Author Topic: UCE 500 cams on AVL 500 ??  (Read 10912 times)

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Reply #15 on: November 25, 2013, 07:08:27 pm
I don't subscribe to this method myself , however, I am just experimenting and have no idea what the results will be. It might just be a classic fail.

Its better to do an informed experiment. I would encourage you to listen to what Ace.Cafe is indicating i.e. valvegear and its ability to tolerate the lift, piston clearance etc. You might end up creating a bigger problem for yourself. 


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Reply #16 on: November 25, 2013, 07:10:32 pm
I see.
So... It's addition by subtraction.

Yes, the tappets could be adjusted to compensate for the decreased base circle diameter .......but Ace is pointing at something very important.


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Reply #17 on: November 26, 2013, 05:18:02 am
I understand the concern and well I guess its too much of a risk with the brilliantly running motor that I have right now. I might give it a pass at the moment.

However, just curious - isn't this the same thing which happen when we use the Cast iron engine cams in the AVL with the small base circle and which results in a higher lift on the same.


ace.cafe

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Reply #18 on: November 26, 2013, 11:38:38 am
I understand the concern and well I guess its too much of a risk with the brilliantly running motor that I have right now. I might give it a pass at the moment.

However, just curious - isn't this the same thing which happen when we use the Cast iron engine cams in the AVL with the small base circle and which results in a higher lift on the same.

The Iron Barrel cams are smaller base circle, yes.
However, they are ground with all the necessary attributes to work as a proper cam in a valve train.

A cam is not just a bump on a wheel. There is the base circle, lash ramps, flanks, nose, included on the cam shape which have functions defined by multiple polynomial curves. These curves translate the progressively different lift rates at various portions of the lift cycle which can be controlled by the valve springs.  The lash ramps have a certain length and lift acceleration, so that the lash is taken up gently, and doesn't hammer the valve train. The  lift cycle is then begun at a slow acceleration, gradually increasing with different mathematical curves blended together to a smooth acceleration curve, and then after reaching the maximum lift rate part-way along the flank, it gradually begins to reduce the lift rate so that it can get over the nose without flinging the valve out of contact. Additionally, flat tappet cams have a slight taper on the lobe and they are not "flat". This taper causes the tappet to spin during operation, so that it has a better wear life.  And the surface is hardened to a high hardness for wear resistance under heavy loading, and after any re-shaping might be done by a professional grinder, the surface is re-hardened to restore the wear resistance of the metal surface.
The reason that they use a cam grinder to do this grinding is because these contours must perfectly follow the mathematical curves programmed into it, and also grind a perfectly smooth contoured surface. This surface which is required cannot be met with normal machine cutting tools, much less a hand file. It needs a precision grinding machine. A cam in an engine is a very complicated piece of engineering that requires specialty knowledge to design, and special tooling to make

None of these geometrical attributes are met by "hand filing" the cam down, and if your diagram was any indication, the plan was to file down practically everything but the nose.
So no, it is not at all the same as using the Iron Barrel cams. The Iron Barrel cams may be somewhat crude, but at least they have the necessary design attributes.

The bottom line is that you can't just go filing these things down in your workshop and expect decent results. It might "work" in terms that the engine will go around and still run, but there will be problems associated with it which may not be initially apparent.

On top of that, the springs may not be(probably are not) able to handle the more rapid accelerations of a faster lift cam, and also might not have enough room between the coils to take that added lift without hitting coil bind. If you have not measured this, then you don't know. And we already know that the AVL has horrible valve springs that can't even control the valve properly in a normal application with normal cams. Then, we would have to see if there is enough room to lift the valve that much without hitting the valve guide. We have to measure that.  Then we have to measure if the valve is going to hit the piston as it goes over TDC.

There's just a lot more to this than you might think.
I can spec-out a cam with all the necessary parameters, but I go to a cam grinder to get it made. I wouldn't try to re-profile a cam, and I have a full CNC machine shop at my disposal.

« Last Edit: November 26, 2013, 12:24:11 pm by ace.cafe »
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TejK

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Reply #19 on: November 27, 2013, 04:35:04 am
Thank Ace for putting things in perspective ! I guess its too much of work and needs very specialised equipment.






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Reply #20 on: November 27, 2013, 01:17:07 pm
Tejk - If you are interested in custom camshaft work, there is a gentleman in BC Canada that specializes in camshaft RE-profiling.  I spoke with him about my project and guess what?  He custom fabbed his own tooling for the Bullet camshafts (for one of his customers) and he is just itching to do some more RE cams.  He has over 3000 cam lobe profiles to choose from in his CAD program.  You just need to call him up and talk to him.  I know for my twin camshafts (2 cams, 2 lobes each) he was only going to charge me $300 a cam I believe (price may have been for the pair but I can't remember).

The name of the Company is Colt Cams.  There is a contact phone # on the website.

http://coltcams.com/

The name of the Gentleman you want to talk to is Jeff.  He seems to be very educated at his line of work and when I last spoke with him he was very excited to use his RE tooling again.

Scottie

EDIT:  You may want to call him soon depending on how interested you are in this.  This is from their website.
Quote
We're taking a little R&R and enjoying some time with family and friends. The shop will be closed December 9th, and will be back in the shop on Thursday, January 2nd, 2014.
« Last Edit: November 27, 2013, 01:19:44 pm by Scottie J »
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TejK

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Reply #21 on: November 28, 2013, 06:22:02 am
Thanks Scottie,

I am waiting for the next possible available 'S' cams if BW has my name on the list.

However, I will get in touch with Colt cams to understand what he cam do with the cores I can send him.


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Reply #22 on: November 28, 2013, 02:56:18 pm
Basically Jeff does the build-and-mill technique at Colt Cams.  He TIG welds the cam lobes to build up the materials, then puts them in the CNC machine and completely redesigns to cam profile to what ever specs you'd like.  I'm not sure what profile he used for his customers RE he did, but I do know he spent a bit of time researching it.

Scottie
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Reply #23 on: December 24, 2013, 07:09:43 am
Basically Jeff does the build-and-mill technique at Colt Cams.  He TIG welds the cam lobes to build up the materials, then puts them in the CNC machine and completely redesigns to cam profile to what ever specs you'd like.  I'm not sure what profile he used for his customers RE he did, but I do know he spent a bit of time researching it.

Scottie

Hi Scottie,
I tried reaching him however it seems he is on a holiday till next year. In any case , I think i maybe getting the S cams soon.

Wish you a merry Christmas and a happy new year !!


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Reply #24 on: December 24, 2013, 01:26:02 pm
Merry Christmas!
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ace.cafe

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Reply #25 on: December 25, 2013, 02:20:35 pm
Hi Scottie,
I tried reaching him however it seems he is on a holiday till next year. In any case , I think i maybe getting the S cams soon.

Wish you a merry Christmas and a happy new year !!

The thing about the S Cams is that they have been tested and proven to work with the existing valve springs to overcome the inherent issues that were preventing higher revving. This is a big advantage.
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Reply #26 on: December 25, 2013, 02:25:59 pm
The thing about the S Cams is that they have been tested and proven to work with the existing valve springs to overcome the inherent issues that were preventing higher revving. This is a big advantage.

That's why YOU need to talk to him and build the best Ace!

Don't get me wrong, I'm not knocking the S Cams, they obviously totally rock!  I'm just saying it would be nice to have a reliable performance supplier here in North America instead of everything coming from Europe.  Those damn exchange rates are ridiculous.
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ace.cafe

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Reply #27 on: December 25, 2013, 02:51:01 pm
That's why YOU need to talk to him and build the best Ace!

Don't get me wrong, I'm not knocking the S Cams, they obviously totally rock!  I'm just saying it would be nice to have a reliable performance supplier here in North America instead of everything coming from Europe.  Those damn exchange rates are ridiculous.

I would only get into something like that with a complete engine kit like we have for the Fireball.
But I will talk to that guy about some other stuff when he gets back.
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Reply #28 on: December 25, 2013, 02:56:00 pm
That's why YOU need to talk to him and build the best Ace!

Don't get me wrong, I'm not knocking the S Cams, they obviously totally rock!  I'm just saying it would be nice to have a reliable performance supplier here in North America instead of everything coming from Europe.  Those damn exchange rates are ridiculous.

Exchange rates KILL us Indians :P


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Reply #29 on: December 26, 2013, 06:54:18 am
Exchange rates KILL us Indians :P

On the plus side 'Royal Enfield' is 'Made in India' so other things work out well for India !!  :D