318 Experts Needed

[jlb1pi]

Hey All  

The seller of the 72 SE I just bought (the black one in my signature) stated in the listing that "the cam was changed without the rods being changed accordingly"[ ]
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=320223668843

The engine starts and runs and I drove it on and off the car trailer under it's own power, and have even driven it down the block and back, and up and down the driveway, but it makes a horrible noise.

It sounds like fan blades hitting the radiator--which they're not-- (you know, that horrible, screeching noise with a background beat of minor thunks...not knocks, not taps...light thunks).

But mostly, the screeches. And even they aren't continuous...it seems to quiet down a little (intermittently) after it warms up some.

It IS coming from inside the engine, (I believe it is NOT the bottom end), actually sounds like it is just below the intake valley pan, toward the front of the motor....I don't have an engine stethoscope, and The Bride doesn't bring hers home anymore...not since she caught me using it to diagnose the Corvair motor.
         

I am going to remove all the fan belts tomorrow and eliminate the remote possibility that it is a water pump bearing, but I'm hoping one or more of you might have had a similar experience, or run across this situation or noise before, or might have an idea what's causing this.

I guess I just want to get an attack plan...Do I continue from the fan belts and pull the valve covers, intake and carb?....I mean how far do I go before I'm spinning my wheels and end up saying, "Crap, I should have just pulled the motor!"

A little more info on the motor...it DOES have a "more than stock" cam in it, that much I can tell from the mild "lopes"...it has an Edelbrock Performer Intake and a Holley 4 barrel, which I'm fairly certain didn't come on 72 318's (I haven't got a model number for the Holley yet), and I haven't found a Build Sheet in any of "the usual" places yet, so I can't tell you what the factory configuration was...(maybe someone with a little more knowledge can narrow that down for me too). Oh, and it has Hooker Competition Headers, with dual exhaust (no H pipe), and I'm reasonably sure THAT wasn't stock either!


Do ya think the seller meant "push rods", when he said the mechanic didn't change the rods accordingly, even though he mentioned "thrown rod" in his listing? (He was a nice kid, and open and up front about the motor, but he didn't impress me as real knowledgeable or even "mechanically inclined".) I mean a normal cam upgrade doesn't necessarily mean "taller" connecting rods, (I don't think)....I'm not all that up on the High Performance aspect of engines (cam and crank swaps, etc.), all I've ever done is stock rebuilds (with everything remaining stock), so cam degrees, and duration, and all of the tangential aspects of installing a larger cam is just "yadda, yadda, yadda" to me.

Any constructive help, input, advice, conjectures, ideas, or experiences would be greatly appreciated, Guys (or Gals!).

Sorry this Post is so long, but I figured if I wrote everything down that I could think of, it would save a whole bunch of questions and replies on this thread.

Thanks again, in advance.
~Jer~

[Plumcrazy]

Removing the accessory belts is a good place to start. You might also try removing one spark plug wire at a time to see if one cylinder changes the noise more than the others.
After that , the next step is a trip to the auto parts store to buy a stethescope.

[Bob]

 

Nope. Nothing comes to mind.

[Nacho-RT74]

After that , the next step is a trip to the auto parts store to buy a stethescope.

simply use a hose will work

[bordin34]

Is there a loose belt that could occasionaly slip? Possibly too much lash? A lifter oiling down?

[jlb1pi]

Nope. Nothing comes to mind.

Helpful as always, Bob.....'preciate it, Ol' Buddy!

[Death1970Proof]

Removing the accessory belts is a good place to start. You might also try removing one spark plug wire at a time to see if one cylinder changes the noise more than the others.
After that , the next step is a trip to the auto parts store to buy a stethescope.

I agree with this....
Im experiencing a similar problem on my small block and have determined that it's the alternator. It's still charging but the bearings are going out on it, it's whines like crazy if you give it a hard pull. It's been on there a good 10 years...damn they just make stuff like they used to