Mike Macartney

REPORTS ON A 1914 HUMBERETTE RESTORATION

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Thanks again for your help Joe. I'll kook up pipe plug and see what I can find.

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You can make the arbor out of aluminum...easier to work and it is a one-time tool so making it suitable for handling by shop gorillas isn't needed. I've done it a couple of times when nothing else would work. Another solution is to buy an "expanding 5C collet". Those are made with machinable ends so you can turn it to exactly the dimension you need. If you buy one that is too big but used and in an odd size, chances are it will be cheap.

 

 

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15 hours ago, JV Puleo said:

Another solution is to buy an "expanding 5C collet".

 

I did buy a set of 4. I thought about machining a larger one down, but as it is brand new, and I have not used it yet, I decided against the idea. Thanks for the idea of the aluminium arbor. After reading your post I was wondering about temporally gluing a bush onto an arbor, as I remember reading that 'old timers' used to use shellac. From looking on the internet; it looks as if it is possible to use super glue, then after machining, use heat or acetone to part the bits.

 

I have just given superglue a try and it works.

 

I made an aluminium spigot to slide the the bronze bush onto. I was going to make the expanding arbor that Joe suggested but then I thought when I had machined it to the correct diameter "I'll just try Superglue".

 

2561.thumb.jpg.a07bd981e48e18c744cbbc01b6d70804.jpg

 

Superglued the bronze bush onto the aluminium and machined the circlip groove. The bush did not move at all on the aluminium.

 

2562.thumb.jpg.b36dfaf549377e46c7e480e3aaa5c7dd.jpg

 

Heated the bronze bush with a hot air gun and used a screw driver between the bush and the 5c collet and in less than 30 seconds the bronze bush came off.

 

2563.thumb.jpg.0d6d757f695e9fd87c607f3e117aa204.jpg

 

Checked that the circlip fitted the groove.

 

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Then checked that the bushes still fitted the drill rod.

 

Time to make the tool for pressing them into the piston from the inside. I need to sketch out some ideas as I need to spread the load on the outside of the piston as it not a regular shape.

 

2564.thumb.jpg.c3d00759385c0054f55559dcc51342df.jpg

 

 

 

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Hello Mike,

You are back and heading in a good direction for sure.  This aspect of your engine rebuild certainly has my interest as I need to complete a similar task on a future Harley Davidson project.  On that project, several Harley guys have suggested using aircraft grade aluminum for the bushings as the heat expansion rate will be very close to the same.  I actually suspect that with your bushings locked in place from the inside and clipped from the outside you will have a very substantial improvement.  I may have missed, but what is the difference in weight between the original cast iron pistons and your new aluminum pistons?

Al

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Hello Al,

I had thought about aluminium. As I had used bronze before in my 1927 Humber 350cc when I replaced the piston with a modern Ford piston I decided to do the same here. I attach the spreadsheet with all the weights of the engine parts. You will see that the Ford piston is roughly 2/3rds the weight of the original cast iron piston. Mike

 

WEIGHTS OF ENGINE PARTS    
Parts Weighed  Kg ounces
Complete Flywheel Assembly 21.800 768.97
Old Rear Flywheel (bare) 9.628 339.62
Old Front Flywheel (bare) 9.884 348.65
The one old main shaft I have 0.482 17.00
The old worn (small) big end 0.044 1.55
Locking clamp, bolt & washer (1-off) 0.026 0.92
Locking clamp, bolt & washer (2-off) 0.052 1.83
Two drilled out flywheel rivets  0.006 0.21
Old big end nut (1-off) 0.040 1.41
Old big end nut (2-off) 0.080 2.82
Original No.2 Piston with rings & pin 0.660 23.28
No.2 Piston Pin 0.066 2.33
Original No.1 Piston with rings & pin 0.704 24.83
No.1 Piston Pin 0.066 2.33
BMW Piston without Pin 0.526 18.55
BMW Piston Pin 0.132 4.66
Circlips? ? ?
Total BMW Piston Weight 0.658 23.21
Ford Piston without Pin 0.338 11.92
Ford Piston Pin 0.106 3.74
Total Ford Piston Weight 0.442 15.59
New Big End Nut 0.044 1.55
Complete Conrod Assembly 1.252 44.16
Conrod Large End (average) 0.813 28.68
Conrod Small End (average) 0.433 15.27
Rear End Flywheel Complete 9.996 352.60
Front End Flywheel Complete (with Big End Pin) 10.460 368.97
Total of the two flywheel parts above 20.456 721.56
The Total above plus the conrod & nut 21.708 765.73
Flywheel Assembly (difference in bits and together) 0.092 3.25
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4 hours ago, Mike Macartney said:

Time to make the tool for pressing them into the piston from the inside. I need to sketch out some ideas as I need to spread the load on the outside of the piston as it not a regular shape.

Couldn't it be something as simple as a C clamp?  Just put a small pad on the outside of the piston where the screw pad would rest.  The bonus is that you can hold the clamp in your vise thus freeing up both hands to position the bushing and tighten the screw to press the bushing in.  Sort of like this: https://duckduckgo.com/l/?kh=-1&uddg=https%3A%2F%2Fwww.amazon.com%2FHeavy-Joint-Removal-Adapters-Trucks%2Fdp%2FB01N7CO50E%3FSubscriptionId%3DAKIAILSHYYTFIVPWUY6Q%26tag%3Dduckduckgo-d-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB01N7CO50E

 

Or a threaded rod with appropriately placed nut and washers.

 

Frank 

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A C clamp would probably work but you run the risk of the bushing starting with a slight cant to one side. I'd want to pull them in straight. A bolt through the center, head on the inside with a washer bearing on the flange and something on the outside to distribute the pressure on the entire circumference of the hole...a piece of bar of the right OD with a hole through the center would do it.

 

Or... if there isn't room. head on the outside. Put a nut and washer on the inside. That is actually better. The bushing should have a very slight chamfer on leading edge so it self-centers.

Edited by JV Puleo (see edit history)
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13 hours ago, Frank Tate said:

Sort of like this:

 

This link did not work???

 

13 hours ago, Frank Tate said:

Or a threaded rod with appropriately placed nut and washers

 

Yes, that is what I am working on but with some extra bits to pull it in square.

 

10 hours ago, JV Puleo said:

The bushing should have a very slight chamfer on leading edge so it self-centers.

 

I have done that on the bushes I have made so far.

 

I started to make a steel bush that was to go inside the bush from the flange end with a clearance hole down the centre for the threaded rod. By this time I was getting tired from the lathe work on the bushes in the morning. I was parting the extra material off the bush and this happened! :o

 

2565.thumb.jpg.c2de55d776863eaec504468d36c5fe5e.jpg

 

The parting tool jammed and it broke the collet.

 

I did in fact carry on and made another one. This time in brass, only because I had a suitable bit of scrap brass available.

 

2566.thumb.jpg.151c4f0ee3a0bc6778bde34b48ff6f82.jpg

 

This 'extra bush' that fits inside the gudgeon pin bush should help to spread the load and keep the threaded rod in the centre of the hole.

 

At least I finished the day on a high.

 

As you can see from the outer side view of the piston that I posted before, this end needs more thought, especially as the bronze bush protrudes out of the hole to give the gudgeon pin a bit more 'bearing surface'. I will go and have a play in the workshop this morning and see what I can scheme.

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Still not sure what I am quite going to do for the outer part of the tool for pulling in the bronze bushes into the piston, I have sketched out some ideas, but it seems that I am now making it up as I go along!

 

2567.thumb.jpg.de4bc596d896a39b6624e74b0514d76f.jpg

 

I started off with this bit of stainless hexagon scrap and drilled it out to a clearance hole for the threaded studding, that I am going to use to pull the bush into the gudgeon pin hole in the piston.

 

I then counter bored it to a depth of a 1/4" and then bored it out to an internal clearance bore of the diameter of the bronze bush.

2569.thumb.jpg.0fc31934beed5ac366ccebb121e6da11.jpg 

 

Will it fit?

 

2568.thumb.jpg.e15543981a6de575acbe496b3f1f56e2.jpg

 

Well that's a bonus! I have got to pack up now, as I am being collected at 12.30pm to go for a Sunday lunchtime beer by my pal Robert, it's a hard life being retired!

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On ‎1‎/‎11‎/‎2020 at 10:50 PM, JV Puleo said:

. . . you run the risk of the bushing starting with a slight cant to one side.

 

Yes, even when trying to pull it straight with a threaded rod! I think I need more of a chamfer for the lead in? Read on . . . :wacko:

 

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I measured the side of the piston where this part of the tool, for pulling in the bushes fits and I started machining the tool to fit.

 

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On one side of the tool more metal had to be removed than the other side.

 

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Checking that the counter bore in the tool will accept the bush by using the Ford gudgeon pin to check it. Why I didn't use the bush, I don't know?

 

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The tool needs a bit more work to fit snugly into the side of the piston.

 

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You can see in the above photo I need to remove some more metal from the tool.

 

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Still needs a bit more taken off the bottom of the tool.

 

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This shows it a bit more clearly with the threaded rod fitted. I did some more machining and filing until the threaded rod was at right angles to the piston.

 

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OK here goes.

 

It became a bit tight and I thought it was me loosing my 'puff' and becoming rather worn out. Then Pete came into the workshop to borrow a trolley jack and I asked him to have a go tightening the nuts. Which he did, until he to found it hard to move the spanners.

 

I then removed the threaded rod to have a look to see what the problem was and found this. . . .

 

2578.thumb.jpg.f09493d4d3c88c3f2660038bfb34bb86.jpg

 

Oooop's!

 

I don't think it is as bad a it looks. The slivers of aluminium piston are very thin and came off easily when I pulled the bush back out.

 

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I then pushed the drill rod in through the bush to see how far canted over the bush was, by viewing the end of the drill rod on the other side of the piston, the side that did not have a bush fitted. It looks worse than it actually is, I think it is the angle that I took the photo, that makes it look a long way out of true.

 

I retired back to the house to metaphorically lick my wounds!

 

I hope I can save the piston, if not we do have one spare piston between us.

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Mike, thanks for sharing your bushing process.  Yup, not always do things turn out just as we would like!  You are on the very edge of success however!  Hang in there, the sun is going to shine tomorrow.

Al

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Probably the method to pull the bushing was not ideal: the piston is a cast part; the surface on which the special tool rested is not 100% perpendicular to the axle. I would imagine a device to guide the bushing using the free hole from the piston and the inside diameter from the bushing. With that, even if the tool is not perfectly perpendicular, the bushing will not be canted.

If you can guide the bushing the right way into the piston, you will probably be able to save it as the shaving was not on the whole surface.

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Possibly if you heat the piston, and freeze the bushing, and work quickly, that may help the situation. On heating the piston, maybe heating slow in an oven to 200 degrees or so? 

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Mike, I think I would use an other bushing that is .001" less and stick it in the other side as a guide. Use the same setup as you did on the first try. That way it would hold the rod in the center to help guide it in straight. You may also make a bushing to take up any play in tbetween the rod and bushing. Just a thought. Mike

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Thanks guys. I appreciate your comments. Now I realise I should have jotted down various ideas for pulling or pushing the bushes into the pistons before I blindly went ahead and used the first method I thought of. I used the treaded rod idea because I had used  that method in the past on bushes and it had worked. Lesson learned!

 

22 hours ago, alsfarms said:

Hang in there, the sun is going to shine tomorrow.

 

Al, I wish it would, I'm fed up with all this rain and windy weather that you lot on the other side of the pond are sending us!

 

22 hours ago, Roger Zimmermann said:

If you can guide the bushing the right way into the piston, you will probably be able to save it as the shaving was not on the whole surface.

 

Thank you Roger. After reading your post I used the original Ford gudgeon pin to push the bush in straight and it worked.

 

15 hours ago, Mike "Hubbie" Stearns said:

Mike, I think I would use an other bushing that is .001" less and stick it in the other side as a guide.

 

Mike, I used a slightly smaller bush and pushed it in (see my reply to Roger above).

 

16 hours ago, r1lark said:

Possibly if you heat the piston, and freeze the bushing

 

I may well do this with the other pistons. A heat gun maybe enough to expand the gudgeon pin bore enough? The problem is we don't have a freezer anymore since it packed up and our fridge does not have a freezer compartment. The fridge may at least get the bush reasonably cool.

 

2580.thumb.jpg.889943143ab6743f89ac160ce3696fd3.jpg

 

By using a slightly smaller diameter bush (0.0005" smaller) and using the original Ford gudgeon pin to push the bush in, it fitted OK.

 

2581.thumb.jpg.eb961202e97a58c5176fbc5774273da9.jpg

 

Now, to design a method of pushing, pulling or both pushing and pulling to fit this second bush in. 

 

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I'll make a spigot on this 'lump' of metal bar the internal diameter of the bronze bush. I am now getting used to using the dial gauge to get the machining lengths correct. This spigot is going to be 3/4" long.

 

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I got close on the correct diameter with the machining. The final sizing I did with emery cloth to get a nice sliding fit. It nearly fits.

 

2584.thumb.jpg.ace0114364105b0d7cbda4858bc1066c.jpg

 

It does now!

 

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You will have to wait until tomorrow so see what I do next.

 

 

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Looking at the photos I have taken since my last post I am having trouble remembering what I have done! Normally, the photos act as an aid to my memory, but not this time.

 

2586.thumb.jpg.ad77a50814f1fd77eeb4cca66dd3534b.jpg

 

I haven't a clue what this shows apart from a bit of metal with a hole down it that fits into the bush?

 

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This part I put in a collet the other way around to machine a flange and pin that would fit inside a 13.1mm (33/64") rod to keep the bronze bush in line when it was pressed in. Now I am starting to remember.

 

2588.thumb.jpg.ef3e2057796b410b3a98b05238b39b51.jpg

 

This must be the 13.1mm pin the size of the gudgeon pin that the other part I am making fits in.

 

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This photo may help to explain the flanged part a little bit better.

 

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It all becomes a bit clearer now - I think! This mandrel slides onto the flanged part.

 

2592.thumb.jpg.246ce0a6cc2fe98abd1a344c6f55e829.jpg

 

This photo explains it even better. I am now starting to understand what I did. I made it in two separate parts so that the flanged part would hold the bush in line with the other bush.

 

The part in the first photo is a mandrel I made to fit through the bush. In the end of it, is a hole to fit the pin that is in one end of the flange the other end of the flange has a 3/4" long pin the size of the internal diameter of the bronze bush. The idea being that the mandrel and the flange with the turned ends will hold the bush inline with the other bush when it is pushed in.

 

2595.thumb.jpg.2ec633d3f51b4699920415418376a121.jpg

 

It worked. Now to drill the oil holes and make the gudgeon pins. I can't believe it has taken me two days to make those two tools! I thinks I will make the other six bushes first and then drill all the oil holes at the same time.

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Two days to make the tool and two hours to do the job is about par for the course.

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On ‎1‎/‎17‎/‎2020 at 12:23 AM, JV Puleo said:

Two days to make the tool and two hours to do the job is about par for the course.

 

Thank you Joe. At least that has made me feel a lot better about the time it has taken!

 

2598.thumb.jpg.810a97f653cf6ba69cbf1a849ce8e00b.jpg

 

I have been looking on the internet for one of these 5C collet holders to use on my milling machine. I had thought about buying a new one from China, when this one popped up on eBay, asking for offers, I managed to buy it for less than half the price of a new Chinese one. I also looks a lot more robust. Having given up smoking since the end of September, I keep thinking that I can spend the extra money I have saved on equipment and tools for the workshop! The problem is, I am probably spending more than I spent on tobacco, never mind, its only money!

 

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Two more bushes machined from one end. I decided to finish the machining of the flange ends after all the rest of the bushes have been machined from this end. I can then then change the 5c collet to fit the smaller diameter and then face off the flange end of the bushes to 1/16".

 

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I had been gaily drilling the end of the bronze bush with a centre drill, then drills and then a reamer. I then realised that the bore on some of the bushes I had made was not central in the bush. I looked for a small enough tool to fit into the tool post to bore them to the correct diameter but could not find anything that I had that was suitable. I then thought about using this tool in the tailstock. I had never tried using this bit of kit before.

 

2603.thumb.jpg.fea96c49c5dfa076e8234492814fcade.jpg

 

I seemed to work for me, so after boring, I put the reamer into the bush.

 

2599.thumb.jpg.40f65712c7a328cfcb68e93223043a4d.jpg

 

It worked and I manged to machine and ream the bronze bush ready for the circlip groove and oil groove to be machined in the bore.Just as I was going to fit the tool holder into the tool post, with the cutting tool for the circlip groove clamped into the tool holder, I managed to drop it. Of course, as Murphy's law states,  it landed with the cutting edge down on the cast iron bed of the lathe and the end snapped off.

 

2600.thumb.jpg.5f25ce2d8502bd578e95add04a06348a.jpg

 

I found another HSS tool that had been ground for cutting internal grooves and measured the width of the groove it would cut. Slightly wider than the tool I broke, but only by 0.003". I thought that I maybe pushing my luck if I attempted to thin the width down by a few thou on the grinder . I recalculated how far in I needed to wind in the compound slide to cut both the circlip groove and oil groove.

 

2601.thumb.jpg.83c4ea8e364b1bd2f19e604aad572735.jpg

 

It worked out at 0.093" for the circlip groove and 0.550" for the oil groove. With a cut of 0.035" deep.

 

2596.thumb.jpg.6bf3463e5a80302ed2f7be14bcf35641.jpg

 

I then tried the circlip in the groove to check that it fitted OK. After two circlips sprung out of the circlip pliers, never to be seen again, I placed some paper roll on the lathe bed to catch any flying circlips! Of course the paper roll worked, or perhaps I should say, the paper roll was not needed, as the next clip fitted without flying out and vanishing.

 

2604.thumb.jpg.b17e37ef52d867a29279be6777ceedc3.jpg

 

Bushes for another two pistons faced off and ready for fitting into the pistons. I don't know if I was now getting over confident, but the next bush I made I somehow managed to bore out at too larger diameter. When I went to ream the bush the reamer was a very loose fit in the bore. Luckily there was just enough bronze bar left to make the final two bushes.

 

2605.thumb.jpg.d54229534367728aee2247ec63d7c7e8.jpg

 

The next jobs are making the gudgeon pins, pressing the bushes into the pistons and drilling the oil holes. After my mistake with the boring I shall leave those jobs until tomorrow.

 

2606.thumb.jpg.68c176cd74c40bc0692d2e6c466c9319.jpg

 

On Thursday afternoon I found that I did not have a 5C collet that would exactly fit the drill rod for the gudgeon pins. I ordered a new 33/64" collet and it arrived on Saturday. I checked it clamped the rod firmly and faced off the end of the bar.

 

We have not had any rain today here in North Norfolk, the weather is cold with bright sunshine. It is supposed to stay like this for most of the week. I don't know if it is just the sunshine, but it seems to have made my breathing a little bit better.

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I suspect it's the dry air – something I doubt you get much of in Norfolk.

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No, Joe not a lot of dry air this winter. We have only just started having a few frosty mornings this winter.

 

"What's for lunch Jane?"

 

2608.thumb.jpg.488347c38c746447e8c42b355286f354.jpg

 

"Pistons on toast!"

 

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Tools, gloves and bits and pieces we might need for pushing the bushes into the pistons.

 

Because the pistons were going to be around 200 degrees C, when they came out of the oven, we had a practise with the tools etc. on a cold piston first of all so we both knew what we were doing. I said to Jane that the bushes would just press in easily and will not need the threaded rod to pull the bushes into the pistons, therefore we didn't practise with that with gloves on!

 

2610.thumb.jpg.ec8d0575ec6f602fc9b87f6054c12751.jpg

 

I was wrong! The first bush we tried to push in, started with a tap from the hammer onto the original Ford wrist pin which was placed through the other pin hole so as to keep the bronze bush square on to the hole. Then it jammed and didn't want to go any further! Out came the threaded rod and we managed to get the nuts and spacers on it without burning our hands, more by luck than judgment. It moved a bit and then did not want to move anymore.

 

2611.thumb.jpg.b59255d95e578d69c785933634c8b087.jpg

 

Rather than try and force the bush in, we put the piston back in the oven to heat up again. You can see from the above photo the bush has not even come out the other side.

 

2617.thumb.jpg.83326fe1183244713067a2368a7a9030.jpg

 

I removed the stuck bushes with the threaded rod and spacers, turned the oven off let the pistons and bushes cool down. The photo above is actually successfully pulling in one of the bushes with the threaded rod, nuts and spacers.

 

After trying the bushes in another piston with the same result of getting stuck. I realised that I had probably made the bushes a bit too much oversize at between 0.0015" and 0.0020" maximum. 

 

2615.thumb.jpg.0a7540987e5d23496a6ee5d49a160038.jpg

 

After lunch, when they were cool I super glued them in turn onto the mandrel that I had made previously and used some 400 grit emery to take each of them down to 0.001" oversize. I forgot to take the camera back up to the workshop with me, so no photos of this operation.

 

2612.thumb.jpg.b5ca98b817fda69b2438bd0beddda844.jpg

 

After heating the pistons up again in the oven, we tried again, they fitted easily, without resorting to pulling them in with the threaded rod.

 

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All 4 pistons now ready for drilling the oilway and final reaming. When the pistons cooled down the bushes were nicely fixed in the pistons.

 

Next job; drilling the oil holes and making the gudgeon pins.

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Nice kitchen! And good job on the pistons. You were both lucky to have not be burnt with your experiment!

 

 

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Nice Job Mike!

 

This where the "Machinery's Handbook" comes in handy for calculating interference fits. (LOL)

 

I remember years ago helping my ex-father-in-law install new sleeves in a Ford 8N tractor. Previously he had knocked the 

old sleeves out by splitting them with a chisel. After heating the block-up with a torch he grabbed the new sleeves

out of the freezer and knocked them in with a hammer and block if wood. As crude as it sounds it worked well!

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Before I machined the drill rod to length for the new gudgeon pins (wrist pins) I measured the pistons to decide on the lengths they needed to be. The idea being that I did not want too much of a gap between the pin and the circlips. They being fitted to stop the pins sliding out of the bronze bushes. I looked on the internet to see if I could find any minimum and maximum clearances for circlips, but had no joy.

 

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Each piston was given a number on a length of masking tape which was then stuck to the inside of the piston. In theory, each gudgeon pin should have been the same length. There were discrepancies between the lengths, presumably due to my machining of the bushes and possibly due to having to change the lathe tool, for cutting the circlip groove, after I managed to drop the toolholder and broken the cutting end off the first cutting tool.

 

I was going to include a photo of the A4 sheet I made my calculations on. I have now decided against that as it looks so scruffy in the photo. It wasn't a simple job of measuring between the two circlips as I did not have suitable measuring tool that would fit inside the bushes. I measured the distance between the outside of the two bushes and took off the distance in from the outer end of the bush to the circlip groove (0.050" x 2) and double the width of the circlip.

 

I was surprised by the difference in length between the four gudgeon pins. If you have only just started reading my posts, you maybe wondering why I am modifying 4-pistons for a V-twin engine? Two are for Kevin, a fellow Humberette owner, in Australia.

 

The next job of drilling the oil holes was easy, when compared to the previous work on the pistons.

 

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Firstly, I used a centre drill to locate the correct position for the hole, drilled with the centre drill, before drilling through the bronze bush with a 3.5mm drill.

 

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I forgot to take any photos of making the gudgeon pins. To date, I have only made the two for Kevin's pistons. I will attempt to remember to take a couple of photos when I make the pins for my pistons.

 

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I marked the two pistons for Kevin with a red and green paint dots on both the piston and the gudgeon pins so they don't get muddled up. I was pleased to find that when I tried the reamer in the piston it went through both bushes fairly easily by rotating the reamer by hand. The gudgeon pin was slightly stiffer in one of the pistons. But as they used to say at Burtons, the UK high street the tailor of the 1960's "They will ride up with wear Sir"!

 

When it came to came to painting the green blob of paint on the second piston, all went well until I put the lid back on the paint tin. I tapped the lid on with a hammer and turned the tin upside down to seal the lid with paint - then the lid fell off, pouring paint onto my tools, lathe and floor.

 

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After a manic 5-minites cleaning up the mess. I seem to buggered myself up, and have to pulled a muscle in my stomach. Today, I have decided to take it easy and not venture out to the workshop. I left the paint on the pistons to dry in front of the workshop fan heater. The stern comment from Jane - "You shouldn't be let anywhere near a tin of paint!"

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Well, in England there is normal red blood, blue blood (in French we say that about the aristocrats) and you manage to have green blood! Anyway, I feel you pain even if I had to laugh!

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