Mitsubishi engine tap/tick
Discussion
Bit of a strange one this-
I've had my Mirage Asti ZR for about 4 months now...in the last month I've had a ticking/tapping sound develop, and I'm a little mystified about it.
The car performs great, and MIVEC kicks in exactly as it should, no other issues.
When warmed up, i get a pronounced ticking/tapping, that comes in at exactly 1600RPM, and is audible until about 3k RPM, where it either stops, or the noise is drowned out (couldn't say which). The noise increases in speed with engine RPM, however it doesn't get louder. It doesn't sound like a heavy knock or metallic. If i listen to the engine it sounds like its coming from the intake manifold area.
The tapping is there,but not that audible at idle, and the car is idling normally. It's a very pronounced noise from inside the cabin at about 2k rpm, sounds like im driving a sewing machine!
Car has had a full service from top to bottom, plugs/leads/oil/filter etc etc, it has also had the valve clearances done. The noise used to be very intermittent (would tap for a few seconds then go, occasionally), but is now constant when the car is warmed up. It was stood for a couple months before I bought it, and not used that much prior to that...since i've had it I've been driving it regularly, and really made an effort to make sure everything has been fully serviced, and I drive it to it's potential, but only when warm...it pulls brilliantly and has really started to run well and pull better as i've had various things serviced.
My mechanic has listened to it, and says it doesn't sound like anything "engine critical", but the noise is quite pronounced, if it's something relatively simple, it would be great to get rid. He wondered if it's just a characteristic of the engine, but i'm not convinced.
Summary-
-warm engine tick/tap, from 1600rpm upward
-tapping increases in speed with engine rpm, but doesn't get louder
-sounds like its coming from intake manifold area, but hard to tell if this is the source.
-car otherwise in good health
any thoughts? I appreciate diagnosing this stuff online can be tricky.
I've had my Mirage Asti ZR for about 4 months now...in the last month I've had a ticking/tapping sound develop, and I'm a little mystified about it.
The car performs great, and MIVEC kicks in exactly as it should, no other issues.
When warmed up, i get a pronounced ticking/tapping, that comes in at exactly 1600RPM, and is audible until about 3k RPM, where it either stops, or the noise is drowned out (couldn't say which). The noise increases in speed with engine RPM, however it doesn't get louder. It doesn't sound like a heavy knock or metallic. If i listen to the engine it sounds like its coming from the intake manifold area.
The tapping is there,but not that audible at idle, and the car is idling normally. It's a very pronounced noise from inside the cabin at about 2k rpm, sounds like im driving a sewing machine!
Car has had a full service from top to bottom, plugs/leads/oil/filter etc etc, it has also had the valve clearances done. The noise used to be very intermittent (would tap for a few seconds then go, occasionally), but is now constant when the car is warmed up. It was stood for a couple months before I bought it, and not used that much prior to that...since i've had it I've been driving it regularly, and really made an effort to make sure everything has been fully serviced, and I drive it to it's potential, but only when warm...it pulls brilliantly and has really started to run well and pull better as i've had various things serviced.
My mechanic has listened to it, and says it doesn't sound like anything "engine critical", but the noise is quite pronounced, if it's something relatively simple, it would be great to get rid. He wondered if it's just a characteristic of the engine, but i'm not convinced.
Summary-
-warm engine tick/tap, from 1600rpm upward
-tapping increases in speed with engine rpm, but doesn't get louder
-sounds like its coming from intake manifold area, but hard to tell if this is the source.
-car otherwise in good health
any thoughts? I appreciate diagnosing this stuff online can be tricky.
I could be (and most probably are) way off the mark here, but the 4G63t in the Evo taps now and again like you describe.
Mine would tend to start to tick when the service was due (every six months) and changing the oil used to solve it.
However, one service the ticking stayed and I eventually narrowed it down to the hydraulic tappets.
After all sixteen were removed, cleaned in paraffin and refitted, the ticking stopped for a few years.
It was quite an easy job to do with an average toolkit so would be my first point of call.
Mine would tend to start to tick when the service was due (every six months) and changing the oil used to solve it.
However, one service the ticking stayed and I eventually narrowed it down to the hydraulic tappets.
After all sixteen were removed, cleaned in paraffin and refitted, the ticking stopped for a few years.
It was quite an easy job to do with an average toolkit so would be my first point of call.
yeah i've heard the lifter tick is common in mitsis.
The tappets in my 4G92 are mechanically adjusted rather than hydraulic, they were slightly out when my mechanic did them...he seems a competent fella, so pretty sure he adjusted them correctly, and i got the clearances from the engine manual, so unless he royally messed up the adjustments, they should be correct.
also i would have thought if the tappets were out of adjustment it would be ticking at idle from cold too?
The tappets in my 4G92 are mechanically adjusted rather than hydraulic, they were slightly out when my mechanic did them...he seems a competent fella, so pretty sure he adjusted them correctly, and i got the clearances from the engine manual, so unless he royally messed up the adjustments, they should be correct.
also i would have thought if the tappets were out of adjustment it would be ticking at idle from cold too?
designforlife said:
yeah i've heard the lifter tick is common in mitsis.
The tappets in my 4G92 are mechanically adjusted rather than hydraulic, they were slightly out when my mechanic did them...he seems a competent fella, so pretty sure he adjusted them correctly, and i got the clearances from the engine manual, so unless he royally messed up the adjustments, they should be correct.
also i would have thought if the tappets were out of adjustment it would be ticking at idle from cold too?
Ah, it won't be my problem if you've got normal tappets.The tappets in my 4G92 are mechanically adjusted rather than hydraulic, they were slightly out when my mechanic did them...he seems a competent fella, so pretty sure he adjusted them correctly, and i got the clearances from the engine manual, so unless he royally messed up the adjustments, they should be correct.
also i would have thought if the tappets were out of adjustment it would be ticking at idle from cold too?
Good suggestion above regarding the exhaust.
You don't say whether the noise started before or after the valve clearances were adjusted however it's very likely to be a problem in that area. Google seems to think this engine has rockers with locknuts like old A and B series Leyland engines or Ford Crossflows. Either there's wear in a rocker bush or shaft, cam lobe, rocker tip or valve tip or the tappet clearances are still not right.
Pumaracing said:
You don't say whether the noise started before or after the valve clearances were adjusted however it's very likely to be a problem in that area. Google seems to think this engine has rockers with locknuts like old A and B series Leyland engines or Ford Crossflows. Either there's wear in a rocker bush or shaft, cam lobe, rocker tip or valve tip or the tappet clearances are still not right.
thats a hard one to call, i mean i noticed after the valve clearances were done, but i'm not sure if that's because I was actively listening and expecting them to be quieter, I remember thinking before they were done, that I needed to get the clearances checked because there was a bit of valve train noise.whether its worse, or the same as before, I couldn't say with certainty...however it's definitely very noticeable when warm, after a 20 minute drive.
I've got the car booked in to have a throrough look at and some tests done, getting the clearances checked again will no doubt feature in this.
Booked in on the 9th of Feb, so I'll update the thread after that...fingers crossed it's nothing too bad, finding another 4g92 engine wouldn't be easy.
If the noise was as bad as you say it is now before the clearances were done then I think you would have noticed it more. However our memories play tricks on us. Logic says it's almost certainly because the mechanic messed the clearances up. Google seems to think they need doing when the engine is hot. That's not easy because engines cool so much by the time you've got the bits apart. Get him to do it again.
generally accepted wisdom on the 4g92 engine from what i've read, is that the engine needs to be overnight stone cold when the clearances are done...now i think on it, i had driven the car up from surrey that morning, and it had sat maybe 4 hours before mechanic started on it, so was probably still warm, albeit not hot.
I admit, reading all this back, it does sound like all of the tappets are slightly out. the given engine clearances in the 4g92 workshop manual are stated as cold.
I guess it exhibiting when warm would indicate they've been done slightly too tight, so are noisy when warm when everything has expanded a bit?
I admit, reading all this back, it does sound like all of the tappets are slightly out. the given engine clearances in the 4g92 workshop manual are stated as cold.
I guess it exhibiting when warm would indicate they've been done slightly too tight, so are noisy when warm when everything has expanded a bit?
designforlife said:
I guess it exhibiting when warm would indicate they've been done slightly too tight, so are noisy when warm when everything has expanded a bit?
Almost certainly the exact opposite. The way valve clearances change as the engine warms up depends on the relative expansion of all the parts concerned and varies from engine to engine. In your case, if Google has found the right pics for me, the cam and rocker won't get hot enough to change much. The aluminium cylinder head will expand taking the cam further away from the valve head but the valve stem will expand too reducing this back down again. Most likely is that clearances decrease a bit with the engine hot, especially on the exhaust valves. However it's probably not a big effect and also probably not that important just how hot the engine is when the clearances are set. More likely is wear in some component is making the clearance setting tricky, or just that the mechanic messed it up. Mechanics do that!Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff