DEMON 2X

[stackerjack]

Line boring the main bearing caps has been at the limits of my equipment on hand. I first ball milled the three center bearing webs and caps with a one inch ball mill to a depth of .460. Then installed the caps and cobbled up a way to attach the block to a face plate on center. My plan is to line bore the three center webs with a boring bar that can reach the first two without any problems but the third one is out of reach. I planned on unbolting the block from the face plate and flipping it around to get the third one. But it took so much time and effort to get it all running true and centered that I would prefer not to do that again. So the setup will stay like it is in the picture until I either make a longer boring bar or come up with something else.

bruskiView attachment 117576

One method I saw on U-Tube was to bolt the block to the cross slide. You need to make up a boring bar with bushes on the ends, which fit the block. The boring bar is then driven, via two universal joints, by the chuck. It's not that difficult, because the holes in the block doesn't need to be at centre height. The saddle is then moved along to bore the holes.

 

[stevehuckss396]

https://www.brownells.com/gunsmith-...ccessories/non-scaling-compound-prod1122.aspx

 

[Joseph Comunale]

That's a neat Valve Grinding set up. Is that part of Steve's plans? or found elsewhere? Can anyone send me a link to it? ( Steve is a friend and a member of the MDMC group... great guy)

 

[bruski]

HI Joseph,
You must be referring to the cam grinding setup. I built that so many years ago from an article in Strickly IC magazine. I will try and find it but it might take some time to do so. Try a search for back issues of that magazine and there articles on cam grinding and see what comes up for you.
bruski

 

[bruski]

I am still alive here. I managed to assemble all of the pistons with there rings onto the rods and have them in the cylinders now. I have been seating the rings by running the bottom end in the lathe with oil in the pan splashing to lube everything for now as there is no oil pump on the block yet.
The pictures are of the timing gears with the idler gear not shown in the picture. It has two ball bearings in it. The other picture is of the rocker arms being machined in the first stage of there shaped profile. I will be using a .25 drill rod running through them for mounting with the pushrod seat screw as the adjustment with a lock nut on top of them.

Bruski

 

[Cogsy]

It seems a lot of people use a similar method to you when 'seating' rings but industry suggests it is the opposite of what you want to do to actually get a well sealing ring. The combustion pressures are required to get the rings to 'bed-in' and wear into a good seal. Here's a couple of links if you want to read about the theory LINK LINK.

 

[bruski]

Thanks for the information, there is always room to learn in my head.

Bruski

 

[The_reach]

Interesting build, love the idea of a 2x demon v8. Have you any plans as to what to do with the model once you've completed it?

Jimmy

 

[Steamchick]

One method I saw on U-Tube was to bolt the block to the cross slide. You need to make up a boring bar with bushes on the ends, which fit the block. The boring bar is then driven, via two universal joints, by the chuck. It's not that difficult, because the holes in the block doesn't need to be at centre height. The saddle is then moved along to bore the holes.

Thanks Stackerjack. Rarely is this method proposed on threads like this.
This is mathematically and technically the correct way to make a parallel bore. Simply, you are describing a circle with the tool and progressing the circle along a straight line of the axis of the bore. The way it is always done in industrial manufacturing.
Personally, I simply mount the block where the tool post would normally fit, and use a boring bar -central tool - mounted between chuck and revolving tailstock.
Or I mount a boring bar (end cutter) in my miller-driller and progress the cut vertically down through the engine block, which is mounted on the cross table. Easy!
Enjoy
K2

 

[bruski]

Jimmy,
I don't have any plans for it in a project, it's something interesting to keep me busy in my shop and out of trouble.

Bruski

 

[The_reach]

I've got several plan sets for various engines to start, whichever i end up doing is like to build a suitable vehicle for them, ive seen some superb rc cars with V8 motors in them but not one as big as yours, Should be a right beast indeed when it's finished!

 

[peterl95124]

I followed an artical in Strictly I.C. magazine 1994 Oct./ Nov. issue page 28 on Master Cam Design by Don A. Bell. Using Steve's cam profile scaled up x 2 gives a base circle of .700 and .140 lift with a flank radius of 1.392 and a nose radius of .062. My master cam has a 2 inch diameter base circle. The radius of the desired cams diameter has to be subtracted from the master cams radius so ( 1.0" - .350" = .650" ) Now add .650 to all the radii on the desired cam. The radius origins remain the same places. The flank radius becomes 1.392+.650=2.042 the nose radius .062+.650=.712 and so on. I hope I didn't confuse you too much. Pictures or drawings are available on this forum somewhere on cam designs.
bruski

Bruski, its now 2023 and, wondering if you're still there ?

and the point, did you ever measure the actual nose radius of the final ground cams ?

I've been drawing my own master cam using Don Bell's technique in Strictly IC (Oct '94) and the problem I keep seeing is that the dwell angle of the nose on the master is much larger than the dwell angle of the nose for my intended actual cam. The master cam does have smooth (tangent) transitions from base to flank and flank to nose, and it has the correct overall open-to-close dwell angle, but the nose-dwell angle doesn't match. Currently I can only imagine what happens is that the resulting nose radius ends up larger than planned, as well as the flank radius, because I don't see how grinding can change the nose dwell angle. So things aren't adding up, still puzzling over it.

is anyone else using a swinging cam cam-grinder, and Don Bell's method for their master cam, has anyone else measured the resultant finished cam profile ?