JV Puleo

My 1910 Mitchell "parts car" project

Recommended Posts

Here's the flywheel end of the crankshaft. In looking at this again (it's been years since I really looked closely at it) I suspect the thrust should go on the rear bearing.

 

IMG_2806.thumb.JPG.c7b9ef64f64158a8dc3d4c2a9c74ba23.JPG

 

With the cap in place.

 

IMG_2807.thumb.JPG.5b0312e28128e201eeaa23611dce647e.JPG

 

And the flywheel itself. It's massive... 16" in diameter and I think it weighs about 75 lbs.

 

IMG_2808.thumb.JPG.785bfd56d59859dd837120ca05f66ca3.JPG

 

The clutch surface on the inside of the flywheel.

 

IMG_2809.thumb.JPG.02e3a7805e06dfa38a5330f44d74a5ba.JPG

 

I did get some work done as well. The cap studs all threaded. I now have to drill the holes for the cotter pins and they are finished.

 

IMG_2810.thumb.JPG.3f4a603496f38c36c7775aeb2d605f46.JPG

  • Like 2

Share this post


Link to post
Share on other sites

What type of bits are you using to cut the Grade 5 steel?  Recommendations for cutting Grade 8?

 

  • Like 1

Share this post


Link to post
Share on other sites

High speed steel. I use carbide very rarely because my lathe is far to old to go fast enough for carbide to work correctly. I find grade 5 difficult to machine. I don't know that I'd even try threading grade 8 but I've successfully shortened bolts and faced them off.

  • Like 1

Share this post


Link to post
Share on other sites

Your going to have to control thrust on the crank with the rear main. Looks like it’s going to be tight......which means challenging and complicated. I would resist the temptation to change or alter the flywheel. Too many people want to “lighten it up” but with such a small engine turning low rpm’s the flywheel mass is an important engineering design addition to make the car drivable.  Your much better off trying to save weight on the custom body your planning on building. Every single pound added to the car is going to drain off performance and speed. I can’t remember, were the rods splash lubrication? I’m having trouble wrapping my head around the entire oiling system. Oil leaking / control on the rear main is not obvious to me in the photos. Also, if the car has splash rods, your going to need to figure out how to keep oil in the pan and windage area for the dippers without running them low with the pump. Whatever was there initially may not be able to handle the pump you built. Maybe a “focus “ on the oiling system with photos would help. I’m not seeing the big picture, and it’s possible to work your way into a corner on the oiling system that you may not be able to work out of. Thoughts? Also, do the main caps have enough material to accept the bronze shells? Or are you planning on making new ones that are larger........then oil pan clearance issues come into play.............”it’s just an old car...........it can’t be that complicated!” 🤔

  • Like 2

Share this post


Link to post
Share on other sites
Posted (edited)

The caps are thick enough to handle the shells. It looks as if they may not have done more than a rough boring of the main saddles and used Babbitt metal to make up the difference. The bearings are almost 1/4" thick.

 

As to the oiling... the pump is on the back of the engine and draws oil up from the sump. Because it's a vane pump it has good suction - unlike a gear pump but if the system is dry from standing a long time I've incorporated a hand priming pump. In operation all it does is replicate the original box oiler which probably generated a higher pressure but much lower volume to the mains. I have eliminated the oil line to the rear of the camshaft since that bearing is now inside the oil pump but I've added a line to the center bearing of the cam. Aside from that, the lines run where they originally did they just get their oil from a different pump.

 

I'll make a drawing of the rear main bearing I'm planning...it will be easier than trying to explain it. Essentially, it will have a large flange on the back end (facing the flywheel) which will serve as a thrust surface and provide a place to put a rear main seal. To install it I'll have to mill away about 1/2" of the width of the bearing cap and crankcase - a scary job and once that I'll have to think about very carefully before I do it.

 

The rods are splash lubricated. There were no scoops on the original rods, just a big hole in the big end cap at the bottom and two feeding the top half of the cap with oil pockets. I've yet to give that aspect of the job much thought. I don't think there is room for a windage tray but I will have to take some measurements when it is possible to put more of it together. There will be very change of the internal arrangements aside from forcing oil to the bearings.

 

Oh...and I've no intention of mucking with the flywheel. I suspect  the business of lightening them is overdone. As it is, if the cone clutch is precisely made and balanced it should be smooth and positive. I think about 98% of the complaints about cone clutches are  the result of wear and poor adjustment. The SG had a come clutch that worked perfectly but it was extremely well made.

Edited by JV Puleo (see edit history)
  • Like 2

Share this post


Link to post
Share on other sites
Posted (edited)

Thanks for the update........things like this keep me up at night! 👍

Edited by edinmass (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites

In answer to one of Ed's questions, here is one of the original connecting rods. Notice that there was no provision for scoops, just a hole in the bottom of the big end cap.

 

1036663370_Rod1.thumb.JPG.6716b5e12207ff0a5983a36f7c6f0446.JPG

 

And two oil holes on the opposite side.

 

2082775052_Rod2.thumb.JPG.a4210dc57101e0e1da4920c4b44cab77.JPG

 

2006628946_Rod3.thumb.JPG.7db67fbe8f183ce70d58d16647129826.JPG

 

Before I drilled the holes for the cotter pins I had to make the washers the nuts will sit on. These are MilSpec washers that have a 7/16" hole in the center (unlike SAE washers where the hole is quite a bit larger than 7/16). The OD is 1" - too large for the application but that was easily fixed.

 

IMG_2811.JPG.241ff84663cf41f1e5e966f5395547c2.JPG

 

By making a mandrel out of a bolt and turning them down to .850

 

IMG_2812.thumb.JPG.b98db8584a54b9d956778392e9ad9fbc.JPG

 

IMG_2813.thumb.JPG.89c7e608a86387f5a62707d6b2943652.JPG

 

Then I put one together to make certain where the hole should go.

 

IMG_2814.thumb.JPG.27d7af79ff50d21ea02a890620158a19.JPG

 

And set my "cotter pin" fixture in the new drill press - which is far better for drilling small holes than the big drill press is.

 

IMG_2818.thumb.JPG.d728ee27f432caeabc9cea02fb9140ea.JPG

 

I tested the first one...

 

IMG_2819.thumb.JPG.f813564165b62c7ef3e429a4452b26b6.JPG

 

Then went ahead and drilled all of them.

 

IMG_2820.thumb.JPG.f9c274903d422618438ff14c37b45850.JPG

 

I received an email from the grinding shop saying my special end mills are ready so I'll pick those up tomorrow morning. In the meantime I decided to make a prototype for the studs that will hold the jugs in place. These are much longer and the washers (which also have a 7/16" hole) have to be smaller so I turned some of the MilSpec washers down to .750

 

IMG_2821.thumb.JPG.dfff672591ec19bfe985fb25312e693a.JPG

 

And cut a piece of 7/16" rod for the sample stud. This is a softer, much easier to work material than the grade 5 which, for this purpose, isn't needed. It likely is still stronger than the original studs were.

 

IMG_2822.thumb.JPG.c103654c38f20c77baf97696f7408b9e.JPG

 

What yhou are seein here is the end of the stud that passes through the top of the crankcase and is locked in place with a nut & washer on the inside.

  • Like 3

Share this post


Link to post
Share on other sites
Posted (edited)

My idea fr the rear main bearing. The front main would be the same although the length is slightly different. The wall thickness of the shell is 5/16" less the thickness of the Babbitt. These dimensions could change slightly but this is about as big as I dare make it.

 

460252537_RearMainBearing.thumb.jpg.de16447b22e0c45b8326e77e6848dc93.jpg

Edited by JV Puleo (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

Just thinking out loud here, Joe. Would the small section of un-oiled babbitt cause a problem. Perhaps not, although that dry outer face looks like a potential thrust surface. The seal would certainly be more secure located inside than it would be if flush with the end.  

 

 

Edited by Bush Mechanic
clarification (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites

A lot to read and take in this morning. Another new one on me "mil spec". I looked it up, now I know it means US military specification. Looking on the internet I could not see a similar military spec for the UK. I was surprised at the large diameter of the lower hole in the big end cap.

Share this post


Link to post
Share on other sites
Posted (edited)

Joe, what you have drawn will be an issue........you can't square off the flair on the end of the crank facing the flywheel flange.........it's has a radius to prevent cracking............that can not be removed......you're going to have to make the bronze meet the profile of the flare....not easy, but if the outer area is large enough, you don't necessarily have to have contact there.......but it would be a good idea. That same applies to the crank throws if you are planning on turning it........to be honest, with only three bearings, I don't think I would turn it down anywhere........I would just polish it and match each bearing to each main..............have you placed the crank on a pair of V block stands and pushed down on the center to see how much deflection you have? It would be a good time to check to see if it's straight also........inquiring minds would like to know! 👍

 

 

PS- Being as anal as I am, I would figure a way to lubricate the thrust face each time I start the car..........may or may not make much difference, but I would sleep better at night knowing it's there........

Edited by edinmass (see edit history)

Share this post


Link to post
Share on other sites
Posted (edited)

As to the radius... it isn't in the drawing because I did it in the graphic design program I design books with. It doesn't have a good way of making a radius but  have been giving a lot a of thought to how to machine one. It doesn't show in the pictures but I suspect the crank was rusty and was bead blasted and painted with primer. The surfaces are not good enough to just polish but it doesn't look as if it has ever been ground...certainly the original bearings look untouched and the crank fits them reasonably well. In fact, on at least one journal it seems to be a bit too big which makes me wonder if it's the crank that came out of this engine.

 

We have a very good engine shop in nearby Mass. They bored the blocks and, in talking to them I came away feeling they were extremely competent. They aren't one of those places that only knows SBCs. I spoke to them about the crank so I'll probably take it back there when I am done fitting the rods. There is a chance I could have the journals welded and reground slightly larger than they are but that would be a function of how much they would have to be ground to get them round and smooth. Pathological as I am, there are a few things that I'd just as soon have done by someone who does it often...

Edited by JV Puleo (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

I've just had an idea re the radius... Use a shell mill made for a 1-1/4 diameter holder mounted on the boring bar. (This is something I've done before so I know it works) The end of the shell mill has to be ground with the radius so it can be advanced into each end of the bearing very gently. If I get a chance, I'll draw another picture.

 

 

Edited by JV Puleo (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites

Thinking about the thrust face... I have some small adjustable drip oilers. I could use one of them to get a tiny amount of oil to the thrust face. As it is, I'd planed to use one to lubricate the throw out bearing. I'm not sure how I'd plumb it but I see no reason why it wouldn't work. I expect the parts under the car to get a bit oiley in operation. I've never seen a brass car yet that didn't or, it it was completely clean, it wasn't being driven.

  • Like 1

Share this post


Link to post
Share on other sites

The "MIL spec" hardware is designated as NAS type, though the older AN designations are still available.  These are strong, high quality bolts and screws usually used in airplanes but now also in race cars, etc.  An advantage is that the shank diameters are tightly controlled to 0.001-0.005" less than the nominal size.  For each shank diameter, the length of the threaded portion is always the same, but the bolts can be bought in 1/16" or 1/8" grip length increments.  As Joe mentioned, the matching washers have tight i.d. control and have a radius on the i.d. edges to match the radius under the bolt heads.  The bolts are also available with heads and/or shanks drilled for safety wires.   The NAS hardware is used when you want a truly precision fit - like a spring bolt through an eye bushing - as well as high strength and a defined grip length.  Ratings differ for shear versus tension applications.  You can buy a broad selection of these through places like Aircraft Spruce or Pegasus Auto Racing, AN sizes to 1/2" or 5/8", NAS sizes up to 1" diameter.  Be prepared for prices much higher than Grade 8's.  

 

Here's some info on AN screws and bolts:  https://www.pegasusautoracing.com/document.asp?DocID=TECH00095 

  • Like 1

Share this post


Link to post
Share on other sites

Ed and Bush Mechanic got me thinking about oiling the thrust so I dug these out... a pair of little drip oilers. I'd thought to use one for the throw out bearing but I could use two and run a very small oil line down to the thrust side of the rear main bearing.

 

IMG_2823.JPG.5b952f2f4f198d18459179e314aa8193.JPG

 

This is the original throw out... Notice the extreme wear on the thrust surface. It doesn't look like they made any attempt to lubricate it or the original owner rode the clutch all the time. Actually, I think both are probably true.

 

IMG_2824.thumb.JPG.ea909f9f63840bf455aeb7cfb57922ec.JPG

 

I finished my prototype stud too...

 

IMG_2825.JPG.bed04e283d7d9f848b1bdc45121fe82d.JPG

 

To get a final measurement I screwed it into the crankcase and put a nut on. It's about .150 tall so I trimmed it down.

 

IMG_2826.thumb.JPG.43da13468136c1fd4f7a80cefe337fe2.JPG

 

Then I tried the stud with one of the jugs. It was also about .150 to .175 long so I trimmed that end.

 

IMG_2827.JPG.abb677d271dde475eba32ec1c7f44778.JPG

 

And got it just about right. I made the brass flange nuts a long time ago. They were originally intended to hold down the valve cages but I decided bolts were a better choice there so, having made 8 of them, I made 4 more to use to hold the jugs down. I put a Bellville spring washer under the nut but in looking at it I'll probably go with conventional lock washers which are more appropriate to the period in any case.

 

IMG_2828.thumb.JPG.c5485bc4ef61c869871cef54538ca774.JPG

 

The finished stud after both ends were trimmed.

 

IMG_2829.thumb.JPG.7c0ec27e474cc09aa04976657e501b93.JPG

 

I also picked up a couple of custom ground end mills this morning and was able to ask about the cutter I have in mind to make the radius needed on the bearings. He didn't think it was a problem. All I'll need are the dimensions and the radius.

  • Like 3

Share this post


Link to post
Share on other sites

The throw out bearing on a brass car is so easy to change, I would just modify the set up to take a modern sealed bearing, and forget it for the rest of my life. I like the drip feed setup..........please do me a favor...........PM me the shop you would like to use for the crank. Best, Ed.

  • Like 1

Share this post


Link to post
Share on other sites

Amazing work.  You guys make my work look like I'm building a snap-together model.  Great to show how this is work done, and how it still can be done with the right tools and knowledge.  There's still a great need for these skills, albeit among a relatively small amount of enthusiasts.

  • Like 2

Share this post


Link to post
Share on other sites
Posted (edited)
1 hour ago, edinmass said:

The throw out bearing on a brass car is so easy to change, I would just modify the set up to take a modern sealed bearing, and forget it for the rest of my life.

 

That's the plan, though I hadn't thought of a sealed bearing. There is a bit of a complication in that this ring fits over a flange and pushes it back. There is't any way to get it over the flange unless it comes apart. However...I'm not happy with the clutch either...it's stamped steel and I cannot think how it could possible be in balance - it's bent too. I'm thinking of making a new cone. I can make a pattern and have my neighbors cast one. There's no way I'd put this piece back.

Edited by JV Puleo (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites
18 hours ago, Gary_Ash said:

The "MIL spec" hardware is designated as NAS type, though the older AN designations are still available

 

Thank you Gary for the link. After all these years of being involved with motor vehicles. this is the first time I have come across the term "MIL spec", or perhaps, at my age I have forgotten it! :)

Share this post


Link to post
Share on other sites

I'm a little surprised there isn't a British version... or perhaps there is a "European" version for metric fasteners. AN stands for Army/Navy. It was an early WWII development  to regularize fasteners and fittings and get away from the logistical chaos of WWI. SAE sizes are also a result of WWI and the difficulty the services had with all sorts of proprietary fasteners. The later systems are all further developments along the same line.

  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

My friend Mike West gave me a really good idea this morning. He was describing the oil level "tell tale" on an engine he's working on and it inspired me to take another look at my crankcase. The business of checking the oil level by removing a plug in the sump has always bothered me. It isn't the sort of thing you can do easily and the temptation would be to not do it often enough. In looking at the crankcase it noticed the location of this hole... (The one in the middle of the photo. The hole at the right supported one corner of the oiler and the hole on the left held a support for the original cast iron intake manifold.)

 

IMG_2831.thumb.JPG.035edac328dc888bd473b844b83701a2.JPG

 

This is where Mitchell attached a line from the box oiler and I'd assumed it was connected to the center main with which it is in alignment. It isn't connected to the bearing at all...it just dumps oil back into the sump. This wouldn't have effected the oiler because box oilers develop a relatively high pressure but with very low volume and have an individual pump for each line. It's an engineering principal left over from very slow turning steam engines. The more modern approach, which was already well understood when this car was built, is to have greater volume and lower pressure. That lubricates the bearing and does a much better job of cooling the bearing. I suspect this boss on the crankcase was intended to hold a rod attached to a float. The location is perfect but there is no hole underneath it for the rod to pass through. This may well be another example of Mitchell's "corner cutting." I think I will make an insert for the hole with a 1/4" reamed hole in it and drill a corresponding hole down through the case so that a float at the bottom will push it up.

 

I also did a bit more on the studs for the top of the case...trimming them all to 3"

 

IMG_2830.thumb.JPG.74e06f40b733c20460f95c75c054b05e.JPG

 

Chamfering the ends an and starting the relief cuts for the threading. The strength of a bolt is determined by the minor diameter - which is why fine thread bolts have a higher torque rating than coarse threads. The relief cuts are .050 deep deep which brings them to almost exactly the minor diameter so despite their appearance, they don't effect the strength of the stud.

 

IMG_2832.thumb.JPG.bc25e56fad74d885a0626573d177f6c7.JPG

 

I'll probably finish this tomorrow and start on the threading which will be a relatively easy, but time consuming job but one that, at least, doesn't have the "tension factor" associated with working on the crankcase.

Edited by JV Puleo (see edit history)

Share this post


Link to post
Share on other sites
Posted (edited)

Here you go Joe,

 

This is the setup Mike and I have. It's a just simple sight glass that screws into the top of the crankcase and has a indicator rod and float.

(very similar to what most home heating oil tanks use) There is a scribd mark on the gauge body that indicates full  - in my case 5 gallons worth of oil.

You could easily downsize it to fit. I bought the gauge glass through McMaster-Carr and cut to length which was the trickiest part. (order extra!)

 

IMAGE_81.thumb.jpg.8adf93d41a2ff1838403f55302780190.jpg

 

M31.thumb.jpg.02e3482efafef826df6c57feef481533.jpg

 

The only possible problem with this setup is that your crankshaft dips and slings oil which means its agitated quite a lot. The Wisconsin's (at least mine) does not. There is a full

length baffle that separates the crank from the sump (100% pressure lubrication - no dip and sling). You may want to provide a thin brass sleeve (open at the bottom and

vented near the top to protect the float from all the turbulence. The sleeve would also keep the float from wobbling around on the end of that thin rod

and violating the social distancing guidelines of the crank.

 

DANG! Just noticed I spelled "Gauge" two different ways on the drawing!"

 

 

Edited by Terry Harper (see edit history)
  • Like 2

Share this post


Link to post
Share on other sites
Posted (edited)

I have a couple of them but don't know if I have one small enough. I'll look. I suppose I could always make one. I was thinking of something simpler but if I can fit one of those in it would be all the more elegant. The problem is that the aluminum boss on the crankcase limits how big the base and the thread are. The hole there is 1/8 NPT but if I go to that size, how big must the pin that connects to the sump be? I wonder what the inside dimension of the glass is?

 

j

Edited by JV Puleo (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now