Swifty's build of Howell V4

[petertha]

Swifty, you mentioned using a brake cylinder hone for liner ID's. Is that for 'pretty close' diameter & reserving final lapping/finishing to occur once the liners are in the block? Or are the liners presently 'we are done' to final size & finish?

Can you give me a typical +/- you are able to achieve between the liners with the hone & about how much material you are removing after the lathe (tool) boring operation?

 

[Swifty]

Petertha, the bores are now finish honed, I left .002" on diameter for honing. They are all well within .0005" of each other, close enough for me. As I got close to size, I slowed the rotation speed down, and increased the back and forth speed with the hone to achieve the nice cross hatch that you need for oil retention. The liners are a slip fit in the block, so will not close down on bore size when fitted.

As the liners are cast iron and I use some WD40 as a lube for honing, it's all very messy, so each time I measure the bore, I have to clean everything. I'm only measuring with a telescopic gauge and micrometer, to get a closer tolerance, I would need better measuring devices and have to clean up more often.

Paul.

 

[Swifty]

Too many other commitments have been impacting on my machining time lately, but I did manage to machine the Crankshaft Center Bearing Holder, this is made out of 2 pieces keyed together. Also done the shaft oil bushing which fits in the bearing holder, the drawing calls up Babbitt, never had any in my life, so I used bronze. It acts more as a guide for oil than a bearing, there are ball bearings on either side of it, so I allowed an easy fit on he shaft. Still a few holes to drill in it yet.




Paul.

 

[gus]

It will be a timely break and come back to gusto and ''GungHo''. It does get a bit frustrating when our project work gets interrupted. For example. Nellie called from her maternal home for Gus to buy her lunch.Stopped work and hour ahead to clean up and she called 30mins later to call off lunch date.
Nellie is on my black list for a short while.Ha ha

I am taking it easy on the toughest part. Break the 1.6mm drill and I am about done.
Drilling the 1.6mm 35 degrees oil passage scares me. Will do a dry run before I plunge in. Step by step detail written. Will keep you posted.

 

[Swifty]

Hi Gus, I have been drilling more oil holes in the block as well as tapping some holes,very nerve racking at this stage of things. One broken drill or tap could ruin everything.

Paul.

 

[Cogsy]

Hi Gus, I have been drilling more oil holes in the block as well as tapping some holes,very nerve racking at this stage of things. One broken drill or tap could ruin everything.

Paul.

I really hope it doesn't happen to you, but if it does go bad you could always use the Alum trick to dissolve the broken piece out of the aluminium block. So now you have a strategy to deal with it, you won't break any!

 

[gus]

I really hope it doesn't happen to you, but if it does go bad you could always use the Alum trick to dissolve the broken piece out of the aluminium block. So now you have a strategy to deal with it, you won't break any!

Hi Cogsy & Paul.
I survived the stress ordeal drilling the oil passages. Any bungle here will be hard to save crankcase.:wall: The mini sensitive drill chuck earned its keep today drilling the 0.018 oil orifice hole on the lathe at 600 rpm.So happy with the outcome ,I bought Nellie ShabuShabu Lunch.

 

[Cogsy]

Gus, you made me Google ShabuShabu - now I want some! Glad you got your holes drilled, I'm thinking about getting a sensitive drill chuck as well.

 

[Swifty]

A little bit more done yesterday, the blanks for the con rods are ready for further machining, I think that it was on Lesgy's build of this engine that I saw the method of putting the bronze in before final machining. I also started on the pistons, they may look strange, but I have allowed a 5/8"dia shank on top of the piston to allow me to hold them for further work, and of course, there is the obligatory spare one as well.




Paul.

 

[gus]

Hi Gus, I have been drilling more oil holes in the block as well as tapping some holes,very nerve racking at this stage of things. One broken drill or tap could ruin everything.

Paul.

Hi Paul,

We shared the same excitement/stress/potential scrap and the joy of making it safe and sound with the last cut/drill/tap. Good reason why I take it very easy with the final details. Part of the deal. Whatever hqppens,we have to move on as life cannot stay still.

 

[gus]

A little bit more done yesterday, the blanks for the con rods are ready for further machining, I think that it was on Legsy's build of this engine that I saw the method of putting the bronze in before final machining. I also started on the pistons, they may look strange, but I have allowed a 5/8"dia shank on top of the piston to allow me to hold them for further work, and of course, there is the obligatory spare one as well.




Paul.

Good idea. Will be cutting piston rings,pistons and con rods next week.

 

[Swifty]

I'm jumping between the con rods and pistons at the moment, the con rods have been drilled and reamed, and the relief groove in each side has been done.



I have turned a holder to hold the pistons with their temporary shank, and used a spotting drill to drill a clamping hole in the piston shanks. The tapped hole in the holder is set back .010 further than on the shank, this pulls the piston tight against the face.





The holder worked out well for facing the pistons to length, they all came out identical once I had set the stop. I will also use the holder in the dividing head when I'm drilling the oil return holes in the pistons.

Paul.

 

[Cogsy]

Fantastic idea Paul, again I will shamelessly steal it for my own use.

 

[jimjam66]

So much to learn here! Paul, my immediate thought on seeing the bronze plugs in the conrod blanks was - how do you keep the bronze concentric? Then I wondered if I was overthinking - the whole conrod is concentric so does it matter if the bronze isn't?

And all the jigs for repeated operations - marvellous! Keep it coming, I'm hooked!

 

[Swifty]

Hi David, I also was worried about the bushes being concentric, but then again, am I ever going to replace them. Although I was very careful with positioning when machining, the chances that they are not quite concentric to their outer dia. is fairly high.

I try to think ahead about how I'm going to machine parts, whilst I'm working on something else, my mind is turning around about the next part. I always find that if I study a drawing of a part for a while, I will come up with a reasonable way of machining them a bit later. You have to consider how you are going to hold the part, what happens when I drill holes in it, will I squash it in the vice, what steps do I have to do first, do I have to drill holes before boring a part out etc. a lot of time can be saved by thinking the procedure through.

Al, I'm sure that I'm not the first one to use that idea to hold parts, copy away to your hearts content.

Paul.

 

[gus]

Fantastic idea Paul, again I will shamelessly steal it for my own use.

Hi Paul,

Singapore Ned Kelly Gus about to pounce on your fixture.
Ned Kelly was quite an infamous guy. Read about his escapades.
Incidently I will be cutting the piston rings now the cylinders were hone today.

 

[gus]

Piston Ring Gap

Please advise gap size,you plan to adopt. 3-----5 thou OK?? 3 thou per inch piston OD came from Otto Engine Works.
Cutting the rings about now before it gets to hot & humid.

 

[Swifty]

That gap sounds fine Gus, I will use the method of cracking the rings and just cleaning up the ends with a needle file, worked well on other engine.

Paul.

 

[Swifty]

A bit more work on the pistons today, the fixture that I made to hold them is working great. First off, held the fixture in a chuck mounted to the mill table, centered everything, them roughed the slot for the con rod in all first, then finished off with an end mill.



Next, I mounted up the dividing head and set the fixture in it. After picking up the centre and end as reference, I set the boring head to the correct size and bored the clearance for the crankshaft.



Next step was to drill and ream the wrist pin hole in them all, then drill the 1.0mm oil return holes, 8 small holes in each piston. I only had one mishap when the 1.0mm drill broke in a hole, just as well I have a spare piston, maybe now is the time to source some alum and remove the drill.




All that's left to do now is the ring grooves and part off the shank.

Paul

 

[Swifty]

The piston fixture came back into use again for machining the ring grooves in. The width of the grooves is .041", I found a tool that was .042" wide, close enough for me. When I made the fixture, I marked it's position in the 3 jaw chuck before I bored it out, so putting it back in that position had zero run out. I did the top 2 grooves in the same set up, having the saddle locked and just moving the top slide. When all the pistons were done, I moved the top slide back and did the other grooves, the 3 ring grooves are .043"deep, whilst the oil return groove is only .015"deep.



Next step was to part the pistons off from their shank, then hold the pistons in the chuck with a bit of soft drink can wrapped around them to prevent marking, and face to length.



I then went back to work on the con rods, I machined the slot in the 2 thicker "fork" rods, then I used the CAD to work out the positions of the holes when I rotated the part for the tapered sides. I just held a bit of scrap plate in the vice and drilled and reamed hole positions to suit, and using buttons for location and the coordinates from the CAD. One side was milled on each, then the parts flipped and the other side milled, this gave me nice tapered sides on the rods.



Next step was to round the ends, I made use of the plate that I used when milling the tapered sides. I set up the rotary table, zeroed the centre and clamped the location plate down to suit the hole in the big end first. I knew the position that I had to move in to with the cutter, just blending into the sides by eye. After all the big ends were finished, I repositioned the plate to machine the small ends. After deburring, I gave the rods a bit of a polish on the buffing wheel, one of the smaller rods was flung away as it caught, I only heard it bounce once. Realizing that it must have landed somewhere soft, I soon found it laying on top of a rag, undamaged.



Here are the pistons and rods together, just placed there and not held by pins yet.



I may get back to finishing the crankshaft next, will see how motivated I can get.

Paul.