power difference between different brand cams

[vortecpro]

I gave Chet Herbert a very good Isky cam to copy, and his copy was 20 HP LEES than the real thing from Isky- So much for the exact same thing

With these simple BBC flattappet engines I build, it seems the Isky cam likes to rev which is important to me, I also accept the gentle lobes are down on HP, but did the Isky's rev for you?





JOE SHERMAN RACING

[DaveMcLain]

What would be pretty interesting is to see what the differences in some of these cams are after X amount of run time. I'd bet that with some of that Comp Cams XE stuff more than 50% are flat in less than 10,000 street miles.

[PRH]

I'd be curious to know what the lobe numbers were for the original Comp cam.

25 or so years ago I was using mostly UD cams.
I had several occasions where I pulled something else out, and replaced it with a UD and saw a nice gain in power.
Many times however, the specs also changed a fair amount from cam to cam....... So not really an apples to apples test.

I have plotted out, with a degree wheel and the cam in a motor, a few Herbert rollers...... They were waaaaay off from the specs.
One was off so far that if you didn't have the number stamped on the end of it, you wouldn't have known what it was "supposed" to be.
It ran fine in the motor, but it was quite a different cam than what the specs were.

[David Vizard]

To further elaborate about title, what's the thoughts on similar cams from different manufacturers? I just freshened /fixed an engine for a customer that I originally did from scratch. I think I have cycled out the last set of JUNK comp cams lifters from the engines I have built. Never again comp anything for me. Anyhow, obviously the cam was ruined too. This is a good running 406sbc, Dart block, Rhs heads, that I ported, it makes upper 600's for hp, so its no slouch. On most internet dynos, it would make way over 700, lol. Just a strong, basic bracket race deal. Anyhow, new rings, bearings, fresh hone, gaskets, and new Erson/Morrell super duty lifters, and a Erson cam, to replace the comp grind that was in it. Lucky there was minimal or zero damage from the shrapnelled lifter. Nearly identical specs. 1 less at .050 on intake, same ex duration, same lobe Sep, and same lobe lift on both in/ex as old cam, installed at the same intake centerline. I just had as similar of a cam I could, so no potential changes needed to converter, gear etc was needed. Any guesses ? I know I have heard claims from at least one speedtalker who says comp cams make 20-40 more hp than any other cams that are the same size. This Dyno also repeats 1 year, 3 years, 6 years, etc later like dead on, so, its 100% accurate. This spring I have freshened and redynoed 3 engines, that were originally dynode there, and the sheets and graphs would have overlayed each other to the point they were nearly identical.

Thoughts? Guesses?

Two cams, differing design techniques - both showed excelent dynamics on the spintron - duration at check points +/- about 1.5 degrees - torque & hp within 1.5% as near as could be measured. Next cam tested with not so good dynamics - about 12 hp down.

[la360]

It's a little off topic, but those whom are chasing records etc, what methodology do you use for testing several camshaft profiles?

I work in research in additive manufacturing, the researchers with use various processes to determine a pool of parameters to use for experiments. Just curious if anyone uses a similar way of thinking to selecting lobes.

[cgarb]

About the Herbert cams...I've dealt with them some, from what I gather they have a very old set of masters and they are limited in what lobes they have. They will tell you they can grind anything, to some extent I think they mess with the master somehow and fudge lash numbers to get "close" to what you wanted. I haven't had any problems with the rollers I've gotten from them, they ran fine and the ones I have check very close at least on the #1 cylinder. I haven't checked more than that I just get the centerline where it needs to be and adjust to see what it likes. My engine is down on power compared to some modern grind stuff so I would expect to see an improvement going to something better for sure. Old lobes that are easy on springs though...I bought my first couple roller cams from them because it was a big price difference from them to other cam companies. They have raised their prices up now some so they aren't quite the bargain they were before. My next cam will be from a more reputable grinder for sure.

[A HotRod]

So for the Average-Cecil-B-Citizen that's wanting his Chevy 355 performance street engine to produce good, strong torque and power, ... and he is going to make 1 camshaft purchase, where does he turn to?

I fully understand the 'catalog concept' and how it really doesn't apply to any one engine and combination.

Who is really going to ask me for the details and honestly and correctly give me what is best?


So, how does one make an educated decision on which camshaft business to go with for quality results?

Glenn

[kimosabi]

So for the Average-Cecil-B-Citizen that's wanting his Chevy 355 performance street engine to produce good, strong torque and power, ... and he is going to make 1 camshaft purchase, where does he turn to?

I fully understand the 'catalog concept' and how it really doesn't apply to any one engine and combination.

Who is really going to ask me for the details and honestly and correctly give me what is best?


So, how does one make an educated decision on which camshaft business to go with for quality results?

Glenn

I like to go for the companies who asks for the most details about the build. Worked out pretty good so far. I go full nerd when building though so providing the most minute details is easy.

[A HotRod]

I like to go for the companies who asks for the most details about the build. Worked out pretty good so far. I go full nerd when building though so providing the most minute details is easy.
[/quote]


....and what companies would that be in your experience?
Glenn

[kirkwoodken]

My observation on Chet's cams is he expected the buyer to know what he was doing. I would never install one of Chet's cams dot to dot! Locating dowel could be anywhere. I sent an old Herbert cam to a MAJOR cam grinder to see if I could get a street grind put on it. Had a tag on it explaining it was 108 LDA BUT cam locator pin was 8 degrees off. Do not try to grind off the dowel pin!!! They ruined the core, put a different grind on it, and ground through the hardness. Despite their advertising, I was not impressed by their work quality. Like Yogi said, "there are some people; you just can't tell "em".

Chet's original rollers were hard anodized aluminum weighing in at 50 Grams. Cam and rollers sold for $100.00. Rollers were kept in alignment with 3/16" square rods inserted into the oil galleys, and went through slots in the lifters. Roller rockers hadn't been made yet, and the SBC's would rev 8000 RPM with stamped rockers and 180 pounds on the valve seats. SOME Herbert cams were EXTREMELY asymmetrical with long lash ramps. The Herbert #40 had 365 degrees duration at lash numbers and they were known to win national events in their day. About all I remember about Chet's cams. Lift was about .525".

[GARY C]

My observation on Chet's cams is he expected the buyer to know what he was doing. I would never install one of Chet's cams dot to dot! Locating dowel could be anywhere. I sent an old Herbert cam to a MAJOR cam grinder to see if I could get a street grind put on it. Had a tag on it explaining it was 108 LDA BUT cam locator pin was 8 degrees off. Do not try to grind off the dowel pin!!! They ruined the core, put a different grind on it, and ground through the hardness. Despite their advertising, I was not impressed by their work quality. Like Yogi said, "there are some people; you just can't tell "em".

Chet's original rollers were hard anodized aluminum weighing in at 50 Grams. Cam and rollers sold for $100.00. Rollers were kept in alignment with 3/16" square rods inserted into the oil galleys, and went through slots in the lifters. Roller rockers hadn't been made yet, and the SBC's would rev 8000 RPM with stamped rockers and 180 pounds on the valve seats. SOME Herbert cams were EXTREMELY asymmetrical with long lash ramps. The Herbert #40 had 365 degrees duration at lash numbers and they were known to win national events in their day. About all I remember about Chet's cams. Lift was about .525".

The only roller stuff I have ever ran was Herbert's and they made it clear that they had to be degreed, I was using my own specs so it was ground off a bigger shelf cam or core. I have a cheap 3 piece gear drive that I use to base line the degree because the crank gear will slide on and off with no effort, then I know where I need to set my crank gear when pressed on and about how much offset bushing needed.

[kimosabi]

I like to go for the companies who asks for the most details about the build. Worked out pretty good so far. I go full nerd when building though so providing the most minute details is easy.

....and what companies would that be in your experience?
Glenn
[/quote]

Ordering a cam from Mike Jones for example is like a frickin hour long interview.

[af2]

I like to go for the companies who asks for the most details about the build. Worked out pretty good so far. I go full nerd when building though so providing the most minute details is easy.

....and what companies would that be in your experience?
Glenn

Ordering a cam from Mike Jones for example is like a frickin hour long interview.
[/quote]
No it's not!!! Only 58 or so minuets.

[kimosabi]

I'd like to point out that I think that is a very good thing. A cam have so many engine specific parameters it's nice to still have grinders who go deeper into it and develop themselves and product. Alot of the shelf stuff as far as I know are based off of pretty old cam designs and/or generalized, while things like head development and not to mention cuin have leaped forward quite a bit over the years.

[kimosabi]

double post