Re: What's going wrong inside my 350?
That probably wasn't an issue as he could turn the converter easily to line up the bolts when he put the flex plate to converter bolts in. At least he didn't say it was hard to turn.
Cracked or broken flex plate is usually a rattle or almost a knock that goes away when you put the trans in gear and put a slight load on it. I got a free engine that "had a knock" from one of those back years ago and drove that engine about 80K after that. You can buy the mechanics stethoscope at O'Reilly's or Autozone for about 8 bucks if you don't have a HF close. The one I use now came from Autozone after one of the ear pieces came missing on my old one. I've done the broom handle thing, hose thing and what not but the stethoscope really works to isolate noises. It made the noise when the converter wasn't connected so that rather eliminates the trans and converter. To be positive you could pull the three bolts out of the flex plate and slide the converter back in the trans with about a half inch clearance and fire up the engine again. If you already had that clearance before forget that step You could raise the truck up and have a helper fire it up to see if the starter drive releases from the flexplate when it starts. You would have to remove the cover if you already put it on but that only takes a minute. You should see it pop back as soon as the engine fires up. I'm not sure if you could catch it by laying a phone or camera on video under it and aiming it up there but if you are working alone that might be worth a try. If it is a fresh from the parts house rebuilt starter a lot of rebuiders machine the mounting surface every time they go though the rebuild plant and after two or three go arounds over the years a lot of metal gets shaved off them. It may just need shims. On old engines with a lot of miles on them I have seen a number of worn out timing chains that rubbed the timing cover with a couple of them wearing though the covers. Like most other guys on here I am not a fan of Fram filters preferring either the Wix or a Napa Gold. Years ago Fram decided to put most of their money into advertising rather than producing the best filter they could and their filters are far from the best. |
Re: What's going wrong inside my 350?
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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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I figured the sound would have been from the torque converter snout rubbing up against the flex plate but that wasn't the case after bolting them together. |
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I appreciate all your input. To answer some of your questions above. -i wouldnt say the engine was to hard to turn but it took a little arm muscle to get it to move. I was using a 1/2" drive with 1 foot arm on it. Probably would have been easier if I used a longer wrench. -yes it made the noise before the torque was bolted to the flex plate so that would eliminate the trans and converter. Yes I did have a small clearance before bolting them together. -I will try to lay my phone down under the truck to get another video. I believe when i checked the starter (engine off), the starter drive(bendix) was back inside the starter. Could the drive/bendix it get stuck in the out/startup position after starting the engine? then one stopped pull back into the starter? |
Re: What's going wrong inside my 350?
(Could the drive/bendix it get stuck in the out/startup position after starting the engine? then one stopped pull back into the starter? )
yes |
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.....bingo.! . |
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Re: What's going wrong inside my 350?
pull that oil filter, cut it apart and have a look see of whats in it and also look behind it (that adapter with the check valve that may be whistling as oil is bypassing). if you find filings in the filter element then you KNOW it's internal and need to stop running the engine since that will cause more damage. that is the quickest and easiest thing to check and causes no more damage if there is an internal issue.
do you have any specs on whats inside the engine? anything different from a stock 350, windage trays, high volume oil pump (which may require a high flow filter) or special timing gear set up etc? have you tried simply swapping the oil filter or listening directly AT the oil filter? some filters have an anti drain back valve built in and this could also be "whistling" as oil goes through it,theoretically. it would be worth a listen maybe. are you sure the oil filter is the correct one for the engine? some filters have the same dimensional size and thread but are made to flow opposite of other filters, so from the inside to the outside or opposite to what a standard 350 would flow. if you have the wrong filter and the filter has an anti drain back valve, then the valve could be fluttering causing the noise or the filter could be bypassing due to low flow through the filter because the filter isn't made to flow the wrong way. you say there was lots of oil flow when you primed the engine but if the system is bypassing it may still have good flow but the oil will not be filtered properly. the bypass is built into the oil filter adapter and is made to open if there is low flow through the filter from cold, thick oil or the filter were to plug up (or you simply have the wrong filter). if a high flow oil pump were used or the builder changed the pressure relief valve setting in the oil pump, then a high flow oil filter may be required. these typically are for race engines where the owners sacrifice filtering for flow. is there a reason why the engine won't stay running/idling by itself and needs to be babysat? possible cause of the noise as well? from memory, does the noise increase exactly with engine rpm or stay the same pretty well or only a slight difference with an rpm change? if something were rubbing on a rotating part then it would change exactly as the rpm changes. if the noise is something like, say, a vacuum leak then it would change with rpm but not necessarily be exactly as the rpm changes, if you get my drift? here is a little video on the oil filter system https://www.onallcylinders.com/2016/...filter-bypass/ here is a video or 2 showing the filter cut away so you can see the anti drain back valves and what the filters look like inside. some filters have cardboard end caps instead of steel so they would be the lesser quality ones, in my mind. https://www.youtube.com/watch?v=HXGHA8DUhGQ https://www.youtube.com/watch?v=X3JulJDNpeU https://www.youtube.com/watch?v=lrAbxCZlZpE |
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Re: What's going wrong inside my 350?
Lots of good suggestions, but I'm leaning towards the torque converter/flexplate area. I thought the torque converter sure looked wobbly as it was running. I'd also like to see a close up picture of the torque converter bolts on the flexplate. Is the flexplate on backwards?
Also, no mention of transmission fluid in this thing. Does it even go into gear? You could also pull a transmission line and start it up and see if fluid is being pumped. No fluid-no transmission pump. If it were mine, I'd disconnect the torque converter, rotate and slide it in until it is engaged properly into the pump. Then start the engine while its disconnected from the flexplate and see if the noise is gone. I would want to eliminate the transmission as a problem and then move on to the next thing to eliminate. |
Re: What's going wrong inside my 350?
dsraven's suggestion to cut the oil filter open has merit. I haven't ever heard a noise that loud from oil flow through a bypass valve but I'll keep an open mind. Thinking back, that noise is vaguely familiar but I can't place it. I have heard a dry rear main seal make noise like that but IIRC that was a one piece rear main, not the two piece you're running now. I suppose a tight set of rings could make a noise and potentially so could a thrust bearing that is too tight fore and aft.
I'm waiting patiently to see how this turns out. |
Re: What's going wrong inside my 350?
One time a truck that came in the shop with a similar sound. Turned out the owner swapped in a used engine and used the flywheel bolts from a stick flywheel (too long) on his thinner flexplate for the automatic that was in the truck. The too long flywheel bolts were rubbing-hitting the back of oil pan flange on the block. Easy to see with a flashlight from under the truck.....
Steve weim55 Colorado |
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Re: What's going wrong inside my 350?
sounds like a spun bearing. Pull pan and have a look.
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Re: What's going wrong inside my 350?
But yea, while I'm careful with audio from a video, that certainly sounds external to me. List off the top of head in priority:
Starter bendix engaged Flywheel to crank bolts too long Flywheel rubbing-hitting something (carefully turn and look for witness marks) Too long crank pulley bolts hitting timing cover Timing chain hitting- rubbing timing cover Fuel pump arm hitting the timing chain Steve weim55 Colorado |
Re: What's going wrong inside my 350?
Haha...I was just thinking of making a list of all the suggestions he's got so far....hopefully your issue will be a simple fix....
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Thanks again for the tips. All I was told from the previous owner was "Fresh rebuilt Chevrolet 350 with .030" bore over and mild cam". After getting the motor and pulling off the intake manifold the insides and the water jackets were gummed up with crud. So was it rebuilt? I dont know. Could the build up in the engine because it sat for such a long time with dexcool in it instead of antifreeze? Not sure. I'll pull the oil filter off and see whats going on inside and replace it with a napa platinum filter. The engine needs to be baby sat because the timing is not set and the carb needs tuned properly. When I got the truck i pulled off the tri-power manifold and old mallory distributor and replaced them with an edelbrock manifold and MSD distributor. I turned the motor by hand to get #1 to TDC and dropped in the distributor for initial timing. I also rebuild the carb with a kit and set it to what I would know would be default settings. So between both things being not set it needs a little babying. The noise does appear to increase with RPM. I hope to have some time tonight or on the weekend to check the starter to see if it's binding up on idling. I will also see if I can get a look at the flex plate bolts and provide an update to everyone here. |
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After I check for starter hang up on the flex plate I will remove the bolts from the torque converter and slide it back. I believe the noise will be the same unless its the starter. As I posted in another short reply above "Before I put in the bolts into the flex plate for the torque converter I made sure to spin it towards the drivers side of the transmission to make sure that it was seated properly. Then after that I slide it forward maybe 1/8" so it would touch the flex plate to put the bolts in." |
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Also if it is.......... I'm going to ring the guys neck who sold me the truck. I'm keeping my fingers crossed and my temper in check for now. |
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