1982 chevorlet 305 low rpm knock then tick

ok i have a chevorlet c10 with 76,xxx miles i have started it this morning and upon start it was hard to get it to idle when i heard a loud knocking noise comming from somewhere in the engine it wanted to die then it revved up to idle and has a steady tick i have checked the engine over with a mechanics stethascope and all the noise is comming from the oil pan in the front of the engine. i am suspecting a bad rod or main bearing the loud knock sound sounded like someone beating on my exhaust near my engine with a ratchet. then it sped up to idle and was a steady ticking noise. valves and lifters are good no bent rods it also is lacking power when at half throttle then i hear a ping and it picks up speed any ideas?


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Sounds like it may be a weak oil-pump having trouble getting pumped up, not saying that's it but could be JMO. the balance hasen't came loose or seperated has it ?



Cole

oil pressure is fine reading between 30-40 lbs and balancer isn't loose or cracked dosent wobble or anything

Whats the temperature where this hapened? and was the eng cold?
Jester

X2 on the temp i took it that it was doing at first start up after sitting through the night.



Cole

yes it is upon a cold start and when it idles it ticks the knock is only when it is way lower than 700 rpm kinda sounds like somthing banging around and it shakes the truck

I dont know the climate you live in Was it parked in 0 temps and was this the first start after setting for a long time in the cold and keep it on the thread to give these other guys a chance to help dont private message me unless I ask you! we need all of our input to trouble shoot vehicles.

jester

it was low 30's outside but it also did it on a 40 degree day this is not a one time occurance every day ive had truck so far it has done same thing checked oil looked like previous owner didnt change oil in about 15k miles and it was thick

ok started the truck up this morning the knocking lasted longer and it was colder in low teens outside and tick is more pronounced after knock stopped

had to drive the truck this morning and had no power at half throttle and even less the further i went i am getting frusterated with this motor about to go buy a short block crate motor if i dont get it figured out. valves sound fine with the mechanics stethascope so i dont think it is valves i just wonder though if the guy replaced the cam and set timing wrong? cause he said he replaced the cam but i believe he did it himself not sure though. also the oil pressure was a little jumpy on the gauge jumping from 30-45 lbs while i was driving it.

First thing to do Change your oil and filter!!!

First get a buddy to help! When you start your truck and its running cold pull one plug wire at a time and tell us if theres a difference in the sound of the knock or if it goes away and what cylinder did this tell your buddy to write it down , then do it when its warmed up and ticking. do this at the plugs (if you do it at the cap spark might jump across the cap and ruin the test) and make sure the plug wires are loose enough to pull off the plugs before you start the engine. And be careful not to get burned!

We're not interested in how the engine runs only in a change in the sound of the knock and ticking ( your going to create a miss when you pull each wire and the engine will shack ignore that for the test)

If you pull a wire and the engine runs exactly the same we are interested in that yell at your buddy to write it down. If you pull a wire and the engine stalls, kick up the idle a little. You should also have your buddy ready to shut the eng off in case you have a problem (it will take you too long to run around the vehicle if there is any trouble) .

I wont be back on your thread till tomorrow or Monday but there should be many people on here who know this test and will help you before I come back on!! If you dont think your mechanicly inclined enough to do this Dont even try it!!!

Jester

ok now only one issue it wont stay running when the engine is making the knocking sound i have to give it gas to keep it running. but i can do it when it is tapping cause it will stay running while its tapping

ok i started the test got down 1-3-5-7 #7 made knock while it was tapping then i went 2-4-6-8 and i didnt get last 2 cyl checked cause when i pulled off #4 it wouldnt run and start so i put plug wire back on the way it was and then it started backfiring through carb im completely lost on where to go from here any ideas? o and cyls 1&3 made no change in the way it ran or knocked 5 made it run rough 7 made it knock 2 had no change in the way it ran 4 messed everything up

Did you change your oil??????? & filter??? after you wrote "ideas?" whats the o stand for? When you pulled #4 you had 3 cylinders not firing at all and it stalled! Do a compression test wet & dry Write down your reading for each cylinder If it checks out good. Fine.

Now: 1 & 3 cylinders arnt firing at all, You have compound problems. Check firing order first thing! If its ok ! visually check inside distributor cap for cracks or carbon tracking if you dont know change it. Change plugs, do this test again, if there are any cylinders that dont change the way it runs I would advise a plug wire change you can do one at a time or you can change all. I would do a good tune up! And get it over with !change the oil and filter 10/30 or 5/30 in real cold weather!! Now do the test again And give the results. If its still #7 that knocks(read bellow)

now #7 was it a louder knock or was the engine just tapping and when you pulled the plug wire it started knocking. If it knocks with the plug wire hooked up and stops when pulled off its probably a rod bearing! With out being there to hear the different knocks Im guessing at what your hearing But a terrible need for a tune up can cause some of this. Your wires can be jumping spark, It can be jumping spark in the cap ( this could cause the wrong plug to fire creating a knock or a back fire) moisture can cause these miss fires too

Jester

o is oh, sorry but i also am in need of a new keyboard cause sometimes it dont type everything