Author Topic: vintage V twin (Read 38628 times)

OKTomT · « **Reply #25 on:** June 08, 2014, 06:32:28 PM »

I got the crank repaired. I really felt that the problem was the tapered crank pin hole because it took one more setup than the press fit hole. But after checking it I found that the offset of the press fit hole was off so I bored it over size and made a new crank pin out of 4130 pressed it back together and the main pins run at tir..002.
I think if I do this again I will make the taper on the pins the same as a morse taper and use a reamer to clean up the holes.
I have started on the crankcase. Here is a picture of what made so far.
spec.
9" od tube x 2.375
end plate .250

billmac · « **Reply #26 on:** June 09, 2014, 10:36:39 AM »

Very glad to see that you got your crankshaft fixed.

Just a suggestion for your fabricated crank case. With the taper roller bearings it is very important that the sides of your crank case are as stiff as possible. A flat plate may lack a bit in that area, but you can easily fix this by welding in some tapered webs radiating out from the main bearing area. This would also make your engine look much more like a typical cast crankcase. With your welding skills this should be fairly easy to do.

OKTomT · « **Reply #27 on:** June 09, 2014, 09:38:04 PM »

Thanks Bill
I will definitely add the webs to the drive side of the case. The cam side will get support from the cam box .
I am working on the cylinder base and need to decide on the v angle. 45 degrees is what I am thinking of using and use a master rod and slave rod rather than a knife fork. Anyone have any thoughts on this ?

billmac · « **Reply #28 on:** June 10, 2014, 05:19:51 AM »

45 degrees would be appropriate if you are making a Harley type engine. How about being a bit more radical and going for a high cam short pushrod design with about 50 degrees to get a Vincent look? It would be a bit more work but visually interesting. I guess the decision depends on what you want to do with the engine when finished. If you want to build a vintage frame around it then perhaps a vintage look engine would be better.

A master slave rod design is typical of radial engines and should be doable in a twin. I think there would be some interesting design issues you would need to resolve though. Cam timing and design would need some thought. Master rod design from a stress viewpoint would be interesting - easy to get some significant bending stresses. Master/slave might be easier in a wide angle twin than, say 45 degrees.

If you have sufficient room, a side by side big end might be easier than a knife and fork, but I'm not sure whether your crank case design will permit this. If it does, then it should aid cooling the rear cylinder a bit - cooling would definitely be a concern for a cast iron (or steel?) rear cylinder/head design.

OKTomT · « **Reply #29 on:** June 29, 2014, 09:42:20 AM »

Hi guys
I have made a little progress on the crankcase Here is some pictures of it.
The v angle is 45 degree.

John Stevenson · « **Reply #30 on:** June 29, 2014, 02:11:21 PM »

Brilliant Tom.

Following this closely but without doing too many 'me too' posts. You are making a nice job of it.

micktoon · « **Reply #31 on:** June 29, 2014, 05:43:26 PM »

Keep up the good work Tom , this looks like it will be as good a post as your last build

Cheers Mick

sdezego · « **Reply #32 on:** July 29, 2014, 03:23:50 PM »

Been a while since I have been poking around so I am a little late to the party, but this looks like another great project!

Not sure what you decided, but I can offer my 1st hand experience and opinion on the bearings. Opposing Tapered (Timken) bearings on the Chain side (properly preloaded) and flat rollers on the cam side. With Flat rollers on the cam side, you don't have to worry about expansion, binding, shimming between cases, etc, which would be a major concern.

I can't speak for other models, but early Harley's used Flat rollers Until evolution came about in '57 and then used Tapered on chain side from then on out with flat rollers on cam side. This was a major improvement in every singe way (1st hand).

I would use either flat rollers on both side (if you want an earlier period correctness) and thrust shims to prevent walk, or Timken on chain side and flat rollers (or bushing) on other but def not tapered on both sides.

Are you going to do an oiling system? Oil hole through shafts and flys into crank pin? ..you mentioned more displacement and more RPM than the last, but not how much more, haha

Regards,
Shawn

John Stevenson · « **Reply #33 on:** July 29, 2014, 05:55:44 PM »

Quote from: sdezego on July 29, 2014, 03:23:50 PM

I can't speak for other models, but early Harley's used Flat rollers Until evolution came about in '57 and then used Tapered on chain side from then on out with flat rollers on cam side. This was a major improvement in every singe way (1st hand).

Regards,
Shawn

A simple oilite bush would be a major improvement on a Harley.

OKTomT · « **Reply #34 on:** August 03, 2014, 12:07:54 PM »

thanks for your input guys
Shawn I am going with tapered roller bearing on both sides and splash lube.

I have made a little progress on the crankcase . Welded in boss and drive side supports, bored the bosses to fit the bearings , added hollow dowel pins , bored the holes for cylinders.

Brass_Machine · « **Reply #35 on:** August 03, 2014, 12:19:59 PM »

It is looking good!

Eric

vtsteam · « **Reply #36 on:** August 03, 2014, 12:33:34 PM »

Yah!

OKTomT · « **Reply #37 on:** September 01, 2014, 12:15:05 PM »

Hi guys.
I have been working on the cylinders. They still need the liners installed and I may cut some more off of the fins to make them thinner.

micktoon · « **Reply #38 on:** September 01, 2014, 05:29:53 PM »

Hi Tom , its coming along nicely

, I dont really think the fins look too heavy as they are myself but no expert on bike engines mind so do not know what they are meant to look like but they dont look wrong to me .
Cheers Mick

Stilldrillin · « **Reply #39 on:** September 01, 2014, 06:07:21 PM »

That looks really good Tom!

You nearly got away from me!

I've just had a crackin', catchup read.......

David D

OKTomT · « **Reply #40 on:** September 30, 2014, 07:24:20 PM »

Hi guys. Thanks for your comments.
I have made a little progress on the engine . pressed in cast iron sleeves in the cylinders and bored them to 3.125, drilled the mounting stud holes in them and the block and built a master rod.
Here is a picture of the rod. I am not sure the slave pin hole is in the right location does any body know how to figure out the proper location??
45 degrees 3.75 stroke

sdezego · « **Reply #41 on:** October 16, 2014, 03:46:11 PM »

I only have experience with KNife and Fork VTwin design.

I would think though that when the Rod angles match the the Cyl Angles (45*), the slave crank pin's centroid should be linear with the Main Crank pin and the wrist pin, and Rod lengths the same at that point. i.e. extend a line though all 3 pin centers at 45* ...that is off the cuff though.

OKTomT · « **Reply #42 on:** October 16, 2014, 08:45:29 PM »

Thanks sdezego.
That is how I think it should work too. but that would put the slave pin hole way out there. I have found pictures of rods that look like the one that I built but no info on the rest of the engine. Here is a picture of my rod in the crankcase and it wont work like this so I am going to make knife and fork rods for it.

sdezego · « **Reply #43 on:** October 16, 2014, 10:34:43 PM »

Kind of interesting actually. I would need to pull out the old kinematics book

Fork and knife would definitely be a sure thing. I thin it is odd that I have never come across this before. But in a quick search, I found this thread http://thekneeslider.com/drysdale-godzilla-v-twin/. Doesn't give you any dims or specific insight, but interesting non-the-less!

vintageandclassicrepairs · « **Reply #44 on:** October 17, 2014, 04:59:09 PM »

HI Tom,
Some vintage V twins used side by side rods with off set small ends,
I think these would be a lot easier to make than knife /fork setup
The other alternative is to source some rods or complete assembly from a breakers or ebay

HTH
John

OKTomT · « **Reply #45 on:** December 06, 2014, 11:50:53 AM »

Hi guys. I built some new rods, pistons and heads. The heads still need the fins cut but I need to wait until I get the valve train worked out first.

vtsteam · « **Reply #46 on:** December 06, 2014, 01:15:32 PM »

Amazing, as usual!

(seems like a contradiction in terms, but it just is, to me....)

krv3000 · « **Reply #47 on:** December 06, 2014, 06:05:17 PM »

shapin up nice

micktoon · « **Reply #48 on:** December 07, 2014, 06:35:44 PM »

Hi Tom , looking nice

, I like the no nonsense industrial look but it looks like it will do the job to me , top class work as usual.
Cheers Mick.

crankshafter · « **Reply #49 on:** January 22, 2015, 07:48:30 AM »

Hi Tom.
Any updates on your V-twin?

CS

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Author Topic: vintage V twin (Read 38628 times)