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Discussion Starter · #1 ·
I just had a head and cam package install. Once the car warms up, I here a lot of valve train noise. I know it is due to the bigger specs on the cam. Cam spec: 232/236 degrees @ .581" lift with 114 Lobe separation. Do you guys have the same noise with this sort of cam. Thinking of going with something a little smaller to decrease the noise and help smooth out the idle, like a 224/228 degrees at .560" to .570" lift. Do you think this should help lower the noise level and smooth out my idle a little. I am willing to sacrifice some horse power for a good smooth idle and less valve train noise. Car made 451 RWHP uncorrected. 435 corrected.
 

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Shane,
Increased valve train noise just goes with having a bigger cam and better valve springs. IMHO, the large power increase is well worth it! I got used to mine right away, makes me grin every time I get on it! Very good numbers BTW. Congrats and enjoy the new found power! :cheers:

Jim L.
 

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Shane, Other than the noise how do you like the steerable aspect of your new H/C package. Your cam sounds like it's on the large side to me. Who makes your cam and how much lobe seperation does it have? I had a 224/228 on a 114 and it ran very well. I have gone to a slightly larger profile to up the HP.

D.J.
 

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Discussion Starter · #5 ·
I do like the new H/C combination. The idle is a little rough and stumbles every once in a while. I have about 200 miles on it since the install. The heads are stock heads fully CNC Ported by Pete Incaudo in Florida.
Darkhalf, I don't know exactly the type of springs he used and for Onequickcoupe, the lobe separation is 114. My times before the H/C install was a 12.02 @ 117.5 mph. Looking forward to taking it to the track this year. Thanks Jim for your feedback.
 

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shane said:
I do like the new H/C combination. The idle is a little rough and stumbles every once in a while. I have about 200 miles on it since the install. The heads are stock heads fully CNC Ported by Pete Incaudo in Florida.
Darkhalf, I don't know exactly the type of springs he used and for Onequickcoupe, the lobe separation is 114. My times before the H/C install was a 12.02 @ 117.5 mph. Looking forward to taking it to the track this year. Thanks Jim for your feedback.
Shane,
This is a damned small world we live in, as Pete is the guy who did my heads too, and if they are like mine, then you have Crane dual springs. My heads have 2.055 Intake valves and 1.6 exhausts (REV Valves) Heads are angle milled for 11.2 compression. My cam is also a 114 lsa but I have a bit
more lift than you. Mine idles with a pretty substantial lope at 1k rpm, but does not surge, buck or stumble even with the
A/C on. I attribute the great driveability to the perfect tuning done by Greg and FRC Tom, using HP Tuners. These guys ROCK! :thumb: :thumb: :thumb: :thumb:


Jim L.
 

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Discussion Starter · #7 ·
Jim, sounds like we have the same heads. Mine are also 2.05 in the intake and 1.60 exhaust. Do you have a lot of valve train noise? I am still trying to make a decision whether or not I should go just a little smaller on the cam. Overall, my idle isn't that bad. It idles around 900rpm. Every once in a while, the car will stumble for a second. It's only if I shut the car off and then start it again within a few minutes.
 

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Shane, My valve train is pretty noisy, but not in a bad way.
It's definitely louder than stock, but I expected that. I wouldn't change to a smaller cam unless I had to deal with emissions testing. Our cams have such a great torque curve and work with the heads perfectly, so I'm not gonna change a thing. If anything changes it will be to a 427! :eek2:

Jim
 

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I got a bigger cam and with it came more noise but at 4000 rpm and above I don't notice it! I guess it's the nature of the beastie! :lol:
 

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I put the windows down and get on it with the PRT's....all you hear is car alarms going off and people holding their ears when she flys by at 140! :jawdrop:

Bob :D
 

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rpallas said:
I put the windows down and get on it with the PRT's....all you hear is car alarms going off and people holding their ears when she flys by at 140! :jawdrop:

Bob :D
Bob you devil!!! You are the guy setting off my alarm.

Honey could you turn up the radio? That lifter noise is giving me a headache. Hell why not the lifters, everthing else does.

Do you think maybe that it may be the aggressive lobe ramps that almost everyone uses now days? Could we setting the valves down on the seats a little too hard and maybe getting a bounce off the seat? Are we compressing the hydraulic lifter so rapidly that we are creating a solid lifter, (if that is at all possible)? I am sure given the advent of the spin-tron the cam manufactures know what's going on here, (at least I hope so). This must be an acceptable byproduct or something they think we won't mind.
Crank up those PRT's and roll down the windows. :eek:

D.J.
 

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What lifters are you running? Preload on you lifters could be your problem. If you are running stock lifters look for 1 1/2 to 2 full turns on the rocker arm bolt from 0 preload. If comp 850-16 O.E. lifters, which are stated as stock replacement, they only like 1/2 to 3/4 of a turn from 0 preload. If comp R lifters they are very touchy and only like 1/5.

stock .060 - .120 preload
850-16 .030 - .050 preload
comp r .004 -.010 preload

all are hot preloads and you will lose about .010 preload from cold adj. due to the expansion of our aluminum blocks and heads.

I recently ran into this problem with the 850s, and a TR 224 cam. I had 1 1/2 turns and at first it was quiet but after 50 miles it is loud. So I am going to 7.35 pushrods. Comp is horrible with their product tech. No instructions and like I said its an O.E. replacement lifter so I just put them at stock specs. WRONG!!! well my pushrods will be in thursday so I will let you know if it makes a difference. Or if I collapsed a brand new lifter!!!!! sucks
 

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Shorter pushtubes less preload more noise
Longer pushtubes more preload less noise
Been there done that!!
Get the Comp pushtube gauge and get correct measurments.
Also CompCam told me that Comp R lifters really need adjustable rockers
 

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your are correct to a point. Too much preload is also going to make alot of noise. If you have more pressure on the top of the lifter, more preload, which will also limit the amount of oil for cushion (travel). So you push all of your oil out on the up stroke and have none when you come back down, or not enough to cushion anything. This will give you too little preload on the way down (plunger depressed due to no oil) and CLACK!!!!! I know this to be true with my car because it is only loud below 3000 rpm. Above that and it is the sewing machine noise. This is all dependent on oil pressure. At Idle it is not enough to counter act the springs and ramp rate with to little oil below the plunger, and once its bled down it will stay like that until you get more oil pressure. By going to 7.35 rods they will allow .050 more oil under the plunger while keeping a .030 preload. It will still bleed down but will still have plenty of oil left for cushion, plenty of preload to keep it quiet, and less of a refill the next time around. this is why preload is so important. Why do comp Rs only have .004 preload? Cause they are used with aggressive cams that have serious ramp rates and tough springs that are going to push down the lifter plunger. The lifter is the same length as stock. It is also built stiffer than stock. just my .02 Oh and I got all this info from LG
 
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