# valve train noise v.1



## 67TEMPtress (Oct 12, 2010)

Ok so my 67 tempest 400 has developed a tap. I will give as much useable info as i can but please understand i am a girl! 
The tap just started one day and has not gotten better nor has it progressed. It is clearly not a knock, its a tap. Id be happy to imitate this noise for you like a true female but this is the internet.
It isnt present at an idle, if it is its too low for me to hear. It is most audible during acceleration, or when cruising below 2000 rpms. At 2000 the exhaust makes a nice hum and may drown it out. Rythmic in nature, there can be a slight miss to the car but when i find the sweet spot with the distributor it goes away so i assume these two factors are unrelated and the car is getting a tune up and timing adjustment when i get the valves inspected.
Engine is not burning or leaking oil. Not burning coolant. Not using any more fuel than usual. Very slight transmission leak, doesnt even leak a pint in a few months with daily driving. No conspicuous exhaust odor is present and it runs 185 degrees unless i sit in traffic at which point it can get up to 195.
I feel as if its lost a tad bit of compression but it could be paranoia setting in. I have had people listen as i drive by and they say they can barely hear anything but pipes. Sexy.
Dude i bought it from said he didnt do a valve adjustment when he had it and suggested i start there. 
I suspect a loose rocker arm or bent push rod, or possibly something as dumb as a spring clacking. Tomorrow im taking it to a recommended mech and asking that he also check for an exhaust leak but i figured you would hear that at an idle. I dont have garage access right now and the noise is disturbing me because i dont want my girl feeling under the weather. What would take me all day a mech can do in a couple hours so im gonna suck it up and take her in. Being a girl though, ive had bad experience with people trying to take me for a ride and this isnt something i know enough about to argue over.
any experience/suggestions? Id really appreciate it!!!!
P.s. i have not used any snake oil additives. Seats were changed 20k ago during rebuild and i use 91 from chevron or shell. Tried octane booster, no change. I think thats it.


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## freethinker (Nov 14, 2009)

if its a stock hydralic valvetrain it doesnt need valve adjustments. do you have headers on that car? i suspect an exaust leak.


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## jetstang (Nov 5, 2008)

Hmm, if it's only during acceleration it still could be pinging if it has a little to much timing. Some Pontiacs do have or have been converted to adjustable valve trains. Honestly, a little rattle in the valve train isn't going to hurt anything. The old rule of thumb to optimize your timing by ear you actually set it to lightly ping under hard acceleration, although this has caused a few broken pistons on Pontiacs so I hear..


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## geeteeohguy (Feb 2, 2008)

Have it checked out by a competent mechanic. One thing you didn't say is if it made the noise when you are not driving the car. Does it make the noise at 2000 rpm with the car sitting in the driveway in park or neutral? If not, it may indeed be spark knock or pinging. Don't know what year your engine and cylinder heads are.....so don't know the compression. If it is a 1970 or earlier unit, and the heads are '70 or earlier, you are at over 10:1 compression, which is too high for any of today's gas. Did it make the noise when you were running octane booster? The cylinder heads will have a big, usually 2 digit number cast into the center exhaust port that is easily seen when you look under the hood of the car. If you tell us what number you see there, we can tell you what heads they are and give you a ballpark on your compression. If your car makes the noise at 2000 rpm when you're not driving it but just sitting there in park/nuetral, it is not likely pinging and could well be a rocker arm, etc. Good luck, and keep us posted.


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## 67TEMPtress (Oct 12, 2010)

Ok so the plot thickens.
Navy fed ****ed us around on our post time for our pay so im going to the mechanic tomorrow. So today i got a corpsman buddy to loan me a stethoscope and i spent 20 or 30 minutes tinkering under my hood while dudes tried to look at my buttcrack.
Ok all lewd jokes aside, my valves arent making noise. No seriously... but theres clicking coming from the carb. Is this clicking turning into the tapping/ticking sound i get when i drive? I suspect it is. 
Sitting back and pontificating on this, it really does have the symptoms of a vaccum leak and some dude once told me it had one before these symptoms actually developed.
I also want the carburator tuned because i believe it to be running a bit rich.
It could also be a timing issue, because it has "advanced timing" but i have no timing light and dont know how legit this home timing job is.
These issues could also be concurrent.
so! 
Im taking it in for sure tomorrow to have these things gone over and hopefully ill drive away with all my old compression back.
Will be happy to get those casting numbers tomorrow when i have some daylight and i will most definitely keep you posted. Im learning much, thanks for being so patient!
Oh yeah! It does make the noise while revving in park so who knows whats really up. Maybe i should make a youtube of this. More to follow.


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## 67TEMPtress (Oct 12, 2010)

Yeah so i took it out on the strand where its quiet n straight n nailed it...
And shes suckin!!!!! Definitely sucking noise and shes tryin to breathe so i think i figured it out. Will keep you guys posted on the outcome!


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## dimitri (Feb 13, 2009)

If you do take it in for a mechanic to look at I would suggest for him to do a compression test of the engine. This is vital information for you to have. Later on down the road you can use it for a comparison.

Dimitri


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## 67TEMPtress (Oct 12, 2010)

So it went awesome! Mechanic loved the car, did exactly what i asked and shes runnin amazing now. 
He moved the hose connected to the distributor from the right side port on the carb (i didnt put it there) to the left, he said it was working against the timing by trying to retard it. I am studying this now so i can get good at this myself.....but! He tuned the carburator, adjusted the timing, confirmed my suspicion that its got an aftermarket performance cam.....for 30 bucks!!!!!! I tipped him well. He also looked it over real well and gave me the thumbs up for all systems go with the exception of a couple electrical gremlins in interior lighting stuff, nothing major.
he said also that the valves sound better than most new cars he works on and i have nothing to worry about! Yay!
On another note, i decided to start looking at casting marks because so much performance stuff has been done to the car. The intake manifold is from a 1973 400/455. Year one lsted it as a firebird actually. The block is also an early 70s 400 not sure yet exactly what it is. Talking with my stepdad he said thats fine because it might explain the cam, maybe someone one knew what they were doing and built a decent car because she sure does run good and even better now. I say it gives me an excuse to turn the machine shop loose on it when i have itt rebuilt.
Suspension is my new project, and paint. Who knows whats after that, my hamsters are workin overtime now that this is fixed and new possibilities are opening up. I cant even fall asleep! 
Thanks so much guys for all your help you made this process easier!!
By the way dmitri, my coworker on the ship has his own dyno so as i progress with this project were gonna keep track. Thank you!


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## PisnNapalm (Aug 28, 2010)

Congrats on getting some of your problems worked out. I too own a Tempest "Mutt". Not much other than the interior is original on my car.

Drive it and enjoy it!


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## geeteeohguy (Feb 2, 2008)

Great news. The only thing that sounds strange is the vacuum retard statement. Pontiacs of this vintage don't have a dual diaphragm distributor: they will only advance when vacuum is applied to the advance unit. Perhaps it was connected to a non operational or venturi vacuum port on the carb instead of a manifold vacuum port as it should of been (and sounds like it is now). What are the big numbers on the center ports of the heads?


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## dimitri (Feb 13, 2009)

Congrats on finding an awesome mechanic. They are hard to come by. 
When it comes to spending money on cars the way I look at it is make sure you keep up with the normal maintenance, tires, brakes, oil, etc. If you plan on keeping the car, try to keep the rust at bay. There is nothing wrong with driving an awesome car with an old paint job and 45 year old interier. Just make sure you try to keep it rust free.

Have fun with the car,
Dimitri


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