blooks across multiple plans

[Craigpat]

My question is this.
I have been going throught the blocks tut. I feel i have a pretty good hang of it and can make basic moving objects cams belts and a rudmentury cam/piston (motor).

right now to the question .
How do you make say a v twin - say 8 motor? its obviously has to go over multiple plans that would have all the pistons involved.

Well thats my head scratcher

thanks for the input
Craig

[JerryFlyGuy]

I wouldn't do anything different for a V8 than I would for a Vtwin.. infact they would look exactly the same..

The idea of layouts and blocks is to just get the basic 2d geometry correct. Once you've got it working then you extrapolate the data into a full 3D file.

There would be no advantage to trying to model the entire set of 8 pistons using blocks or layout sketchs.

[Craigpat]

im pretty sure i just understood what you said. i guess what what i am not understanding how to do is make piston 3 & 4 set back 4 inches from 1 & 2. The tut does go into much detail fro advanced moving models. i do have 2 very indepth dvd tuts but i did not see a blocks tutorial in it.

a though on what you said jerry. would you say make the 1/2 piston and the copy that to make the 3/4. the only thing that would be changing is the cam basicly at that point. Im not realy concerned with head, cam, intake, exhaust valves just trying to get basic understanding for concept.

thansk again for you thoughts
craig

[JerryFlyGuy]

Basically if you remember that blocks are used to get the 'basic' geometry to work and nothing more.. you'll be ok. Now in your case pistons 3-8 will have the same geometry as 1/2 so you only need to model 1 &2 in blocks and if it works.. you'll know for sure that 3-8 will work also.

Next your going to use the blocks to make 3D models of the various parts [piston, rod and the first two crank journals only at this point].

You put these parts into your assembly. Now you have [if you mated it correctly] a working model of the 1/2 bank of cylinders. Next your going to insert 3/4 and mate it as well. Also, your going to have to continue building the crank outwards and I would use this addition on the crank to change the 'timing' of the stroke. Each set of cylinders hit's TDC at a different point in rotation so your going to change this timing when you build the crank. Then your going to mate the rods to the crank. By doing this in this general order you'll be able to build the crank/rod/piston assembly down the length of the block.

Then I would build the block around this assembly.. [maybe add the cram prior to building the block].. Followed by the heads and their valved and then the intake exhaust etc..

Hth

[Craigpat]

Wow great thanks for the insight.
I think iwas having trouble getting my head around it. May be a 1 cyl RC plane motor or lawn mower eng would be a good start.

Thanks much
Craig

[JerryFlyGuy]

Generally it's better to start small Once you've done it once w/ a single or v-twin.. then a larger multi cylinder would be much easier to approach and complete..