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it all depends on the size of the cam but rollers are able to have steeper ramps so the valve is opened up more over the same duration when compared to a similarly spec.d hyd cam.
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I think it has more to do with actual cam specs than weather or not it is flat tappet or roller.The custom ground solid roller in my car sounds nice,but not overly aggresive,but when I ordered it,aggresive sound wasnt one of the things I wanted.
Guy |
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It has a lot to do with the cam duration and lobe separation angle.
Cams with long duration and tight LSA, (108 or less) have a lot of valve overlap. This combined gives the motor the nasty, racey, take no prisoners idle. Mechanical race rollers also seat the valves harder than hydraulics do, (more aggressive valve action) adding to the idle sound. Music to the ears. Hydraulics are for the girlie man. Real men set their own valve lash. |
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Lope for the Dope
All the dudes are right Like my drag cars I ran 512 lift solid I like to set up my dial gauge in the pits and watch the amateurs gasp when they saw those Harvey Crane needle bearing rockers that set me back an arm and a leg in the day.That being the much long ago early sixties.That ride ,a 10 second 57 chevvy was floating Harveys 298 R and at shut down and relighting my cigar waiting for the old lady to get the other 57 tow car down to me,About 12 seconds later,she and my son hooked it up. and I drug on my cigar.If I ever found that car I'd put it on the street cause it whistled like a crasy man when that baby was revved to 10 grand.Of course so much more was in the Blue printing that today guys have egoes and rumpity rumpity rump is more important to them than winning at the NATS.I really didnt givea darn who heard a thing.All I did was keep in a real straight line,shift that rock crusher ,and the rear cog at times a 5 57 take me home first.Sound came out the headers by the way.And it was a study in fear every run,Lotsta beer on the way home and if we.I had a team.were lucky that day.
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Thanks for the replies. I had thought about going with a solid instead of a hydraulic. I've never had a solid before and I figure now is as good a time as any.
Moontanker, my ride is a 57 Chevy. I plan on taking it to the dragstrip when I get my new cam in. Thanks again for the replies everyone. |
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sound has more to do with timing events than lift, though lift does have some effect. If you want a race sound you'll have to run a race cam though, which means giving up street manners. There are tricks to getting a nice sound while still retaining street manners but it still won't quites sound like an all out race cam.
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Like has been said, its duration and overlap that make the sound more than the lifter type, but you can make a roller sound slightly meaner using its ability to have faster lift ramps.
I knew a guy (may he rest in peace) who used to work for Lunati before retiring. He ground me a roller cam for my Olds 307 that was very mild (207/214 on 112) but he made the exhaust opening ramps very aggressive. It didn't rock and roll like a long-duration cam, but the exhaust did have a little "spit" to it that let you know that some work had been done. But... that didn't mean that it was the roller lifters that caused it, just that the roller lifters allowed for a faster ramp speed which very mildly simulated a meaner sound. |
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A good solid cam matched with the proper heads, compression, etc. should satisfy you an dcan be done relatively cheaply. about $200 for the cam, lifters, and springs compared to 3X that forl roller stuff. Roller stuff is very nice but if you just want a cool toy and aren't searchin gfor every last ounce of power not really needed. Flat tappets have survived for about a century, they still work, even if rollers do work better.
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Thanks for the replies. I'm not going to use a roller, like ap72 said the price can be 3 times higher.
I may go with a Summit or Jeg's grind. They are $89 for the cam and lifters and they are made in the U.S.A. I heard one of the name brand cam makers grinds them and they get reboxed. Thanks again! |
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check out some Elgin grinds, there's more of a selection and the price is about the same. Competition products carries a lot of the Elgin cams but you may have to use another vendor for a less commonly chosen cam. You can find a cam that is a better match and Elgin cams are very durable. Summit cams are okay but the selection is limited. I should also note that compared to a hyd. roller cam you will be giving up some power, perhaps 5-10% when compared to an agressive hyd. roller. There is no free lunch.
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I've had both hydraulic and solid lifter camshafts - but in today's world with the availability of good hydraulic pieces, I can't be bothered adjusting the rockers. Yeah, I've heard the stories of "I only have to do it once a year". That can be true, but the truth is, if you want good performance and are racing the car on a regular basis, you adjust those @#$% things every time you go out - and sometimes, even between rounds for just that little bit more horsepower - and yes, by varying the lash, and depending on the weather, it can either be go home a winner or an also ran. Then of course, if you don't have a good 'feel' for adjusting those rockers, then you might as well have that hyd. cam.
The rumpety rump idle doesn't always make the best running engine - there are other factors - like heads, compression ratio, exhaust system, ignition just to name a few Myself, I'm now using a hyd. roller camshaft in my 5.0L '31 Ford, their E303 SVT with Crane roller rocker arms and heavier Crane valve springs/retainers/locks. While it sure isn't the hottest grind available, it's a nice compromise for street and does sound kinda nice even thru the big 50 series Flowmasters. An old photo before the rest of the car went together:
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you can do a search for a cam overlap calculator. Just key in the duration for both the intake & the exhaust , enter the lobe separation. Then it will give you the overlap. The more overlap the more overlap the more lope. That is over simplified, but it will work. I have a comp cams solid flat tappet with 64 degrees overlap, in a 350 SBC & every time I take the car out someone makes a comment about how good it sounds.
Now if you want a cam that will work best with your combination there are a lot more factors to take into consideration. If you can give your compression ratio, stroke of the crankshaft & rod length. I will give you a suggestion of what I think will work well for your setup. |
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