incy-spider
ClioSport Club Member
Also... to add! When valves let go that swarf metal from the piston goes all through the inlet and out the exhaust
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Engine building, timing, upgrades etc
- Thread starter colesy
- Start date
Also... to add! When valves let go that swarf metal from the piston goes all through the inlet and out the exhaust
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frayz
ClioSport Club Member
You have increased the CR with the 197 pistons which would have made it more fuel/timing sensitive. If it was previously mapped right on the limits of PI then you will have crossed that line with the increase in compression. But surely they would have explained this to you when it was there?
You said the head was destroyed, so the foreign material in the intake will have come back via the intake ports and again is likely a result and not a cause.
Im purely guessing here and sugesting a possible series of events:
If you were driving around for 300 miles on the previous cal you could well have been subjecting the motor to alot of PI and not known. Was this driving under full load at any point?
Then it goes for mapping and they start running full load WOT runs. They may or may not have seen the amount of ign advance and will have seen the amount of knock produced. The ECU will only be able to pull a set amount of timing which in this case is clearly not enough for the PI to be controlled.
This is likely when your damage was done. By time they found the issue it was likely too late.
Like i say, i wasnt there, i dont know what happened, nor am i passing blame to any one party here. Just a possible/likey series of events.
Clio 182 cup
Completely agree I’m not out to blame anyone it’s Happened now and s**t happens just hope when I go back with this engine and the 197 cams and inlet it’s all goes Ok other wise I’m gonna burn the thing 😂
incy-spider
ClioSport Club Member
Christ!! Looks like the piston parted ways from the wrist pin and punched the s**t out of the combustion chamber. That’s crazy
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Clio 182 cup
Looks exactly like that don’t it 😭 expensive lesson to learn
frayz
ClioSport Club Member
Ah, not a melted piston then, kinda expands on the cal issue somewhat. I was going off the basis of a melted piston.
Are there any signs of heat on the remnants of the piston or of the cylinder walls?
Without analysing the components it’s tough to say, what the failure mode was. Pistons generally don’t just fail by themselves, certainly not at this level.
Sorry to see such a mess, I hope you can get another motor together with minimal downtime and cost.
Are there any signs of heat on the remnants of the piston or of the cylinder walls?
Without analysing the components it’s tough to say, what the failure mode was. Pistons generally don’t just fail by themselves, certainly not at this level.
Sorry to see such a mess, I hope you can get another motor together with minimal downtime and cost.
gambit
ClioSport Club Member
182 Trophy
Excuse the ignorance but how did you check for valve clearance on the higher crowned 197 piston and new valves? And then also check to ensure a valve does not drop when assembly occurs? Also do most engine builders X-ray or inspect for micro fractures on pistons before install or how do they do it? I’m doing a similar build and want to ensure I don’t have same thing occur.
incy-spider
ClioSport Club Member
What’s the big end looking like on the failed cylinder?
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Clio 182 cup
I didn’t have the clearance checked others have run the same set up and there is bigger valve reliefs in the piston to allow. I didn’t have them x rayed either prob a silly move in hindsight
Clio 182 cup
I will do but seems it was just a based failure unfortunately
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I haven’t taken he sump off yet but when I do I’ll have a look as I’m planning on salvaging as much as possible out of the engine which I don’t think will be a lot tbh
Robbie Corbett
ClioSport Club Member
Can't really see from the pictures and haven't read the whole thread yet however:
With pre-ignition or severe det you generally get signs across more than one cylinder unless one cylinder is significantly different (uneven manifold flow, sharp edge in combustion chamber). Pre ignition is also quite easy to feel/hear, det can be inaudible without cans/trace.
I would suggest that either the piston in that cylinder has suffered ring land failure or the injector on that one cylinder has failed wide open. Did you check ring gaps?
I don't agree with X-raying pistons unless its some crazy build. Its expensive and depending on equipment doesn't show as much as people would think/like. There are various NDT methods which work well such as eddy current testing, florescent ink testing etc. However a good visual inspection of parts has never really failed me.
Interesting failure and sorry its happened to you!
With pre-ignition or severe det you generally get signs across more than one cylinder unless one cylinder is significantly different (uneven manifold flow, sharp edge in combustion chamber). Pre ignition is also quite easy to feel/hear, det can be inaudible without cans/trace.
I would suggest that either the piston in that cylinder has suffered ring land failure or the injector on that one cylinder has failed wide open. Did you check ring gaps?
I don't agree with X-raying pistons unless its some crazy build. Its expensive and depending on equipment doesn't show as much as people would think/like. There are various NDT methods which work well such as eddy current testing, florescent ink testing etc. However a good visual inspection of parts has never really failed me.
Interesting failure and sorry its happened to you!
Robbie Corbett
ClioSport Club Member
I know you work in this field and have seen more dyno failures than most however am wondering if you work with OEM quality builds.... after market/diy builds perhaps might not be so... capable of dealing with abuse so early on? Agree in general that a bottom end (ie bearing or bolt) issue would show its self pretty damn quick no matter who built it, ring troubles can take a little longer imo.
I've mapped several fresh engines on chassis dynos, all of them (from memory) I aborted early on in the session due to various issues ranging from low oil pressure, or oil pressure which declined across runs, over heating engines because they were tight. Plus I found the tune changes by a fair amount once an engine is fully bedded in.
I would be going no where near a dyno with a 300mile old self built engine, no way of knowing if rings were fully seated, this may well have been the primary cause of failure too. Also, they should never ever have gone right for a full load run, should have been babied upto full load which leaves plenty of time for finding weird timing issues. TBH if their mapper didn't notice a timing issue like this with an advance table they should be so familiar with they can recite then I would be asking questions.
From what your saying it sounds as if their mapper did a full load run, heard det then checked advance table before doing another full load run? wtf?
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Clio 182 cup
Hi guys, bit of advice needed, I’ve fitted new engine put it all back exactly the same but without the 197 pistons I can’t see to get it to fire, I’ve done new plugs, new leads All sensors been checked. It just turns Over but doesn’t fire every now and again it does a massive bang from us burnt fuel could a faulty crank sensor cause this ? Very odd it all worked and now it’s come back and ecu has been flashed and i can’t get it to start 🤬😡
incy-spider
ClioSport Club Member
Earth on the back of gearbox bolted on? Near the ns shaft?
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I’ve just taken the crank sensor off as had a brain fart and Remembered that when I took the gearbox off the block there was a few chunks of metal inside the gearbox casing from where the piston had come out the side of the block and into the gearbox housing and if you look closely at the crankshaft sensor you can see where it’s been smashed by debris rattling around inside I know these are very temperamental senors do you think this could cause it to not work
incy-spider
ClioSport Club Member
Or timing, but I expect he’s on the money with the crank sensor
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Clio 182 cup
Hopefully it’s not timing haha just literally timed it with a 8* tool I’m praying it’s crank sensor or it’s going on the sea 😂
Robbie Corbett
ClioSport Club Member
Either leads in wrong order, or crank sensor would be my first guess
The bang is often when 1&4 is swapped with 2&3 (assuming this is wasted spark, which is likely is with no cam sensor). Could also be the crank sensor intermittently giving a signal causing a badly timed spark. No spark, no bangs.
The bang is often when 1&4 is swapped with 2&3 (assuming this is wasted spark, which is likely is with no cam sensor). Could also be the crank sensor intermittently giving a signal causing a badly timed spark. No spark, no bangs.
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Robbie Corbett
ClioSport Club Member
Other things that can stop an SD engine from starting are:
Coolant temp sensor (reading too hot would mean a lean start and some pops)
Air temp sensor (although this often gets ignored on start up)
Map sensor (although normally a car will fire and then die)
empty tank! You would be amazed how often that happens
immobiliser - however when mine was dicking about it would only crank for 5 revs max and then stop by its self.
If you can hear the fuel pump running while cranking its not the crank sensor, if the rev counter reads anything while cranking its not the crank sensor.
Does exhaust smell of fuel?
Any fuel on plugs?
If yes to either it probably not the crank sensor.
Where is south are you, I'm in Surrey and my car is currently out of action, if your close (pm me) you would be welcome to borrow some bits off mine to check (crank sensor etc).
Rob,
Coolant temp sensor (reading too hot would mean a lean start and some pops)
Air temp sensor (although this often gets ignored on start up)
Map sensor (although normally a car will fire and then die)
empty tank! You would be amazed how often that happens
immobiliser - however when mine was dicking about it would only crank for 5 revs max and then stop by its self.
If you can hear the fuel pump running while cranking its not the crank sensor, if the rev counter reads anything while cranking its not the crank sensor.
Does exhaust smell of fuel?
Any fuel on plugs?
If yes to either it probably not the crank sensor.
Where is south are you, I'm in Surrey and my car is currently out of action, if your close (pm me) you would be welcome to borrow some bits off mine to check (crank sensor etc).
Rob,
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incy-spider
ClioSport Club Member
Any joy!?
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Clio 182 cup
As much as I hate to admit it, it was my fault I fitted the exhaust cam upside down 🤦🏻♂️😂
incy-spider
ClioSport Club Member
Balls!! Timing slightly out then [emoji23][emoji23][emoji23][emoji23][emoji108]
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JamesBryan
ClioSport Club Member
How did you manage to do the timing if one cam is 180° out compared to the other?
The tool wouldn't go in because the slots are offset from centre.
The tool wouldn't go in because the slots are offset from centre.
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The exhaust cam was out but the inlet one was correct and my exhaust cam side will fit both ways
JamesBryan
ClioSport Club Member
I mean the horseshoe tool.
One cam slot would be below the centreline and the other would be above, meaning the tool wouldn't slot in straight.
Having just a small tolerance to fit it is easy. I first install the grp n timing having the exhaust 180degrees rotated.
Then I install both in same way. It does not matter if both are as in manual or 180 rotated.
JamesBryan
ClioSport Club Member
Both 180° rotated is ok yes, but not just one.
I just find it hard to believe it wasn't spotted sooner and that the car did quite a few miles. It would have ran like s**t, timed up like that 😅
Robbie Corbett
ClioSport Club Member
You can get the tool in with the exhaust cam 180 out however the locking plate will not sit flat and the top hole in the Renault tool won't line up.
Robbie Corbett
ClioSport Club Member
I don't think it ran at all. OP couldn't get it started. If your in a rush and its getting dark you would be amazed at whats possible
JamesBryan
ClioSport Club Member
That's what I mean, it 'can' be done but as you've said things wouldn't like up properly 😅
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