Please help, my vn is in trouble, really loud knocking noise

[vks]

hey all i started my vn this morning to warm it up as usuall and when she settled down to idle i discoverd one of the lifters was making noise i thought id leave it to warm up and see what happens, i went inside to get my wallet when i came back she was making a really loud knocking sound, sort of resembeling the sound of a diesel, i opend the bonnet again and the sound was coming from the same bank as where the lifter was making noise earlier,before i turned it off i checked if the engine ligth was on but it wasnt, i turned it off to prevent any furthur damage if there is any, can anyone please help me, your posts would be much appreciated

vks

[redcedar]

sounds nasty!!!!!!!!!!!!!!!!

[CSL]

take off your rocket cover and have a squiz at your rockers, check the springs for damage cracks breaking,
does it miss a cylinder???

[vks]

no its not missing, iv got the rocker covers off now no sign of bent pushrods or damaged springs, im takin the intake off now so ill keep you informed

thanks guys

[Shortstuff]

I had that happen on one of my old cars. It ran fine one moment, then sounded like a bag of nails the next. Never misfired though. It only happened twice while I owned it, but was REALLY noisy and did sound a bit like a diesel. Luckily I worked at a Garage at the time, and a mechanic looked at it and told me it was a noisy tappet.

[CSL]

either a tappet has bent/broken, or it could be your flywheel has let go does it sound like marbles? or more muffled knock sound???

[pandaman]

My first suggestion would be the same as CSL, take the rocker cover off on that bank and check if all your rockers are firmly attached. If the rocker gear is fine and it's still doing it there are a number of possibilities especially if it's a muffled knocking sound, as CSL also mentioned flywheel is one of them. Another fairly disturbing possibility is a dead bigend bearing or two can be indicated by a muffled knock, although they tend to start clunking a bit higher up through the revrange if memory serves. Anyway don't mean to alarm with all this talk of major failure, could also be something dead simple. If you check your rockers then report back I'm sure we can throw round some more ideas once you've got some more intel on the situation.

[Stevob]

err, check oil level first.

[pandaman]

err, check oil level first.

ahhh, but everyone is doing this on at least a weekly basis right guys? Not keeping an eye on the fluid levels in an old car is asking for trouble.

[Stevob]

ahhh, but everyone is doing this on at least a weekly basis right guys? Not keeping an eye on the fluid levels in an old car is asking for trouble.

I check my oil every 3 minutes...just to be sure.

[pandaman]

I check my oil every 3 minutes...just to be sure.

Lol, the old paranoia eh? On my old car I used to check it every day because I knew the rear main seal was on the way out, I lived in dread that one morning I'd check it and it would have dumped the lot on the driveway.

[Stevob]

Nah, even if I was that paranoid and I could easily open the bonnet by myself, I still wouldn't check it that often. My car uses about 1 litre every 20,000km.

Btw, every time I need to open the bonnet by myself, I have to get out a jumper lead, tie a knot in it, loop it over the bonnet release handle, pull until tight, keep tension on it as I go around the door, lean over and whack the front of the bonnet so it pops up. Quite a funny sight.

[xcop5l]

check your harmonic balance the v6s are prone for the rubber coming unstuck. they make one hell of a knocking noise. just grab on to it and turn it if it turns then goes tight thats your prob.

[Don Sutton]

hey all i started my vn this morning to warm it up as usuall and when she settled down to idle i discoverd one of the lifters was making noise i thought id leave it to warm up and see what happens, i went inside to get my wallet when i came back she was making a really loud knocking sound, sort of resembeling the sound of a diesel, i opend the bonnet again and the sound was coming from the same bank as where the lifter was making noise earlier,before i turned it off i checked if the engine ligth was on but it wasnt, i turned it off to prevent any furthur damage if there is any, can anyone please help me, your posts would be much appreciated

vks

If it's an auto it might be the torque convertor drive plate cracked. If you stop the engine and restart does it still make identical noise? As you say it is a knocking noise rather than a tapping sound I think it is less likely to be a tappet unless the valve is stuck open hitting the piston in which case it would be missfiring. Your later post says it is not missfiring so points back to either bigend or piston unless it is the torque convertor web plate. Torsional knocks can be caused by loose crankshaft pulleys/harmonic balancer and the noise changes characteristic when loaded or reved slightly. Big end and piston get noisier when reved or loaded. Use a piece of plastic tube or long screwdriver to try and pinpoint the location by putting one end to your ear and the other to various locations around the engine and see where noise is loudest.

[vks]

Hey guys i pulled the heads off, there were no valve springs damaged, no bent pushrods. I was shocked to find a screw inside the cylinder just floating around, i have no idea how it got there since i have never pulled the engine apart until now. The only possible thing i can think of is that i ran the car without an airfilter in the airbox once,maby the screw got sucked up through the throttle body. I have no idea but the problem is sorted now thanks guys for all ur posts. i really appreciate it

vks

[Don Sutton]

Hey guys i pulled the heads off, there were no valve springs damaged, no bent pushrods. I was shocked to find a screw inside the cylinder just floating around, i have no idea how it got there since i have never pulled the engine apart until now. The only possible thing i can think of is that i ran the car without an airfilter in the airbox once,maby the screw got sucked up through the throttle body. I have no idea but the problem is sorted now thanks guys for all ur posts. i really appreciate it

vks

So what youre saying is your engine was screwed!

[vks]

lol pretty much, i gave aveything a clean new gaskets the lot, put it back together and it runs sweet now, so its all gud

[vks]

thanks everyone heaps for your replies much appreciated

vks