Lateral play in cam pulley / knocking sound on idle
15 February 2018, 04:37 PM
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Lateral play in cam pulley / knocking sound on idle
Hi all,
i have a 55plate WRX with PPP, but no real mods. 70k, full Subaru history.
recently changed cambelt and all pulleys, and noticed a small amount of fwd/back play in main pulley on the driver’s side. It’s minimal, a mm or 2 but can feel it if I hold pulley and pull fore and back.
there is no play in the same pulley on passenger side.
it starts and runs fine, from what we can test - bit of a ticking or knocking noise from somewhere around that side for first 10-15secs after starting (maybe just new belt bedding in? Has not been started for 2 months until this week) then goes quiet, but not had chance to run it properly or get car warm as Rads are off at the moment so no cooling.
should I build it all up and see, or should I be looking at possible issues now before it is driving again?
Someone was talking to me about camshaft endfloat but I cannot find any info online, and I am no mechanic!
thanks!
i have a 55plate WRX with PPP, but no real mods. 70k, full Subaru history.
recently changed cambelt and all pulleys, and noticed a small amount of fwd/back play in main pulley on the driver’s side. It’s minimal, a mm or 2 but can feel it if I hold pulley and pull fore and back.
there is no play in the same pulley on passenger side.
it starts and runs fine, from what we can test - bit of a ticking or knocking noise from somewhere around that side for first 10-15secs after starting (maybe just new belt bedding in? Has not been started for 2 months until this week) then goes quiet, but not had chance to run it properly or get car warm as Rads are off at the moment so no cooling.
should I build it all up and see, or should I be looking at possible issues now before it is driving again?
Someone was talking to me about camshaft endfloat but I cannot find any info online, and I am no mechanic!
thanks!
Last edited by Tronco; 16 February 2018 at 08:05 AM.
15 February 2018, 04:42 PM
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Should add, it took a knock to the front right, and I have been repairing since that, hence rads off etc. and took it as opportune moment to replace cambelt.
sadly did not check if that play was there before changing the belt and puleys
sadly did not check if that play was there before changing the belt and puleys
15 February 2018, 09:00 PM
#3
You can get a bit of end float on the cams depending on mileage,previous engine failure etc but if it's had a knock on that side, it may have broken one of the thrust control faces on the camshaft or if someone has whacked the cam pulley bolt to loosen it, it will break the thrust face too.
Mick
Mick
16 February 2018, 07:57 AM
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Thanks - it did take the knock around that area.
i have run it now, wit rads back in and there is a steady knock coming from somewhere around that side of the engine - although not from exactly where the pulley is (seems further back into engine, and higher up?) and only present at idle, disappears when revved.
i have a video of the noise - not sure how to upload it tho?
The knock is regular, distinct but not loud, about 4 beats per second.
i have run it now, wit rads back in and there is a steady knock coming from somewhere around that side of the engine - although not from exactly where the pulley is (seems further back into engine, and higher up?) and only present at idle, disappears when revved.
i have a video of the noise - not sure how to upload it tho?
The knock is regular, distinct but not loud, about 4 beats per second.
16 February 2018, 11:26 AM
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More info.
I called a specialist (Paul Finch) and had some time on the phone with him. Could be a whole list of things....... piston slap, cambelt tensioner issues (he has seen quality issues with Gates cambelt kits, dodgy tensioners or something), tappet sticking, camshaft endfloat plate broken (is this the same as thrust control face mentioned above by Merlin24?) although Paul said he'd expect camshaft to jam up if that happened.
Long and short of it is, as it goes quiet with any revs, and has not been run for a while (and what is there to loose - it either needs repairing or not, and if I drive it, it will still either need repairing, or not!) I should try getting up to temp, under load - put a few miles behind it - and see what occurs!
I called a specialist (Paul Finch) and had some time on the phone with him. Could be a whole list of things....... piston slap, cambelt tensioner issues (he has seen quality issues with Gates cambelt kits, dodgy tensioners or something), tappet sticking, camshaft endfloat plate broken (is this the same as thrust control face mentioned above by Merlin24?) although Paul said he'd expect camshaft to jam up if that happened.
Long and short of it is, as it goes quiet with any revs, and has not been run for a while (and what is there to loose - it either needs repairing or not, and if I drive it, it will still either need repairing, or not!) I should try getting up to temp, under load - put a few miles behind it - and see what occurs!
16 February 2018, 10:24 PM
#6
IIRC, the maximum cam endfloat is around 0.005~0.006" (0.12~0.15 mm) and Valvetrain noise will generally be heard/occur half engine rotation speed and more of a tick in most cases ( not to be confused with Injector tick/exhaust gas leak from headers or up-pipe/loose spark plugs ).
Causes of a knocking could be :
Piston slap from cold.
Cambelt Tesioner knock.
Front pulley loose/keyway worn.
Crank endfloat/clutch noise (press the clutch to see if the noise changes).
Does the oil pressure warning light go out straight away on starting ?
Mick
Causes of a knocking could be :
Piston slap from cold.
Cambelt Tesioner knock.
Front pulley loose/keyway worn.
Crank endfloat/clutch noise (press the clutch to see if the noise changes).
Does the oil pressure warning light go out straight away on starting ?
Mick
17 February 2018, 04:13 PM
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Thanks Merlín.
It does seem to be a knock on the half-rotation of the engine. It has the the normal sort of higher pitch injection ticking in the background, then this deeper-sounding knock at half that tempo.
It goes away immediately on revs, comes back only at idle - and we think it quiets off at idle when engine is warmer, but have only had rads on and coolant in it late this week, and front wheels and bumper are off so not tested properly warm.
It'll be back together next week and can run through the above:
Oil light on starting
Check clutch operation/change of sound.
Any change when properly warmed/driven.
Sound seems to be further back than cambelt so not sure on tensioner, and it is new but suppose could be an install issue - how would I check.... cover off (rads out again then!) and watch it spinning?
Was also thinking if I dropped oil out of it, put it through a fine cloth and checked for any bits of anything - guess this would point toward something broken around cam (thrust plate etc.?) would it?
Engine was flushed and new oil & filter only a few days before the bump, so it should be pristine.
I spoke to Paul Finch of Finch Motorsport, who echoes your thoughts, Merlín. He said poss piston slap, endfloat plate, tappet sticking, etc. and suggested get it on the road, up to temp and under load (put some miles on it) and see what occurs.
It does seem to be a knock on the half-rotation of the engine. It has the the normal sort of higher pitch injection ticking in the background, then this deeper-sounding knock at half that tempo.
It goes away immediately on revs, comes back only at idle - and we think it quiets off at idle when engine is warmer, but have only had rads on and coolant in it late this week, and front wheels and bumper are off so not tested properly warm.
It'll be back together next week and can run through the above:
Oil light on starting
Check clutch operation/change of sound.
Any change when properly warmed/driven.
Sound seems to be further back than cambelt so not sure on tensioner, and it is new but suppose could be an install issue - how would I check.... cover off (rads out again then!) and watch it spinning?
Was also thinking if I dropped oil out of it, put it through a fine cloth and checked for any bits of anything - guess this would point toward something broken around cam (thrust plate etc.?) would it?
Engine was flushed and new oil & filter only a few days before the bump, so it should be pristine.
I spoke to Paul Finch of Finch Motorsport, who echoes your thoughts, Merlín. He said poss piston slap, endfloat plate, tappet sticking, etc. and suggested get it on the road, up to temp and under load (put some miles on it) and see what occurs.
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17 February 2018, 05:34 PM
#8
If it has got a broken thrust face on the camshaft, the broken piece will normally sit on the windage tray on the bottom of the engine and not work it's way into the bottom of the sump pan.
It's quite possible it's the new tensioner, depends which way up it has been stored prior to fitting - I always put a new tensioner on the hydraulic press, pull the pin and press it through it's stroke a couple of times prior to fitting.
It might be worth whipping the left hand (passenger side) cover off again, run the engine and use a stethoscope or long screwdriver to listen to the tensioner - the noise will be quite pronounced if it is.
Hopefully something simple
Mick
It's quite possible it's the new tensioner, depends which way up it has been stored prior to fitting - I always put a new tensioner on the hydraulic press, pull the pin and press it through it's stroke a couple of times prior to fitting.
It might be worth whipping the left hand (passenger side) cover off again, run the engine and use a stethoscope or long screwdriver to listen to the tensioner - the noise will be quite pronounced if it is.
Hopefully something simple
Mick
02 March 2018, 12:11 PM
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So, checked cambelt and pulleys - the play is no longer there in the pulley (odd!) but nonissue with tensioner or anything.
Stuck a long screwdriver onto the rocker cover of the passenger side - can definitely hear the knock from in there. Drove it a mile or so, noise goes on driving, once revs get up. Creeps back on idle but not so loud.
Someone said stuck hydraulic lifter? I'm lost. Going to do some miles this weekend and see what happens, as it has not been run properly for months.
If it blows up, I'll let you know
Stuck a long screwdriver onto the rocker cover of the passenger side - can definitely hear the knock from in there. Drove it a mile or so, noise goes on driving, once revs get up. Creeps back on idle but not so loud.
Someone said stuck hydraulic lifter? I'm lost. Going to do some miles this weekend and see what happens, as it has not been run properly for months.
If it blows up, I'll let you know
07 March 2018, 06:02 PM
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Thanks Mick.
Ran it, knock is intermittent (or at least varies in volume) but am getting some oil smoke after about 15 miles, from engine bay low down.
I think it is the cam cover gasket (?) leaking oil out onto the exhaust.... (at least that is what I was told by somebody smarter than me!) so have stopped running it and am going to get the engine stripped down and investigate in depth.
I've decided that whilst I'm there, I'll look at some "improvements".... not sure what yet, but my vague aim is to put an improved engine back in..... try to get some longevity, reliability and maybe a bit more fun out of it.
Any "must do" improvements on a decent foundation of an engine that you'd recommend? Better camshafts? (Think I'll be replacing one anyway)
I'm meeting with the mechanic tomorrow to see what he thinks
Ran it, knock is intermittent (or at least varies in volume) but am getting some oil smoke after about 15 miles, from engine bay low down.
I think it is the cam cover gasket (?) leaking oil out onto the exhaust.... (at least that is what I was told by somebody smarter than me!) so have stopped running it and am going to get the engine stripped down and investigate in depth.
I've decided that whilst I'm there, I'll look at some "improvements".... not sure what yet, but my vague aim is to put an improved engine back in..... try to get some longevity, reliability and maybe a bit more fun out of it.
Any "must do" improvements on a decent foundation of an engine that you'd recommend? Better camshafts? (Think I'll be replacing one anyway)
I'm meeting with the mechanic tomorrow to see what he thinks
08 March 2018, 01:59 PM
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Ok - broken camshaft! As predicted Mick, thrust face has broken.
Anyone know if I can get a replacement quick-ish? Awaiting quote back from Roger Clarke but if I could source a good used one... even better. Tried eBay and some online import places, but no 05 WRX cams.
Anyone know if I can get a replacement quick-ish? Awaiting quote back from Roger Clarke but if I could source a good used one... even better. Tried eBay and some online import places, but no 05 WRX cams.
Last edited by Tronco; 08 March 2018 at 02:05 PM.
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