Well I've done done quite a few totally trouble free miles since my camshaft seal replacement etc and all has been perfect....until now. Last night I notice a strange squeek from the engine as I turned it off and it was milling down. To cut the story short I pulled the water pump and alternator belt and pulled the fuel relay then cranked the engine, the noise persisted. When the engine is cold it is fine and all is fine when the engine is running. Anyway the video speaks 1001 words so please have a look and let me know what you think because I am really stumped with this one and I don't feel to good about it. https://www.youtube.com/watch?v=eYrgb7_jq9s&feature=youtu.be All the best, Bell
Any help would be greatly recieved.. https://www.ferrarichat.com/forum/308-328/449992-bad-mystery-engine-noise.html Regards Bell.
Let me start by saying I am entirely unqualified - relative to the serious techs on this forum - to diagnose an engine problem like this one. HOWEVER, I had this exact sound from my jeep engine twice in the past two years. Once was the a/c compressor was failing and the pulley was seizing, causing the belt to squeak against it. Another time, same sound, was a drive pulley. I only mention this by way of saying, see if any pulleys are seizing. Perhaps the engine is pulling strong enough at high speeds to keep them spinning, but - at lower speeds - they're quasi-seizing again. Total stab in the dark, but happened on my jeep. Nearly identical sound.
Bell, can't be good at all, try taking off the cambelt covers and examine the belts. I'm sure the TDC marks are correct but maybe verify them again? Start the car without having the accessory belts on and see if you here the noise better with just the crank shaft turning with starter. This one is over my head. PS, I would give Dave Helms a call if you have exhausted options. Best, Mike
Bell This same noise while cranking: I had with a VM Motori diesel engine a week or 2 ago. The engine ran dry on coolant. The sound came from the warped cylinderheads who lost compression back through the air filter and through head gasket. It's a sort of compression blow of sound. Last week i went to Camberley to get a new engine, which they assembled wrongly. Did you measure compression on all cyl? Does she still fires up? ( on the vid she isn't) O dear big troubles in little Italy.....
Yes Bart, all compressions good on that side where the noise seems to be coming from, noise persists even with plugs out that side. No belts on car at all only cambelts and no noise from sproket drive bearings or tensioners. Engine runs perfectly, Just that noise on hot cranking.
You measured only 1 bank? I work regularely with a stethoscope, and they are pretty solid on backtracking engine noises (bearings and stuff), but are you sure all 8 cyls are ok? Do tou feel a sort of backdraft in the intakechannel (airfilter)
Yes I felt that the noise was coming louder from the rear bank so left the front alone for now I haven't felt the suction from the air filter but the engine runs sweet, all guages normal, idle is smooth. No changes when I depress the clutch.
The noise is a relatively slow pulse so my guess is that its maybe related to one piston/cylinder or set of valves rather than anything rotational (camshaft etc). Does it still make the noise if you crank it with the plugs out (i.e. zero compression) ?
I suppose if you took all the cams (and plugs) out & cranked it you'd then know whether it has anything to do with anything in the heads or whether its in the short block....
Iain :I suppose if you took all the cams (and plugs) out & cranked it you'd then know whether it has anything to do with anything in the heads or whether its in the short block.. Jessup: I thought that too, but if it only does it hot. You better be fast at pulling cams! Yes I had thought that but I really don't want to go there just yet when it might be something....Simple...Bloody hell I'm hopeing. And no way can I pitstop change cams ha ha I still feel it's some kind of oil starvation to a cam because although they are rotating as you said, they are under an irregular loading and it kind of sounds like a multi squeek, not just a single piston going up and down. I might put the cams and belt back on and see how quick the oil comes out of the journals as I crank the engine. ie are those oil ways really clear or is there a partial blockage. Hmm I just don't know.. Hot Idle Oil Pressure is good
Its a bit loud for this but.. seal squeal? You could try squirting WD40 onto the cam seals and see if it stops. What about something in the bell housing rubbing on the ring gear? Crank sensor rubbing? Or is the noise definitely from the top end?
Crazy thought. Some have reported noise from oil cooler usually while cool but none the less a source of noise. Perhaps this is a pulse of oil vs trapped air in the lines/oil cooler. I refer you to this thread: http://www.ferrarichat.com/forum/showthread.php?t=444119 It is close to the side you feel the noise is coming from. When all else fails read the damn manual. - wife
Did you put all the cam shaft caps back in the right order, and in the right orientation? Is there oil starvation under one of those cam shaft, or caps? Did you use any silicon as gasket dressing?
Did you replace all injector seals? Perhaps an injector seal that loses air in compression phase? Have you got a endoscope (you can borrow) to take a peak inside?
Maybe there a possibility its something external to the engine such as exhaust mount which is being transmitted back, maybe try grabbing the engine and rock it back and forward on its mountings, see if the noise happens.
Bell, how are the journals on the cam and on the caps, any sign of scoring, heat, or oil starvation? Next did you pull out those shim buckets and check for the same thing? Also you can try and blow compress air into those oil galleys just to make sure there are no blockage of some kind.
Hi Crowndog, yes I too have heard about the oil cooler noise issue and checked for that and nothing. MNExotics, cap and rotor look fine although the seal was leaking a bit but I knew about that. All injector seals checked and not leaking Bart. Andy, true there could be something rubbing on the flywheel, a loose bolt, it's possible. Sound does conduct in odd ways but it still sounds like a cam to me even though there is no damage to them. Yelcab, yes all cam caps in right order checked and double checked even did a video. Yes I used smallest amount of silicone dressing but I'm very careful only to apply to the outer 1/3 rd of the joint thus no material at all can enter the engine when torqued down. Removal of the covers confirmed this. OIL STARVATION TO CAMS. You raised this and I have to and I'm still on this as a possible. Q1. Why does it only happen when hot cranking? Q2. Why has it only happened since I changed the oil 3 days ago? I've had the car a year, oil in car was new but don't know the spec. New Oil is Mobil 2000 10w-40W semi synthetic. Q3. Why does noise persist on cranking but goes when running. Q4. Why does removal of the plugs have no effect on the sound. MY THEORY 'so far': I think it's oil starvation to the cams, even though I can find no damage to them, Reason? Answer? Q1. Is that the oil pressure has dropped due to hot oil so now hot cranking oil pressure is lower than cold. Answer? Q2. Is the new oil is thinner when hot than the old 'unknown' oil, thus the new oil lubricates less well in areas of 'possible' oil starvation. Answer? Q3. The noise goes once the engine is running because the increase in oil pressure tips the ballance and the cams get just enough lubrication to stop them failing. Answer? Q4. Removal of plugs with no change would indicate that the short engine is fine. Other Things Found: Bits of very old gasket sealer in the oil when I drained the old oil. Removal of the oil filter housing revealed 'concerning' amounts of sealer on the gasket. This I believe is a direct oil pipeline into the heart of the engine. However the internal 'bead' of sealer did look intact and so to be sure I removed it to stop future possible ingress into the oil system. However where else has this previous mechanic been with his gasket sealer? This is pure theory on my part, so please challenge it guys, data and arguement are most welcome. All the best, Bell Bloke. PS. Mike, I'm just off to do that now, my next port of call.
I would have thought a tight bearing is more likely than oil starvation. Not sure if this would cause visible damage. When oil pressure builds up during running it probably masks the problem. If a cam journal and bearing is absolutely mirror-smooth this might be an indication. This would vary with oil viscosity too. What about replacing the cams with all oil cleaned off, turn the engine to non-TDC and see if the "feel" of the cams is right when rotating them? Maybe one is slightly tighter than the other. If so you could loosen each cap in turn. Not sure how this would have happened simply by removing/replacing the cams though unless one was loose before and was line-bored in a loose state. Is the repetition rate of the noise equal to crankshaft or camshaft speed?
