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Engine noise identification

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I have a long term project that I built with my son. We started when he turned 13 and it took 4 years to complete. The engine is a 318 .030 with Speed Pro L2266 pistons, 302 casting iron heads with big valves and minor port work, small RV type Lunati cam, performer intake and am edelbrock 600 cfm carb. Ignition is mopar electronic.
After the initial fire-up ( started immediately and had been pre-primed, lots of zink break- additive and plenty of break-in lube on the cam) engine ran for about 40 minutes everything seemed OK, 75 psi oil pressure. Began to drive it to put some miles on it for break-in. Began having significant lifter noise. Pulled the valve covers and discovered that 2 cam lobes had gone away. Drained and pulled pan, removed cam and lifters, flushed engine using the oil pressure switch tap on back of block. Dissembled the oil pump, cleaned and checked. Began re-assembly. New cam and lifters, got the engine mostly back together with the exception of rocker arms and shafts as well as pushrods. Career move stalled the project for 3 years.
Recently returned to project. Purchased new factory style rocker arms, shafts and pushrods. More zink, pre-lubing, cam break-in grease and additive. Installed buttoned it all up. Reinstalled AC system. Restart, ran for about 30 minutes. Oil pressure at 75 psi, temp 180, all the rockers seem to be oiling correctly. Drove it for about 30 minutes at varying speeds no heavy loads. Pulled into shop and hear a knock. Knock seems to increase when AC compressor is engaged. Tried to identify but could not pin it down. Replaced AC compressor but still have the knock which is again louder when the AC compressor is engaged. Timing is 15 btdc and AF gauge is around 11:1, automatic transmission with a 2200 stall convertor.
I now have brain lock and am looking for suggestions, would appreciate any help!
 
Doesn’t sound good but there are many kinds of knocks. If it sounds awful don’t run it. If it’s mild I like taking a breaker bar and putting it to my ear and touching different places. Often you can hear it better and tell better where it is coming from.

Rods
Mains
Flex plate loose
Lifters
Wrist pins
Debris in chambers

Those are the choices that come to mind. None are much fun.
 
I'd look to rule out the easier stuff first. Pull the accessory belts off and run it and see if it's still there. Check for an exhaust/header pipe hitting, fan/shroud contact, those pesky converter bolts...good luck.
 
Check the balancer bolt and crank pulley bolts. And then check the flexplate bolts if an automatic.


And you should load that new engine, just don’t over rev it. I like to stay below 3000 for a few hundered miles. Loading it helps seal the rings. Don’t drive like granny.

Do you happen to know the piston to cylinder wall clearance?
 
It has a set of old school CalCustom valve covers. Wondering if there is some interference. Have a stethoscope with a hose on it, have been trying to identify the noise but as yet no luck. The increased knock under the load of a Sanden compressor has me puzzled. Would not think the compressor load would be enough to make the noise significantly louder.
 
Check the balancer bolt and crank pulley bolts. And then check the flexplate bolts if an automatic.


And you should load that new engine, just don’t over rev it. I like to stay below 3000 for a few hundered miles. Loading it helps seal the rings. Don’t drive like granny.

Do you happen to know the piston to cylinder wall clearance?
Local machine shop built the short block so I don't know about the cylinder wall clearance. The balancer and pulley bolts are a good idea, as well as the flex plate bolts.
 
Probably just me, but when I need to hear a noise to actually identify it?
 
I'd look to rule out the easier stuff first. Pull the accessory belts off and run it and see if it's still there. Check for an exhaust/header pipe hitting, fan/shroud contact, those pesky converter bolts...good luck.
I will put it on the lift tomorrow and check the converter bolts, and collector flange gaskets.
 
Probably just me, but when I need to hear a noise to actually identify it?
I'll try and get a video. Just seems like the video's usually make it harder to tell where the noise is coming from as it picks up all the ambient noise as well. We will see.
 
Check the balancer bolt and crank pulley bolts. And then check the flexplate bolts if an automatic.


And you should load that new engine, just don’t over rev it. I like to stay below 3000 for a few hundered miles. Loading it helps seal the rings. Don’t drive like granny.

Do you happen to know the piston to cylinder wall clearance?
LOL, that's the first time anyone suggested I might drive something like a granny, but your point is taken Thanks!
 
Well when the AC is running it's placing more pressure on something. Take all the belts off and see if there's still a noise. Could very well be bottom pully or harmonic balancer. I've also heard guys running too long of a bolt on the bottom pully and the bolt cuts into the timing chain cover.
Good luck!
 
You will hear many guesses from converter bolts to rocker arms to piston slap and everything in between. Post a video on Youtube of the actual noise, and take yourself an automotive stethoscope, or just use a big dowel rod (Broomstick) and put it against the motor and bellhousing areas and listen to more closely pin down the location.

HTH, Lefty71
 
My say is rod knock getting louder with ac pull on crank.
What sound if reved quick and let off?
 
My money is still on rod knock....and maybe even an additional valvetrain ticking (if that isn't a
header I'm hearing). Definitely can hear bottom end knock, though...
 
Checked the converter bolts, front pully bolts, everything ok. I am going to pull the valve covers and look for signs of rubbing.
 
Pull a plug wire one at a time with compressor running.
If noise goes away on one of the cyl you pull,either rod bearing or wrist pin problem.
Hope not????
 
Pull a plug wire one at a time with compressor running.
If noise goes away on one of the cyl you pull,either rod bearing or wrist pin problem.
Hope not????
Really hope not. fingers crossed. Did talk to a couple of my buddies, both old time hot rodders. When I mentioned the noise and showed them the videos they both laughed and said that the old cast aluminum valve covers were notorious for valve train noise. Suggested loosening and trying to reposition. Barring that they both suggested thicker valve cover gaskets. Both said those covers should be wall art and not on a car. They both had had multiple sets in the 60's and said there always seemed to be some kind of issues, from being too thick, holes improperly drilled, filler cap and breather cap fitment. Stay tuned......
 
Noise issue solved! My problem was three fold. Two rockers were slightly touching the valve cover on the passenger side. Leaking collector gasket. And the issue with the increase in noise when the ac compressor was engaged was found when I removed the passenger side valve cover. The bolt that the alternator pivots on was too long and was in contact with the valve cover. When the compressor was engaged the bolt was transmitting the vibration from the compressor and the valve cover was acting like a drum and amplifying the compressor noise. So new correct length bolt solved that issue. I also installed new taller valve covers and a set of Felpro #1646 thick gaskets ( 0.313) for a little more height. Issues seemed to be solved for now. Thanks for all your suggestions!
 
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