Pacific Vapor Engine from Morrison & Marvin Castings

[Dave Otto]

Thanks everyone,

I believe (but I may be wrong) that the original cross over cam had the tracks cast in from the foundry. If this is the case it would have been the art of the pattern maker that created the profile. On the copy of the original print which I have seen; it says that the cross over cam is cast iron. I just not exactly sure how much of it was cast and how much machined.

When Lester made the cam for his original model; he built a fixture that mounted on the mill table. It had a shaft driven by a DC gear motor via roller chain. The shaft (arbor) had the ability to float axially in it's bushings and was spring loaded against a master template via a stylus. He created the master template that was essentially one half of the track. So it basically it was a flat disc with a ramp in one section.

As the arbor was rotated by the gear motor it would move left to right following the master profile. Using a small end mill this would cut one track and 1/2 of the cross; when at final depth the cam blank was reversed and the other track cut which also completed the cross.

I have pictures of it somewhere but I would need to check whit Lester for permission to post them.

Thanks,
Dave

[Dave Otto]

Hi Everyone

Here are some photos of machining the valve lifter; I machined most of it on my CNC at work and then finished it up in my shop at home. This was a milestone for me as all the timing parts are now finished and after the exhaust valve is completed and it's seat cut, it will be on to a different part of the engine.

I chose to make this part from scratch and as I have indicated before I made some modifications to change the alignment of these parts. 

I just want to say if anyone is curious, there is nothing wrong with the castings or drawings; this is just something I wanted to try and as I indicated awhile back; if it didn’t work I would use the castings machine them to the print.

The valve lifter was designed in a 3d CAD program and printed on one of our rapid prototype machines to check the fit.  Once satisfied the basic shape was programmed and run on the CNC.


Here the bottom side of the lifter has been roughed out with a ¼” ball end mill.


Then followed by a 1/8” and finally a 1/16” ball end mill.


Ready for the next operation, made two just in-case.


The block is flipped over and the top side is surfaced. The web pieces holding the chucking pieces on are located where the slots will be.

Standing on edge the holes are spotted and drilled.


Ready for the finishing operations.


I needed the bronze shoe so it was made before the lifter was finished. Here a piece of prop shaft (Naval Bronze) was turned and faced and set up in the mill.


The profile of the shoe is machined.


Then back in the lathe the shoe is parted off.




The first chucking piece is cut off.


The lifter is set up on a fixture plate, indicated in and clamped down.


The shoe slot is milled using the recently completed shoe to check the fit.


Back to the saw the other lug is removed.


Due to the shape this operation took some creative use of parallels to hang on to it.




Before and after;  cutting the slots was kind of a tedious process mainly because I didn’t want to screw up after putting that much work into it.


The swing arm is set up and drilled for the pivot bolt.


And finally a fit check with the new parts; I’m a happy guy!


Here’s a different view.


Just for grins here is the printed part alongside its machined counterpart. The 3d printer got a workout as I was trying to get a design that I was happy with.

Thanks for checking in,
Dave

[ths]

Beautiful Dave, but it is cruelty to many of us. Oh well....

Hugh.

[b.lindsey]

Incredible work and photographs Dave. I am so looking forward to seeing all this work together in this beautiful engine. The crossover cam alone should be fascinating to watch!!

Bill

[vcutajar]

CNC at work and at home, 3D printing = major tool envy.

Maybe I should consider changing my workplace.  Nah, still love my job.

Great part Dave.

Vince

[NickG]

Wow, some complex parts there Dave! What material did you print the part in? I've only seen videos of plastics printed up until now. 

[peatoluser]

beautifully made and beautifully photographed. loving this thread

peter

[Dave Otto]

Thanks for the kind words guys.

Nick the printed part is ABS plastic; I painted it gray as the light colored plastic is hard to get a decent picture of. 

Here are some pictures of making the exhaust valve.

I decided to make a two piece valve using a cast iron head and stainless steel stem; this is the way the valves on some of the old engines were made. Due the length of this valve (over 6”) this one was a good candidate.


Starting with the chucking lug that was cut off of the valve chest; it was turned, faced, drilled, reamed and parted off.


I pressed the valve head onto a 1/8” dowel pin to hang on to while facing it to length.


Then the top end of the stem hole was opened up with a 60 degree countersink.


A piece of precision ground stainless rod is used for the stem. Here it is being turned for the press fit of the head.


The head was pressed onto the stem and is ready to be peened.


While heating the end of the stem with a torch to a red heat the stem is peened to lock the head on to the stem. There is a piece of steel on the bench under the vise supporting the end of the valve. A few taps with a small ball peen hammer and it is done.


After facing the head notice the 60 degree chamfer is now completely full of valve stem. I don’t think that head is going anywhere.


Next a seat cutter was made; ala George Britnell. I made it with 5 flutes hoping that it would have less chance of chatter.


Here it is after heat treating a little cleanup and stoning.


The cutter worked great; here is a picture through my microscope (wanted to see if I could do it); the valve seat shows as a dark circle near the edge.


Here is another shot with the valve chest tilted a little. You can see the seat better in this picture.


After  just a little lapping with extra fine Timesaver compound you can see the contact area on the valve.


Here is the completed valve next to the seat cutter.

Thanks for checking in,
Dave

[Dave Otto]

Hi everyone

Here are some pictures of making the exhaust spring and keeper. I’m getting pretty close to being caught up on my build posts. The Pacific sat neglected for the last couple of months due to other comments but I made good progress on the cylinder head this last week and should have pictures posted in the next few days.



Starting out the spring wire is passed through the tensioner and then through the cross hole in the mandrel.


Then the wire is bent over to keep it from pulling out of the mandrel.


Starting the winding process; the lathe quick change is set to give the proper number of coils per inch. At first a few close wraps are completed; the lathe carriage is moved by had to keep the coils tight. Then the half nut is engaged and the carriage is moved by the gearing. I usually turn the spindle by hand making sure to keep tension on the wire.


When the proper number of coils are wound the half nut is disengaged and a few tight coils are wound at the far end.


Then the tension is backed off and the wire cut with some music wire nippers.


After the spring is removed from the mandrel the excess coils are cut with the nippers.


After the excess coils are removed the ends of the spring are ground flat with the belt sander.


The keeper is an easy turning job. Here it is mostly roughed out; a boss was turned to fit in the inside of the spring to help keep it centered on the valve stem.


Transferred to the mill the set screw hole is located, drilled and taped.




Here is the spring and keeper mounted on the engine.

Thanks for checking in,
Dave

[Don1966]

Dave, those are some awesome photos. Thanks for the education, I have gain more knowledge following along with you. Great progress and a beautiful job so far, you must be getting close to completion.

Don

[NickG]

The valves and seats look a perfect seal, great stuff.

[ColH]

Great work Dave.

Can you post some details of your spring wire tensioner?

Thanks
Col

[Marinus]

Wonderful Dave

Do you sandblast the brass bits?

[steamer]

That is beautiful work Dave!   What kind of lathe do you have?.....Looks Hardinge like...but different..

Dave

[ths]

Very interesting Dave, and yes, the spring tensioner!

Hugh.