JV Puleo

My 1910 Mitchell "parts car" project

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No but it was a fairly common aspect of engine design at the time. In this case it is rather exaggerated. I forget now what the reason was. I think Model T Ford cranks are off cnter but not as much. (Never having worked on a Model T engine, I can't say that from personal experience.)

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Posted (edited)

Its a means to minimize side thrust. My Wisconsin is the same way. (3/4" offset)

Sometimes you will find offset piston pins which is another method. A good thing to know when your

rebuilding an engine!

 

According to an article I found offset piston pins are much more effective at reducing side thrust

than offsetting the bores from the crank center line.

 

T.

Edited by Terry Harper (see edit history)
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I think the Mitchell is offset 1" which is the most I've ever heard of.

I drilled the hole for the cam bearing retainer this morning.

 

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And then reamed it to 5/16".

 

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The holes will now be in perfect alignment with each other and the retaining bolt.

 

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I also counterbored the cap so the bolt will sit in it firmly.

 

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Next, I cut a piece of 1-1/4 hex stock to make a lock nut. Because it is larger than my hex collets I had to resort to the "3-jaw in the 4-jaw" chuck setup.

 

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I faced one side, drilled and threaded it. I'll finish this later, after I've taken the chucks off.

 

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Next I put the steel hex stock that will be the actual bolt in the machine to turn it round on one end. This didn't work. There isn't enough material in the chuck to hold it without slipping back.

 

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But, this piece is going to be drilled and threaded on the hex end to receive a banjo fitting so I decided to do that first.

 

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To get a flat bottom on the hole I used a 29/64 end mill - the hole size for the 1/2-20 banjo bolts.

 

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After threading the hole, I put a piece of threaded rod in a collet to hold the hex end of the bolt and keep it from turning. I'll use this to finish the lock nut as well.

 

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I got about half-way through turning it round before I decided to quit for the day. Hopefully, I'll finish this piece tomorrow.

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My Metallurgique has a substantial offset. It makes top dead centre interesting, as the piston and crank reach TDC at different points in the cycle. And the down stroke has a different duration to the upward stroke of the piston. Yes, re-read that bit. The graphs and diagrams explain it, but I found it difficult to get my head around for a while. 

 

I believe some modern engine designs are now offsetting their gudgeon pins, as well. Give them time, and maybe they'll try carbies and distributors, too!

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I hadn't thought about that but it must be the case with this engine as well. I'm going to have to figure the valve and ignition timing from scratch because even if I had the original specs (which I don't) I've changed the compression and the cam...it might be rather complicated and I can't say that is one of my strong points.

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Joe, looking through some of your early posts I came across your 12V generator combined, with the parts from a Bosch magneto. On the Humberette I have the incorrect magneto which has the wrong V-angle for the ignition, off hand I can't remember if it is 50o or 55all I know is that the correct magneto for the Humberette engines are apparently impossible to find. The mag that is on the car has been modified with electronic ignition, I am not impressed with the way it has been fitted and I intend to re do it. It would be good if I could also incorporate a small 12V generator to charge the 12V battery, for the ignition and the lights. The acetylene  lamps I will convert with LED bulbs. I have looked on the internet to try and find some useful information, but after about an hours searching, all to no avail, I remembered your early post about the subject. Do you have any information that may help me? 

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Posted (edited)

Yes. And you won't find anything on the internet. I pretty much dreamed this one up myself but I know it will work because I did it many years ago with a 1911 REO. I had to store it for the winter and the only way to get it to the storage garage was to drive it. I simply added a contact to the center of the cap, mounted a coil (a very old one) on the firewall and wired it as if it was a distributor. I'm happy to share what I've figured out but you might also do a search on this site. Several years ago a fellow restored a two-cylinder Buick and did something similar although he used a 12-volt alternator from a Kubota loader mounted inside the mag case. I think something like that might work better on the Humberette. I'm not satisfied with the job I did. It was just about the first thing I made and I made several errors. There are very small 12-volt alternators that might work just fine....

 

I've decided to go to a Bosch ZU4 mag and mount a generator or alternator where the oiler went. I haven't yet thought out how to disguise it but it will be something similar to the one I made from the mag... only without the distributor. You'll need a "parts" 2-cylinder mag, preferably the largest that will fit in the space or make the case to fit the distributor head on the mag.

 

I don't understand the "V-angle". It would seem to me that a 2-cylinder mag or distributor would just have 2 lobes opposite each other but you know a lot more about electrical engineering than I do.

 

Edited by JV Puleo (see edit history)
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Posted (edited)

I found it but this computer has a problem copying things. Do a search on "1911 Buick Model 14" and you should find it. The pictures, which were from Photobucket, are trashed but the description of what he did is there. I think I'd already made mine when I read this and thought "what a good idea."

Edited by JV Puleo
add comma (see edit history)
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Thanks for the fast reply . . . . interesting. I have just got back from a follow up doctors appointment. They were not happy with my breathing and are sending me hospital yet again!

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Get well mike and the hell with anything else right now! 

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Since my last post I've discovered that making the special hollow bolt to retain the cam bearing is a lot more demanding than I'd anticipated.

The lock nut was easy...

 

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Then everything went sideways. I made the bolt out of apiece of 1" hex. It has have a fairly large head because that is where the oil connecting banjo fitting will go.

 

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Threaded 1/2-20

 

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It worked fine, except that I made it too short. So, I made another. That was long enough but I made an error in the threading. The error was so small that I couldn't actually see it but it caused the bolt to be slightly off center and this design absolutely requires that it be perfectly straight. I only discovered what I'd done wrong much later, after I'd tried a third solution - making the bolt in two pieces.

 

This requires attaching the piece of threaded rod to the head. I'll do this by fitting a tapered pin and, if that works, try brazing it in place.

 

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This does allow me to get the vertical height exactly right...

 

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After I adjusted the height I put a little Locktite on the threads to hold it in place while I drill it. If this works, it will be fine. If it doesn't it gives me the perfect measurements to make another from one piece. I'm not particularly put out by all this. You have to expect that a few things won't go as planned and when that does happen I'd just as soon it didn't happen with original parts...I can always make another of these.

IMG_2749.JPG

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Hollow bolt, two pieces, brazing... that's like no, no and no. :)

 

Nice job Joe, always enjoy your posts.

 

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On ‎3‎/‎11‎/‎2020 at 8:40 PM, chistech said:

Get well mike and the hell with anything else right now! 

 

They let me out of hospital last night after being in isolation in there for 3-days. I seemed to have been the first person in the Norwich hospital with suspected Coronavirus and appeared to have been a "Guinea Pig" for their testing and isolation of suspected cases. Later today I will write, I hope, an amusing post of my time at the hospital, in my 1914 Humberette posts. I wasn't worried at the time, as nobody in Norfolk or Suffolk, had be recorded as having been found to have the virus.

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Mike, though I’ve never met you in person, we’ve spent lots of time learning about one another and others here through our threads. I consider you and a select few, my old car family and I’m truly concerned about your wellbeing,  like I know, some others are also. Please take care of yourself and get better first and foremost. The weather is starting to cooperate so I’m sure it won’t be long where you’re feeling much better. Take care my friend.

 

sorry for posting this here joe but I’m sure you have the same sentiments and wouldn’t mind

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Thank you Ted, I have the same feelings for the guys I have 'met' on this forum. All of you please keep safe as the virus is now spreading quickly in the western world. I seem to be much better now, hopefully this feeling will last and I can get on with some work. Mike 

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Posted (edited)

I could claim to have been away from my project for a few days but, in truth, I've been struggling with making the retaining bolt for the center camshaft bearing. This my 4th...and I'm finally satisfied with it.

 

First I made the hex portion... in this case I gave it a deep chamfer on the bottom. My problem has been consistently brazing the threaded portion in place in such a manner that none of the braze got into the threads. This has proved a lot harder to do than to describe. In addition to the deep chamfer, I used a small mandrel to turn a ring of 1/8" bronze brazing wire into a perfect circle...the same technique you would use to make a spring. The wire is springy and it took me 3 or 4 tries to get the correct dimension so that when it sprung out it would be tight on the threaded part of the bolt. The wire now fits down inside the chamfer.

 

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The threaded portion is too long for any of my drills so it was necessary to drill it from both ends. If I'd attached it to the hex piece first, I would not have been able to use the collet to hold it. This worked quite well although its only a 3/16 hole and it was necessary to withdraw the drill regularly to clear the chips in order to make certain it was going in perfectly straight.

 

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The Exact height of the threaded section was calculated and the two pieces assembled, with some brazing flux, on the rotary table using heat blocking putty to keep from getting the table hot.

 

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At just about this point I had a call from a friend who wanted to work on one of his projects so I waited for him and before he began we brazed the two pieces together. We did that by having my friend hold the torch while I turned the handle, rotating the piece so that it got uniformly hot all around until the brazing wire melted.

 

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This technique finally worked although I do have a little clean up to do on the lower surface - though as it doesn't show and doesn't obstruct anything that is more a matter of my own obsessive behavior.

 

I then turned the top end of the hex to the diameter of the banjo fittings I have. This is how it is supposed to look. An oil line will be connected from the pump output line to the banjo fitting giving me oil pressure on the center cam bearing. Depending on how the pieces fit, I may extend that line to the front cam bearing as well.

 

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But, until the engine goes back together it is difficult to plan the plumbing.

Edited by JV Puleo
typos...I hate typos (see edit history)
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Joe, Those Franklin brake line banjoes look great!  Lets have a visit soon!  Mike

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You bet...I'm especially at loose ends now since the Baltimore Gun Show was cancelled and the National Archives in Philadelphia is closed, both of which I was supposed to be visiting this weekend.

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This year, with planned shows for the Olds, I figured I wouldn’t get as much done as I wanted. Now it looks like all I’ll be doing is working on cars and no showing. I really want to get the shows out of the way while the restoration is fresh so I can start driving It more.

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Yes... I'm certain that is a disappointment but at times like this I like to remember a saying for the Pirkei Avot that "every misfortune is an opportunity." Fortunately (or unfortunately) I'm a very long way from ever going to a car show. That said, this morning I cleaned up the underside of the hollow bolt I made. It won't make it work any better but at least I'm finally satisfied with the job. The one in the front is the finished item...those behind it have gone into my "mistakes" box.

 

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And, if you were wondering, this is how it works. The projection on the end of the bolt goes through the cap and into the bearing so when it is tightened down the bearing can't move and oil will be delivered directly to the rotating surface.

 

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My mill is still tied up while I try to solve another problem so I decided to make the insert that will screw into the crankcase and provide a seat for the banjo fitting that will oil the center main bearing.

 

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Threading it 1"-20

 

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I then turned it down on the ends. The short end will go into the crankcase but, as the threads won't go all the way to the bottom I put a rebate on it. The other end is turned down to .900 for the banjo fitting. It's still a bit long so I'll trim it down to 3/4" but it's otherwise done.

 

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Monday I'm going to visit the cutter grinding shop and have a 1" end mill taken down to .950 - the hole size for a 1"-20 thread. I'd rather do that with an end mill because I want a flat bottomed hole and I have another fix the end mill will work for so it worth the effort.

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Since I have to get a cutter ground for the job that was in the mill – and that will take a few days – I decided to start putting in the threaded liners. Working on the original parts (as opposed to making parts) is always tension inducing so it took me a while to set this up. The first step was to take a 3/8-16 bolt and put a center hole in it. It was screwed into one of the holes in the crankcase and used to center the spindle.

 

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You can tell you've got it straight if the center balances on the bolt when you drop the table.

 

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I then used a 29/64 end mill to take the threads out.

 

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And, without moving anything, threaded the hole.

 

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And screwed the first insert in with a little Locktite on the threads.

 

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I ended up having two long phone calls with authors I'm working with so I only got 4 of them done before I decided I'd had enough for the day. There is nothing to be gained by pushing it....all the mistakes come when you are tired.

 

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There are 14 more of these to do and then I have to do the main bearings...so I'll be busy for a couple of days.

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I am still amazed with your solution to a very odd cam bearing design. I wonder what Mitchell was thinking ?  Is the remainder of the engine a better thought out design ?  

A BSA Gold Star motorcycle I worked on years ago had bronze thread inserts in the head. Very similar to what you are doing for your crankcase. Each one had two small diameter drive pins to lock them place once they were installed . Done at the factory so no doubt a very accurately made drill jig to get the position just right.

 

Greg

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The rest of the engine design is just "ordinary." Nothing unusual but the workmanship is often very questionable. I think they were forcing the issue, trying to make the engine as cheaply as possible because they reduced their prices across the board in 1910.

 

I had BSA's when I as younger and remember that. RR also did it. Heldt goes so far as to say that threading aluminum is a poor idea but a lot of people did it to save the added expense.

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Posted (edited)

I used to work on British Paxman RPH diesel genset prime movers a fair bit. They evolved from a small locomotive powerplant and had quite a few design quirks in order to make them as compact as possible. Not as convoluted as a Napier Deltic,,

but they still took a bit of a knack to get them apart without breaking anything and back together without oil leaks. Lots of external oil lines. Fork and blade con rods that came out through the crankcase doors. But very long service engines , ours had hundred's of thousands of hours on them.

 

 

Greg

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Edited by 1912Staver (see edit history)
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It has been a hectic Monday...I dropped off some end mills to be ground and then went to look at a Blazer. My current truck is tired and needs quite a bit of work. I'd do it but I doubt it will pass inspection at the end of next month in any case. I'm told (and I am almost completely ignorant of these things) that there is a valve in the transmission that is malfunctioning and that it prevents the emissions sensors from setting so my "check engine" light stays on. Replacing the transmission (which may not solve the problem) is just too expensive and, truth to tell, I would rather have something I can fix and that is not subject to the vagarites of electronics. So, I bought an '89 Blazer. I'd like to thank Ted Brito (Christech) for giving some pointers on what to look for.

 

I did get back to the shop long enough to finish the 18 threaded holes for the sump inserts...

 

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I'll put the inserts in tomorrow. The cast bosses in the crankcase are not uniform in thickness and I don't want them to stick up on the top so they have to be done one at the time and, if they protrude on the bottom, filed so the gasket surface is flat.

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