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Trying to figure out where the knocking is coming from, on engine
Have a knocking coming from under hood. what could it be bad pulley,valve,rod,timing chain,belt, water pump,lazy lifter??? can you help just started n driving me crazy,, i'm disabled n need my car for transportation or else im stranded???
Re: trying to figure out where the knocking is coming...
It all depends how loud the knock is. A tapping valve can be caused by low oil level, or dirty oil. Topping up or changing oil will solve the problem. A really loud valve tapping is abnormal. Cars sometimes make what you call a spark knock when accelerating hard. Extremely loud knock coming from deep within the engine is a bad sign, which means the engine has failed. Further examination would reveal metallic residue on the dipstick.
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the serpentine belt is an accessory drive belt --a/c --alternator--power steering--water pump--etc it does not have affect on timing ---if you have an engine knock while running that would more than likely be a "rod knock" "piston knock" from a burnt main bearing,piston wrist pin ,damaged rod --if your timing was off poor running ,misfire,no start ,banging in upper engine valves hitting piston,
could be anything from belt noise to lifter tick to rod knock..lifter tick is under the valve covers..rod knock sounds like hitting the block with a hammer..if its rod knock see what your oil pressure is.. should be around 30 to 45 psi cold..warm will be as low as 15..depending on oil type..most lifters can be adjusted by removing the cover and doing adjusting depending on the vehicle..good luck
A KNOCKING SOUND IN THE ENGINE IS MOST LIKELY CAUSED BY ONE OF THE FOLLOWING
1. PISTON SLAP: Makes a sharp metallic noise. Idle engine and short out each cylinder plug. The noise will disappear when plug with bad piston is shorted. Noise will also disappear at acceleration. This can be caused by worn or out of round cylinder, or broken piston ring. Correct problem by re-boring cylinder and/or replacing piston.
2. VALVE NOISE: Makes clicking or rattle noise. Caused by excessive wear on valve stem or lifter, out of adjustment, or stuck valve. Correct by adjusting valve clearance, replace worn valve or lifter, regrind cam, replace valve guide and /or valve. A stuck valve can sometimes be loosened by passing oil through the carburetor while engine is running.
3. ROD BEARING KNOCK: Makes sharp metallic noise similar to a piston slap. Detection is opposite of piston slap. Rod knock is not heard at idle. Knock becomes louder as engine speed is increased. Caused by excessive rod bearing clearance. Correct by adjusting rod bearing clearance to .0015 inches by removing shims. May require re-pouring rod bearing.
4. REAR MAIN BEARING KNOCK: Makes dull knocking or thud noise. Detected at speeds between 20 and 50 MPH. Knock will normally decrease or disappear while pulling or decelerating. Noise will be detected the loudest at normal driving speed, when not pulling or decelerating. Correct by adjusting bearing clearance to .001 to .0015 inches. If knock is excessive, crank should be checked for out of roundness. May need to re-pour all main bearings to correct.
5. TIMING GEAR KNOCK: usually the most difficult to diagnose. If gear is loose or badly worn it will knock in all ranges. Run engine slightly above idle speed. Slowly open and close throttle. Knock will continue to be present, but just as engine slows down knock will become a slight rattle. Remove timing pin and reinsert into timing hole on timing gear cover. Press timing pin tightly against timing gear and accelerate slightly above idle. Knock will significantly be reduced or disappear. Correct by replacing both timing gear and crank gear as a matched set. The two gears should have a backlash clearance of .003 to .004. If more than .009 inch backlash, an oversize (.005) timing gear should be installed.
6. WRIST PIN SLAP: This can not be detected by shorting out the cylinder plugs. Rapidly accelerate and decelerate the engine speed. The engine will pass through a certain speed range when the wrist pin will rattle at about the same pitch as a valve tappet noise. This can be corrected by installing a new wrist pin bushing in the rod or new wrist pin f badly worn. Wrist pin should fit the piston and connecting rod with a tight metal to metal fit. The pin can be pushed into the piston and rod with a slight pressure of the hand. Pin to rod clearance is .0003 to .0005 inches.
A KNOCKING SOUND IN THE ENGINE IS MOST LIKELY CAUSED BY ONE OF THE FOLLOWING
1. PISTON SLAP: Makes a sharp metallic noise. Idle engine and short out each cylinder plug. The noise will disappear when plug with bad piston is shorted. Noise will also disappear at acceleration. This can be caused by worn or out of round cylinder, or broken piston ring. Correct problem by re-boring cylinder and/or replacing piston.
2. VALVE NOISE: Makes clicking or rattle noise. Caused by excessive wear on valve stem or lifter, out of adjustment, or stuck valve. Correct by adjusting valve clearance, replace worn valve or lifter, regrind cam, replace valve guide and /or valve. A stuck valve can sometimes be loosened by passing oil through the carburetor while engine is running.
3. ROD BEARING KNOCK: Makes sharp metallic noise similar to a piston slap. Detection is opposite of piston slap. Rod knock is not heard at idle. Knock becomes louder as engine speed is increased. Caused by excessive rod bearing clearance. Correct by adjusting rod bearing clearance to .0015 inches by removing shims. May require re-pouring rod bearing.
4. REAR MAIN BEARING KNOCK: Makes dull knocking or thud noise. Detected at speeds between 20 and 50 MPH. Knock will normally decrease or disappear while pulling or decelerating. Noise will be detected the loudest at normal driving speed, when not pulling or decelerating. Correct by adjusting bearing clearance to .001 to .0015 inches. If knock is excessive, crank should be checked for out of roundness. May need to re-pour all main bearings to correct.
5. TIMING GEAR KNOCK: usually the most difficult to diagnose. If gear is loose or badly worn it will knock in all ranges. Run engine slightly above idle speed. Slowly open and close throttle. Knock will continue to be present, but just as engine slows down knock will become a slight rattle. Remove timing pin and reinsert into timing hole on timing gear cover. Press timing pin tightly against timing gear and accelerate slightly above idle. Knock will significantly be reduced or disappear. Correct by replacing both timing gear and crank gear as a matched set. The two gears should have a backlash clearance of .003 to .004. If more than .009 inch backlash, an oversize (.005) timing gear should be installed.
6. WRIST PIN SLAP: This can not be detected by shorting out the cylinder plugs. Rapidly accelerate and decelerate the engine speed. The engine will pass through a certain speed range when the wrist pin will rattle at about the same pitch as a valve tappet noise. This can be corrected by installing a new wrist pin bushing in the rod or new wrist pin f badly worn. Wrist pin should fit the piston and connecting rod with a tight metal to metal fit. The pin can be pushed into the piston and rod with a slight pressure of the hand. Pin to rod clearance is .0003 to .0005 inches.
Hi :) Well it could be that you have blowen a timing chain and the pistons are hitting the valves or a connecting rod has broke and is banging agaist the inside of the block.
is the loud knocking sound coming from the top section, or the bottom section of the engine, if it's from the bottom, it could be a connecting rod, that is going bad, also if it's from the top of the engine, could be in the rocker arm assembley, this is where your valve spring, rockers, and retainers, and tips of valves are located, also have someone to see if the knock sensor is bad, normally , these are located not to far from the crankshaft pulley up from the bottom of engine.
After it's warmed up to operating temp, if it makes the noise at idle but goes away reving the engine, I would guess that a lifter has gone bad. Rod bearings as a rule knock all the time. It's hard to diagnose these things over the internet, because there are so many variables when it comes to noises.
You need to warm the car up and then while it is running, open the hood and try to pinpoint the source. lifter noise will sound like a "tick" and come from somewhere near the top. Rod bearings will sound like a 'knock" and will come from the bottom of the engine.
please check for bad fan! is it leaking any fluid at all? the radiator fan may have a bad clutch on it. it needs to be checked!! the fan relay in black box under the hood may be faulty also. it should not be getting hot! this can and will cause engine damage! the knocking sound you heaqr are your engine valves and your engine rods knocking! [number#1 check for bad engine fan #2 check for bad water pump, number#3 check for blockage of coolant to your engine. this could cost you an engine!! not to be looked over. hope this advice saves your motor and alot of money! merry christmas from me and mine to you and yours!
If the engine knock is coming from deep inside the engine, the I agree, the rod is knocking. If the sound is coming from closer to the top, it could be a valve lifter or push rod you are hearing. This isn't as bad, they last longer and synthetic oil or oil treatment helps. If this doesn't happen all the time, if it's occasional or you hear a pinging noise, you could just have a bad knock sensor.
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