Gun drilled AAH cams...
06-07-2004, 05:58 PM
#1
AudiWorld Super User
Thread Starter
Gun drilled AAH cams...
<center><img src="http://pictureposter.audiworld.com/711/drilledcam.jpg"></center><p>
Try as I might this is the best pic I can come up with of the gun drilled cam bores. This is a shot thru the front (see the machined flat for diamond-shaped pulley washer).
Shop that was supposed to do this misunderstood and "low-balled" me on the $150 price over the phone. However, in their defense when I got there they admitted up front they misunderstood and would split the difference with me. Still made em over $400 if I let them do it. When they found out I had a lathe they told me how to make an adapter that could be built for less than $100. They even ran me some CAD plans of their adapter free of charge. They didn't tell me the drill bits to do this would cost well over $400ea and that 2 should be used, ie" one for drilling a small "pilot" bore and the next for drilling to finish size. Dont wanna break these drill bits!!
But I have a whole new appreciation and understand of why they would've had to charge me so much. Takes an entire (LONG) day just to gun drill a pair of these and another day to drill/tap the rear of the left cam for Heli-Coil or threaded insert to re-install hall plate for CPS (cam position sensor) after drilling it's threads out.
I'll get a weight-savings on this mod later in the week (still have to disassemble the extra AHH heads to get the cams out) but I'm guessing I removed 1/2 lb per cam or more. Whatever a forged 12" x 9.5mm iron rod weighs. But at least 1 pound for the pair.
And I know that some are thinking eminent failure/doom on the horizon for me with this one. But I'm thinking it aint EVER gonna happen. I spent a lot of time researching and talking with people on this topic. I've left far more wall thickness than they recommended using both incrementally and percentage-wise numbers and my cams are forgings while their's are mostly cast billets.
Next I'll send these out and have em re-heat treated and surface hardened, further increasing their strength. I'll also be doing a high tech surface friction treatment. I'm also going to see what kind of specs I can pick up from a custom grind. I'll stick to grinding only and not go with any metal-plasma build-up enhancement that would add lift. I'll see if I can make em better, increase duration and by how much or stronger performing for my specific state-of-build with my custom heads and that pesky 6,300 redline. If I can improve the performance, pick up some additional torque I will. If not I'll run em as-is after heat treating, surface hardening and surface anti-wear coating.
Try as I might this is the best pic I can come up with of the gun drilled cam bores. This is a shot thru the front (see the machined flat for diamond-shaped pulley washer).
Shop that was supposed to do this misunderstood and "low-balled" me on the $150 price over the phone. However, in their defense when I got there they admitted up front they misunderstood and would split the difference with me. Still made em over $400 if I let them do it. When they found out I had a lathe they told me how to make an adapter that could be built for less than $100. They even ran me some CAD plans of their adapter free of charge. They didn't tell me the drill bits to do this would cost well over $400ea and that 2 should be used, ie" one for drilling a small "pilot" bore and the next for drilling to finish size. Dont wanna break these drill bits!!
But I have a whole new appreciation and understand of why they would've had to charge me so much. Takes an entire (LONG) day just to gun drill a pair of these and another day to drill/tap the rear of the left cam for Heli-Coil or threaded insert to re-install hall plate for CPS (cam position sensor) after drilling it's threads out.
I'll get a weight-savings on this mod later in the week (still have to disassemble the extra AHH heads to get the cams out) but I'm guessing I removed 1/2 lb per cam or more. Whatever a forged 12" x 9.5mm iron rod weighs. But at least 1 pound for the pair.
And I know that some are thinking eminent failure/doom on the horizon for me with this one. But I'm thinking it aint EVER gonna happen. I spent a lot of time researching and talking with people on this topic. I've left far more wall thickness than they recommended using both incrementally and percentage-wise numbers and my cams are forgings while their's are mostly cast billets.
Next I'll send these out and have em re-heat treated and surface hardened, further increasing their strength. I'll also be doing a high tech surface friction treatment. I'm also going to see what kind of specs I can pick up from a custom grind. I'll stick to grinding only and not go with any metal-plasma build-up enhancement that would add lift. I'll see if I can make em better, increase duration and by how much or stronger performing for my specific state-of-build with my custom heads and that pesky 6,300 redline. If I can improve the performance, pick up some additional torque I will. If not I'll run em as-is after heat treating, surface hardening and surface anti-wear coating.
06-07-2004, 07:38 PM
#3
New Member
Join Date: Jul 2003
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
you shaved off about 0.6812lbs.....
They only had the calculation for cast iron, but I'm sure the weights aren't that off.<ul><li><a href="http://principalmetals.com/utilities/primecalculator.htm">For future referance on your continuing endevors :-)</a></li></ul>
06-07-2004, 07:57 PM
#5
AudiWorld Super User
Thread Starter
"forged "should be about 40% more dense than "cast"...
at least on aluminum but I don't know about cast vs forged iron or how that affects iron weight. I'll take it at either value. It's over a half pound off either way and thats a chunk!
06-07-2004, 08:05 PM
#6
New Member
Join Date: Jul 2003
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
I looked around for a calculator that had forged, but they all seemed like the same generic calc on
different server. Just thought I'd try to help ya out a bit. You could sweep up all of the shavings and put them on the scale (f that)!
06-07-2004, 08:33 PM
#7
AudiWorld Super User
Join Date: Sep 2001
Posts: 17,620
Likes: 0
Received 0 Likes
on
0 Posts
Curious...
Why not do this to aftermarket 268 or 272 cams? That way you'll have the good overlap for higher rpms, and they'll be lighter too. Or is this more of a test?
-Mike
-Mike
Trending Topics
06-07-2004, 08:49 PM
#8
AudiWorld Super User
Thread Starter
My research has shown the stock AAH cams have a much broader power curve...
at the expense of some peak HP. But, if one does a 15mph/2nd gear rolling start with a 264/272 and AAH cams the AAH should beat either other profile to 60mph/redline. The AAH will pull harder from down low and the power curve on the larger duration/lift cam is too narrow to catch up when it hits it's stride. Now from a 4k rpm roll all that changes. But I'd rather keep the early 900-redline rpms than pull like a banshee for only 2k rpms from 4k+ to 6.3k. Put the larger duration/lift cams on and you only move the torque band up and not down. If the rev limter is set at 6300 RPM's you've gained power for 2,000 RPM's up top and lost torque for 3,000 RPM's on the low side (sub-1k rpms is only for idle purposes). I'd rather have a car with a 5,300 rpm power curve than one with a 2,300 rpm power curve.
On the average roadcourse a 264/274 duration cam would be like driving a manual trransmission car with only two gears due to the rev-limiter. I'd always have to be in a lower gear than necessary just to keep the RPM's up, not at all unlike a turbo'd car due to it's inherent low rpm lag issue. On a "long-track" thats different but those are all going away due to safety issues/concerns. On a drag strip the 264/272 cams would be the clear choice but I'm "pure" road race.
Throw the 6300 rev-limiter out or raise it a thousand rpms and I'm all over doing this mod with bigger/better-profiled cams. But those cams are for european cars that have european ECU's and can alter or eliminate their rev-limiter altogether or for stand-alone engine management systems. They may offer some enhancement for U.S. drivers in terms of peak HP but they run out of RPM's before they can even get to their peak torque on Hitachi ECU'd cars. Sure they pull like hell from 4k to redline. The sad part is it was still climbing and making power when it was shut down by the ECU. I dont want a cam that makes it's peak torque 500-1k rpms after the ECU shuts it down! I want cams that deliver peak HP/TQ within my RPM range and not cams that can never get to their peak HP/TQ.
And even if you could get the rev limiter raised then you'd run out of valve springs at/before 7,000RPMs and they'd float with a higher lift/duration cam. And while the valve springs are easily doable upgrade the rpm-raising for today remains a pipe dream.
I will definately have less peak HP with AAH cams than a 264/272 profile cam. But I'll have the more forgiving, easier to drive and dynamic cam for the application. And I haven't even begun researching a custom re-grind for the AAH cams which could easily, cheaply and dramatically enhance an already good, cheap and readily available alternative to the high-dollar cams. Especially when you consider people leave 20% of those cams potential on the table, unused in a Hitachi ECU'd car.
The AAH least for me is the best I can do with the carved-in-stone parameters I'm stuck with.
On the average roadcourse a 264/274 duration cam would be like driving a manual trransmission car with only two gears due to the rev-limiter. I'd always have to be in a lower gear than necessary just to keep the RPM's up, not at all unlike a turbo'd car due to it's inherent low rpm lag issue. On a "long-track" thats different but those are all going away due to safety issues/concerns. On a drag strip the 264/272 cams would be the clear choice but I'm "pure" road race.
Throw the 6300 rev-limiter out or raise it a thousand rpms and I'm all over doing this mod with bigger/better-profiled cams. But those cams are for european cars that have european ECU's and can alter or eliminate their rev-limiter altogether or for stand-alone engine management systems. They may offer some enhancement for U.S. drivers in terms of peak HP but they run out of RPM's before they can even get to their peak torque on Hitachi ECU'd cars. Sure they pull like hell from 4k to redline. The sad part is it was still climbing and making power when it was shut down by the ECU. I dont want a cam that makes it's peak torque 500-1k rpms after the ECU shuts it down! I want cams that deliver peak HP/TQ within my RPM range and not cams that can never get to their peak HP/TQ.
And even if you could get the rev limiter raised then you'd run out of valve springs at/before 7,000RPMs and they'd float with a higher lift/duration cam. And while the valve springs are easily doable upgrade the rpm-raising for today remains a pipe dream.
I will definately have less peak HP with AAH cams than a 264/272 profile cam. But I'll have the more forgiving, easier to drive and dynamic cam for the application. And I haven't even begun researching a custom re-grind for the AAH cams which could easily, cheaply and dramatically enhance an already good, cheap and readily available alternative to the high-dollar cams. Especially when you consider people leave 20% of those cams potential on the table, unused in a Hitachi ECU'd car.
The AAH least for me is the best I can do with the carved-in-stone parameters I'm stuck with.
06-07-2004, 08:53 PM
#9
Member
Join Date: Sep 2001
Posts: 2,302
Likes: 0
Received 0 Likes
on
0 Posts
Dumbass question: how do you tell forged from cast?
Also, where do you go to have cams heat treated and surface hardened? For example, under what heading would one look under the local Yellow Pages?
06-07-2004, 09:04 PM
#10
New Member
Join Date: Jul 2003
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
I wasn't quite sure either, pretty good explination.........
<ul><li><a href="http://science.howstuffworks.com/question376.htm">I like this website for a lot of other things too</a></li></ul>