Comp XE262AHs installed: Sounds like a Powerstroke at idle?

[trinity_gt]

Finally got my XE262AHs installed in my 02 GT at a very reputable shop. The car idles well and gained right around 20HP in the process, seems to run really well otherwise and so on but...

One thing I noticed while poking around was that the engine has attained a sound characteristic that I can only describe as a "diesel" at idle. It's not really a "nasty" sound per se: no specific knocking or anything. Just a general "timbre" that reminds me very much of a diesel at idle. I can't really localize any one noisy area of the engine. It almost sounds loudest coming from the valley/intake manifold of all things.

As mentioned these are Comp XE262AHs and they were degreed. Although I also purchased the Comp springs, I was assured that the 262s do not need a spring upgrade and so decided to sit on the springs for now, leaving the factory parts in place. The sprockets, chains, guides, tensioner arms and just about everything else is brand new. I also had FRPP 24# injectors installed at the same time.

I also learned that what I thought was my previous best dyno of 268/313 was, apparently, hopelessly optimistic. Upon delivering the car to the shop, a dyno test showed only 250HP at the wheels in its "before" configuration. I had just come off the highway so I thought it might have been heatsoaked some but it appears that the dyno I've got showing those numbers was far from right. Perhaps in the spring (when it comes out of storage) I'll take it back to that optimistic dyno and see what it does. Anyway, after the cams and dyno tune it went to about 270HP with absolutely no loss down low.

I'm not too concerned about the diesel-like sound characteristic of the thing if it's making good power and otherwise not making any untoward noises but I'm curious if anyone else has any like stories to relate?

 

[ADRENLN]

well, i can say i cant really tell if its my cams clicking or somthing else tapping these days. its too hard to tell the 2 apart for me.

i mean i know my cams are making noise but if somthing else starts to tap its covered up.

 

[trinity_gt]

well, i can say i cant really tell if its my cams clicking or somthing else tapping these days. its too hard to tell the 2 apart for me.

i mean i know my cams are making noise but if somthing else starts to tap its covered up.

Mine's weird. I don't really hear "tapping" in that sense. It's definitely not a lifter tap as far as I can tell. It's funny.

In the vid I took, I can hear a period knocking-like sound that I really didn't get a sense of when I was actually there. I don't know if this is some sort of aliasing thing or beating effect in the audio or if it was actually there and the camera picked it up while I missed it...

I'll try to get a vid clip up that shows the sound soon.

BTW, the oil is Mobil 1 5W30.

 

[hotmustang331]

iv heard that its actually the injectors getting louder for some reason....but im not too sure if I believe that. I know mine has that sound at the engine, but it doesnt bother me at all.

And if you dont have LTs, 270RWHP sounds about right.

 

[COramprat]

I'm beginning to think that is a characteristic of these cams in these cars because alot of people have made comments about how strange the sound is. Mine does the same thing and all of the info I have found says it is normal. Enjoy...

 

[trinity_gt]

Dammit. I've got to find a way to make my vids smaller. A 2-minute MPEG of the engine and the idle is still coming out to 53-Mb... Still working on it. :|

[Edit]: Mkkay, extracted it to an MP3 about 1.5Mb. Hopefully my ISP doesn't barf at a little volume:

http://ca.geocities.com/[email protected]/Images/Cams262_Eng_Idle-lowres.MP3


BTW, here's a theory: Combine these cams' increased overlap with the fact that we have a thin plastic intake manifold. Is it possible some of this noise we hear is simply exhaust noise getting into the manifold during the overlap period? Because the manifold is so thin and plasticky, maybe it's just doing nothing to mute the sound.

 

[Kurgan]

XE262AH's don't have that much overlap. Not compared to say.. VT stage 2 N/A cams. The VT's have a 108 LSA. Lower LSA means more valve opening overlap. Your Comp 262s have a 113 LSA. I believe the stock cams are 114 LSA, so it's slightly more overlap with the Comp Cams.

From what you've described and from listening to your sound clip, it sounds like it's just valvetrain noise and maybe a little noise from your injectors. Both noises sound like a clicking noise. As long as you're not hearing pinging (detonation) or tapping (PTV) or knocking, it's not critically alarming. It's not uncommon for aftermarket camshafts to make our already somewhat noisy valvetrains just a little noisier.

It's also quite possible you have a lash adjuster or chain tensioner that's not pumping up to full with oil pressure. When the cams were installed, those lash adjusters had to be bled and the chain tensioner had to be compressed to be reinstalled. Lash adjusters not pumping up to full would put a little more gap between the camshafts and the followers when rotating along the base circle, causing a louder clicking noise as the cam lobe rolls over the followers.

 

[RedHorse04]

My 262s in my 04 gt sound just like yours. I call it chatter. I have had my cams in 6 months and had no problems. They also made my exaust twice as loud, did it do that to yours to. At first it took me alittle bit to get use to the sounds from the engine but I was assured by some guys who really know there stuff that it is normal.

 

[trinity_gt]

XE262AH's don't have that much overlap. Not compared to say.. VT stage 2 N/A cams. The VT's have a 108 LSA. Lower LSA means more valve opening overlap. Your Comp 262s have a 113 LSA. I believe the stock cams are 114 LSA, so it's slightly more overlap with the Comp Cams.

Correct me if I'm wrong, but LSA is only part of the equation. The lope shape and thus the timing of the valve events strongly affects the amount of overlap.

For instance, while the cams share very similar LSAs, the 0.050 duration of the Comp 262 at 226/230 is quite alot larger than the 184/191 of the PI cam. Even though the lobes are similarly separated, the increased duration also increases the overlap, no?

Second, how much would be needed to create noise in the intake manifold?

 

[trinity_gt]

My 262s in my 04 gt sound just like yours. I call it chatter. I have had my cams in 6 months and had no problems. They also made my exaust twice as loud, did it do that to yours to. At first it took me alittle bit to get use to the sounds from the engine but I was assured by some guys who really know there stuff that it is normal.

Great to hear

I'm so bummed that I haven't even driven it yet and now it's going into winter storage...

 

[Kurgan]

Correct me if I'm wrong, but LSA is only part of the equation. The lope shape and thus the timing of the valve events strongly affects the amount of overlap.

For instance, while the cams share very similar LSAs, the 0.050 duration of the Comp 262 at 226/230 is quite alot larger than the 184/191 of the PI cam. Even though the lobes are similarly separated, the increased duration also increases the overlap, no?

Second, how much would be needed to create noise in the intake manifold?

You're right in that duration does play a part in valve overlap, but a mild cam like the 262 isn't going to have as much overlap as a VT Stage 2 cam or the Comp 270 cam. I have the 270 cams and my valvetrain isn't as noisy as yours. It's not the extra overlap making the valvetrain noisy. The extra overlap does make your exhaust louder, though.

 

[RedHorse04]

Hey kurgan I was told that the cams were pushing more air threw the exaust and that played apart in making the exaust louder is this true. My exaust with an o/r hpipe was unbarably loud. I put the stock h pipe back on and it is still really fricken loud.

 

[trinity_gt]

You're right in that duration does play a part in valve overlap, but a mild cam like the 262 isn't going to have as much overlap as a VT Stage 2 cam or the Comp 270 cam.

True, but it's more than stock and that's all I have to compare to.

In fact, thinking some more, it's not the overlap per se but the altered timing events themselves. The intake valve is opening sooner than before. Assuming symmetrical lobe profiles, 226-184 (the difference in the 0.050 intake-side duration) gives 42 degrees. Dividing by two (additional duration is spread acorss opening sooner and closing later) means the intake is 0.050" open roughly 21 crankshaft degrees sooner with the 262s than the stock PI cams. I'd imagine that alone would alter the intake tract noise quite a bit simply because there's still quite a bit of exhaust stroke left when the valve is even 0.050" open.

I have the 270 cams and my valvetrain isn't as noisy as yours. It's not the extra overlap making the valvetrain noisy. The extra overlap does make your exhaust louder, though.

Thing is, in listening to mine, I'm not convinced it's a mechanical "valvetrain" noise. What I'm hearing is not localized to a valve cover or the front cover. It's a diesel-at-idle like character that, to me, it sounds more like it's emanating from the valley...or the intake manifold itself.

As long as others are saying their's make similar sounds (e.g. RedHorse) and as long as it don't blow up, I can live with additional noise like this.

BTW, the power gains of 20 I mentioned were peak to peak. At 110MPH (the plot I've got doesn't show RPM and I'm too lazy to calculate it right now...) the difference is more like 35HP...

 

[steveb24]

im pretty confused here. i dont understand how to "degree" a cam in. im a nuts and bolts kind of car workers.. show me where it goes and what to take off and ill get the job done. now i tried to read that article on degreeing cams and i just cant do it. when i think about how the cams sit in there, i dont get it. the cam could only be placed in the seats in one position. if the motor wasent at tdc, the keyway slot on the cam gears wouldnt line up with the key way on the cams.. resulting in you not being able to get the cam to sit in. i only could get them in this way and dont understand how else you could install a cam, or "degree" them in. i obviously have no idea what it means, but how could swapping the cams straight out cause harm. btw, i gained over 30 rwhp at 6200 rpm.

 

[trinity_gt]

im pretty confused here. i dont understand how to "degree" a cam in. ... i only could get them in this way and dont understand how else you could install a cam, or "degree" them in. i obviously have no idea what it means, but how could swapping the cams straight out cause harm.

The cam card tells you what the ideal lobe centerlines are (i.e. point of maximum valve lift occursat N degrees of crankshaft rotation.) The might want 109-degrees.

The problem is that when you assemble everything together, often there are sometimes errors or unfavorable tolerance stacks that move the actual in situ centerlines from the ideal. There are a number of things involved in synchronizing the crankshaft and the cams: crank keyway, sprockets and their keyway/tooth accuracy, chains, cam sprockets and their keyway/tooth accuracy, the cam keyway and their accuracy with respect to the cam lobes and so on. To expect all this to line up perfectly by just bolting a bunch of stuff together is asking for it.

So if you assemble the valvetrain and then put a degree wheel on it, you can check just how close, or far off, the result of putting all these many pieces together is. If things are out of line, you have a couple of options. Sometimes just choosing a new sprocket from thr parts bin will do. Sometimes you need to grind a key a bit to allow a sprocket to rotate some on the cam and get things into time before tightening down the cam bolt. Hell, sometimes you might have to return the cams for a new set if things are really bad.

I believe that in the majority of cases, grinding the egg-tooth on the cam sprocket will allow enough movement to allow alignment. The key way actually plays no role in maintaining time once the bolt is cinched down: the compression provided by the bolt ensures the sprocket and cam stay in phase.

btw, i gained over 30 rwhp at 6200 rpm.

Sweet!

 

[Mike97gt]

Correct me if I'm wrong, but LSA is only part of the equation. The lope shape and thus the timing of the valve events strongly affects the amount of overlap.

For instance, while the cams share very similar LSAs, the 0.050 duration of the Comp 262 at 226/230 is quite alot larger than the 184/191 of the PI cam. Even though the lobes are similarly separated, the increased duration also increases the overlap, no?

Second, how much would be needed to create noise in the intake manifold?

You are right. LSA is part of equation.. duration also has a big factor in it.

 

[steveb24]

yes.. but its not like i just forced them on and bolted it. thanks for the good info tho btw.. but when you install them with the chains still on, i dont see why you would need to factor them in to the "worry about" equation because they were never moved, and the key way i lined up by turning the motor which turned the chains and cam gear till the keyway lined up with the cam. than it sat in fine. im sure im misunderstanding something, but the chain retention method seems fool proof to me + the fact that nobody i know (like 6 or so ppl) that have done that with 262's or stg 1's have had any probs / seen less gains than the ppl who had them done by a shop (dont know whether thier shops degreed them or not).. i dont know, im just out to gain some more info in my head for next time

 

[RedHorse04]

Because your stock cams are off up to 7 degrees from the factory so if you just slap them you could have PTV contact. To me that is not really that hard to understand. Pleople that use the anderson ford motorsports tool, or any other tool to do there cams are just lazy and asking for trouble. Take the timing cover off and at least check the cams or you may be buying a new motor. PERIOD.

 

[steveb24]

well ive never heard of ptv from ppl i know with the same cams who did the install the same way, so ill be iight i guess. ive winded it out at 6500 too in 3rd and 4th and it feels like it wants to go more but i got my rev limiter to hold me back from really messin it up. my point is, if it hasent done anything yet its not gonna happen, and the way they were installed is just fine.

 

[COramprat]

Thing is, in listening to mine, I'm not convinced it's a mechanical "valvetrain" noise. What I'm hearing is not localized to a valve cover or the front cover. It's a diesel-at-idle like character that, to me, it sounds more like it's emanating from the valley...or the intake manifold itself.

As long as others are saying their's make similar sounds (e.g. RedHorse) and as long as it don't blow up, I can live with additional noise like this.

BTW, the power gains of 20 I mentioned were peak to peak. At 110MPH (the plot I've got doesn't show RPM and I'm too lazy to calculate it right now...) the difference is more like 35HP...

I've listened to mine quite closely too and that is why I think it is just a charateristic. Maybe injector noise, maybe funny airflow but it hasn't seemed to have an effect on mine either. I gained 26 peak HP with mine.