Engine/Trans Seriously Bad Noise

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JRod01

JRod01

Jesus is my Savior!
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After firing up the car last week, about 20 seconds into the first fire warm up, a horrible sound started from what sounds like the transmission or coming from there anyways. I realize sounds can travel in a car so that makes it even tougher. It's not a slow sound or knock like a spun bearing. It's very fast and follows the rpm's. My first thought was okay, it's the torque converter bolts or crank bolts. And after spending two days removing the transmission, I found that it's neither the bolts or the flexplate. It honestly sounds like a machine gun and as I said earlier, follows the rpms. I checked engine pressure, it's good. Also under each valve cover, all there and in tact. If you would like to hear it, I can email the sound clip to you. I wish I knew what is causing this. Any and all input is appreciated, thanks!

JRod
 
Flex plate installed backward ?
TQ properly engaged to front pump ? If not the drive neck on the tq make already be broken.
A long tube like a trans funnel makes a good stethoscope listening thingy if you want to try narrowing down the location.
 
My first thought was also the torque converter bolts. Even if they are tight might want to check that they are not bottoming out on the converter before torquing down on the flex plate. That happen to me once on a new build.
 
Could the starter drive gear be making contact with the ring gear? I had that happen once. Sounded like a machine gun. The starter had one abnormally large hole (been so long I can't remember if it was the upper or lower hole) and I loosened the bolts and rotated it away from the engine and the noise went away.

BTW: a flex plate can't be installed backwards. The crank bolt holes won't line up.
 
Checked everything suggested so far. I may not have gone to a great depth to see if a lifter is sticking. The trans is now removed and I couldn't see any cracks in the flexplate or smearing on any bolts. I'm certain I seated the torque converter fully. I did suspect the starter but the bendix seems fine. No metal gouged on the flyweel or starter gear. And definitely filled to the proper level. If anything, it may have had too much in there. Could that have caused damage? Too much fluid?
 
JRod01 said:
Checked everything suggested so far. I may not have gone to a great depth to see if a lifter is sticking. The trans is now removed and I couldn't see any cracks in the flexplate or smearing on any bolts. I'm certain I seated the torque converter fully. I did suspect the starter but the bendix seems fine. No metal gouged on the flyweel or starter gear. And definitely filled to the proper level. If anything, it may have had too much in there. Could that have caused damage? Too much fluid?
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Not unless it was a bunch extra. Even then it doesn't usually make noise. Most of the time it pukes the excess out.

The time mine had the starter to ring gear interference it didn't leave any marks either. I didn't run it long that way though.

Have you tried spinning the input shaft on the trans. by hand to see how it feels and sounds? If not you might want to give that a try.

Did you pull the valve covers and spin the engine over to check all the rocker arms to see if any had a lot of play in it that would suggest a collapsed lifter?
 
If you didn't have enough tranny fluid, it will make noise and the noise will increase/decrease with engine rpm.
 
fishy68 said:
Not unless it was a bunch extra. Even then it doesn't usually make noise. Most of the time it pukes the excess out.

The time mine had the starter to ring gear interference it didn't leave any marks either. I didn't run it long that way though.

Have you tried spinning the input shaft on the trans. by hand to see how it feels and sounds? If not you might want to give that a try.

Did you pull the valve covers and spin the engine over to check all the rocker arms to see if any had a lot of play in it that would suggest a collapsed lifter?
Click to expand...


I did spin the the torque converter on the input shaft and it seems okay. I realize that isn't the same however. I will try turning the engine over and checking for a collapsed lifter. It's a hydraulic cam. Does that make a difference?
 
Probably not your problem but a foreign object in a cylinder sounds just like a machine gun. I had a piece of head gasket work its way into one of my cylinders, and that is what it sounded like. It was of course the end of that piston and the block.
 
JRod01 said:
I did spin the the torque converter on the input shaft and it seems okay. I realize that isn't the same however. I will try turning the engine over and checking for a collapsed lifter. It's a hydraulic cam. Does that make a difference?
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A hydraulic lifter can collapse where-as a solid won't. That would make the probability higher.
 
Cracked/broken piston skirt? If not too much trouble, pull the oil pan and look for (gasp) pieces.................:banghead:
 
Wow, okay. I will check the engine also. I honestly hope it isn't however. But thanks everyone.
 
The slug in the crank used for balancing is hitting the block. This is due to the machining or the thrust bearing not correct. I pulled my hair out on this once. And have seen it again on assembly because I look for it now.
 
has the block been sleeved or does it have a stroker crank. could be a rod tapping the bottom of a cylinder. Pull the plug wires off one at a time. This will tell you if its cylinder related as far as rod bearing or piston pin and which one
 
It's a stock stroke and all the plugs are pulled and look just fine. There is a windage tray but I don't think the stroke has enough in it to hit that. And I believe all the slugs were tig welded into the crank. The block isn't sleeved either. This is a very fast repetitive noise that follows the rpm band. The trans is now out and being looked at. Will keep everyone updated. Thanks.
 
Do you have a harbor freight near you? I just got one of their flyers and they have an inspection camera on sale for only $70. It's probably a cheap one but if you don't need to use one much it would probably do the job. If the trans turns out ok, which I bet it does, the camera may come in handy to look into the cylinders to see if a foreign object is in it. About 30 yrs. ago when I was a kid I had a baseplate screw drop out of a carb (open plenum intake) and it went down into the cylinder and sat on top of the piston and made the same type of noise you say yours is making.
 
Never run a open plenum without the safety plate beneath the carb, i imagine you know this now, but since you didn't elaborate for others to make sure that when using a open plenum you use a safety plate between the carb and intake i brought this up since it seems to be a common mistake among many to not use one.
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take a compression test or pull oil pan,not unless something broke in the trans,or like they said could be a sticky lifter
 
Supershafts said:
Never run a open plenum without the safety plate beneath the carb, i imagine you know this now, but since you didn't elaborate for others to make sure that when using a open plenum you use a safety plate between the carb and intake i brought this up since it seems to be a common mistake among many to not use one.
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Click to expand...

Good point, my oversight. I was a kid and just learning stuff when that happened, some I learned the hard way:banghead:
 
Okay. The trans/converter/flexplate/and bolts have all been thoroughly inspected and all checked out okay. Keep in mind this sound is very fast like a baseball card in a spoke wheel. Not a slow ticking. It also follows the rpm band. So now that the trans and parts are ruled out. I'm going to drain/strain the oil and cut the filter and look for metal. It also has been suggested that the spot welds on the windage tray may have broken loose. Again, this motor was dyno'd and run through several pulls. I realize that things go wrong but I'm of the thinking that if anything bad was going to happen to that motor. It would've on the dyno. Also, all the spark plug electrodes look just fine. No damage. And they're long reach plugs in aluminum heads. It never hurts to check, but I just find it difficult to be the engine making this ridiculous noise.
 
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