I'm stumped... 302 in the ranch- under load sounds like the fans hitting the shroud-

OK... under load- the car sounds like the fan is hitting the shroud... or a bat cable is glancing off the fan- I couldnt find anything it could be hitting- pulled the fan. ITS STILL THERE under load.

What in the hell could be making this noise- its been doing it for about a year- I usually don't step on the gas hard enough to hear it so....

it sounds like its coming from up front- maybe the starter hanging up somehow? Its driving me crazy- anyone have any ideas??

its a 302/c4 combo-

 

i have a 350 in an OT truck, i'm thinking i have a worn exhaust lobe on the cam, it idles fine, drives ok but with the air cleaner off and i give it a quick rev it makes a cracking sound out the carb.

 

yeah its not that- it seriously sounds like a cable hitting the fan- or some bolt- im gonna drop the starter right now- were just getting ready to head to Texas... pretty sure I'll be find its just annoying as hell not knowing what it is-

 

Could it be the backside of the dampner touching the front cover? Mine did that years ago.

 

I have heard that noise from a Cracked Flex plate.

Happens ath the crank bolts ... eventually the center of the flex plate breaks out .

Youll know what the noise was when that happens

 

could you be hearing pre-ignition knock? Dial back your timing a couple of degrees and/or add some high octane fuel and go for a ride. Perhaps the noise will go away.

cheap/easy to find out.

 

+1 had it happen to a Boss's O/t work van it sounded about like what your describing.

 

Times 2

 

X3 on the cracked flexplate.....been there and done that.

 

****. OK- im on it-

 

yup flexplates crackin around the boltholes......look at the ring gear while runnin with the cover off ...........it wobbles.....

 

Thanks guys- heading over to my buddy brinkers to get this fixed- hoping I can find a flex plate from one of my friends today- otherwise I'll have to wait till monday. At least we get get the old one out.

 

If its not the flex plate, take a look at your motor mounts. The engine torques to one side under load or when you rev the engine. On a Chevy the engine torques to the p***enger side, probably same for a Ford. If the driver side motor mount is bad, the engine will torque to the p***enger side causing the engine to lift up, and causing the fan blade to s****e the fan shroud. Been there.

 

Also check to make sure your alternator pully cooling blades are not hitting the bracket or the mounting bolts on high rev's. Had a smallblock making a noise and to isolate the problem pulled the belt and it shut up.

 

The last 302 that I had that sounded like that had a worn-out thrust bearing on the crank. Under load the crank was walking forward and the torque convertor bolt were hitting the back of the block. Put a prybar behind the crank pulley and see if it walks back and forth. It should move some but not much.

 

Tuck,

In looking for a flexplate make sure you have the right imbalance,
Due to Ford changing firing order in the mid/late 80's, the imbalance was changed as well.
If you get a pre flexplate on a post engine (or vice versa) you will get a tremendous vibration.
The imbalance depending on year of your engine will either be 28oz or 50 ounce, don't mix in match....

I hope others will have more specific info....

Also, I have heard of flexplate bolts backing out and s****ping on the inspection cover, check for loose or scared bolts and/or for a scar on the inspection cover..

Good luck,

moe

.

 

Can't be the fan hitting the shroud. OP says he removed the fan and the noise is still there.

 

Yeah I eliminated this too pulled the fan and all the belts- and it still did it-

It started doing it after I was at a burnout party my buddy j's.. the cracked flex plate makes a lot of sense considering how it started.

I orig thought I busted a motor mount and figured the motor was thrusting into the shroud! The motor mount was bad- fixed it- still did it.

SO- were ripping into it- I'll report back with our findings! I'll make sure I get the right imbalance- thank you for all the help!

 

Ding, ding, ding..............I do believe we have a winner.

 

This is probably the problem. HRP

 

Brake torque it in reverse if it's a motor mount it won't make the noise because it will be the other mount but the flex plate will still be the same.

 

Flex plate in the wifes chevy was cracked,could'nt hear it under acceleration but clicked loudly on the idle.

 

How so? Engine doesn't know which way the trans output shaft is turning. The engine is still turning in the same direction with trans in forward or reverse. The torque reaction is the same, and always the opposite of engine rotation.

Bob

 

...........Yep, he's absolutely right. That would be rather interesting if engines started rotating the other way just to go in reverse haha

 

Ditto ALL the above.

4TTRUK

 

If it aint the flywheel id be looking at the pinging scenario, even if it did happen after a burnout distributors have been known to move on their own! itd be really really easy to check that one off the list fast too, mark where the dist is and move it a smaall amount, like 1/16, if its a little better move it another 1/16, move it till it stops it entirely. then the timing is good.

and the thrust problem ive heard before but it was with a stick shift car and when a person was pushing in the clutch the noise would start. so you never know.

JEFF

 

Yep, I've had it happen to me. The bushing fell off or broke off on the mechanical advance. No pinging sound as you would think. I check that engine in my Chevelle every which way and nothing. One day while timing it I brought up the RPMs to see how much total timing I had and Holy ****. The timing was so far off the scale in advance it was crazy.

 

check the starter gear it may be sliding back under load i had one do that to me an that was it ''

 

If you brake torque it in reverse the engine doesn't turn the other way but the drive shaft does which will torque the engine the other way and try to lift the p***enger side instead of the drivers.

 

If you still dont find the problem after all the above mentioned checks look at the keyway in the front dampner.I had one break out on a sbc last summer it sounded like the fan hitting the shroud. Problem was it also ruined the crank snout.