Engine noise

I have just driven my GTD for the first time since the exhausts have been quietened down and are not blowing anymore.
It is nicely quiet in the cabin now, but I am aware of a slight mechanical noise from behind my left ear.
Now I would guess it's possible that it's just normal mechanical noise from inside the engine that I've not been able to hear before, but as I'm a bit paranoid about these things, I wonder if there's anything I should check?
Lifting up the rear deck, it's JUST possible to hear it from the front of the engine if you put your ear next to it.
Don't get me wrong, it's not a terrible thrashing/knocking sound, it's just I'm attuned to these things after several engine problems in the past. As I say, I may just be hyper-critical, after all you don't drive a normal car with your ear only 6 inches away from it.
I guess it's reasurrance I'm after.
Oh yes, it's a 302 with hydraulic lifters and good oil pressure.

 

[ChrisL]

John,
I know the feeling. A noise in the engine that you had never noticed before and the uncertainties begin to mount. It can ruin a perfectly good driving experience. I had a similar experience when I first drove my GT40. I could hear a definite tapping that got louder under load. Turned out to simply be the sound of induction. It was just a matter of never before having driven a car with the air intake just inches from my ear. /ubbthreads/images/graemlins/grin.gif

Incidentally, if you describe the mechanical sound, someone might be able to chime in with an explanation specific to your situation.

 

[Paul Thompson 'Hooligan']

Hi john

Is your oil pressure showing good on the guage? hot and cold?

Describe the noise.. is it a continuous whirring type sound? or more of a tapping?, or knock? Does it sound slow and regular at idle? Does it change if you remove each plug lead in turn?

If you press a long scredriver handle against your ear and touch the other end (tip) to the rocker covers - front rear and both sides, can ypu determine where the sound is loudest? This will also make describing the type of sound easier too. Of course if you've got one, use an 'engineers stethoscope'. /ubbthreads/images/graemlins/smile.gif

 

[Andy Besic]

Describe the sound and the circumstances surrounding it. Idle, under load, decelleration, high rpm etc.

 

[Howard Jones]

It's the fuel pumps.

 

Another trick to find the noise is to take a used piece of garden hose cut to your desired length and put one end to your ear and move along till you find what you are "hearing for".Kevin

 

[Howard Jones]

And, if it's not the pumps then here is what was wrong with mine. The alum Ford SVO heads have air injection ports at both ends of the heads. These passages run into the head and then on into the exaust ports on the four corners of the motor. 1,4,7,8

The reason for this is that the heads can be used on both sides of the motor. ALL four ports must be pluged. If one is left unpluged then you get a noise that sounds like a rocker, lifter, etc. Check em. I don't know if the iron heads have them but you should check anyway.

I think the hole is threaded with 1/2 X 18 or something like that. You can get some nice plugs from Ford or you can cut off some bolts and lock tight them in place. I used a stainless bolt that I cut a slot into the end of after removing the hex and then screwed it into place with a screwdriver.

 

[wpeter]

an exhaust leak can have a ticking sound almost like a lifter.

 

[Howard Jones]

Jwhat, That is exactly what I thought it was. I went so far as to take the rockers off the heads, check the push rods for straightness, recheck rocker shims, reshim all valves and was about to take all the valve springs off and check them for spring pressure when I found one of the aformentioned plugs missing.

Those little tic tic tic's will really make you crazy if you're a Virgo.