along.--(The cap was in a different peice).

 

[NickG]

Great work Brian :bow:

 

[kcmillin]

Wow, I did not know how small this thing is.

What is the bore and stroke?

Kel

 

[Brian Rupnow]

Wow, I did not know how small this thing is.

What is the bore and stroke?

Kel

0.75" bore x 0.8" stroke

 

[Brian Rupnow]

This morning I was out and about and went to all of my metal suppliers. No-one had any 3 1/2" diameter brass, so I picked up a peice of 660 bronze tube 3.5" O.D. x 2.75" I.D.. The flywheels are going to be two peice, with a bronze outer rim and an aluminum center.---Will post drawings as I go along. Also picked up my Viton o-rings and the groove info, which I will put up later.

 

[Brian Rupnow]

Seeing as I had less than stellar results with my one peice crankshaft (due to a misaligned tailstock which has since been fixed), I have decided to go with a built up crankshaft. I was out this morning and bought a one foot length of 1/4" x 3/4" cold rolled steel flatbar. I cut two peices slightly longer than 1.5" and with the sides lined up in a pair of vice grips I used my trusty mig welder to but a bit of weld on each end to keep things lined up. I don't really trust my "tilt a whirl" vice to keep things truly flat and square (the jaw kicks up) so I clamped the two welded peices to the mill table with a bit of sacrificial aluminum underneathe them, and drilled and reamed a pair of 0.375" holes.

 

[Brian Rupnow]

Next trick was to put the vice back up and put in a 1/32" x 45 degree countersink in each side/each hole to get a good solid ring of silver solder in there. ---I forgot this step while things were still clamped to the table.

 

[Brian Rupnow]

Flipped the peices around in the vice and drilled and reamed 4 holes 0.094" through where the shafts will go---

 

[Brian Rupnow]

I cut two shafts 3/8" dia cold rolled x 5" long, put a c'bore in each end of each peice, centered them, set the correct distance between the peices of bar, then drilled and reamed the shafts in place--each time I finished one hole I would drop a peice of 0.094" cold rolled into the hole to ensure no movement. Here you see it before disassembly and clean up for silver soldering. You will see where I am going with this---