Possibly a cam only in my 5.0???

Modidy · Mar 8, 2011

Okay, so I have had a few mustang owners check out my Mustang. It sounds like it has a cam in it when idling. It definately has a lop to it when at idle(about 750rpm), and the needle is almost dead steady! To my knowledge it was stock. I know it's not a miss because it just had the emission's inspection done. It passed so clean, you would have thought it was a new car. The HC's are 15 at high speed, and 16 at low. They have to be below 114 and 117 respectively. The NOX numbers are 265 and 372. They have to be below 796 and 879 respectively. The CO reading were 0.00 both, and the acceptable highs were 0.63 and 0.65 respectively. Upon some investigation, I can see that the exhaust manifolds have been off, and possibly the heads. So I have a few question's for you guru's here.

1) What type of gains would you have with a cam only install?

2) What type of gain can I expect if I were to add a Cobra upper and lower intake?

3) Can you identify stock heads from GT40's without taking anything apart? (I drive it dailey and don't want it down now)

On a side note, I also am curious about my trans. The 1-2 shift is firm, but not harsh. It will even chirp the 1-2 shift under WOT at about 5K rpm (maybe a little higher), then it really seems to pickup in acceleration. When it chirps, the shift feel even smoother than under moderate acceleration. I think this car may have been previously modified, but put back mostly to stock by the first owner. The second owner seems to be unaware of any such mods. The car has right at 16k miles, but starts and runs great! I would drive it across country.... well after I put a spare tire in it that is..

Let me know if I left out any details, or if you need more info to help answer my question's.

Win · Mar 8, 2011

Really no gains at all with a cam.

The heads are your main bottle neck.

Yeah you can see III bars on the front of 40's and IIII bars on the P heads.

Also when you run your car are you running a O/R normally and just switch to a catted for emissions. I know when i had a O/R X on my car for a little while it sounded like it had a cam. Do you have a Auto or 5sp?? Chirping or barking the tires between gears in a 5sp is easy normally. With the Auto it can mean a few things. It either has a shift kit. The tranny fluid is dirty and needs to be changed.

Rice_slayer · Mar 8, 2011

I'd be concerned if it didn't have a cam in it, how the heck would the valves open and close?!?!

All seriousness, post an idle video. A stock cam vs. any aftermarket cam is very VERY noticeable

.

Modidy · Mar 8, 2011

Win said:
Really no gains at all with a cam.

The heads are your main bottle neck.

Yeah you can see III bars on the front of 40's and IIII bars on the P heads.

Also when you run your car are you running a O/R normally and just switch to a catted for emissions. I know when i had a O/R X on my car for a little while it sounded like it had a cam. Do you have a Auto or 5sp?? Chirping or barking the tires between gears in a 5sp is easy normally. With the Auto it can mean a few things. It either has a shift kit. The tranny fluid is dirty and needs to be changed.

Where can I find he bars on the heads? My car is an Auto. The fluid is fresh, and has less than 500 miles on it. The car still have the stock cats on it, but does have a flowmaster 40 series catback exhaust. Also, just so we are clear, I haven't added anything to this car since purchasing other than a complete tune up(plugs, air filter, oil filter,wire's, fuel filter), TB cleaning, new TPS, trans service,rear shocks, tire's and new mufflers. The idle is dead on, no fluctuating while at idle.

Rice_slayer · Mar 8, 2011

Probably just your mufflers, I remember when I put my o/r exhaust with a magnaflow catback on my car, sounded COMPLETELY different from factory. Stock cams have like .444 lift I think, which isn't bad. Probably just sounds a little beefier because you have different mufflers. Believe me, you can easily tell between a stock and aftermarket cam. Before my tune, my mild Trickflow stage 1 cam would shake my car at idle lol.

BigTang · Mar 8, 2011

easy way to tell if its got a cam(and what cam it is)

pull the valve cover, put a dial indicator w/ magnetic base on the valve cover rail and the indicator on the top of the intake valve retainer. Rotate the engine and look to see how far the valve travels down. .450ish? stock cam.
go down farther? Wanna know what cam it is? bring the valve all the way back closed and bring it back to .08(.050 x 1.6 rocker) open look at the marks on the balancer and see where you are. you can get most of the valve events that way. do the same for closing but stock at .08 before it closes. its not an exact science as you loose some through the lifters compressing but its a quick way to get a ball park of what cam is in the car.

Modidy · Mar 8, 2011

Rice_slayer said:
Probably just your mufflers, I remember when I put my o/r exhaust with a magnaflow catback on my car, sounded COMPLETELY different from factory. Stock cams have like .444 lift I think, which isn't bad. Probably just sounds a little beefier because you have different mufflers. Believe me, you can easily tell between a stock and aftermarket cam. Before my tune, my mild Trickflow stage 1 cam would shake my car at idle lol.

I've listend to a few stock 5.0's with just a catback, and mine... there is a definate difference in the loping sound. Also, it does shake my car at idle, and yes the motor mounts are good... I don't have an o/r pipe and the mufflers I put on were replacements for the flowmaster 40's that were on it when I bought it. I still have the stock converters on it.

Modidy · Mar 8, 2011

BigTang said:
easy way to tell if its got a cam(and what cam it is)

pull the valve cover, put a dial indicator w/ magnetic base on the valve cover rail and the indicator on the top of the intake valve retainer. Rotate the engine and look to see how far the valve travels down. .450ish? stock cam.
go down farther? Wanna know what cam it is? bring the valve all the way back closed and bring it back to .08(.050 x 1.6 rocker) open look at the marks on the balancer and see where you are. you can get most of the valve events that way. do the same for closing but stock at .08 before it closes. its not an exact science as you loose some through the lifters compressing but its a quick way to get a ball park of what cam is in the car.

I will try this the next time I have a day off to tinker with it. Thanks!

So if it does have a cam, with the stock heads, what gain can I expect with a Cobra upper and lower to go with it?

Addermk2 · Mar 8, 2011

stop wasting our time, and post a video

ttocs · Mar 8, 2011

very little.

Rice_slayer · Mar 9, 2011

Addermk2 said:
stop wasting our time, and post a video

This! Instead of "assuming" your car has a cam because you feel a little lope doesn't mean it does. Most of us can tell a factory cam from an aftermarket one.

ttocs · Mar 9, 2011

it could even be just a simple vacuum leak. The reality that ANYONE would take the time to pull the stock heads off, replace the cam and then put the stock heads back on is little to none as again it would not really be worth the time/money to get very little performance gain.

DFG_magic · Mar 9, 2011

A dirty MAF or slow o2 sensors will also cause the car to bump at idle. You'd know without a doubt if the car had an aftermarket stick in it.

Venom351R · Mar 10, 2011

You need to find out if you actually have a cam before you start assuming you have one in there b/c the idle seems a little different. As mentioned a few things can cause it to sound like it has a aftermarket cam but its just tune up related issues.

Guy that likes Ho ho's w/ his stock cam 5.0

http://www.youtube.com/watch?v=raOsWzsO0dY&feature=related

Non stock pushrod with a custom cam

http://www.youtube.com/watch?v=qrCxcgji_XA

Modidy · Mar 12, 2011

Kind of busy the past couple of days, and right now, only have my Iphone to snap a video. The sounds doesn't come out great on it, but you can hear it. Like I said, not sure, but curious. I bought this vehicle a few months back as sort of a project/daily driver. It had been sitting the better part of the last two years. I did a complete tune-up, trans service, tire's, rear shocks, mufflers and all new vacum line's. I also cleaned out the EGR, MAF and replaced the TPS. I don't know for sure, but a couple of guys who have heard it in person, one of which builds his own mustangs (has two nice SN95's), both said it sounds like it. It's not a miss, passed emission sniffer clean! I was standing there when they did it, so no funny stuff going on there. That's about all I can think of for now. I am considering some mild mod's. You can see the heads have been off previously on this engine.
Someone posted above that it makes no sense someone would just throw in a cam... no, it doesn't make sense, but not everyone does everything that makes sense when it comes to modding there cars, or looking for a little more go cause he had to take the heads off to repair an upper end issue... who knows. The previous owner says it wasn't done by him, and I don't know the first owner.

http://www.youtube.com/watch?v=rXuh8UtADmc