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Discussion Starter · #1 ·
Hi

I threw a Comp Cams hydraulic flat tappet cam in my 454 last year and ran it last summer in my chevy street car. It works good (I think) but makes that "sewing machine" noise at times - especially on the passenger side.

It's a Extreme Energy part number 11-250-3. Has advertised duration (@ .050 lift) of 240 and 246 deg int/exh, and .578 lift int/exh with 1:7 ratio rockers. 110 deg lobe seperation. I have Crane Energizer roller rockers (I think).

Pretty basic stuff right - nothing radical.

why do these hydraulic cams make that "sewing machine" noise? A couple guys have told me already that the Comp Cams cams do that.

My question is two part:

1) is it true that this cam is known to make noise - or is it something in my setup that is causing this?

2) is it just the Comp Cams cam that does this or would any other cam from another manufacturer with the same specs make the same noise?

thanks.

Lee
 

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I believe the comp extreeme energy series flat tappet hyd cams have an agressive lobe design that litterally lets the valves slam/slap back down into the seats which is where the sewing machine/tapping sounds are comming from.

Scott
 

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Discussion Starter · #3 ·
I believe the comp extreeme energy series flat tappet hyd cams have an agressive lobe design that litterally lets the valves slam/slap back down into the seats which is where the sewing machine/tapping sounds are comming from.

Scott
so the noise is from the valve contacting the seat then right? I wasnt sure if it was that or the rockers contacting the push rods, or the rockers contacting the valve stem. I know it's got self adjusting hydraulic tappets but I thought maybe with those type of cams the hydraulic tappets can't keep up with the aggressive lobe design.

lee
 

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For what it's worth I just took my comp cam out and replaced it with a Crower I had the same noise you are describing, now with the new cam it is nice and quiet.

Scott
 

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Discussion Starter · #5 ·
For what it's worth I just took my comp cam out and replaced it with a Crower I had the same noise you are describing, now with the new cam it is nice and quiet.

Scott
Can you give me the model number of the new cam so I can compare the specs on it to the one I have now.

thanks

Lee
 

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It's well known, much talked about, issue with Comp's XE cams Lee. If you run a search on the topic you'll turn up many threads.

If you don't want the sound the only option is to replace it.

Dan
 

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Discussion Starter · #7 ·
It's well known, much talked about, issue with Comp's XE cams Lee. If you run a search on the topic you'll turn up many threads.

If you don't want the sound the only option is to replace it.

Dan
Dan - Help me out - I'm not an engine guy. I don't mind the noise if there are no ramifications to it. In other words, if it's just noise, and no resulting long term problems I'm ok with that. If on the other hand, I will have premature failure and wear with the rockers, valve seats, push rods, cam, etc, then I have a problem with it and may replace the cam soon (and opt for a roller setup).

your thoughts?

Lee
 

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I ran the same cam in my 454. I also had the same noise. I switched cams to special grind from a local cam company, and still had the noise. I read an artical about this and it has to do with how fast the lifter comes down. I also read that Lunati and Crane have a new lobe design to help with this for a high lift flat tappet hydr. cam.
 

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Lee,

When I first had my 396 rebuilt the marketing info for the hydro XE grinds made them sound like a win-win. I wanted the engine to be quite so I even decided to stick with the exhaust manifolds. Was more in keeping with the nature of the car.

Unfortunately, Comp made NO mention of the noise these cams produce. After I fired it for the first time I noticed the sound. I probably adjusted the bloody valves 5 times, and the engine builder was even kind enough to come and listen to it. We thought maybe the roller tipped rockers were the cause so he even supplied me with a set of stock rockers. No change. It wasn't until after a series of emails to Comp that they finally came clean and admitted that my hydraulic lifter cam pretty much sounds like a solid lifter cam, only not all the time. Sounded rather "ratty" to me.

Kinda pissed me off. Then, after 3k or so miles, it started to loose an exhaust lobe. That kinda pissed me off too, even though I know it had nothing to do with the lobe design of the XE's.

Replaced it with a different hydraulic of similar specifications and the noise went away.

I now run a solid lifter cam and love it. And it always sounds like a solid lifter cam should.

From what I understand from reading posts here the XE grinds do not cause any issues aside from the noise, even though logic would suggest that letting the valves hit the seats hard would be problematic. Lot's of folks run those cams without issues. I just couldn't stand the sometimes quiet, sometimes ratty sounding. Drove me nuts.

Dan
 

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Discussion Starter · #10 ·
Lee,

When I first had my 396 rebuilt the marketing info for the hydro XE grinds made them sound like a win-win. I wanted the engine to be quite so I even decided to stick with the exhaust manifolds. Was more in keeping with the nature of the car.

Unfortunately, Comp made NO mention of the noise these cams produce. After I fired it for the first time I noticed the sound. I probably adjusted the bloody valves 5 times, and the engine builder was even kind enough to come and listen to it. We thought maybe the roller tipped rockers were the cause so he even supplied me with a set of stock rockers. No change. It wasn't until after a series of emails to Comp that they finally came clean and admitted that my hydraulic lifter cam pretty much sounds like a solid lifter cam, only not all the time. Sounded rather "ratty" to me.

Kinda pissed me off. Then, after 3k or so miles, it started to loose an exhaust lobe. That kinda pissed me off too, even though I know it had nothing to do with the lobe design of the XE's.

Replaced it with a different hydraulic of similar specifications and the noise went away.

I now run a solid lifter cam and love it. And it always sounds like a solid lifter cam should.

From what I understand from reading posts here the XE grinds do not cause any issues aside from the noise, even though logic would suggest that letting the valves hit the seats hard would be problematic. Lot's of folks run those cams without issues. I just couldn't stand the sometimes quiet, sometimes ratty sounding. Drove me nuts.

Dan
thanks Dan

great information.

I'll probably run it for another year or two and then go to a solid roller setup.
 
G

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Get a cam from UDHarold and be done w/ it!!

He has told us how he does them so that they are NOT noisy!!

You can search here or in Performance for his told info about this..

pdq67

PS., and fwiw, I do figure that the XE line of cams are going to end up w/ shorter live's due to their very aggressive designs!! You just can't beat on a valvetrain and expect long life outta it, imho....

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Discussion Starter · #12 ·
Get a cam from UDHarold and be done w/ it!!

He has told us how he does them so that they are NOT noisy!!

You can search here or in Performance for his told info about this..

pdq67

PS., and fwiw, I do figure that the XE line of cams are going to end up w/ shorter live's due to their very aggressive designs!! You just can't beat on a valvetrain and expect long life outta it, imho....
who or what the heck is a "UDHarold"?
 

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who or what the heck is a "UDHarold"?
That's pretty funny.....you must not spend much time here!!:thumbsup: :thumbsup:

He's a cam designer, worked for some of the biggest makers around. Do a quick search for his user name on here and you'll see he has an impressive resume! UDharold is it. Im sure in some of his old posts, this same problem has been picked apart many times. It's interesting reading.
 
G

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Get hold of Harold here if you want to!!

"I work for Custom Camshaft Company, a division of Arrington Manufacturing.
I stay at my house in Senatobia, MS, and telecommute to work in Martinsville Va. My office phone is 662-301-1245, and so far I'm having to take my wife to work, she's a Staff Accountant in Memphis, so I'm not here before 9:00 AM CST or from 4:00 PM to 6:00 PM CST. I answer the phone when it rings, and have sold several cams to Team Chevelle members."

Harold was the owner of Ultradyne cams until it went belly-up.

He designed CC's great old CC 268HE as well as Lunati's VooDoo line of cams so he definately KNOW'S what he's doing!!

He's really great at enlightening us about the how's and why's of camshaft design IF you want to do a LONG search here to get to all the info he has graciously offered up to educate us guys through the years....

pdq67

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This figures....I just bought a XE262 Grind 12-238-2 Fairly mild cam I know. It's for a fairly mellow cruise night prowler and is in a 327 in a 68 Chevelle. It only sees 2500 miles a year max and maybe a 300-600 mile trip in there somewhere. Is this aggressive closing rate THAT much? I have purposefully run a very light lash (barely past the "quiet point") on an L-79 cam I used to run. Yep you get a tad bit of valve noise. Always figured it was the headers amplifying it. Are there any longevity #s with these cams? I just had the heads redone and am getting ready to put it all together. I don't need to recreate a problem. Having supposedly been trying to fix a ZDDP related issue in the first place. My luck never seems to go my way! GREAT!
 

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Yeah I run a XE 274 and I sure wish i would have known about the noise before I installed it.. On paper it looks like a great cam with a broad power range which is all good of course, but I just HATE the noise it makes when the engine is up to full running temp....

I can't imagine how loud it would be in a car running a quiet exhaust...
 

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Has anyone had an issue with the XE pounding the seats out of thier heads? I just had an old set of Power Pak 520s redone with 1.94s and no hardened seats. I have contacted a bunch of engine guys, one that had first hand experience with an XE274 and all said hat it isn't as bad on the exhaust seats as a solid cam...I have run solids before and the noise does not bother me as much as the thought of beating the crap outta my valvetrain needlessly.
 

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The XE's use an aggressive intake lobe only...the exhaust lobe is from the older magnum line, and aren't as hard on parts.
FWIW, the noisy XE268 in one of my 355's has been running strong for about 7 years now, with lots of long trips and heavy towing between 2 different trucks.
 
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