Something other than spark-knock that could rattle
 

I have a rythmic rattle coming from the direction of the right side of the engine at 1500-1700 rpms under light to medium load. It's not very loud, my dad can't hear it, but I can and it drives me nuts.

I've tried retarding the timing in the past, and tried premium gas, neither of which seemed to change it.

The last couple days I tried premium again with the intention of retarding the timing at the same time, but tonight I realized it's already at 7-8*TDC, which hopefully explains my loss in mileage over the last month.

So other than a loose rocker, or maybe rod or main bearing (the engine is new) what else could possibly cause a rattle.

I tried attaching a stethescope to the plenum and routing the tube up through the hood and through the window, but I couldn't hear anything (couldn't hear it without the scope either, as the noise with the window cracked drowned it out)

Re: Something other than spark-knock that could rattle
 

I recently had to have my engine swapped due to knocking (at first it was light also in the mid range but 20,000 miles later the engine blew and the knocking was really bad) and i came to find out it was the pistons, the mechanic told me that the pistons were burned out, like you the knocking was coming from the right side of the engine and i thought it was the heads but i was wrong. But your engine is new? How many miles are on it and maybe they sold you a bad engine? Have you tried heavier oil maybe that will get rid of the knock.

Re: Something other than spark-knock that could rattle
 

Other than internal parts, the P/S pump bracket could be rattleing. There is a bolt that goes into the block behind the pump, really hard to see with the pump on. It tends to break and the bracket can rattle against the block at certain RPMs.

If it's comming from inside the motor though, it's probably a bad valve train or rod. Sorry. There's not much else in there.

Re: Something other than spark-knock that could rattle
 

My 305 had a real low rattle at high idle (low RPM) that sounded like it was coming from the right side of the engine, and it turned out to be the Cat Converter. The Knock Sensor was picking it up and making the engine perform bad. Changed the Cat and solved the problem. Don't know if that's got anything to do with your problem. Would not hurt to check.
Good Luck...

Re: Something other than spark-knock that could rattle
 

If the valves are sticking just slightly that too can cause it to rattle and give you bad gas mileage.

Re: Something other than spark-knock that could rattle
 

My heat riser on my 84 trans am did this very annoying rattle the butterfly seperated from the actuator rod ... not sure if your car has this though. but its a valve that fits between the exhaust manifold and the Y-pipe.

Re: Something other than spark-knock that could rattle
 

First off, define the term "right side" for us. Is this the right side of the engine from the driver's seat facing the front of the car, or the right side of the engine from the front of the car (driver's side)?
If it's the driver's side, you could have a bad bolt or something that is letting something rattle. Or, your power steering pump bearings are worn out (I have to get a new one soon). On the passenger's side, any number of things could be loose.
But, that's the easy stuff. You could have a loose rocker, bad lifter, worn connecting rod, worn piston and rings, worn out bearings, any number of things INSIDE the engine, which will all cost $$$ to fix.

Hope this helps a little bit...

Re: Something other than spark-knock that could rattle
 

I have a rattle coming from the drives side. Happens at 1200 - 1600 rpm. sounds like a rocker is loose. And gets louder once the engine is nice and hot

Re: Something other than spark-knock that could rattle
 

Right side as I'm sitting in the drivers seat looking forward. So probably not the PS pump.

I built the engine myself with all new pistons, rings, cam, lifters, rods, guides, roller rockers, springs, etc. The crank had been balanced by a shop.

My dad and I tightened everything to spec. I suppose something might not be tight enough though, like a rocker.

The noise started suddenly after a couple thousand miles if I remember correctly.

I haven't tried putting the backend on jackstands and running it in gear yet, but I"m sure it wouldn't put enough load on it.

Anyway, soon as I get my new car tuned up, I'll start messing with the fbird. Or maybe I'll wait until spring when it's warmer.

Re: Something other than spark-knock that could rattle
 

mine does this too at a light when I accelerate for a couple seconds, its not my cat, but it doesnt d oit when i run the highest octane, sure is annoying, if its spark knock what can u do to stop it besides better gas

Re: Something other than spark-knock that could rattle
 

Retard the base timing until it stops I guess. I've never dealt with pinging, so I'm not sure what the best fix is.

I tried high octane, and it didn't effect the noise. When I went to retard the timing, I found out it was already at 7-8. So I put it back to 10.

I still have the sound, but my mileage seems to have gone back up, so I kinda win.

I'll just have to tear into it I guess when once I'm ready. Right now I'm busy with the truck and the neon.

Re: Something other than spark-knock that could rattle
 

If the knocking started after a few thousand miles it sounds like something has come loose. I would check accessories and the rockers.

Re: Something other than spark-knock that could rattle
 

What type of oil did you break the motor in with?

Sounds to me like a rounded off camshaft and its your valve train rattling.

Re: Something other than spark-knock that could rattle
 

mobile1 hd30 for the first 500

Mobile1 5-30 next 500

Mobile1 5-30 next 10000

I guess I can pull the cam while I'm at it. I wonder if something happened when my dad didn't run it at higher rpm the first 20 minutes.

Anyway, it died the other day on the way home. Kept shutting off like I turned the key off.

I'd get it restarted, and it would die instantly, or it would go a couple hundred feet.

Finally it ran long enough to get home, but it bucked a few times from momentarily cutting out.

The voltage has been charging lower and lower lately while idling at stoplights. I'd have to rev it to 1000 just to keep it at 13.