Mike Macartney

REPORTS ON A 1914 HUMBERETTE RESTORATION

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Still messing about with bottom end of the Humberette V-twin engine, will I ever get back to working on the body or the chassis, or, even get the body back on the chassis? It's not that I am getting fed up with the engine work, but I do find it very time consuming.

 

When I had the flywheel between centres, in the lathe, with the two conrods 'dangling' down, I noticed there was quite a lot of sideways movement of the conrods on the main big end pin, when the two flywheels were bolted up. To me, it seemed excessive at perhaps a 1/10th of an inch? I had a read of some of my books to see if I could find any information as to how much slack was acceptable. The only information I found was in "Tuning for Speed". I quote "The correct amount of side-clearance varies according to the design, but is rarely of great importance, 0.010" to 0.020" being about right in most cases." I decided to attempt to check the existing side clearance more accurately than my 'guestimate'. To this end, I decided to bolt one side of the big end pin up firmly into one side of the flywheel.

 

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Using the press I pushed the pin into the taper and tightened the nut on the other side, while the pin was under pressure. It would be useful to know the pressure I exerted, perhaps one of these days, I may manage to get around to fitting the press with a gauge?

 

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I dug out my kit of Plastigauge, but it did not measure wide enough for the gap that I thought existed. I decided to use some plasticine instead and pressed it into the join between the big end pin and the flywheel.

 

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I bolted the other flywheel onto the other end of the big end pin and bolted it up reasonably tight. Then undid the nut and broke the seal on the taper by bouncing the flywheel, that I wanted to remove, on a block of wood. With one of the flywheels removed I could see that the plasticine has squashed flat. Now to attempt to peel the squashed plasticine off the flywheel.

 

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One bit came off easily and I measured the thickness of that. Say about 0.072". If I go by what I read, the side-clearance needs to reduce by about 0.050", or do I go by the statement that says "it rarely matters"?

 

I'll get on with something else, while perhaps one of you, with more experience than me, may have come up with a suggestion.

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I wonder if it matters. The side to side movement of the big end will be limited by the position of the small end in the piston.

 

 

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While I don't know the exact side to side measurement, the big end of connecting rods on a 31' chevy 194ci engine are adjusted for bearing tightness by removing shims, replacing the cap and nuts, then tapping the end sideways on the journal with a small hammer. The engine manual says that the big end should move with light taps but not be able to just slide from side to side. One has to think there has do be a considerable amount of distance of travel to use this method to check the big end bearing tightness. I realize the Chevy 194 is not a V twin motor or a rod rotating between two flywheels but one could assume there was a rule of thumb back then for sideways movement which probably helped with the lubrication of the bearing. Between the piston and the large end having some room to move, the rods were allowed to find their happy spots while the engine was running it would seem.

Edited by chistech (see edit history)
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Thank you Joe and Ted for your comments. I do like the idea that some sideways movement may help with the splash lubrication.

 

I used to have an engineering pal who lived at the local pub, (literally), he was always interested in the work I was doing and used to come down to the workshop sometimes to help me. After working in the garage I used to go up the pub each evening about 5pm, have a couple of pints and chat over my ideas and engineering problems. Sadly he died of cancer about 4-years ago. I gave up going to the pub after that, as the only chatting around the bar nowadays seems to be about football or cricket. I do miss being able to chat to somebody face to face on a regular basis about car related problems, although the members on this forum have helped me a great deal, thank you.

 

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At present, I am really struggling to get the two flywheels lined up to the 0.003" runout that I had previously, between the two shafts. Each attempt seems to make the difference even bigger. I'll get there in the end, but it does get a bit 'mind boggling' towards the end of the day. Perhaps I'll do better today? I want to get the shafts roughly lined up so I can put the assembly back in the crankcase, fit the jugs and check the piston heights again, before I decide on what pistons to use.

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About 10 plus years ago, my son did a ton of amateur motorcross racing. I started him on KTMs and he was on them until he had to start financing his own racing as while I found them the best mechanically, they were also the most expensive. Because of the much better reliability of the KTM engines over their Japanese counterparts, we did much fewer engine rebuilds than most other racers but we still had to do some. When replacing the rod, we took the crank assembly to the shop where they pressed it apart, replaced the rod bearing and rod if needed, then placed the assembly in a very rigid jig made especially for that crank. It was pressed back together then checked in another jig for any run out. More often than not they needed nothing more as the KTMs are very well made as most Austrian things are. My sons friends had many issues with their motors and their rebuilds.

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On Sunday, as next doors packing bench and weighing machine was not being used, I decided to have a change from my attempts at getting the flywheels aligned and weigh the engine parts.

 

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I also decided to weigh the spare flywheels that I managed to obtain to see what difference the weight was with the ones I had machined.

 

Weighing the small end is a little bit of a compromise with this V-twin conrod setup.

 

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I placed the small end of the conrods on the scale one way round and rolled the flywheels so I measured the weight in three positions on the scales and noted the weights. The scales are set on kilograms.

 

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I then rotated the flywheel assembly by 180 degrees and carried out the weighing operation again.

 

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As can be seen from the above photo I tried to have the conrod approximately horizontal when the small ends were lying on the middle of the scales. I will average all the small end weights taken when I transfer the weights from my notebook to an Excel spreadsheet. The difference between each of these readings was not as great as I had thought.

 

Jane needs to use my laptop, so I add some more information about the weighing latter.

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Following on from my enforced break!

 

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I also weighed the various pistons, the cast iron originals, BMW 315 and Ford Zetec pistons, that I maybe able to use. Looking at the weight on the display, this piston is very light! :)

 

Going back to the alignment of the flywheels after my weighing. I will post the weights when I have them in the spreadsheet.

 

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A thought occurred to me, if the two flywheels were placed on two parallel steel bars, they would not be far off true when bolted up together. Hence, I used the lathe bed.

 

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This time, rather than having dangling conrods I held them up with a bungy strap.

 

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. . . . and set up the two dial gauges to see how much run out there was this time.

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Mike,  Being particular is the best idea.  You are sure covering all of your bases!

Al

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It seems a while since I reported on the work that I have been doing on the Humberette. Looking at the date of my last post, it was ten days ago. Where does the time go when you are enjoying yourself!

 

Fun and games where had attempting to get the two halves of the crankshaft bolted up together, with both ends of the main shafts in line. Previously I had managed to have a maximum of 0.003" runout. This time I kept 'chasing my tail' and getting nowhere fast!

 

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I resorted to marking the amount the shaft was out, on the outside rim of the flywheel, in white pen.

 

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Still making no progress with the alignment, I wondered if the gap between the flywheels was not even all the way around? I then marked the gap, in thousands of an inch, in orange marker pen.

 

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The biggest gap was 0.831".

 

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. . . . and the smallest 0.797". By now I was getting completely flummoxed as to where the problem was. Each time I needed to hit the flywheel in the high position, to try and line them up, I removed the flywheel assembly off the lathe as I did not want to 'thump it' while it was between centres. After two or three days messing about I still could not get to the previous best alignment of 0.003". From memory, I think I finally managed about 0.007". By now I was 'loosing the will to live' and decided that 0.007" would do for the time being, as I only wanted to put the crankshaft assembly in the crankcase, so I could check the compression height again. As last time I measured it, the difference was about 4mm?!? That was the reason that I stripped the engine to find out why.

 

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I had a good look at second crankcase I had bought, although some of the parts of it were in good condition, the underside was very corroded. Possibly the engine, at one time, had been stilling on muddy ground for a considerable period of time.

 

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I decided to use the original crankcase. I placed the flywheel assembly into the front crankcase and found that when rotated it seemed to be touching something. Originally, when I took the engine apart there was a steel spacing washer between the flywheel and the rear case and not one between the front case. When I removed the flywheel assembly from the front case I found that the nut for the big end pin was just touching the bronze bush for the camshaft gear. In the photo above you can just see two bright marks on the camshaft bush.

 

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I fitted the spacing washer on the front shaft and assembled it again, everything turned OK, so I fitted the rear casing and still the flywheels turned round smoothly. The crankcase and flywheel assembly balanced OK on the Workmate bench. I was concerned that it would be a stability problem if I started trying to fit the barrels (jugs) without the engine casing fixed to something solid.

 

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Before I set about making a simple engine stand I had to make some alloy spacers to make up for not having the gearbox fitted to the rear casing.

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Hello Mike,

I read all the pages of your blog. Mike, you show exceptional craftsmanship. I like this kind of restoring a car, performing all the work yourself , and learning a lot during the process, most satisfying. Reading about the engine, it seems to me as very compact, but rather a complicated and well designed engine. I am anxious to see the first start of the restored engine, keep my fingers crossed. A question: are the crankshaft bearings made of bronze with a Babbitt lining, or just bearing bronze without Babbitt lining?

Regards,

Harm

Edited by Sloth
Corrected syntax error (see edit history)
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19 hours ago, Sloth said:

I like this kind of restoring a car, performing all the work yourself , and learning a lot during the process, most satisfying.

 

Hi Harm, there are some parts of the restoration I would have liked to have done myself. For example: spraying the top coats of paint on the body, the interior trim work and making the top (hood to the English speakers on this side of the big pond!), fitting the beaded edged tyres onto the rims, are three of the items I have had to ship out. The final paintwork was carried out by the guys who used to work with me at Jaymic. I sold them the company when I decided to retire 15-years ago. Interior trim - well, I would have been happy to learn, but at my age I think it would have taken longer than I haver got left! I attempted to fit the tyres myself, but I just did not have the strength or the 'puff' to manage it, again I left this to the guys at Jaymic. In the past I have left the engine work to the guy who used to build engines, gearboxes and diffs for Jaymic. Since joining this forum about a year or so ago I have found a number of members to ask and advise on problems. My machining skills are limited, but from following others on this site I am getting much better and more accurate. The main thing is I am enjoying myself. It is just a shame that I could not afford to retire at 25!

 

To answer your question on crankshaft bearings, they are just bronze with no Babbitt lining.

 

I am pleased that you decided to post details of your 1903 Cleveland. I am enjoying following the progress. I do like your workshop and equipment. Seeing the Sun engine tuner and the distributor testing machine, makes me wish I had not scrapped or sold some of the equipment that I had collected over the 30-years of my time of running Jaymic. At one time we where a Bosch Jetronic Centre and I do still have D-Jetronic, K-Jetronic and some Motronic test equipment, whether I will ever use any of it again is very debatable.

 

16 hours ago, mike6024 said:

Are the cylinders identical, interchangeable? I was wondering if the connecting rod heights are different could the cylinders possibly be different?

 

Mike, they are handed. I have found the problem of the heights. You will find out the answer shortly

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Mike, I am amazed at the work that you do. I enjoy every post. I can't say enough. John

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Many thanks John. Your comment is very much appreciated, but I feel I am unworthy of it, when compared to some of the others on this AACA forum, the work that some of the others do is truly outstanding.

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I slept on the idea of the engine stand. I felt I needed just something simple. Also, I wanted to use bits of metal I had lying around, rather than buying it new. The next morning I had a measure up of the box section I had available.

 

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I refitted the original engine mounting plates.

 

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. . . . and came up with this.

 

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It seemed to hold the engine nice and firmly.

 

One of the old nuts that bolted the big end pin to the flywheel was a nice tight fit on the thread at the gearbox end.

 

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This big old spanner turned the engine over easily.

 

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The right hand barrel was fitted and bolted down. The dial gauge was then fitted and the engine turned over to find the top dead centre. The gauge set to zero and the engine rotated again just to check it was still sitting on zero at TDC.

 

I am now going to keep you in suspense, until tomorrow, when I will inform you of the answer to the compression height differences between the two cylinders.  

Edited by Mike Macartney
photo in wrong place (see edit history)
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1 hour ago, Mike Macartney said:

Many thanks John. Your comment is very much appreciated, but I feel I am unworthy of it, when compared to some of the others on this AACA forum, the work that some of the others do is truly outstanding.

No, Mike, you are on par with everyone else. believe me! John

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I'll keep you in "suspenders" no longer!

 

I started by measuring again with one of the pistons on TDC. It is a little difficult with these water cooled barrels as there are a number of measurements and calculations to make.

 

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I started by measuring the depth from the top of the outside of the barrel down to the bottom of the waterway, which is the outer cast iron casing of the combustion chamber.

 

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Now, I have got to try and measure accurately, the thickness of the inner threaded part down into the actual combustion chamber.

 

Then a thought came to me. How about using a bit of plasticine?

 

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I pushed a roll of plasticine down the hole until it flattened the end of the plasticine on the top of the piston. Then I squashed the plasticine to the side, into the thread, first with a thin steel rule and then a biro, to give the plasticine a good definition of the thread.

 

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This is how the plasticine came out.

 

These are the measurements I got.

 

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Cylinder 1.

 

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Cylinder 2.

 

Conclusions to all this work?  It appears there was an Operator Malfunction with the original measuring!

 

At least all the stripping of the engine wasn't in vain. I did find the problems with the loose rivets holding the flywheels to the shafts and the very worn big end on the smaller conrod.

 

Now I can get on with attempting to do some productive work making some bits for the engine.

 

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Let's start by making some nuts.

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18 hours ago, John S. said:

No, Mike, you are on par with everyone else. believe me! John

Absolutely John,  I couldn’t agree more!

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To bolt the barrels (jugs) to the crankcase I need to make 16 nuts at 3/8" BSF. From my previous restoration work, on vintage motorcycles, I have made nuts and bolts, in the past, out of stainless steel, as it saves having to nickel plate them. So I thought I would do the same with this Humberette engine.

 

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First one half made. Does it fit?

 

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Well, it appears to. The other end will need machining, but, I will wait until I have made all 16, then make a male threaded jig for machining a flat face all these 16 nuts.

 

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I thought I would show you this 3/8 socket with a square hole to fit threading taps. I bought a set on eBay a few years ago quite cheaply. They have a magnet inside that stops the tap falling out. I have found them very useful, especially when you have a lot of threaded holes to clean out on a bodyshell.

 

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Only 3-more to make! I do get very bored making the same thing over and over again.

 

I interspersed the nut making with . . . .

 

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Making a holder for the 5C collets. . . .

 

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. . . . another eBay buy. Most of them are Hardinge, I had started buying some new Chinese collets (in the blue plastic box) and then this large box load came up for auction. Probably, I will never use most of the sizes. I also picked up the magnetic lathe chuck that you can see to the right of the photo.

 

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The rack screwed to the shelf. Now I will have to get the collets put in order of size.

 

Yesterday I went to collect a hand shaper that I bought on eBay on Sunday evening.

 

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Edited by Mike Macartney
extra photo removed and spelling mistake (see edit history)
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That's a nice collection of collects. Now with everyone buying equipment I guess I need to start searching for something now. 

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Mike....Some guys seem to have all the fun.  I relate with the boring part of machine work, but the end result is definitely work the effort.

Al

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1 hour ago, Laughing Coyote said:

Now with everyone buying equipment I guess I need to start searching for something now.

 

This story may amuse you. Our eBay account is my wife's, so is the PayPal, all the tools and equipment I buy on eBay goes on her credit card. She hasn't complained yet!

 

 

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Hello Mike,

Hardinge collets = top quality equipment.

Congratulations with the shaper! Shapers are a nice and useful addition to the shop tools. I have one and use it often, they are more versatile than most people think.

Regards,

Harm

 

Edited by Sloth (see edit history)
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Mike!  You have a keeper in your wife!  DO NOT upset the basket!

Al

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