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    Too many posts! JohnW's Avatar
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    Default CX camshaft problem

    Folk, or those with more CX experience than I have, please advise.

    The lovely CX is repeatedly developing one very noisy tappet (within 1,000 km of adjustment). I'm smelling a cam follower - camshaft lobe problem.

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    I have a reground camshaft and a set of refaced cam followers that came with the car 10 years ago or thereabouts.

    Would you use them or buy new?

    Any comments welcome.

    For the record, the 123 distributor is fantastic.

    Thanks
    JohnW

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    Too many posts! JohnW's Avatar
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    Bump!

    Come on folk please, someone must have a view on this?

    Cheers
    JohnW

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    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
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    Fellow Frogger! Rob T's Avatar
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    OK. My opinion only.

    If the valve clearance doesn't change (much) over time, I'd leave it alone. Just keep driving and enjoying. You know that if you pull the engine to just change the cam shaft, it will balloon into a "and I'll just fix that while I'm at it" job.

    My experience...

    My (recently sold) CX always had a noisy tappet. I checked and adjusted many times - but did it less over the years as I came to believe that it wasn't a portent of failure. It was never out by more than a few thou. It was my daily driver for about 15 years. So it was a high mileage car, but it had the same compression figures for the 15 years that I owned it. The timing chain would also rattle. Given that it spent much of its working life driving A/C (that actually worked - sort of), I assumed that the timing chain would be on its last legs. So last time the engine was out (about 3 years ago) I took the cover off. It would have had ~ 300 k km on it by then. I expected that I would need to replace both sprockets, the tensioner and the chain. But close inspection revealed very little actual wear. Sure it wasn't new, but I couldn't believe how good it looked considering age and mileage. The pushrod motor is pretty agricultural by todays standards - but it does seem to go on forever...
    Robert Thorne
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    Too many posts! JohnW's Avatar
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    Quote Originally Posted by Rob T View Post
    OK. My opinion only.

    If the valve clearance doesn't change (much) over time, I'd leave it alone. Just keep driving and enjoying. You know that if you pull the engine to just change the cam shaft, it will balloon into a "and I'll just fix that while I'm at it" job.

    My experience...

    My (recently sold) CX always had a noisy tappet. I checked and adjusted many times - but did it less over the years as I came to believe that it wasn't a portent of failure. It was never out by more than a few thou. It was my daily driver for about 15 years. So it was a high mileage car, but it had the same compression figures for the 15 years that I owned it. The timing chain would also rattle. Given that it spent much of its working life driving A/C (that actually worked - sort of), I assumed that the timing chain would be on its last legs. So last time the engine was out (about 3 years ago) I took the cover off. It would have had ~ 300 k km on it by then. I expected that I would need to replace both sprockets, the tensioner and the chain. But close inspection revealed very little actual wear. Sure it wasn't new, but I couldn't believe how good it looked considering age and mileage. The pushrod motor is pretty agricultural by todays standards - but it does seem to go on forever...
    Thanks Rob. Well, the problem is precisely that it DOES change, and fast. It's gone from silent to really noisy in under 1,000 km, twice. Not a problem I anticipated....

    So, the question remains, use my reground camshaft, which came with the car, or buy a new one? I suspect the reground one is the answer, a new one being about Euro 600 from CX-Basis.

    Cheers
    JohnW

    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

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    Fellow Frogger! Rob T's Avatar
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    The risk with re-ground cams and followers is that the case hardening gets ground thru leaving relatively soft base steel. Note that the core steel is still high quality, high tensile, but not nearly as hard. The case depth would typically be about 0.5 mm, so it is not hard to grind too much off. HOWEVER, anyone that can regrind cams would be aware of this and I think it is likely that they would discard any parts that wouldn't clean up OK.

    So, since you already have the parts - just use them.

    You should be able to determine if the wear is on the camshaft lobe by measuring the lift. After looking at the cross section diagrams in the manual, I think you will have to measure the pushrod travel at the rocker. So you will need to set up some sort of stand to hold a caliper or dial gauge steady. Just compare the lift relative to the other intake or exhaust valves. This should tell you if one cam lobe is worn. If the cam follower surface is breaking up, I would expect extra wear on the cam lobe too. So this measurement should still reveal some useful indication, especially if you do it twice at ,say, a 1,000 km interval.

    I would also do a compression test. Do it with the engine as near normal operating temperature as you manage without getting burn't. Do a dry run first and then tip about 10 ml of engine oil down each bore (thru the spark plug hole). The oil seals the rings better and should give higher readings. If it doesn't then that is an indication that valve seat isn't sealing as well as it might. Expect a BIG cloud of smoke when you start it up again.

    And a comment about oils. I also frequent a couple of other 'last century' car forums, and the same discussion goes round and round. But the bottom line seems to be - use the oils that your engine was designed around and change it to suit your driving usage. These older engines need the high zinc additives (ZDDP) that have been removed from modern oils. Modern synthetic oils are NOT better for these engines. I think the change interval should be 5,000 km or 12 months in the Australian climate. This assumes that you drive far enough to get the oil fully up to operating temperature long enough to 'boil' off any contaminants - at least 30 minutes. If you live in a cold climate and do short trips then change it more often. I typically used the 'original' Castrol GTX or Penrite 'high mileage' high ZDDP oils. Don't use synthetic or synthetic blend oils.

    Equally, I wouldn't use 'old' oils in a modern engine. My new BRZ specifies 0 - 20W oil. It runs almost like water even when cold. This engine has very close internal clearances, variable valve timing actuators with very small passages and roller rockers. It is designed around the thin oils, so using a higher viscosity oil is NOT better.

    Turbo diesels with particulate filters are different again. In short, use the oils that the manufacturers originally specified.
    Robert Thorne
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    Real cars have hydraulics DoubleChevron's Avatar
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    I just use ZDDP in my old cars ...

    Navone Engineering Inc. Ľ Product Categories Ľ ZDDP Oil Products

    probably doesn't need it if you run the right sort of mineral oil... But I use it in the cx turbo 'cos it runs modern synthetic oil and has from new.

    seeya,
    Shane L.
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    Quote Originally Posted by Rob T View Post
    The risk with re-ground cams and followers is that the case hardening gets ground thru leaving relatively soft base steel. Note that the core steel is still high quality, high tensile, but not nearly as hard. The case depth would typically be about 0.5 mm, so it is not hard to grind too much off. HOWEVER, anyone that can regrind cams would be aware of this and I think it is likely that they would discard any parts that wouldn't clean up OK. So, since you already have the parts - just use them.
    Thanks Rob - appreciate the input and sensible suggestions. I do know the previous owners were meticulous and competent, so the reground cam is probably fine.

    The oil business does go round and round, as you say. Shane's ZDDP link was interesting (Thanks Shane) - it just might be a reason for breaking old rules about not messing with engine oil additives! I run Penrite 20-50 in the old Renaults and can't remember what is in the CX at present, but it isn't synthetic or semi-synthetic.

    This is a bit odd, for me at least. I've owned the car for years now and it hasn't done huge mileages or not had regular oil changes. This is the only time I've every had a cam problem, but of course the engine has done 230,000 km. Whilst they are bullet-proof etc etc, it is 34 years old, has had numerous owners no doubt and out of warranty!

    Last year, we were parked at a little place where we were having breakfast overlooking the sea and were approached by a bloke who saw the car and reckoned he'd owned it about 25 years earlier! (Red C-matics aren't exactly common in Perth.)

    Cheers
    JohnW

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    1000+ Posts jo proffi's Avatar
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    Prety sure penrite full synth has zddp added.

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    Quote Originally Posted by jo proffi View Post
    Prety sure penrite full synth has zddp added.
    It poisons the modern sensor and converters doesn't it I imagine you would need to look at a sythetics brewed for classic vehicles.

    seeya,
    Shane L.
    'Cit' homepage:
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    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
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    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


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    Quote Originally Posted by JohnW View Post
    Thanks Rob - appreciate the input and sensible suggestions. I do know the previous owners were meticulous and competent, so the reground cam is probably fine.

    The oil business does go round and round, as you say. Shane's ZDDP link was interesting (Thanks Shane) - it just might be a reason for breaking old rules about not messing with engine oil additives! I run Penrite 20-50 in the old Renaults and can't remember what is in the CX at present, but it isn't synthetic or semi-synthetic.

    This is a bit odd, for me at least. I've owned the car for years now and it hasn't done huge mileages or not had regular oil changes. This is the only time I've every had a cam problem, but of course the engine has done 230,000 km. Whilst they are bullet-proof etc etc, it is 34 years old, has had numerous owners no doubt and out of warranty!

    Last year, we were parked at a little place where we were having breakfast overlooking the sea and were approached by a bloke who saw the car and reckoned he'd owned it about 25 years earlier! (Red C-matics aren't exactly common in Perth.)

    Cheers

    John - that engine is a close cousin to the 5 main D engines. Is it an exhaust tappet or intake? If exhaust what can sometimes happen with the D engines is that the bolts securing the spindle will start to stretch causing the clearance to change. You re-adjust and it happens again in short while. If you don't take care of the underlying problem the bolt breaks inside the block Seen that problem a couple to times. The exhaust bolts are easy to remove if that is where the problem is. The other thing that I have seen - and this one is fairly common - the brass bushing(s) inside the tappet(s) start to wear just due to high millage. That then causes excess wear on the tappet spindle and the valve clearance constantly changes. The other possibility is that the lifter on valve is wearing abnormally. If the engine feels strong in other respects - any you have not had to advance the engine a bit to compensate for a lack of power, the cam itself is most likely OK.

    Normally when cams and/or lifters are reground (at least in my area - Los Angeles) the parts are case hardened. In addition cams should be Parkerised, a manganese phosphate coating, that is electrochemically coated on the metals surface. When I had my cam (DS21) done 12 years ago that is what the shop did. Have over 138,000 miles on that rebuild and have only had to adjust the valves a couple of times.

    Steve

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    Quote Originally Posted by Citroenfan View Post
    John - that engine is a close cousin to the 5 main D engines. Is it an exhaust tappet or intake? If exhaust what can sometimes happen with the D engines is that the bolts securing the spindle will start to stretch causing the clearance to change. You re-adjust and it happens again in short while. If you don't take care of the underlying problem the bolt breaks inside the block Seen that problem a couple to times. The exhaust bolts are easy to remove if that is where the problem is. The other thing that I have seen - and this one is fairly common - the brass bushing(s) inside the tappet(s) start to wear just due to high millage. That then causes excess wear on the tappet spindle and the valve clearance constantly changes. The other possibility is that the lifter on valve is wearing abnormally. If the engine feels strong in other respects - any you have not had to advance the engine a bit to compensate for a lack of power, the cam itself is most likely OK.

    Normally when cams and/or lifters are reground (at least in my area - Los Angeles) the parts are case hardened. In addition cams should be Parkerised, a manganese phosphate coating, that is electrochemically coated on the metals surface. When I had my cam (DS21) done 12 years ago that is what the shop did. Have over 138,000 miles on that rebuild and have only had to adjust the valves a couple of times.

    Steve
    Thanks Steve. That is very interesting information. By spindle, I presume you mean what I'd call the rocker arm shaft? The bolt you refer to is one holding the rocker shaft onto the cylinder head, that is actually a cylinder head securing bolt? Must dig out some bits and look more closely as my questions might be a bit off the mark.

    My suspicion is cam follower wear (i.e. lifter) and my hope is that the cam lobe is OK.

    I must chase up the previous owner and find out exactly what was done to that reground camshaft - excellent points.

    Regards
    Last edited by JohnW; 17th October 2014 at 01:12 PM.
    JohnW

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    Default CX camshaft problem

    I've seen pushrods mushroom at the bucket end. Can't remember if it was on a D/CX though...

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    Quote Originally Posted by Citroenfan View Post
    John - that engine is a close cousin to the 5 main D engines. Is it an exhaust tappet or intake? If exhaust what can sometimes happen with the D engines is that the bolts securing the spindle will start to stretch causing the clearance to change. You re-adjust and it happens again in short while. If you don't take care of the underlying problem the bolt breaks inside the block Seen that problem a couple to times. The exhaust bolts are easy to remove if that is where the problem is. The other thing that I have seen - and this one is fairly common - the brass bushing(s) inside the tappet(s) start to wear just due to high millage. That then causes excess wear on the tappet spindle and the valve clearance constantly changes. The other possibility is that the lifter on valve is wearing abnormally. If the engine feels strong in other respects - any you have not had to advance the engine a bit to compensate for a lack of power, the cam itself is most likely OK.

    Normally when cams and/or lifters are reground (at least in my area - Los Angeles) the parts are case hardened. In addition cams should be Parkerised, a manganese phosphate coating, that is electrochemically coated on the metals surface. When I had my cam (DS21) done 12 years ago that is what the shop did. Have over 138,000 miles on that rebuild and have only had to adjust the valves a couple of times.

    Steve
    Tell him how many times the head has been off since the rebuild. Twice? Thrice? Quatro?

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    Quote Originally Posted by Mungous View Post
    I've seen pushrods mushroom at the bucket end. Can't remember if it was on a D/CX though...
    I doubt it is the pushrod - that would reduce the clearance anyway wouldn't it? However, the point you make indirectly is that there are quite a few things to check and think about before pulling out the scalpel!

    Many thanks.
    JohnW

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    Quote Originally Posted by daffyduck View Post
    Tell him how many times the head has been off since the rebuild. Twice? Thrice? Quatro?

    Doing the Daffy Duck dance with the AussieFrogs app and a cane.
    And those were the only times (twice in 138,000+ miles) - your memory is failing........

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    Quote Originally Posted by JohnW View Post
    Thanks Steve. That is very interesting information. By spindle, I presume you mean what I'd call the rocker arm shaft? The bolt you refer to is one holding the rocker shaft onto the cylinder head, that is actually a cylinder head securing bolt? Must dig out some bits and look more closely as my questions might be a bit off the mark.

    My suspicion is cam follower wear (i.e. lifter) and my hope is that the cam lobe is OK.

    I must chase up the previous owner and find out exactly what was done to that reground camshaft - excellent points.

    Regards

    Spindle = rocker shaft. Only the the bolts on the inlet shaft are part of the head securing ones. The ones holding the caps on the exhaust shafts are much less robust. And those are the ones ( in two cases over many, many years) that I have seen let go. I suspect, but have no finite proof, that it may well have been the result of improper assembly - not by the factory.

    Your suspicion is most likely the real reason. Solid lifters in the D/CX engines are a weak point. And the problem can be greatly aggravated by infrequent oil changes

    Steve

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    Quote Originally Posted by Citroenfan View Post
    Spindle = rocker shaft. Only the the bolts on the inlet shaft are part of the head securing ones. The ones holding the caps on the exhaust shafts are much less robust. And those are the ones ( in two cases over many, many years) that I have seen let go. I suspect, but have no finite proof, that it may well have been the result of improper assembly - not by the factory.

    Your suspicion is most likely the real reason. Solid lifters in the D/CX engines are a weak point. And the problem can be greatly aggravated by infrequent oil changes

    Steve
    Thanks Steve. Really appreciate your thoughtful input. I've found my spare reground camshaft and set of refaced cam followers after not seeing them for years! CX-Basis have them listed new for nearly Euro 600.... Not cheap but there is a certain appeal in fitting a new one, given the work involved. I imagine that as the noise has grown twice, the camshaft lobe will almost certainly be damaged too - in fact I wouldn't be game not to replace the camshaft now. As there's a slight coolant leak from the head gasket, it's time to pull it off anyway, which is some consolation.

    Re those exhaust side securing bolts, I'd put money on your being right and that it wasn't at the factory. People all too easily overtighten smaller bolts into alloy heads. Interesting that the bolts stretch rather than stripping the alloy thread.

    Must visit San Diego sometime. Obviously a North American focus for Citroen and Renault folk!!

    Cheers
    JohnW

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    Quote Originally Posted by JohnW View Post
    Thanks Steve. Really appreciate your thoughtful input. I've found my spare reground camshaft and set of refaced cam followers after not seeing them for years! CX-Basis have them listed new for nearly Euro 600.... Not cheap but there is a certain appeal in fitting a new one, given the work involved. I imagine that as the noise has grown twice, the camshaft lobe will almost certainly be damaged too - in fact I wouldn't be game not to replace the camshaft now. As there's a slight coolant leak from the head gasket, it's time to pull it off anyway, which is some consolation.

    Re those exhaust side securing bolts, I'd put money on your being right and that it wasn't at the factory. People all too easily overtighten smaller bolts into alloy heads. Interesting that the bolts stretch rather than stripping the alloy thread.

    Must visit San Diego sometime. Obviously a North American focus for Citroen and Renault folk!!

    Cheers
    Hi John - No, not San Diego - I am some 290 or so Kms north of there . OTHO those bolts do 'bite' quite a distance into the head material. Where both broke (different cars) was just above the joint between the mounting point between the rocker support arm and the head. Again, not sure what actually caused the failure and as I have only seen it twice will most likely never really know .

    Pulling a head on a CX I would think is a bit more of a chore than a DS - esp. if one is working with EFI. You need to realize that the CX was never 'officially' sold here - the ones we got were either via Trend Imports (there may have been others) or private party imports. OTOH with the water leak you now have a good excuse for other family members on your being absent for some time as well as a dour disposition .

    Having rebuild a few D motors over the years I have to say that the cam's, at least the ones I have seen, tended to fair fairly well even with really despicable looking lifters.

    Good luck with project.

    Steve

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    1000+ Posts daffyduck's Avatar
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    Failures on those broken studs were on super high mileage heads. Metal fatigue is likely the smoking gun. Lots of people now replace the studs as a course of routine practice.

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    Quote Originally Posted by Citroenfan View Post
    Having rebuilt a few D motors over the years I have to say that the cam's, at least the ones I have seen, tended to fare fairly well even with really despicable looking lifters.

    Good luck with project.

    Steve
    Not so well in CX motors. Lobes can be quite worn when measured. Lifters suffer very badly. I would say that this is the weak spot in an otherwise bullet proof design!
    Last edited by gerrypro; 14th October 2015 at 11:29 AM.
    Cheers Gerry

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    Quote Originally Posted by gerrypro View Post
    Not so well in CX motors. Lobes cam be quite worn when measured. Lifters suffer very badly. I would say that this is the weak spot in an otherwise bullet proof design!
    Gary,

    Not saying the cams were not a bit worn - they just seem(ed) to fair a bit better than the lifters . OTOH that section of the D/CX engines was their weak point - no question. OTOH when I rebuilt the motor in my 72 in 2001 (car was basically salvaged from a 'crushing' fate with some 496,000+ miles on the chassis) I had the cam and followers reground by a shop near me. When I had to pull the head a second time at just under 100,000 miles due to an overheating problem (radiator) the lifters were still pristine as were the cam lobes. So the shop must of have done something right .

    Steve

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    Quote Originally Posted by daffyduck View Post
    Failures on those broken studs were on super high mileage heads. Metal fatigue is likely the smoking gun. Lots of people now replace the studs as a course of routine practice.

    Walt,

    Possible - however in both cases (the one you and I fixed at Rendezvous a few years back) + the only other one I have seen, both cars had their heads worked on not to long prior to the problem. Best bet is to measure the suckers and inspect closely for signs of corrosion. If in doubt - replace -as you mentioned. I have also seen people lube the threads prior to inserting and/or not chase the threads in the head/block before reassembly. Both not good.

    Steve

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    1000+ Posts Wildebeest's Avatar
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    Johnno,
    A quick indication of cam or follower wear. Is the adjustment screw going further into the locknut on the offending [noisy] tappet?
    But you already knew that eh?

    A compression test has been mooted. I've found that even with a cam lobe being worn to the point of barely opening the valve a normal reading will show. This being at cranking speed. OTOH at running speed a whole new series of events happen.

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    Quote Originally Posted by gerrypro View Post
    Not so well in CX motors. Lobes cam be quite worn when measured. Lifters suffer very badly. I would say that this is the weak spot in an otherwise bullet proof design!
    Ah. That would be my starting assumption, despite born optimist character! Thanks.
    JohnW

    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

  25. #25
    Too many posts! JohnW's Avatar
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    Quote Originally Posted by Wildebeest View Post
    Johnno,
    A quick indication of cam or follower wear. Is the adjustment screw going further into the locknut on the offending [noisy] tappet?
    But you already knew that eh?

    A compression test has been mooted. I've found that even with a cam lobe being worn to the point of barely opening the valve a normal reading will show. This being at cranking speed. OTOH at running speed a whole new series of events happen.
    Many thanks Wildebeeste. Yes to both, but so pleased to get the discussion's comments. I'm 95% sure we'll be changing camshaft and followers. The real question is whether to lash out on a new camshaft, a known quantity, or use a reground one that I didn't have done myself. Maybe I can get the reground one tested for hardness, or indeed get it hardened? Not sure.

    No rush anyway, as this work won't happen until December - I am carefully getting ducks in line right now.

    Cheers
    JohnW

    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

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