[NeoJuice]

Originally Posted by dsraven

-remove the engine oil filter and cut it apart with a good utility knife (or filter cutter) to check for anything metallic in the filter medium. while it is off check the filter adapter and bypass valve to ensure it is all bolted up correctly and the bypass is operational and not causing a squeal. if in doubt simply replace the adapter since they are fairly cheap anyway. like mentioned in an earlier post you could send out an oil sample but that is a bit spendy and takes time. anything major will have caused something to show up in the filter so this would be considered a preliminary check before doing that. if metallics are found then pulling the engine apart would be the next step. also, like said, use a good quality filter, especially on a new engine, to trap as much debris and new engine break in metalics as possible. personally I would not use a Fram filter on my lawnmower but that is just me. some will use a cheap filter on new engines because they feel it is expensive to put a good filter on and then simply swap it out right away after a few runs or hours on the engine. to me that is reverse thinking and I would use the best filter I could on a new engine because that is when you know there will be fluff from shop rags, dust and dirt from the rebuild process etc. and that is when you need the best filter you can get. just me being me though
-ensure you have end play in the crankshaft since no end play could also make the thrust bearing work overtime and possibly make noise
-check for any vac leaks that may cause a whistle. look around the base of the carb to ensure any and all vac ports are used or capped and there are no cracked hoses or leaking vacuum actuators like a trans modulator hose/tube/valve. check the brake booster manifold fitting, hose, check valve. carb base gasket etc. pinched modulator hose or tube at the bell housing to engine flange (hey, it happens).
-check to ensure there isn't a timing tab rubbing on a pulley, check the pulleys to ensure any bolt on pulleys or accy are tight and fitting correctly. look for any odd rub marks on anything up front. look at the vibration damper and check for movement of the outer ring. a quick marker line across the two parts will show any movement after the engine has run and been shut down. squished out or deformed rubber in the damper joint of the 2 parts is usually an indicator of a possible problem or future problem. I have seen some of these parts "cleaned" improperly using solvents that attack the rubber ans cause the 2 parts to move/separate
-check for any odd heat marks or paint discoloration on the timing cover that may indicate an issue with a loose timing component or wrong fastener used inside there
-check the valve covers to ensure they are installed correctly. if installed incorrectly the rockers can rub on the covers. if not too inconvenient you could also remove a cover and check to ensure the top end is getting oiled properly and everything looks like it should
-check mechanical fuel pump and/or pushrod for issues. the pushrod could be "held' with a bolt in the front area of the engine if there is a bolt used there that is slightly too long. this would likely cause the pump not to operate but it only takes a sec to check anyway
-run the engine and use a stethoscope with an open hose around the base of the carb and top/front engine area to eliminate this area. check the distributor as well because a bad distributor shaft bushing could make a similar noise or a ruptured vac advance diaphragm may whistle. the same goes for a trans shift modulator valve
-jack the truck up high enough and block it to safely work under the truck if the engine were running. try to keep the angle of the truck the same as when it sits on the ground so you have the best chance of reproducing the noise
-remove the torque converter cover and look inside it for any metallic dust or other tell tale signs.
-remove the vac line at the shift modulator and look for fluid inside the hose that may indicate a ruptured diaphragm. ensure the metal vac tube (if equipped) is in good condition and doesn't have a torn off mounting bracket that could cause a whistle through the spot weld holes on the tube
-look up inside the bell housing at the starter drive and flywheel tooth contact area. check deep into the teeth to see if these parts have been bottoming out during contact. a quick spray with some paint in the tooth area would show the contact pattern after the starter was used. small block chevies usually need a few shims and some trial and error to get the starter drive to contact the flywheel correctly. they may just not sound right or they may engage and stay engaged if not shimmed properly. a starter that stays engaged will make noise and may fly apart when the engine is revved. this is due to the rpm the starter is forced to work at when the engine revvs up plus the crude drive tooth engagement would make noise at rpm. you could also remove the starter and physically check it out. if you disconnect power to the distributor you could use a remote starter switch or some other method (like a buddy in the cab) to crank the engine while you watch how the starter is working to ensure there is no problem there.
-check to ensure the torque converter is slid all the way into the crankshaft. since the engine was ran without the torque bolted in the snout of the torque or the end of the crankshaft may have been slightly damaged so they may not have been able to slide fully into the together. this would mean the flex plate would be required to take up the slack by flexxing or becoming slightly bell shaped. this may cause a harmonic when running. when unbolting the torque the 2 parts should be able to be slid together without having to be pulled in with the bolts. the torque should also be easily slid into and out of the crankshaft. when pushed back into the trans there is also a dimension as to how far the torque is allowed to be pulled out of the trans to bolt up to the flex plate. too much dimension here would mean the torque is not fully engaged in the trans pump correctly. not enough dimension could also be a problem. since the trans and engine were apart and you didn't do the work you are coming into it with no history as far as what was done or if the torque is the correct one etc
-check the front of the torque to ensure there was no damage that may cause interference of the internal converter moving parts with the "dent" in the converter shell or a distorted fastener mounting flange, if any dents or distortion are present.
-check to ensure a torque drain plug (if equipped) was/is positioned so it lines up with a hole in the flex plate. if not the flex pate could be distorted causing the harmonic.
-check to ensure all the flex plate to crankshaft bolts tightened down correctly and fully. we assume the correct length bolts were used. cracks in the flex plate are common around the mounting flange to the crankshaft
-check the flex plate for cracks all the way around the crank flange and also around the torque mounting areas. turn the engine by hand and check the whole way around. look for metal powder anywhere and also flex the flexplate as you go and listen for the sound of metal moving on metal as would be heard if there were a crack. check to ensure the flex plate was installed the correct way around and not backwards. these checks in this area can be hard to do but could be made easier if you placed some long bolts in the trans bell housing to engine mounts and use them as line up pins to slide the trans back enough to see into the area. that way ir could be easily slid back together after and wouldn't require support (that would be in your way) while slid back
-check to ensure the flex plate to torque mounting bolts are the correct length and did not cause a dent or distortion of the torque shell that, again, may cause interference with the internal converter moving parts
-check to ensure you have the correct converter for your trans (hey, it happens)
-if these things all look good then bolt everything back up carefully except leave the converter cover off. install a new oil filter and top up the fluid
-start the engine and slide under (carefully, ensuring no loose clothing etc) and use your stethoscope to try to pinpoint the area where the noise is coming from. use the open hose at first and then the probe rod to be more specific. I highly recommend a stethoscope because it deadens ambient noise so you can zero in on a particular area. be aware that the hose can also get snagged on moving parts. what I have done is grab a scope that has the ability to replace the hose with a longer hose so I can be physically further away from moving parts.
-check for exhaust system whistles which can be caused by welds that have slag inside the pipe unseen from the outside or poor pipe connections with flanges or bits inside the pipe that can whistle when the exhaust passes them. I have also see partially plugged mufflers cause whistles that would seem like an engine issue. a couple of weeks ago I was brought a truck that needed an engine, as diagnosed by a dealership, and found the only issue was a plugged catalytic converter and some tune up issues. not saying that could be your problem, just saying eliminate what you can (good job on removing the belts to eliminate the accy's by the way. good thinking there)
-if you still have a noise you will need to pinpoint if it is engine or trans. you may need to unbolt the torque and slide it back then start the engine and do the stethoscope thing again. if you don't have room between the torque and flex plate you may need to space the engine away from the trans enough to get the job done. if you think it is trans then start by pulling the trans pan off and looking inside. I recommend to drain the pan into a clean container so you can look for metallics in the oil and know that whatever found can only be from the trans (or engine if dumping that oil as well). if you do this and your pan does not have a drain plug then now would be the perfect time to remedy that to make things easier in the future.

keep us posted, post pics and video as you see fit. the one link to a video did not have sound (for me anyway)
what is that behind your trans, overdrive unit? possibly an issue there could make the sound you hear?

DSRaven,

Thank you for all the tips. I read through all your post and I'll update a couple notes.

-I don't believe there is any vac leaks. Carb ports are plugged off. Distributor is plugged off. I also tested removing the PVC and air breather from the valve covers.

-I checked the bolts on the front pulley and harmonic balancer and they are both tight. As far as I can tell there appears to be no wobble in the balancer/pully when the motor is spinning.

-before I installed the distributor I used my oil pump priming tool and turned it over with my cordless drill. plenty of oil was getting up top to the heads and had good oil pressure.

-I don't have a torque convert cover at this time so it's exposed.

-When i noticed the torque converter wasn't bolted up to the flex plate I could spin it with my hand. When I installed the bolts it was easy to slide the torque towards the flex plate. I installed all the bolts by hand easily without having to forcefully pull the torque into the flex plate. Turning the motor over with a 1/2' drive and about one foot wrench was tight but not anymore then i would say normal. I had to turn over the engine to install the distributor to get TDC on cylinder one.

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