Eric's cam challenge

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replicaracer43 said:
Very interesting. Comp cams quality control has been in a downward spiral for a few years now.
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This spring I had a customer who thought there was a problem with a BBM roller I’d sold him.
I had Comp run it thru the Adole 911 laser camshaft measuring machine……..way more accurate than a cam dr.

That particular cam measured out excellent, not just the lobe accuracy, but bearing roundness and runout, lobe runout, bank angle accuracy, etc………he had other issues.

What I found interesting is Eric was comparing data derived from two different machines.
I wonder if he would accept flow numbers from someone else’s bench, or if he’d want numbers from his own.
Oh wait, we know the answer to that.

I can only think of a few of cams that I measured that strayed pretty far from the specs on the card.
This was like 25 or so years ago.
One was a Herbert roller for a SBC, and two were NHRA stocker cams for a Pontiac.
 
PRH said:
This spring I had a customer who thought there was a problem with a BBM roller I’d sold him.
I had Comp run it thru the Adole 911 laser camshaft measuring machine……..way more accurate than a cam dr.

That particular cam measured out excellent, not just the lobe accuracy, but bearing roundness and runout, lobe runout, bank angle accuracy, etc………he had other issues.

What I found interesting is Eric was comparing data derived from two different machines.
I wonder if he would accept flow numbers from someone else’s bench, or if he’d want numbers from his own.
Oh wait, we know the answer to that.
Click to expand...
Very good point
 
I’m not saying that what Eric found is impossible, but If I were Joe Carrol I’d be sliding that cam in a block and measuring it up for myself.
 
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PRH said:
I’m not saying that what Eric found is impossible, but If I were Joe Carrol I’d be sliding that cam in a block and measuring it up for myself.
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I think the biggest take away, is if you dont measure it, you dont know for sure. Common sense really, but the vast majority of DIY engine builders and hobbyists look at the cam card and assume the cam is ground to those specs.
 
PRH said:
I’m not saying that what Eric found is impossible, but If I were Joe Carrol I’d be sliding that cam in a block and measuring it up for myself.
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Eric and Daniel (Powell machine) both said they see that a bunch from comp cams. I sure hope that isn’t true.
 
And people check the ICL on one cyl [ & not the rest......] & worry if it is 1 or 2 degrees out.....
 
Bewy said:
And people check the ICL on one cyl [ & not the rest......] & worry if it is 1 or 2 degrees out.....
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And how many perform a positive-stop TDC check on all of the pistons,..... that can be an eye opener on occasion.
 
Joe Carrol still came in 3rd with the cam specs being all over the map, but funny thing his stated spec were pretty similar to DV who did 14th, so maybe the cam being off helped him :)
 
PRH said:
This spring I had a customer who thought there was a problem with a BBM roller I’d sold him.
I had Comp run it thru the Adole 911 laser camshaft measuring machine……..way more accurate than a cam dr.

That particular cam measured out excellent, not just the lobe accuracy, but bearing roundness and runout, lobe runout, bank angle accuracy, etc………he had other issues.

What I found interesting is Eric was comparing data derived from two different machines.
I wonder if he would accept flow numbers from someone else’s bench, or if he’d want numbers from his own.
Oh wait, we know the answer to that.

I can only think of a few of cams that I measured that strayed pretty far from the specs on the card.
This was like 25 or so years ago.
One was a Herbert roller for a SBC, and two were NHRA stocker cams for a Pontiac.
Click to expand...
How many MP cams have you measured? Back when I was building a good many engines, I measured all of them I used, whether MP or some other. What I found interesting is, after the MP cams were "redesigned" sometime in the 80s, that's when I started seeing their number skew way more than normal. I don't know if they changed their measuring practice or not, but that's certainly what it seemed. I know they "said" to use .850 instead of the industry standard .750 for figuring duration @.050", but I never found that accurate anywhere near 100% of the time. It almost seemed as if the redesign was more of a way of keeping their camshaft information proprietary. Maybe I'm putting too much of a conspiracy spin on it, but I don't know any other explanation.
 
273 said:
Joe Carrol still came in 3rd with the cam specs being all over the map, but funny thing his stated spec were pretty similar to DV who did 14th, so maybe the cam being off helped him :)
Click to expand...
14th? I thought he was 20th.
 
273 said:
Joe Carrol still came in 3rd with the cam specs being all over the map, but funny thing his stated spec were pretty similar to DV who did 14th, so maybe the cam being off helped him :)
Click to expand...
Nevermind. I was lookin at it outta the wrong eye.
 
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