REPORTS ON A 1914 HUMBERETTE RESTORATION

[mike6024]

 

Here's the picture. And you can see the way it is photographed, the "short" rod is off at an angle. So it should be the same length if measured from the center of the big end journal, to the center of the wrist pin.

 

This is called a "master and link connecting rods" arrangement and is also supposedly used in aircraft engines, radials.

 

 

 

 

Edited July 28, 2019 by mike6024 (see edit history)

[Bloo]

39 minutes ago, mike6024 said:

 

 

So Mike measured the compression height difference to be 4 mm which is 0.16 inch. More than 1/8 inch, but not too much more.

 

 

Note this picture is confusing because it makes the "short" connecting rod look shorter than it really is functionally. The "short" rod should be off at an angle, I think the angle between the cylinders, and so the wrist pin, and the main big-end pin, and what I'd call the "hinge pin" are all in a straight line.

 

So Mike was going to double check his compression height difference measurement. It is even possible that when this engine was originally assembled the two pistons were different, in the pin to crown dimension, and at some point it got disassembled and put back wrong.

 

BTW, I actually came across some custom Harley connecting rods which were made like this, one long rod and another short, with the "hinge pin." Claim was it was done because it was stronger than the fork and blade. I'll see if I can find it again. So it is not some wild design.

 

 

SO which way does it go? And does it matter? Would one direction result in a different compression height? I doubt it, but it is hard to visualize.

 

Also, rod length affects dwell time at TDC, and how quickly the piston falls after leaving TDC. It would be really interesting, I think, to measure piston drop past TDC vs degrees of rotation. Could Humber have made piston height different intentionally trying to compensate for a difference?

 

 

 

 

Edited July 28, 2019 by Bloo (see edit history)

[chistech]

4 hours ago, mike6024 said:

 

Here's the picture. And you can see the way it is photographed, the "short" rod is off at an angle. So it should be the same length if measured from the center of the big end journal, to the center of the wrist pin.

 

This is called a "master and link connecting rods" arrangement and is also supposedly used in aircraft engines, radials.

 

 

 

 

Yes, radial aircraft engines use a rod system like that including even model radial engine for RC planes. I mentioned earlier that possibly the engine had two different pistons as far as wrist pin location to get the pistons even height in the bore. It would be easy to make two pistons that way I would think.

[Mike Macartney]

Thank you for all your posts, ideas and links. It gives me a lot to read and think about.

 

I found the level. Is this a machinists level?

 

 

From reading a little bit about them, I thought they were adjustable? This one just has the 'tube part' screwed to the base with socket head screws. I laid it on the bed of the lathe and lathe is level from the headstock to the tailstock end of the bed. When laid across the bed, headstock end, middle, tailstock end, the rear of the lathe needs to come up, the same amount along the back of the lathe. The main bed casting of this Woodhouse & Michell lathe is very substantial. I shall wait now until I have finished machining the other flywheel, before I have a go at levelling the lathe, as I do not want to disturb the jig that is in the chuck.

 

Yesterday I machined off the corners of the flywheel. As a bit of an experiment I used a carbide tool on the side nearest the chuck and a high speed steel tool on the side that faces the tailstock.

 

 

3/16" bevel on the chuck side.

 

 

3/16" bevel on the tailstock side turned out a lot smoother finish!

 

 

The machined finish to the old cast iron was not as smooth as I thought it would be. The lathe tool did 'chatter' on some of the machining. What could be the reason for this 'chatter'? Looking on the bright side the surface finish may help with the splash lubrication!?!

 

 

I checked around the area where I had previously checked and nothing had moved, that was a good sign.

 

Now to put permanent 'Loctite' on the countersunk screw threads and torque them up.

 

 

I put some clean thinners in the plastic jug. Removed a screw and put it in the thinners to clean off any grease and muck with a brush.

 

 

I used a small brush to clean out the thread in the cast iron, then used cotton buds to make sure I got all the dirt and grease out. The screw and threaded hole were then give a 'blast' with the compressed air gun.

 

 

The thread lock was then carefully put on the screw thread, replaced, torqued up to 11 ft lbs and marked with an orange chalk marker so I new which screws I had finished with.

 

 

The screw diametrically opposite was then removed cleaned etc. etc. until all of the screws had been locked in place.
 

 

Look at the colour of this thinners after cleaning all the threads.

 

 

This was the job I was worrying about, removing the shaft and flywheel from the jig. Will it come out of the jig without removing the jig from the lathe? A wooden wedge was placed under the flywheel part, so as not to put any strain on the jig while I attempted removal. The 6-nylon tipped grub screws were loosed off. A little tap with a plastic headed mallet and the flywheel slid out perfectly. A quick clear up and I was ready for my friend Robert to pick me up for a couple of Sunday lunchtime pints down at the Black Boys pub.

 

Today, I'll start on the other flywheel and shaft, which is in fact the front one. It should take a lot less time, as I vaguely know now what I'm doing, the holding jig should also work OK for this second flywheel.

[Terry Harper]

Mike,

 

The chatter could be for any number of reasons. Tool length, rigidity of the setup etc or it could just be the iron itself.

During the casting process if the iron cools too quickly it becomes what I have heard is referred to as white iron. Its

tough stuff!

 

I had a valve guide cast that was nearly impossible to machine. The tool literally skidded across the surface where as a

good quality grey Iron is a pleasure to machine or turn. So... it could just be the quality of the casting. It could also have become

work hardened when it was originally machined - but I am not sure if that's typical of cast iron or not. I know it is for brass.

Edited July 29, 2019 by Terry Harper (see edit history)

[Spinneyhill]

Before relying on the level, test it. Put it on the lathe bed in a place easily repeatable. Turn it 180^o and put it there again. The bubble should be in the same place in both directions. If not, adjust it so it is.

[Roger Zimmermann]

It may be a totally dumb question: you are refinishing the flywheels with steps I'm not always understanding, probably because I I'm miles away to understand how this engine is functioning. My point is following: if you are machining the flywheels, you are removing weight. Is the weight not a critical factor in those engines?

[Mike Macartney]

2 hours ago, Spinneyhill said:

Turn it 180^o and put it there again.

 

I now feel a complete 'WALLY', I have been overthinking this - wondering what I have that is completely level to check it on!

[Stude17]

"The machined finish to the old cast iron was not as smooth as I thought it would be. The lathe tool did 'chatter' on some of the machining. What could be the reason for this 'chatter'? Looking on the bright side the surface finish may help with the splash lubrication!?! "

 

Make sure the cross and compound slides  are properly adjusted to remove backlash/excess movement and slow down your spindle speed.  It is a slow process when machining the face of large diameter objects in the lathe if you want a smooth surface finish.

[alsfarms]

Mike, good for you on the flywheel truing up process.  You simply can't be to careful with that work if you want the engine to run, run good and most of all last!  I have been very busy with farm work and other responsibilities so I have barely had time to read of your ongoing work, and simply have not had time to respond very often.  My own threads have somewhat been neglected also.  You are about to the point that you are going to need to simply attack the con rods.  Here is my "two cent" thoughts on the rods.   You know that you need pistons, the existing rods are marginal, or do you feel they could be reworked to put them in a satisfactory and workable condition?  Do you have enough meat in the top end and bottom ends, of the rods, to machine them to accept a bearing or only room for bushings?  Pistons can be had in a wide variety of compression heights, to fit the length of the con rod and give you a calculated CR (Compression Ratio).  I'm sure you are up on "CR", but sometimes I scratch my head when reading postings where acronyms are used in place of words and I am lost for a minute.  I do have the thought that the rod lengths should be the same .  So many danged issues come into play if they are not the same length and in my thinking the OEM manufacturer would need to do much more engineering to accommodate uneven rods.  I simply don't think they would make such a compromise on purpose!  So, I would engineer them, in some form, to have the same exact length.  If re-engineering is absolutely not possible, then I would probably consider "biting the bullet" and have a pair built to your required specifications, (if you have no luck with any of the aftermarket sources for custom rods).  Just a question, have you looked into other aspects of the bottom end of the engine, as in cams, cam drive gearing, oiling, lifters and etc.?

Al

Edited July 29, 2019 by alsfarms
spelling (see edit history)

[Mike Macartney]

3 hours ago, Roger Zimmermann said:

if you are machining the flywheels, you are removing weight. Is the weight not a critical factor in those engines?

 

It's not a dumb question at all. All I am doing is getting rid of the runout on the flywheels. When I put the crankshaft assembly (both flywheels, big end journal and conrods bolted together) on the lathe, mounted between centres and rotated the crankshaft assembly the flywheels wobbled from side to side. I hope I have removed the 'wobble' by machining some metal off each face of the flywheel so that they will now run true. I have not removed large amounts of the metal, so it should not make much difference to the running of the engine. They seemed overly heavy compared with similar veteran an vintage motorcycle engines I have overhauled in the past.

[Mike Macartney]

3 hours ago, Stude17 said:

Make sure the cross and compound slides  are properly adjusted to remove backlash/excess movement and slow down your spindle speed.  It is a slow process when machining the face of large diameter objects in the lathe if you want a smooth surface finish.

 

I did have the rotational speed as slow as I could get, and the feed very slow. I'll try a slower feed rate on the next flywheel. Maybe I had the cutting tool a bit far out. I'll check to see if I can adjust the backlash. Thanks for your help and suggestions. This is the first time I have tried machining cast iron.

[JV Puleo]

35 minutes ago, Mike Macartney said:

 

It's not a dumb question at all. All I am doing is getting rid of the runout on the flywheels. When I put the crankshaft assembly (both flywheels, big end journal and conrods bolted together) on the lathe, mounted between centres and rotated the crankshaft assembly the flywheels wobbled from side to side. I hope I have removed the 'wobble' by machining some metal off each face of the flywheel so that they will now run true. I have not removed large amounts of the metal, so it should not make much difference to the running of the engine. They seemed overly heavy compared with similar veteran an vintage motorcycle engines I have overhauled in the past.

 

They are probably heavier than they need to be. That was a common engineering error made before WWI - and probably into the 20s at least.

 

[Mike Macartney]

2 hours ago, alsfarms said:

I have been very busy with farm work and other responsibilities so I have barely had time to read of your ongoing work, and simply have not had time to respond very often.  My own threads have somewhat been neglected also.  Here is my two cents thoughts on the rods. You know that you need pistons, eh existing rods are marginal, or do you feel they could be reworked to put them in a satisfactory and workable condition?  Do you have enough meat in the top end and bottom ends to machine then to accept a bearing or only room for bushings?  Pistons can be had in a wide variety of compression heights to fit the length of the con rod and give you a calculated CR (Compression Ratio).  I's sure you are up on "CR", but sometimes I scratch my head when reading postings where acronyms are used in place of words and I am lost for a minute.  I do have the thought that the rod lengths should be the same in the same.  SO many danged issues come into play if they are not and in my thinking the OEM manufacturer would need to do much more engineering to accommodate uneven rods.  I simply don't think they would make such a compromise on purpose!  So, I would engineer them, in some form, to have the same exact length.  If re-engineering is absolutely not possible, then I would probably consider "biting the bullet" and have a pair built to you required specifications, (if you have no luck with any of the aftermarket sources for custom rods).  Just a question, have you looked into other aspects of the bottom end of the engine, as in cams, cam drive gearing, oiling, lifters and etc.?

Al

 

I should think your farm work keeps you pretty busy this time of year. Conrods - if I can't find some suitable fork and blade con rods at a reasonable price, I will go with what I have. There is no rush so I am taking my time and learning more about machining as I get more used to the work on machining the wobble out of the flywheels. I don't think there is room for a bearing in the big end, I will have to replace the bush in the smaller conrod as there is a lot of slop in this one. I am starting to think it may have been my measuring, or writing down the incorrect measurement on the compression height differences. We will see when the crank is finished and I start putting the engine back together to recheck.

[JV Puleo]

I think I'd make a plug with a center hole for the big and small ends and use them to get an accurate measurement of the distance between centers. If it is equal - or within a few thousandths - perhaps the easiest thing would be to renew the bushings and use the rods. Seeing them apart like this I can't imagine that the short rod has been changed. With what? Other parts for this engine were probably never easily found.

Edited July 29, 2019 by JV Puleo (see edit history)

[chistech]

Here is a small 3 cylinder radial RC plane engine main rod. You can see the provision for the other two. Thought I’d post a picture just to go along with my previous post. Sorry Mike, it’s not going to help you one bit as it’s probably less than 2” long. It does show that they still use the same technology today though. This is a three cylinder four stroke engine made in Japan .

 

 

Edited July 29, 2019 by chistech (see edit history)

[Spinneyhill]

7 hours ago, Mike Macartney said:

 

I now feel a complete 'WALLY', I have been overthinking this - wondering what I have that is completely level to check it on!

That doesn't matter. The bubble just has to be in the same place in both directions. Both centre and off-centre are fine. If it is off-centre to the right, it must be the same distance to the right both ways, for instance.

Edited July 29, 2019 by Spinneyhill (see edit history)

[Spinneyhill]

Just get an app for your cell phone. Many phones have an accelerometer to rotate the screen and that can be used as a spirit level. It may even be more accurate than your stride level.

[Stude17]

9 hours ago, Mike Macartney said:

 

I did have the rotational speed as slow as I could get, and the feed very slow. I'll try a slower feed rate on the next flywheel. Maybe I had the cutting tool a bit far out. I'll check to see if I can adjust the backlash. Thanks for your help and suggestions. This is the first time I have tried machining cast iron.

Yes try it with as little overhang on the cutting tool as possible  as it all adds  up to the dreaded chatter.  If you are using a carbide tipped tool make sure that you do not stop the lathe while the tool is still engaged with whatever you are machining as you will no doubt break the tip of the tool when the chuck "rolls back".  Keep up the excellent work.

[Mike Macartney]

11 hours ago, Spinneyhill said:

Just get an app for your cell phone. Many phones have an accelerometer to rotate the screen and that can be used as a spirit level.

 

Hi Spinneyhill,

 

What a great idea

 

It may possibly be a bit of a problem?!?

 

Here is a photo of my cell phone.

 

 

It still works OK. Has never needed to be repaired and has the same battery, as when I bought it 2000!

 

I thought this might amuse you.

 

Thanks for all your help and suggestions.

 

I still feel a real WALLY for not 'twigging' about rotating the spirit level.

 

Mike

[Spinneyhill]

LoL! No Wallys here Mate. Is that really a cell phone? I vaguely remember my first one being a bit like that, except a pretty metallic red. You have had a good run for it to last that long,  but I expect the battery life is minimal now?

[Mike Macartney]

18 hours ago, JV Puleo said:

I think I'd make a plug with a center hole for the big and small ends and use them to get an accurate measurement of the distance between centers. If it is equal - or within a few thousandths - perhaps the easiest thing would be to renew the bushings and use the rods. Seeing them apart like this I can't imagine that the short rod has been changed. With what? Other parts for this engine were probably never easily found.

 

Joe, I was thinking of making shafts to go through the big ends and small ends. These shafts can then be placed on blocks of the same size to show up any twist or measured to highlight any bend in the conrod. I think it is worth checking this, as I have gone so far into the engine and have no idea what happened to the engine before I got it.

 

I am having a bit of a problem with the flange on the other shaft. The metal seems to be bloody hard! Drilling the holes out for the clearance hole for the 5/16 UNC countersunk screws was a bit of a problem. I ended up having to increase the hole size by drilling in 0.1 millimetre increase of drill size each time until I got the clearance hole for the screw. The photo below shows the burrs. (sorry about the quality of the photo, I still haven't managed to get used to my daughters old camera, perhaps I should buy a new cell phone that can take photos!)

 

 

I got some of the burrs off in the lathe, but the lathe tool polished the burrs rather than cut them. I tried a file, that didn't work, so in the end I used emery cloth wrapped around the file. I am now in the process of lapping the shaft flange into the other flywheel. I hope I will be able to cut the countersinks on the other side. I'll get to that problem after I have finished the lapping.

[Mike Macartney]

17 hours ago, chistech said:

Here is a small 3 cylinder radial RC plane engine main rod. You can see the provision for the other two.

 

Very neat. Engines for model aircraft have certainly come on a pace since the last time I saw one. That was probably in 1958 in the playground at school!

[Mike Macartney]

36 minutes ago, Spinneyhill said:

I expect the battery life is minimal now?

 

Surprisingly, it only needs charging about once a week, maybe less. It mainly gets used if we need to text somebody. Mobile phone reception where we live is rubbish, even when we send a text we have to go to the end of the garden and hold the phone up in the air to send the message.

[chistech]

I had that same Nokia model. One of my favorite phones ever. Now I have a stupid “smart” phone the size of a small city! Hate it.

[Spinneyhill]

22 hours ago, Mike Macartney said:

when we send a text we have to go to the end of the garden and hold the phone up in the air to send the message.

Sounds familiar. I frequently receive a text that I missed a call 15 minutes ago. I suppose a text needs a lot less bandwidth than a call. The telcos don't care about rural customers; there aren't enough of us!

Edited July 31, 2019 by Spinneyhill (see edit history)

[Mike Macartney]

I did say in my posts that I would not include anymore photos of rebuilding the other main shaft/flange and flywheel which make up this V-twin crankshaft assembly. Replacing the loose rivets with countersunk screws has been a big learning curve for me.

 

My last post showed the problems I had with the main shaft/flange with the steel appearing to have been hardened. And the drilling of the clearance holes for the 5/16 UNC countersink screws being a bit of a problem. I was rather concerned that the material of the shaft would be a real problem with cutting the countersinks for these screws.

 

I have included a couple of photos to show a couple of things I did differently.

 

I bought a drill chuck with a No. 3 Morse taper to fit into the milling machine quill without having to use a 2 to 3 Morse adaptor. I thought it would make the drilling the countersink holes more accurate. It seemed just as bad, if not worse, than using my old drill chuck with the Morse adaptor. Perhaps I should I have spent more money on it? It cost £29.55 (approx.. $35.00). Of course it may be the condition of the inside of the No. 3 Morse taper in the part that fits into the milling machine?

 

 

After lapping in the main shaft/flange to the cast iron flywheel I made sure all the holes would accept the 5/16 UNC screws by trying to fit the socket head cap screw first, as they were easier to hold and get started, rather than using the countersunk screws. On the screws that that would not start easily, I tried using the tap by hand, if I could not start from the flange side,  I turned the flywheel over and put the tap in from the threaded side and used the tap to cut away the small amount of offset on the flange side. It seemed to work and eventually I managed to screw in all six cap screws.

 

 

Once all six screws were in place I started attempting to cut the countersinks in the milling machine. I removed one cap screw at a time. Using a drill as a mandrel to centre the threaded hole on the milling table, I clamped it down ready to start drilling.  I have some short drills, about 1/2", or just under, that seem to drill through anything. I used one of these first to just start the cut for the countersink. It seemed to work, maybe the shaft flange had been originally case hardened? It still proved difficult cutting the countersinks. Once the countersink was drilled out to the maximum diameter, I cleaned up the swarf/cutting lubricant with thinners and managed to screw in the countersink screw. I then removed the next cap screw and repeated the process another five times. Believe it, or not, just countersinking these six screws, on this second flywheel flange, took me all day!

 

Today I will get on with modifying the countersink screw heads so they are clear of the big end of the conrod. I measured the amount I have to remove from the heads with a depth gauge, once all six had been screwed in for the first time.

[JV Puleo]

I suspect what you are running into are the vagaritys of heat treating in period. Were it not attached to a piece of the crankshaft I'd suggest annealing it buy heating it red and burying it in sand so it will cool slowly but I'd be afraid that might cause warping and you don't want to soften the crank. The best solution may be to go slow and resign yourself to ruining a few drills and maybe the countersinks...if they work at all. If it were really hard, the drill wouldn't cut at all.

 

While materials engineering was quite good by 1914 it wasn't as precise as it is today so you can't always rely on two pieces being identical. When I had the jugs of my Mitchell bored the gentleman who did it noticed that one jug was a better casting than the other...they were clearly different, not in the sense that the poor one wouldn't work but reflecting the difficulties they had at the time getting absolutely consistent results.

 

I have no problem believing it took all day. I've had the same thing happen many times with what should be a simple job. But, it got done and that's the most important part.

Edited August 1, 2019 by JV Puleo (see edit history)

[Mike Macartney]

20 hours ago, JV Puleo said:

I have no problem believing it took all day.

 

I must admit the time went quickly, it just surprised me that fitting the six screws had taken me all day. I can see why engineering shops shy away from working on engines of this age. I would hate to have to estimate for such a job. Some of the parts of the flange machined easily, other parts were the devil himself.

 

Took the level apart to see if there was any adjustment screws anywhere. The only screws where the ones visible.

 

 

I found that an 0.018 feeler gauge brought it level. Thanks Spinneyhill. I have a few sets of feeler gauges I may cut off a piece to put under the spacer, between the tube and the base. I think at this stage of my machining experience, that I will be chasing my tail, if I attempt to make a spacer 18 thou thicker! Although, I suppose it would be good practice for me.

 

Still learning about lathe tools to use for which jobs! I thought this tool would be good for machining the face of the flywheel.

 

 

Wrong! This is the surface finish it made.

 

 

Tried again with this tool.

 

 

This worked much better and gave a reasonable finish.

 

 

Facing the other side of this flywheel is a little difficult as I have to have the carriage on this side of the flywheel as the flywheel is just too large a diameter for the carriage to pass underneath the flywheel. I don't want to remove the flywheel shaft from the jig unless absolutely necessary .

 

With a bit of luck and a following wind I may get around to bolting the two halves together with the big end journal tomorrow to see how they line up.

[Mike "Hubbie" Stearns]

As far as the level goes, how about using a rubber o ring? It would squeeze down to whatever you need and hold the screw tight. It would also give you the option of readjusting if needed in the future. I use levels all the time and they can get dropped

[Mike Macartney]

12 hours ago, Mike "Hubbie" Stearns said:

As far as the level goes, how about using a rubber o ring?

 

What a good idea. Thanks for that, I'll give it a try.

[Mike Macartney]

The rubber O-rings worked a treat on levelling the machinists level. Thanks for that tip Mike.

[Mike Macartney]

It's time to bolt the second flywheel permanently to the shaft/flange on other half of the flywheel. Then align the two shafts, on each one of the flywheels, by bolting in the big end pin. It will have to come apart again at a later date to fit the conrod. At this stage I just want to make sure that the two shafts are in line after replacing the rivets for screws.

 

 

As before cleaning the thread out with thinners and fitting the countersunk screw with permanent Loctite (or similar). Sods law being what it is - the last screw I tightened with the torque wrench stripped the hexagonal hole in the screw. My fault entirely, I had not pushed the Allen key socket far enough into the hole. Rather than machine up another screw to fit, as I had done previously, I replaced the damaged screw with a new one and machined the head down with it screwed into its hole and torqued up. I checked that all the screw heads were not sticking proud by machining the area where the screw heads were by 5 thou under the height of the flywheel face around them.

 

 

Using a short plank of wood, a couple of wooden wedges and my new large drill chuck I was able to line up the two flywheels to fit the big end pin through both flywheels.

 

 

The nuts were fitted to the big end pin and tightened up about three quarters tight so that pin tapers would still move to line up the shafts.

 

 

With the shafts roughly aligned it was time to replace the drill chuck for the rotating centre so that I could rotate the flywheels to check the alignment with the dial gauge. I left the wedges under the flywheel until the revolving centre was in place so that the extra weight of the second flywheel didn't move the other halt of the shaft at the headstock end of the lathe.

 

 

 

By tapping the second flywheel with a hard rubber mallet I was able to get the shafts to align within 3 thou.

 

 

I then gave another tap and that gave me a run out of over 20 thou! I then started chasing my tail and could not get back to the 3 thou. I gave up for the day and hope I will have better luck with the alignment of the shafts tomorrow morning. From reading 'The Vintage Motorcycle Workshop' it appears that runout of 0.0025" is acceptable.

 

 

[Luv2Wrench]

The secret is knowing which tap should be the last tap.

 

[Mike Macartney]

This morning I did the last tap  and it worked out fine! I'm happy now.

[chistech]

Tap???????  I thought that was something you put in the keg after you were done trueing up the flywheels!

[JV Puleo]

boy... that looks good. I think you've nailed it.

[mike6024]

10 hours ago, Mike Macartney said:

The nuts were fitted to the big end pin and tightened up about three quarters tight so that pin tapers would still move to line up the shafts.

 

So this big-end pin fits into tapered holes, is that what this means?

 

And if the flywheels are not aligned well, you can adjust that by rotating the pin?

 

 

[Mike Macartney]

18 hours ago, chistech said:

Tap???????  I thought that was something you put in the keg after you were done trueing up the flywheels!

 

I think I will save the 'barrel of beer time' until I have finished the car!

 

17 hours ago, JV Puleo said:

boy... that looks good. I think you've nailed it.

 

I would have struggled without your help - thanks Joe.

 

14 hours ago, mike6024 said:

So this big-end pin fits into tapered holes, is that what this means? And if the flywheels are not aligned well, you can adjust that by rotating the pin?

 

Yes that is correct. I apologise for not explaining that before. Here is a photo of the pin for the big end.

 

 

 It is threaded both ends and has a taper both ends.

 

 

Yesterday morning, before lining up the flywheels/shafts, I remembered I had this '32oz Dead Blow hammer'. It was ideal for 'tapping' tapping the RH flywheel while holding the LH flywheel.

 

 

With the flywheels being so large a diameter, getting the dial gauge into a suitable position was a bit of a problem. I could do with a better mounting for the dial gauge as the big knobs on the adjusters always seem to get in the way.

 

 

While the flywheels were aligned I ran the lathe tool across to cut them down to the same diameter. Taking a 5 thou cut off the LH one, the lathe tool just touched the surface of the RH flywheel. I checked the thickness of each flywheel and found I need to take another 38 thou off the RH flywheel. I also need to chamfer the corners of  LH flywheel.

 

 

I have found that these coloured liquid chalk markers that I bought have been very useful with this job. I had thought that the marks would rub off easily, but they seem to stay on very well. I think they will wash off with a bit of water.

 

The nuts for the big end. . . . .

 

 

. . . have been rather butchered in the past! I am struggling to work out the thread. The diameter inside the nut is 0.659" (16.74mm) and the OD of the thread on the big end pin is 0.729" (18.62mm). Across flats the measurement is 1.203" (30.55mm). The thread pitch seems to be 18 tpi. I have not checked the thread angle yet, I will find my metric pitch gauge set and see if it is a metric thread.

 

If I have to make new nuts what grade of steel should I use?  In the 'Radco book' it says to use EN8 for crankpin nuts. Should I harden them after machining?

 

 

The wear on the crankpin and the main big end bush seems to be minimal. I think I would be best leaving this one in place.

 

The smaller pin for the secondary conrod definitely needs the bush or pin replacing as there is a lot of slack in this one. As changing to fork and blade conrods, now seems out of the question, I will start today by separating the two conrods before checking what needs doing to them.

 

 

[Roger Zimmermann]

On ‎8‎/‎1‎/‎2019 at 1:23 PM, Mike Macartney said:

 

 

 

 

I admit that I don't understand how this engine was built. You had a lot of work and trouble to attach something with these 6 screws and turn the flywheels. What is the purpose of all that? Now you will insert the crankpin held with 2 nuts...I looked back 2 or 3 pages but I did not find the explanation of all that trouble, if there is an explanation. Mike, can you bring some light is that complicated system? Thanks!