Technical 305 making knocking noise

My 305 engine started making noise while it was in driveway.

 

And then what ?

 

Well drive it into the garage and replace the 305 with a tree-fitty.

Seriously man, can you give more details

 

My vid clip is too large for site, I am creating a you tube account.

I can not figure out what the sound is. I think maybe lifters, but want some opinions before I start taking everything apart.

 

You do have the right amount of and did not run out of oil I take it?
They sell a stethoscope in the tool section of Autozone, O'Reilly's, Sears and probably Harbor freight for about the price of a six pack of decent beer that you can listen to the engine at various spots to try and pinpoint the noise.
You can pull one plug wire at a time with it running to see if you have a rod knock but need a pair of insulated pliers to do it or get knocked on your butt by the spark. That's not proof positive but a real good indicator that you have a rod bearing gone bad if the knock quits or gets faint when you pull the plug wire on the cylinder with the bad bearing.

One more thing before you do any thing drastic. if it is an automatic put it in gear and put a load against the trans to see if the knock goes away. A cracked or broken flex plate or loose converter bolts can cause a hell of a knock and got me a free truck with an Olds 350 in it that I put in my 51 Merc back years ago. At an Idle in the driveway the thing knocked so loud that you thought the rods were coming though the side of the block but the knock quit when you put it in gear with your foot on the brake and gave it a bit of gas. Three minutes with a 9/16 wrench and I had an engine that I put probably 80 K on in my Merc including a trip to Texas and Bonneville in 1988. Something to try before you tear it all apart.

 

How much oil pressure ?

 

Broken flex plate, or exhaust leak, by the head.

 

Yes, if it's a rod bearing you'll loose oil pressure. The spark plug idea is good and will work. The flex plate idea is also good.

 

^^^^^ why I love the Hamb

 

The oil is to the full mark. The oil pressure is at 35lbs. I took off the cover and inspected the flexplate for cracks. I turned the engine to see all sides. I tried a real stethoscope with the end taken off and cound not narrow it down. By ear, sounds like it is under intake, but don't know for sure. I need to by insulated pliers because felt the shock through my arm yesterday before I finished.

 

454 in the 55 chevy did the same shit while loading it on to trailer. thought the worst. put up on rack and flex plate to crank bolts had loosened up just a hair. Slid trans back removed bolts and reinstalled with some locktite on threads. All healed. amazing. I was doing the happy dance. noise gone. Yruhot

 

The cracks that make this noise will be on the flexplate in an area that you cannot see. You will need to back the transmission up enough to get a ratchet in in there, and remove it.

 

Sounds like semi auto rifle fire.

 

The vehicle is a 56 GMC. The engine is a 305 with 416 heads, air gap intake, edelbrock 650 avs carb, stock exhaust manifold, edelbrock 2102 cam, stock rockers, 700r4 tranny.

I bought the engine a couple months ago (they had it advertised as a 350, should have looked at it better before buying). The engine was running good for a few days(over a few weeks) before noise started. I only drove it around the block once before problem. I tried adding 5 gallans of 92 octan3 to tank.

 

Did you bolt the flex/converter/trans together yourself? Torque the bolts for the fly wheel?

 

Holy crap !
That's freaking noisy

Sounds like the pistons are swapping holes. Something in that engine wants out in a bad way.

Sounds like something rubbing, a bearing knock is more like tapping on the block with a hammer sound.

That fan looks bent,

that engine went from quite and smooth right to that in the driveway all of a sudden?

 

I KNOW WHAT IT IS.....most likely
its a bad camshaft. the late 70's 305's all eat camshafts due to the crap metal they used in them. i had mine in my 79 impala go. when i pulled it out i shit you not the number #1 lobe was nearly round.

 

Will it make a difference if I put it drive or neutral?

 

U

hard to use a stethoscope to pinpoint the noise when something is shooting at you.

 

The fan is a weird on

I Installed myself. I used new star washers and loctite. I hooked up the transmission as well

 

The fan is originally from a 327 engine that was is truck before. it didn't make any noise.

 

[QUOTEdassBadger, post: 10910592, member: 127999"]I KNOW WHAT IT IS.....most likely
its a bad camshaft. the late 70's 305's all eat camshafts due to the crap metal they used in them. i had mine in my 79 impala go. when i pulled it out i shit you not the number #1 lobe was nearly round.[/QUOTE]
I

I was thinking of pulling intake manifold to check lifters for wear, could be the cam. It is an edelbrock cam, not stock.

 

I have unistalled the fuel pump and engine ran the same without it. It was a well spent $2.98 (.99 for one gasket and 1.99 for other) to rule that out.

 

1 minute video. Took over 1 hour to download to you tube.

 

I didn't design it, just painted it pontaic blue metallic and installed it. Mine is old, not this reproduction.

 

Take your fan belt off and run it a little bit. Water pumps (especially with bent fans killing the bearings) and alternators can make hard to find noises. Please replace that fan before you kill yourself.

When you have that belt off, check your harmonic balancer, they can sometimes work lose.

Take the valve overs off and get each cylinder up to TDC one at a time and see if you have lash on any cylinders. Lash on a hydraulic cam = a bad adjustment to begin with, a stud pulling out of the head, a bad/broken rocker arm, bent pushrod or valve, or bad cam/lifter.

SPark

 

Yes ,pull the valve covers first and see if any rockers are off the pushrods or some aren't moving at all

 

I agree with taking the belt off and see what it sounds like. That bent fan will eventually kill the water pump bearing. It sounds too irregular to be something serious.

 

^^^What SPark said. Had a 289 that the rocker stud pulled out of the head on that sounded like that. Spark has the best ideas yet. I'm thinking water pump maybe also. Pull the belt and run it, then valve covers.

Andy