Starting on upper crankcase parts

 Now that I've wrapped up the crankcase I can move on to some new parts and challenges, and boy did I come up with a conundrum.  More about that later.  First, I have a couple of plugs I need to do. The first is 615106; PLUG - UPPER GENERATOR DRIVE OIL HOLE (VERTICAL).


It fits in the bottom of this oil passage hole.


Next is 608747; PLUG - UPPER GENERATOR DRIVE OIL HOLE (HORIZONTAL) and it's gasket 604127; GASKET - UPPER GENERATOR DRIVE OIL HOLE (HORIZONTAL) PLUG


It fits in the horizontal oil passage adjacent to the previous one.


601643; BUSHING - UPPER GENERATOR DRIVE is going to support a shaft which will come much later.



Moving on we have a bunch of screw inserts.  These are used because aluminum is a relatively soft material so they make the aluminum holes larger, which spreads the stress out over a larger area, and use a brass insert because brass is much harder than aluminum to take the stresses over the smaller areas around the studs and bolts themselves. These will be installed, torqued, and then machined flush at the end.

600697; SCREW BUSHING - UPPER OIL CONNECTION: The first image has the boss shown, then machined off in the second image. In the last image the inserts are shown installed.


The rest of the screw insert images will follow the same pattern.

601620; SCREW BUSHING - UPPER OIL PIPE CLIP

609908; SCREW BUSHING - UPPER TO GENERATOR BRACKET BOLT


615249; SCREW BUSHING - UPPER TO WHEELCASE


This next one is interesting.  

618124; SCREW BUSHING - VARIABLE PITCH PROPELLOR OIL PASSAGE BANJO CONNECTION BOLT

It's for the banjo fittings that go into the top front oil ports that are actually for the variable pitch propeller oil supply.  They get installed and torqued like the other...


Then they get two holes drilled in each which are tapped for No. 5 screw thread...


Then a couple of 601710; LOCKSCREW - VARIABLE PITCH PROPELLOR OIL PASSAGE BANJO CONNECTION BOLT SCREW BUSHING get screwed into those holes and torqued.


Then, like the rest, they all get machined flush.


And finally we come to the main bearing cap studs and the conundrum. The studs come in two lengths, 5.75 and 7.3 inches respectively.  Now there are actually 5 different ones, but the other differences are in width of the parts and are miniscule so they are not noteworthy here. First is 618233; STUD ASSEMBLY - UPPER CRANKSHAFT BEARING CAP "A" SIDE NO. 1, 7, it's one of the shorter studs.  As it's name implies it goes in bearings 1 and 7. It's mate is 618239; STUD ASSEMBLY - UPPER CRANKSHAFT BEARING CAP "B" SIDE NO. 1, 7.  They both look like this:


They get installed like so: 


The other three parts numbers are as follows:

618235; STUD ASSEMBLY - UPPER CRANKSHAFT BEARING CAP "A" SIDE NO. 4
618237; STUD ASSEMBLY - UPPER CRANKSHAFT BEARING CAP "B" SIDE NO. 2, 3, 5, 6
618241; STUD ASSEMBLY-UPPER CRANKSHAFT BEARING CAP "B" SIDE NO 4 AND "A" SIDE NO 2, 3, 5, 6

The are a bit longer:


618235 installs okay, it ends up the same height as the previous ones because it's screw hole is bored much deeper.


The problems arises when we install the other two sets:


As you can see, the studs for bearings 2, 3, 5, and 6 are about an inch too long.  I've checked the bearing caps and they do not change height significantly so this would leave a large gap between the bearing cap seats and the threads on the studs. I have studied the blueprints for the crankcase 618110 quite closely and I know the model has the holes bored exactly according to spec in the drawings, but I think there must be an error. The bosses for the holes in those 4 bearings are the much deeper bosses that match the #4 bearing bosses. It's just the holes, they match the holes in bearings 1 and 7, but 1 and 7 have bosses that are much shallower.  So I think the error is in how deep the holes should be drilled, but I need confirmation before I am willing to change them at this point.

Anyway, that's my work for the last couple of days, I hope you are all weathering the covid in good spirits and are looking forward to the holidays.  Talk to you in a couple days.
















Comments

Post a Comment

Popular posts from this blog

609100 ASSEMBLY - CRANKCASE UPPER HALF is complete and posted to GrabCAD!!

Image
 Hey guys, welcome back with big news.  The upper crankcase assembly is complete!  I've been working on it for a year now, almost to the day.  If you want to be technical it'd be a year and 4 days, but who's counting? Here's a few renders of the completed assembly first. It may not look like a ton has changed since the last update, but I've added in the timing marker that mounts to the No.1 main bearing cap. It's to help align the crankshaft with TDC (Top Dead Center of the number one piston) during assembly. Something most Rolls Royce made Merlins do not have is this lifting eye, which was next on my list.  This is exclusive to the Packard and Continental Merlins. Next I modeled this cool little banjo fitting. I don't know why I find it cool, I just do. There are two of these used on the oil supply to the variable pitch propeller mechanism.  These attach to the top front of the reduction gear housing. I'm not sure if they are turned right, yet, I'll
Read more

THIS BEAST IS COMPLETE!!!!

Image
 I've finished doing all the machining operations on 618110; CRANKCASE - UPPER HALF, which means the part is finally complete. I feel like that's an odd thing to say after almost a year of work.  To wrap it all up in just a couple weeks feels a little bit off to me.  But it is what it is. And, at the very least, what it is is complete. :D Again, I've highlighted all the operations I've done in this part in blue so if it is blue, then I have "machined" some material away there. Aside from about 300 - 400 holes, there was the bearing seats, a bunch of spotfaces, and the mounting pads were very thick as cast. The cross section being blue was a result of how I did the materials in the part to make it easy to highlight the machining operations.  It'll go away when the rest of the blue does. It just struck me as I was doing the screengrabs for this page but there are no cooling passages in this crankcase.  I mean I realized they had huge oil coolers to do the co
Read more

Something something studs

Image
 Not a huge update so first I'll post a couple of images of the current progress, then we'll get into the meat of the post. So, the astute follower might notice that the assembly has gotten a lot more studly.  Studs have taken up the majority of my time over the last few days, 25 of them to be exact. Other than that I did the main bearing caps. There are three different part numbers but two of them are the same with minor differences. 620792 and 620793 are practically the same part except 620793 has two small holes with spotfaces in the front for the timing marker. 620793 is the No. 1 bearing cap, while 620792 is used for almost all the rest of the caps except No. 4. The No. 4 cap is 601423 and it's a bit beefier. Or maybe you'd call it a bit studlier. bah dum bum tsss
Read more