Hey all. I've got an 82 with around 140k miles on it and when I first start it, it has what I can only describe as a knocking sound and it's extremely concerning. This issue disappears within 2-3 minutes of starting it up and only occurs when the car has sat overnight. Does anyone have any ideas as to what my issue could be? Thanks.

 

Any knocking sound from an engine is always a major concern that must be addressed.
The fact that it goes away, stays away untill it once again sits for a few hours makes it sound like a lifter or lifters bleeding down. But 2 -3 minutes to pump up a lifter seems a long time.
oil pressure good??
Perhaps have someone who has some experience with engine's give this a listen.
And forget the silly videos. I've been working on engine's for 50 years and over a speaker from a video it's always impossible to tell where the sound is coming from.
my thoughts however based on the symptoms is a cam and lifters is in your near future.

 

a 4 foot piece of garden hose makes a pretty good stethoscope to localize where the noise is originating. usually a tired engine with the beginnings of a rod knock will knock 4 or 5 times as the oil pressure comes up. about 2 or 3 seconds, not minutes.

 

rod knock, piston slap, excessive main bearing wear.
lots of possibilities.
Would you describe it as a tick, or a hearty knock?
most of the time ticking is valve train related. Knocks are normally something worse.
one of my engines had a similar thing, knock on start up for a min or two. I drove it until I started losing oil pressure, probably about 6 months timeframe, then I pulled it for rebuild, one cam bearing and one main had a lot wear.
things you could do, pull the oil pan off and take each main cap off one at a time. Do the same for rod caps, see if there is any wear.

 

And let's face it, 140K on a gen1 small block really is a bit past its due date.
Perhaps start thinking on the lines of a rebuild or replacement engine.
Knocking is bad!

 

Hi Mark Dawson64
Just started taking mine apart the other day. 68000 miles. Wanted to do a fresh up on the engine while everything else was apart.. It is hard to post sounds even exhaust sounds. You could have some piston slap if it’s like a rattle knock or lift gone if it’s a loud tick tic tick. This is my connecting rod bearing and piston. Good enough wear for the mileage.

 

Hey guys. Bad news. Driving it today my oil pressures have dropped significantly. I believe we may be nearing the end for my little 350

 

Yeah, that doesn't sound good. I wouldn't start it anymore for sure until you find out what the issue is, but it may be too late now already. GL

 

it is an 82. i don't think numbers-matching is a big deal. especially as there were no engine options. you got a 350 x-fire or you went to cali and got a 305 x-fire... so saving the original block is lower on the list of factors to consider.

 

I would plan on an engine rebuild in the near future and like suggested above I would not run the engine much now that you are pretty sure that something is wrong with the engine. If it were my car I would pull the original block and rebuild it versus replacing the entire engine. If you removed it or have it removed and give it to a good machine shop they can have it back to stock in fairly short order. I don't know where you are in Virginia but finding a good speed shop and getting their recommendations on a reputable re-builder is another good option. The cost of re-building a small block are not that bad when you compare it to some of the other engines like the 427 in my Corvette.

When I rebuilt my big block I made a deal with a local speed shop where they supplied the parts (at agreed price markups) for my engine needed and that I got to help re-assemble the engine with my involvement and labor. I learned all about the big blocks as they were new to me but I learned a lot and got a great build all at the same time. My engine builder had tons of experience on the big block Chevy engines and knew many ways of finding "extra power" while re-assembling the engine. It was truly a learning experience as well as an adventure for me as I now feel very comfortable with the 427 having been involved in every part of the re-building process. I was lucky as I was not in a hurry for the engine so we took our time and I got better prices that way. In the end I had a very nice looking and powerful L88 Replica engine that makes serious horsepower.

If you are pretty handy with tools it might be good to get the engine pulled and then take it home and remove the parts and just deliver the short block to a machine Shop and have them rebuild it. If you want to make more power then you can look at aftermarket cylinder heads as there are lots of options for the small block engines. I have rebuilt small blocks at home before and they are more manageable than the 427 I have in my C3. The 427's cylinder heads weigh over 100 pounds each and that made the job harder for me. If you want to stay with the stock heads just get them rebuilt at the same time. I had hardened seats put in my heads to allow for the use of Oxygenated gasoline for the long term. With the low cost of quality performance High Flowing cylinder heads they might be a worthwhile upgrade compared to rebuilding the stock heads.

While the engine is out you have time to clean and repaint the engine bay and really make your Corvette look good afterwards. After my rebuild a local Corvette shop re-installed the engine did an outstanding job as they re-painted the under the hood area and rebuilt the shifter while we were putting the car back together. I had a shop reinstall the engine as I was not comfortable re-installing the 427 myself in the back yard. I knew my limitations and the end results were outstanding. If you are in Northern Virginia I can suggest a shop that could do an awesome job for you. Good Luck and look at this as a good time to help improve on your Corvette versus being bummed about having to rebuild the engine.

 

once again. 82. crossfire. you have to decide if you are staying with the OE induction-efi setup. buccaneer will weigh in. 1st generation of GM TBI efi. and the intake is limited to about 325 hp airflow. if you want real power, an aftermarket efi should be considered. either a fuel rail setup or a 4 bbl tbi on a single plane intake. efi conversion is easier on the 82 than earlier cars as it already is an efi car, if you are ok with the car's current performance level then running what you got is the way to go. you can upgrade the induction system later. or not. you can find a short block foraround 1000 bucks. you can get a holley sniper or similar for around the same. plus 200 for an intake. both at the same time is twice as much at one time.

 

Hey guys! Thank you for all your valuable input, I’m learning a ton. I know many of you said that videos are redundant, but I took one anyways. It sounds like it’s more from the top of the engine when I really got in and took a listen. What do you guys think after listening? It made that noise for ~1.5 minutes before smoothing out.

 

Hard to tell with video’s but if it was mine and your just looking to run it without a rebuilt. I would check the oil presser with a mechanical gauge and remove the valve covers to check your valve train. I’m not an expert and videos can be can be tricky. It sounds like the valve train.

 

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4 foot piece of garden hose. it will tell you where the noise is loudest. which will tell you a lot. hose in 1 ear and run other end along the valve covers and get underneath and run hose along side of block pointed in towards crank. while engine is making the noise, of course.