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Discussion Starter #1
Well looks like I may have spun a bearing in my 383. I started having a horrific knocking sound from the bottom end. I'm planning to pull the motor next weekend or the week between Christmas and New Years if I get the week off.

What should be my next step once I pull the motor, complete disassembly, new internals, etc? Any ideas on what kind of cost I'm looking at with potential machine work and parts that may be needed? I have rebuilt a couple motors in the past so I should have to necessary tools to disassemble and reassemble the motor, although I've never dealt with this particular issue before, so no idea what I'm up against. What really sucks I have less than 1000 miles on the motor.

One step forward and 2 steps back, I'm pretty bummed out about this one for sure :(
 

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You can always drop the pan to be sure it's a rod bearing then pop the cap off and take a look. Should be able to move the big end of the rod back and forth a little if the bearing is bad. Just depends how long it was run like that and much the bearing disintegrated. Cost could be a new rod bearing and gasket to completely go through the motor. I'd take the pan off then make a decision from there if it was me. It sucks! I had 2 rod bearing failures months apart. Motor had to come out both times.
 

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If it's knocking, then engine is going to have to come out because it will have damaged the crank throw also. You can pull the pan and take a look, but I can almost guarantee you the crank will need to be ground or replaced and you'll need a new rod.
Same goes for if it is a main bearing, except it may have chewed up the main bearing bore and that is not good. If you are lucky, you might get by with a new bearing cap and a line bore job in addition to grinding the crank.

Good luck, whatever the problem is.
 

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Discussion Starter #4
Thanks for the responses guys. Yeah I'll get started on getting it ready to pull out. I think I'll just pull it because as bad as it is now there is no way it won't need to come out so I might as well prepare for the worst. I've been trying to read up on this topic to get an idea of what to expect work and cost wise. It looks like the entire engine will need to be disassembled and throughly cleaned and checked by a machine shop? Any idea what something like this will cost, I realize prices will be different depending on area and shop ect but just trying to know what I could be facing to get the nova back on the road. Anyway this sucks either way...there goes my transmission upgrade budget :(

If anyone from the area knows of a good machine shop around Houston please let me know. I've never dealt with a machine shop so I'm open to suggestions.
 

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If the sound is "horrific" this is probably not your issue but with such low assembled miles,if it's an auto,check the converter bolts in case they worked loose.Had a buddy this summer with what sounded to me,and a couple other gearheads,exactly like a rod knock.A very distinct,loud tunk,tunk,tunk.Kinda came and went slightly with engine RPM but definitely sounded like bottom end.Started disconnecting stuff to yank the engine and found the converter to flexplate bolts had loosened.First time I've seen that and this thing has been together for years.Snugged them up and all was good.I was surprised how that racket radiated into the engine.Free repair but I think he was a bit bummed.Was going to build a bigger,badder motor since it was coming out.
 

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No one will know just how much will need to be done until it comes apart.

If you think it's bottom end, start by dropping the pan. Go from there.

If anything needs to be machined, more than one thing will need to be machined (or replaced). Plan on at least $1,000.
If you can squeak by with just a crank and rod grind, and new bearings, even better. (Not ideal, but workable.)
 

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Discussion Starter #7
I did check the bolts on the convertor and flex plate a couple of weeks back. That's what I was hoping the problem was when it first started. I've never experienced this before so I YouTube'd it like most people. It started as a very random noise that was hard to pinpoint. I thought convertor or flex plate and started there by loosened the convertor to check the flex plate bots and from what I could see they looked good. Once I tighten the convertor back it stopped (remember it was originally stated as a very faint noise) so I figured that was it and I rarely drive the car. It eventually got really bad really quickly. I wish I knew enough to really have looked into it when it was just a periodic random noise I probably would have saved a lot of work and money.

Once it's determined it's a lower end problem should I disassemble it and take it to a shop or take it there complete for them to check it out and determine what it will need?
 

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I’ve had flex plates fail on a couple of small blocks and the sound is very similar to a rod knock. The flex plates can crack in the field around the crank and makes a knocking sound as it rotates and flex’s. Also had one where the welds around the ring gear to the flex plate were no good and it created the same sound.

Don’t rule this out until you thoroughly inspect the flex plate.
 

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Machine shop: USA Racing Engines(the old *** Shop)
(713) 645-4000 · Address. 7562 Dillon St; Houston, Texas 77061

If it's a lower mileage engine, resize and check other rods if spun rod bearing. If I have one rod resized I typically have them all done. You can hone it or have them check/wash/hone the block and install fresh cam bearings. Then just freshen your build with new bearings/rings and gaskets.

If you need a crank, I like the Scat 9000 cast if not needing a forged crank. I put the 9000 in my buddies 383 and I put the forged crank in my 383.

USA Racing has a pretty good turn around and just did some balance work for my buddy as I just put together his 408 Ford stroker motor than they balanced his assembly.
 

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Machine shop: USA Racing Engines(the old *** Shop)
(713) 645-4000 · Address. 7562 Dillon St; Houston, Texas 77061

If it's a lower mileage engine, resize and check other rods if spun rod bearing. If I have one rod resized I typically have them all done. You can hone it or have them check/wash/hone the block and install fresh cam bearings. Then just freshen your build with new bearings/rings and gaskets.

If you need a crank, I like the Scat 9000 cast if not needing a forged crank. I put the 9000 in my buddies 383 and I put the forged crank in my 383.

USA Racing has a pretty good turn around and just did some balance work for my buddy as I just put together his 408 Ford stroker motor than they balanced his assembly.
While I favor the Scat 9000 stroker crank I found my last one to be suffering from QC issues. The rod journals were not consistant in size to the point, and against my better judgement, I had to use different sized rod bearings on 2 journals. It's still a good crank in my opinion, hopefully this was a one off. Not sure how that happens with a CNC setup.
 

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Discussion Starter #12
I’ve had flex plates fail on a couple of small blocks and the sound is very similar to a rod knock. The flex plates can crack in the field around the crank and makes a knocking sound as it rotates and flex’s. Also had one where the welds around the ring gear to the flex plate were no good and it created the same sound.

Don’t rule this out until you thoroughly inspect the flex plate.
I hope that's the case. I took a pretty good look from underneath the car a few weeks back. It's pretty hard to see up there so I'll have to really check it again because I'd love if that was the case.

Thanks SBC1320 for the contact info. I'll give them a call depending on what I find. Fingers crossed and hoping for something simple.
 

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Does the sound have a rhythm to it or is it erratic? Does it sound like it's bouncing around. If it has a rhythm it might be something that can be fixed. That's a "maybe". But if it is erratic and bouncing around, It's most likely something bad.

Bill
 

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Trust me. I understand the sickening feeling you are experiencing. Those flex plates are crap.. I’ve had three small blocks come into my possession with bad flex plates not knowning that they were afflicted with bad flex plates and thinking the worst case scenarios.. The last one was the one with the bad welds I linked to earlier.. My fingers are crossed on your behalf.. Best of luck.
 

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Discussion Starter #16
Trust me. I understand the sickening feeling you are experiencing. Those flex plates are crap.. I’ve had three small blocks come into my possession with bad flex plates not knowning that they were afflicted with bad flex plates and thinking the worst case scenarios.. The last one was the one with the bad welds I linked to earlier.. My fingers are crossed on your behalf.. Best of luck.

Man I'm praying this is the case. You've given me renewed hope to take a closer look.
 

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Happen to me too.BUT!!!! it was my oil pick up tube that broke! And luckily it didn't damage anything.but it was knocking like crazy
 

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Discussion Starter #18
Well just to update this thread for anyone that may be reading this later with a similar problem. I finally got the engine out and dropped it off at the machine shop. When I pulled it and removed the oil pan everything looked pretty good. No rods seemed loose or noisy when rocked ect. The machine shop guy had the same conclusion and stated it looked fine. I did have a lot of metal flakes in the oil when I drained it. The machinist disassembled it and I'm having him put the bottom end back together, he suggested new bearings also. I've looked over the flexplate and it looks like new, I've also looked for any worn or rubbing spots around the transmission bellhousing and nothing, everything looks good. I'm at a loss and not too happy not having a definite cause but I guess I could have also had a grenaded engine. I'm not sure what the gold flakes in the oil could be from bc the machinist says it has aluminum bearing and nothing should be making that color flakes.
 

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Gold color metal flakes in the oil is almost certain to be bearing material. All bearings look to be aluminum but they have a copper layer. If he doesn't find anything in a rod bearing it will probably show up on a main bearing. If no bearing is spun on the rods or mains have him check the thrust bearing. When the oil pan was pulled was there gold flakes in it also.
 
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