Flareside

Right now, I'm in the middle of a head/cam swap. The car is in pieces... I have a new set of AFR heads to install along with a comp XER 220/224+2, .588 lift, 115LSA cam. A few days ago, I got to spend some time around an F-body car with a similar XER grind cam and Comp 918 springs that had some pretty annoying valvetrain noise. I now know what people are talking about when they mention "sewing machine" sounds coming from modified LS1 engines, and I don't really want that for my car. You could even hear it over the exhaust while driving. That noisy cam has me rethinking my plans!

Who's running an aftermarket cam in an LS1 and is happy with the noise? Is the extra noise caused by the cam or the spring swap? I also have a Lingenfelter GT2-3 cam and LS6 beehive springs that I'm considering installing instead of the Comp XER grind. LPE claims that this cam and spring combo will be quiet and live a long life, even though it's got lift similar to the XER (.578)

allanlaw

I think valve train noise comes with the territory, the amount may vary. I'm running dual springs, I'm not sure if that contributes to the noise. But in balance, it's not that bad, especially if you have the vent fan going and/or some tunes on the Bose, or the window open.

Tony @ MPH

I know what you mean. My motor has a mild cam and some decent springs so the lope isn't bad, but the sewing machine noise is a LITTLE annoying.

I have heard that Harland Sharp rockers do reduce the amount of sewing machine noise you get. I think they are around $300? They definitely look cool...

Mitch C

If you are concerned about valve train noise. You can choose a cam that has less aggressive lobes than a XER grind. For example MTIs B1 makes little or no valve train noise.

WALLstAL

It could also be the lifters, I heard the comp R lifters cause some noise also. Did he have them replaced on that F body you listened too??

GotMoJo

I have a comp XER grind with slightly larger lift and it's noisy. I have learned to live with the noise.

You can go with a less severe ramps but with reduced HP.

Flareside

Thanks All. The goal is to increase power without compromising the perfect nature of the car. No lope, no 10k valve spring swaps, no sewing machines. I'll give up power for good manors any day of the week. Good heads, good exhaust, etc., should still give me a nice boost without compromising the car. I'm even considering passing on the AFR heads and installing the GM/LPE CNC LS6 heads instead because they support the normal LS6 valvetrain that will live a long life along with the LPE cam. The GM heads have a 35cc larger intake port (240cc), and I'd rather avoid that, but it's a compromise no matter which choice I make. Small high flow AFR ports along with a somewhat noisy, high maintenance valvetrain, or intake ports that are larger than I would like, and a valvetrain that's similar to stock LS6.

Right now, I'm leaning toward the LPE cam instead of the Comp XER. There's lots of data out there about the GT2-3 grind that says it provides a nice 25hp boost without excessive noise and/or maintenance. Everyone seems to agree that any XER grind will be pretty noisy, but I'm still trying to find more first hand experiences. The XER may provide more power "under the curve", but if it also adds a bunch of noise and valvespring maintenance it's no bargain in my book.

Believe it or not, I've got both the AFR and GM heads , as well as the Comp and LPE cams sitting at my house right now because I can't decide. The car is apart and ready, so I really need to make a decision soon!

I'm probably going mock up each cam in the motor this weekend to measure just how much different they really are at various points. I'm curious if the LPE ramps are really more gentle, or if it's more perception than reality.

Flareside

Nope, the lifters were stock. The car ran well, and it has been together for about 6000 miles now, so I think it's in good shape. I'm yet to find someone with a Comp cam and dual springs that thinks their valvetrain sounds close to a stock LS6. Anybody?

C5JONNY

A supercharger may be more up your alley.

Flareside

No way. Talk about extra, non-stock noise! The ATI is way too loud for me, and I'm not a fan of the Mag hoods that are out there.

ArKay99

Valvspring life is also dependent on material along with ramp rate and lift. Ramp rate and lift DO play a large part in spring life but spring material is also a big player. In order to get the seat pressure required for a more aggressive rate and high lift cam while keeping the stock sized springs the spring manufacturer has to use a more brittle alloy. Because the alloy is more brittle the life expectancy goes down. Couple that with higher valve acceleration and more lift and you have reduced spring life. I think that valve noise is from the valve snapping shut against the seat. If you remove one of your springs and put on a light pressure spring, like the ones used to measure p/v clearance, and move the valve with your finger and then let it snap closed you will hear a nice thwock! Some guys have used a long duration cam with slow ramps and lifts around .550". If you use a very lightweight valve like the stock LS6 valve or titanium valves you can use the LS6 springs which are good to around .570" lift with a mild ramp rate and have long lived springs ~100k.

Having said all that, the springs that come standard on the AFR heads are a dual spring good to .650" lift. I don't think one has broken yet if they are installed properly and broken in using the proper heat cycleing.

I have the Harland Sharp rockers, AFR heads, and a Comp 224/228 .581"/.588" 112lsa+2 XE-R cam and it is queit as a mouse when I start my car. It is fine until the oil gets to operating temp, then I have 'some' sewing machine effect. It goes away if I am cruising @ around 1600-1800rpm and the oil pressure goes above 40psi. Then it returns if the oil pressure drops below 40psi for a few seconds. I have .050" preload on my lifters. I am using a set of new Comp 850's.

Hope this helps.

phils C5 vette

I had a TR224 installed last week. First I was scared that the noise was something wrong, but now I guess it's normal sounding for a cam swap. The engone sure does run great, but it sounds like the sewing machine from the inside. I dont notice it as much from the outside, but I do hear it more from the inside. Im the summber when the top is down, Ill be thinking the sound went away

Rainy99

The sewing machine noise doesn't bother me much... It reminds me of the power waiting under the hood

7LitreC5

I have the Comp 220/224 115+2 cam in my car along with AFR 205s. I also have Yella Terra roller rockers.

I do have some valvetrain noise but it is not as loud as many other cars that I have heard. This cam idles almost like stock and works great with the AFR heads. I certainly have way more off boost power than I did before the heads and cam.

I am very happy with the 220/224 115+2 cam!

Flareside

Great info, thanks!

I really do want to run the AFR cam if the noise isn't too loud. What springs are you running with it? I'm ok with a little more noise, but not the type of noise that will have passengers asking me what's wrong with my car...

Another option I'm still considering is upgrading to the Ferrea hollow stem valves, then running a lighter single spring (LS6 or comp 918). I think that would really help with the noise issue. I talked to LPE about it, and they insist that the LS6 springs are fine with a .580 lift cam.

7LitreC5

I am running the standard springs and valves that come on the AFR 205 heads. I think that the springs are Patriot golds. You can hear the valvetrain noise in the car but it isn't real loud.

I'd be really cautious about the LS6 springs. I am not sure that they have enough spring pressure to handle the ramp rates of an XE-R cam even if they would handle the lift.

ArKay99

Be VERY careful when going to a lighter spring seat pressure, especially with an XE-R grind. If you go on Comps website you can find specs on most of their cam lobes. Then you can get the number and order a cam from them. Like I said above, there have been a few guys that have speced a cam with slighly longer duration and within the lift limits of the LS6 springs. Perhaps you should consider a set of those springs, titanium retainers and a set of valves the weight of the LS6 valves. THat would be a small cam but the heads would still flow well enough to give you good gains. GM has calculated the spring rate needed to maintain the valvetrain integrity to about 6600rpm using the LS6 valvetrain weights. If you change any of those and use something even slightly heavier you will risk floating at lower rpm's. I'm not sure of the weight of the Ferrea hollow stems, but since the cap is larger there is a chance they weigh more.

Flareside

I probably wouldn't run the .580" XER cam with LS6 springs, maybe a Comp 918, but the data I have available does raise a few questions. LPE has supposedly installed over 150 GT2-3 cams and used the stock LS6 springs without any issues. That cam is made by Comp, and has specs that look very similar to an XER. The intake lobe is 207 duration and has .572 lift, exhaust is 220, 280 advertised, and has .580" lift, pretty agressive and very similar to the AFR cam on paper. Why do the LS6 springs work for one of the most successful shops in the world if they can't handle a fast ramp and lift over .570? The data is wrong somewhere, and I'd usually believe the word of a shop like LPE. I believe valvetrain weight also plays a big part here, the lightweight LS6 parts go a long way toward reducing seat pressure requirements.

Anyway, these are my thoughts, still haven't committed to either combo...

The AFR cam/head combo should get me better throttle response because of the more aggresive cam and smaller ports, but it will also make more noise and require regular spring changes. The GM CNC head/LPE cam combo will make similar power on top, but it won't have the low end of the AFR heads. Should run a long time without maintenance. Too many damn compromises!

phils C5 vette

I have the 918 springs. I have valve train noise. I am a Modaholic. As long as it's "normal" for the mod, I can live with it. If I was the only one with the noise, Id be scared. The back of my car sounds cool. The inside of my car sounds a little tappy. So you want to race?
Im not sure if differant springs, rockers, hollow valves, Ti retainers, or a pray is going to change that noise much. I dont know if the sound is the valve pushing down so fast, of the springs themself, but the noise happens.

ArKay99

I'm not flaming you for your thoughts I think you are doing the right thing by bringing these concerns and thoughts up for discussion. I certainly would take LPE's advise concerning LPE products, but I would also take AFR's advise concerning AFR products. The specs on the LPE lobes seem close to XR grinds. They are a little slower because the advertised duration is wider which actually translates into a longer effective duration than an XE-R lobe. As far as valvetrain component weight the lifter is probably the single heaviest component probably making up 80% of the total weight of the mechanism. However by using a 1.7:1 ratio rocker some of the inertia is offset.