Strange Noise
Strange Noise
Gents.
Been about 5 years since I have been on here, and I wanted to see what y'all think about this one:
I pulled my car out of storage (in the military, finally got a chance to play with it again) and have been tuning it up/ getting it on the road. There is a strange noise that I CAN NOT track down. Here is the run down:
305, 700r4. 82k miles on the motor, 5k on the tranny. Car is carbed with an HEI (non computer controlled) nothing on the front of the motor but an alternator, clutch fan, and water pump. (no smog, no air, no PS). The motor uses no oil and no water other than what is normal. The carb is tuned properly and was recently went though. The timing has been set, and any adjustment in base timing makes no change in the noise.
Anyway the car makes a noise only on shutdown, only when hot (as in the motor has been running for 15-30 minutes), and not every time. It sounds like a pinging noise, like someone is striking a piece of metal with a ball peen hammer. It doesn't make the noise when the motor is running, only when it is cranking/shutting off
I have replaced the Alternator (it needed it anyway), it didn't fix the problem. The motor had the oil pan, valve covers, and intake off recently, and everything looks good inside. I have ruled out rod knock, main cap bearing knock, piston slap, detonation and valve train noise. I think the noise goes away when I pull the belt off of the motor (at least I haven't been able to duplicate the noise with no belt). All bolts on the upper and lower pulleys are tight.
So I guess here is my question: what could be causing this? I am going after the water pump next, checking the flexplate bolts, and going through the distributor; but to be honest I am perplexed because this noise doesn't match any of these items; and there is nothing wrong with how the car runs or drives.
I thought it could also be the mechanical fuel pump, but again, there is nothing wrong with the fuel system.
I have worked on several small blocks, and consider myself to be a decent mechanic, but I cannot pin this noise down. So any help would be appreciated
Been about 5 years since I have been on here, and I wanted to see what y'all think about this one:
I pulled my car out of storage (in the military, finally got a chance to play with it again) and have been tuning it up/ getting it on the road. There is a strange noise that I CAN NOT track down. Here is the run down:
305, 700r4. 82k miles on the motor, 5k on the tranny. Car is carbed with an HEI (non computer controlled) nothing on the front of the motor but an alternator, clutch fan, and water pump. (no smog, no air, no PS). The motor uses no oil and no water other than what is normal. The carb is tuned properly and was recently went though. The timing has been set, and any adjustment in base timing makes no change in the noise.
Anyway the car makes a noise only on shutdown, only when hot (as in the motor has been running for 15-30 minutes), and not every time. It sounds like a pinging noise, like someone is striking a piece of metal with a ball peen hammer. It doesn't make the noise when the motor is running, only when it is cranking/shutting off
I have replaced the Alternator (it needed it anyway), it didn't fix the problem. The motor had the oil pan, valve covers, and intake off recently, and everything looks good inside. I have ruled out rod knock, main cap bearing knock, piston slap, detonation and valve train noise. I think the noise goes away when I pull the belt off of the motor (at least I haven't been able to duplicate the noise with no belt). All bolts on the upper and lower pulleys are tight.
So I guess here is my question: what could be causing this? I am going after the water pump next, checking the flexplate bolts, and going through the distributor; but to be honest I am perplexed because this noise doesn't match any of these items; and there is nothing wrong with how the car runs or drives.
I thought it could also be the mechanical fuel pump, but again, there is nothing wrong with the fuel system.
I have worked on several small blocks, and consider myself to be a decent mechanic, but I cannot pin this noise down. So any help would be appreciated
Last edited by James Watson; Oct 19, 2013 at 09:45 PM.
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