Full Lightweight Timing Kit
02-06-2009, 12:48 PM
#101
Travis, there appears to be concern re; the 3 bolt connection, then why not go with a lock pin to secure the cam gear sprocket to the hub of the cam gear. The hub could be machined w/ holes @ 1 degree intervals around the circumference. The gear sprocket would have holes that line up with the hub holes and a couple of lock pins would secure the hub to the sprocket. Indexing would be a matter of removing the lock pins, making the adjustment, putting the lock pins in. No worry of cams coming out of adjustment.
The only down side, aside from the increased cost of machining the hub and gear sprocket with the holes is adjustment goes from .5 degrees to 1. IMHO, that's something that most people could live with.
The only down side, aside from the increased cost of machining the hub and gear sprocket with the holes is adjustment goes from .5 degrees to 1. IMHO, that's something that most people could live with.
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02-06-2009, 01:04 PM
#102
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The cam gears will not slip. The fasteners are designed for a 5000 pound preload so each fastener at the absolute worse conditions hold 125 ft lbs of torque a piece. More realistically they will hold around 200 ftlb pounds for a combine pulley static slip of 600 ft lbs. The outer ring would probably fail (which is made of 7075) before the inner ring would slip.
To turn a cam you actually only need probably 20-30 ft lbs in the worst conditions. The idea above I worked through, and its too complicated, heavy, and surprising weak unless you use multi-pins.
Its not like your holding a flywheel. The camshaft gears only spin at 1/2 engine rpm, and the amount of force it takes to turn the cam doesn't go up as rpms go up. It stays about the same, plus a little more for additional sliding friction. Otherwise your valve train would be costing you like 50 hp on top. 10 ft lbs cost you 13 horsepower at 7000. Just imagine what it would be if it took 30-40ft lbs 53 horsepower??
To turn a cam you actually only need probably 20-30 ft lbs in the worst conditions. The idea above I worked through, and its too complicated, heavy, and surprising weak unless you use multi-pins.
Its not like your holding a flywheel. The camshaft gears only spin at 1/2 engine rpm, and the amount of force it takes to turn the cam doesn't go up as rpms go up. It stays about the same, plus a little more for additional sliding friction. Otherwise your valve train would be costing you like 50 hp on top. 10 ft lbs cost you 13 horsepower at 7000. Just imagine what it would be if it took 30-40ft lbs 53 horsepower??
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02-06-2009, 01:13 PM
#103
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This is both versions..
http://www.boundaryengineering.com/standard.jpg
(Large picture warning!)
The carbon version isn't final, but it kind of gives you an idea of what the carbon looks like.
The Boundary products that use carbon parts all go under "Carbon Series" and are offered as an upgrade to the standard with aluminum. The aluminum parts are still lighter then the stock gears, but certainly heavier then then the carbon.
Accuracy is very good on these, you could easily set half a degree on either version.
Weights are:
Stock 385 grams
All Aluminum 235 grams
Carbon Series 175 grams (less then half of stock!)
If you want to get really serious and ridiculous with weight we can put titanium fasteners in. The fasteners are nearly the heaviest part. Expect a real price premium with titanium hardware though. It is very expensive to stock!
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02-07-2009, 12:24 AM
#104
The cam gears will not slip. The fasteners are designed for a 5000 pound preload so each fastener at the absolute worse conditions hold 125 ft lbs of torque a piece. More realistically they will hold around 200 ftlb pounds for a combine pulley static slip of 600 ft lbs. The outer ring would probably fail (which is made of 7075) before the inner ring would slip.
To turn a cam you actually only need probably 20-30 ft lbs in the worst conditions. The idea above I worked through, and its too complicated, heavy, and surprising weak unless you use multi-pins.
Its not like your holding a flywheel. The camshaft gears only spin at 1/2 engine rpm, and the amount of force it takes to turn the cam doesn't go up as rpms go up. It stays about the same, plus a little more for additional sliding friction. Otherwise your valve train would be costing you like 50 hp on top. 10 ft lbs cost you 13 horsepower at 7000. Just imagine what it would be if it took 30-40ft lbs 53 horsepower??
To turn a cam you actually only need probably 20-30 ft lbs in the worst conditions. The idea above I worked through, and its too complicated, heavy, and surprising weak unless you use multi-pins.
Its not like your holding a flywheel. The camshaft gears only spin at 1/2 engine rpm, and the amount of force it takes to turn the cam doesn't go up as rpms go up. It stays about the same, plus a little more for additional sliding friction. Otherwise your valve train would be costing you like 50 hp on top. 10 ft lbs cost you 13 horsepower at 7000. Just imagine what it would be if it took 30-40ft lbs 53 horsepower??
Don't get the purpose of this post wrong, I'm not criticizing your gears, I actually like them. However, many people have expressed their "concern" with the fact that only 3 bolts are used to set the hub to the sprocket. I was just suggesting a way to address those concerns, maintain adjustability and offer something a little different than just another "adjustable cam gear".
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02-07-2009, 02:03 AM
#105
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Heavier and more somewhat complicated, OK but weak, not on your life. If the lock pins are fab'ed of 7075 or for a truely exotic part Ti-6Al, all you would need is 2. Once the holes are lined up where you want them (for timing or indexing) on the hub and sprocket, put in the lock pins opposite each other and your done.
Don't get the purpose of this post wrong, I'm not criticizing your gears, I actually like them. However, many people have expressed their "concern" with the fact that only 3 bolts are used to set the hub to the sprocket. I was just suggesting a way to address those concerns, maintain adjustability and offer something a little different than just another "adjustable cam gear".
Don't get the purpose of this post wrong, I'm not criticizing your gears, I actually like them. However, many people have expressed their "concern" with the fact that only 3 bolts are used to set the hub to the sprocket. I was just suggesting a way to address those concerns, maintain adjustability and offer something a little different than just another "adjustable cam gear".
I take all criticism with open arms. I was just giving you the reason I did what I did and why I thought it was well thought out. I just didn't put 3 on there and say "awwwh that is good enough." I sat down and really looked at it at the friction force generated, what forces were acting on it, and ways to prevent accidental loosening.
Another reason I also wanted to do it this way is that I've included wave lock washers so that when you loosen the cam gear you've still got tension on the gear. I don't know how many adjustable gears you've used, but I've found it is really annoying when you've got the cam bound in a high spring rate area and you loosen the bolts (or take out the pins would give you the same result) and the center just rips over to get unbound and smashes into the maximum adjustment. This setup helps keep the cam where its by providing friction and you can adjust it without too much of a problem.
We'll get the reports back soon enough on it though. I won't release them until I'm happy, and if it doesn't work I'll add another bolt. It is just as easy as that. I don't think we'll have a problem though.
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02-07-2009, 11:45 PM
#106
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I've often wondered why adjustable cam gears don't use some sort of teeth on the hub/gog interface to keep movement at bay. instead of lock pins or more bolts. I understand that it would be hard to machine. and I'm not questioning your methods, just the status quo.
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02-08-2009, 11:57 AM
#107
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Alot of it comes from the KISS principle. I worked on different designs for along time on this trying to be clever. When it came down to it I had something that was expensive to make, had to have the most accurate machining possible to just work, and what did you really gain? It is different but when it came down to it your still just setting the timing, and the less the end user has to think about using some sophisticated heavy expensive pin/locking mechanism I think the better off he'd be.
I'm thinking about changing the aluminum centers just a little bit.
Here is a rendering. What do you think? Keep the old design or use the new one? It is a lighter by 13 grams then the old one. Strength is definitely not compromised. Pretty much a style preference at this point.
I'm thinking about changing the aluminum centers just a little bit.
Here is a rendering. What do you think? Keep the old design or use the new one? It is a lighter by 13 grams then the old one. Strength is definitely not compromised. Pretty much a style preference at this point.
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02-09-2009, 12:55 PM
#108
All things being equal, it's pretty hard to argue with the lighter version of the lightweight timing kit.
The filled in one looks hot, but if I want more weight just for looks, I'll get the girlfriend a boob job. Not that I imagine one can do a lot with 13 grams :-)
The filled in one looks hot, but if I want more weight just for looks, I'll get the girlfriend a boob job. Not that I imagine one can do a lot with 13 grams :-)
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?
02-26-2009, 07:06 AM
#113
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I'm selling the last engineering samples I have for 300 even, with cam gears that have aluminum centers. As soon as the testing gets completed we'll be in full production. I'm waiting on drgoodwrench to letme know if changes are necessary. I know I have a couple of little things to tweak.
These sets should fit all the long nose crank motors, I have a thread over there. Its in the group buy section. I think its a little buried.
These sets should fit all the long nose crank motors, I have a thread over there. Its in the group buy section. I think its a little buried.
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02-26-2009, 04:38 PM
#115
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I still haven't gotten a cam gear for the 99-00 from Abe. I sent him a message about it not too long ago too. Not sure where he got off to. If I just had one example I cold set it up no problem.
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