F4R.774 Piston Detonation

[Trophyboy2017]

Hi all

New member to the forum and my 1st post. I'm a member of the Rs Megane Forum but popped on here to see if any engine guru's/techs can help me out.

Basically I developed a misfire a few month ago in my 56k Meg 225 Trophy after being stuck in a traffic jam for 2 hours. Kept car running as it was raining and windows were steaming up but kept an eye on temp gauge and everything stayed normal. Then once i got going the EML started flashing and car went into limp mode. Anyway managed to creep it home (3 miles) and put my scan gauge on it. Came up cylinder 2 misfire. Did a compression test and cylinders 1-3-4 were all 150 psi, cylinder 2 had nothing.

So fast forward a few months and managed to pull the engine out and strip it down and the piston on cylinder 2 had melted through rings & lands. Pics below of full strip down.

I know it could be a 6 million dollar question but I'd like to know what could of caused this in order to eliminate it happening again. When stripping it down everything seemed in order.. Headgasket was fine, oil pick up clear, oil & water pump ok, sump clear etc. Crank journals are fine as were the big end/mains bearings. There was a bad score mark on one of the cam seats as seen in pic but been told its nothing to worry about too much.
The valves were severely coked up and solid chunks of burnt soot on them. Could it have been an over fuelling issue leading to detonation?

Any help/info/ideas on this would be much appreciated guys as im gonna be rebuilding it one im back from holiday in a few weeks.

Cheers

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[R3k1355]

Under fuelling is much more likely than over fuelling, I'd be looking at the injector on that cylinder first.
Did you fit new aftermarket injectors to the car?

The valves look kinda crappy as well, has it been mapped?

 

[White16valver]

Kudos on the mechanical skills, I wouldn't know where to start.

Is it on standard management? It's not been remapped? What sort of MPG were you getting?

I have to admit that I'm not sure if overfuelling would lead to detonation - I thought that detonation was more a timing issue.

If it was severely overfuelling, could it have been bore wash stripping the oil out of the cylinders and increasing friction/heat? That's a bit of a guess TBH as I thought that sort of thing only happened when one was running massive injectors and huge power.

 

[Trophyboy2017]

Under fuelling is much more likely than over fuelling, I'd be looking at the injector on that cylinder first.
Did you fit new aftermarket injectors to the car?

The valves look kinda crappy as well, has it been mapped?

Thanks for replying mate. No its running standard OEM injectors but 5 weeks prior to this i sent the injectors away to be ultrasonically cleaned (Fellow member offering cleaning service)
They came back, fitted them and car ran fine until this happened.

I haven't had the car long and has no trace of a remap in reciepts or history so im not 100% sure. It was booked into RS tuning 2 weeks after this happened so this was just my typical bad luck.
Im still leaning towards a fuelling issue though as i cant see anything mechanically that has failed.
Cheers

 

[BoatNonce]

Gone lean I reckon.

 

[NorthloopCup]

Standard power? Or running more boost? It could be that the heat from the engine was evaporating the fuel or knocking the Ron content down. Seen that happen before.

 

[Trophyboy2017]

Standard power? Or running more boost? It could be that the heat from the engine was evaporating the fuel or knocking the Ron content down. Seen that happen before.

I believe it's standard power but not 100% sure bud as there is nothing in reciepts to say its had a remap of sort. It was booked into RS Tuning 2 weeks after this happened so was just my typical bad luck.

Only mods it has is a custom induction set up i made with ITG filter and bigger intercooler. Everything else is standard inc exhaust. I was in modding mode bit by bit before this happened.

Induction kit below

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[NorthloopCup]

I believe it's standard power but not 100% sure bud as there is nothing in reciepts to say its had a remap of sort. It was booked into RS Tuning 2 weeks after this happened so was just my typical bad luck.

Only mods it has is a custom induction set up i made with ITG filter and bigger intercooler. Everything else is standard inc exhaust. I was in modding mode bit by bit before this happened.

Induction kit below

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Well it's run lean for some reason or another. Could've been signs of a dying fuel pump as well potentially.

Very tidy car you've got there though buddy looking at the engine bay shots.

That block doesn't look like it'll hone up either, but I could be wrong. Overbore is the only option then, so that's forged pistons.

 

[R3k1355]

Do Megane's kill their injectors like the Clio's do?

Looks like one injector has given up the ghost and refused to dispense fuel?

 

[NorthloopCup]

Do Megane's kill their injectors like the Clio's do?

Looks like one injector has given up the ghost and refused to dispense fuel?

Good point actually. Yes they do s**t themselves.

 

[JamesBryan]

Flashing EML is usually an injector on these Meganes.

Looks to have leaned out.

 

[Trophyboy2017]

Well it's run lean for some reason or another. Could've been signs of a dying fuel pump as well potentially.

Very tidy car you've got there though buddy looking at the engine bay shots.

That block doesn't look like it'll hone up either, but I could be wrong. Overbore is the only option then, so that's forged pistons.

Yeah it does point to something fuel related going from everyone's reply.
Where is the fuel pump located as ill replace that to eliminate that too.

Thanks buddy, prior to the engine letting go i gave the bay a freshen up, painted mostly everything that was removable without separating head from block and had all the bolts/fixings zinc plated.
Then... it blew the dipstick out which i forgot to mention earlier and ruined all my hard graft.
I'll be doing exactly the same before it goes back in including decat, exhaust & new turbo re-core as it has lots of play in the shaft.

I took the block down to a local engine builder and he did say it will hone very easily as the lip is very small. That shiny aluminium on bore thats melted on cylinder wall just flakes off with a brass scraper.

Due to funds... Mortgage, kids etc and already ploughing £2.5k on a full paint job, forging is not an option at minute buddy.

Plans are:

Block degreased & all 4 pots honed & skim
New piston
New set of rings, king racing big ends & mains bearings
Complete bottom end seal kit
New cambelt/water pump kit
New OEM injectors or maybe 630's
R26r clutch kit
Head stripped, cleaned, skimmed & fully rebuild with new stem seals. Valves are are fine they said.

And anything else I can think of while building it back up as ill do it myself for the experience.

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[Trophyboy2017]

Yeah it does point to something fuel related going from everyone's reply.
Where is the fuel pump located as ill replace that to eliminate that too.

Thanks buddy, prior to the engine letting go i gave the bay a freshen up, painted mostly everything that was removable without separating head from block and had all the bolts/fixings zinc plated.
Then... it blew the dipstick out which i forgot to mention earlier and ruined all my hard graft.
I'll be doing exactly the same before it goes back in including decat, exhaust & new turbo re-core as it has lots of play in the shaft.

I took the block down to a local engine builder and he did say it will hone very easily as the lip is very small. That shiny aluminium on bore thats melted on cylinder wall just flakes off with a brass scraper.

Due to funds... Mortgage, kids etc and already ploughing £2.5k on a full paint job, forging is not an option at minute buddy.

Plans are:

Block degreased & all 4 pots honed & skim
New piston
New set of rings, king racing big ends & mains bearings
Complete bottom end seal kit
New cambelt/water pump kit
New OEM injectors or maybe 630's
R26r clutch kit
Head stripped, cleaned, skimmed & fully rebuild with new stem seals. Valves are are fine they said.

And anything else I can think of while building it back up as ill do it myself for the experience.

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Plus it's just a weekend summer toy and I dont do trackdays or after huge power.

If I can just build a strong standard engine with a few mods and 250/265 remap ill be made up with that.

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[JamesBryan]

Fuel pump is in the tank mate. Get to it from under the rear seats when you lift them up.

 

[Trophyboy2017]

After reading an old thread on here which was about induction kits and fuel/air mixture i noticed this reply from a chap.

(The ecu can only compensate a little bit with an induction kit, you suck in more air meaning you lean out the fuel mixture and that causes problems and can melt pistons and thats not nice cos its costs quite a bit to fix)

Wondering if the custom induction kit i have has caused it to run lean?? Or does the ECU compensate for more air intake?
Do induction kits have to be mapped in?

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[White16valver]

After reading an old thread on here which was about induction kits and fuel/air mixture i noticed this reply from a chap.

(The ecu can only compensate a little bit with an induction kit, you suck in more air meaning you lean out the fuel mixture and that causes problems and can melt pistons and thats not nice cos its costs quite a bit to fix)

Wondering if the custom induction kit i have has caused it to run lean?? Or does the ECU compensate for more air intake?
Do induction kits have to be mapped in?

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I guess the only way to get empirical evidence is to book a rolling road session and run back-to-back runs with the standard air filter setup and then swapping to an induction kit, as that would mean being able to keep track of the Air/Fuel mix and the ability to abort the session if it's clearly running lean.

Not very helpful now, of course...

 

[NorthloopCup]

@Trophyboy2017

Get them to measure the bores. I can let you know what the upper level is for bore wear if you need to know - this is what renault specify as well. I've found that the majority of f4r's are in the upper limit for bore wear.

The plans for the future sound good mate, but I'd just replace the oe injectors with oe items. The 630's aren't needed unless you go for more like 280/300. Nothing wrong with future proofing the engine though!

As for the induction kit - I honestly can't see it causing the problem. How longs it been on? I would've thought it would throw a code up before it allows the engine to run dangerously lean. That's a combination of heat and fuelling imo.

If you need any help with gaskets or piston rings, let me know. I can get you excellent prices on all genuine renault gaskets kits. From memory it was around £12 per ring set - this was genuine renault stuff as well, not mickey mouse cheap shite.

 

[R3k1355]

It blew the dipstick out?? Like properly blew it right out and belched oil all over the place?

Thats bad.

 

[R3k1355]

(The ecu can only compensate a little bit with an induction kit, you suck in more air meaning you lean out the fuel mixture and that causes problems and can melt pistons and thats not nice cos its costs quite a bit to fix)

Wondering if the custom induction kit i have has caused it to run lean?? Or does the ECU compensate for more air intake?
Do induction kits have to be mapped in?

Nah, usually the ECU has a small amount of compensation and when it runs out it just hits the fuel cut (usually sending your face into the windscreen)
Thats assuming the ECU is stock of course.

 

[bloke]

i'd be tempted to get the injectors flow tested, always nice if you can find out what's killed it. presume the injectors have a filter in them? was this replaced and were the flow tested or where they just cleaned?

 

[Trophyboy2017]

@NorthloopCup
Yeah that would be great if you could let me know what the upper bore level is buddy? I can measure with a vernier in morning or does it need to be lower down in bore?
Don't suppose you have bolt torque settings have you? Gonna need these when building her back up.

I'll have a think about the injectors but as the OEM ones are shite i may opt for 630's and map them to suit. What are standard pistons good for BHP wise as i know there obviously made of chocolate as are the rods haha.

With the mods i already have im prob looking more towards 280 but I'd never go over that without getting forged pistons & rods.

The induction kit was done when i detailed the engine so prob 5 weeks ish. It never threw any codes up but i did have a throttle body fault code and I can't remember for the life of me what it was. Also boost pressure sensor code which ive now replaced with 2 new ones.
I was also running a blanking plate for chatter and im now wondering if this has wrecked the turbo as id heard conflicting stories about it wrecking them. I've now got a properfekt to install instead of the blanking plate.

Mate that would be a massive help with regards to rings, seals & gasket kits etc. I was gonna order Victor Reinz top & bottom complete sets as i heard Victor Reinz make all seals & gaskets for Renault but how true this is i dont know buddy.

Im gonna need the usual:
Cylinder Head Set - 7701475375
Lower Engine Seals - 7701477218
Piston Ring Set - 7701474725
Thrust Washer -
End Crank Case Gasket - 8200760071
Front Crank Seal - 7700103245
Rear Crank Seal - 7703087224
Sump Gasket - 8200282199
Dipstick - 8200962990
Oil Pump Chain Kit - 7701472674
Water Pump Kit - 7701479043
Thermostat Hous Gasket - 7700104129
Exhaust Mani Gasket - 7700105843
Turbo to Mani Gssket - 8200392165
Turbo Stud/Nut Kit - 7701473143
Turbo to Cat Gasket - 7700115198
Cam Seal Kit - 7701471372

Think thats all I can think of for now buddy. Thanks so much for all your help. Really appreciate it.

 

[Trophyboy2017]

It blew the dipstick out?? Like properly blew it right out and belched oil all over the place?
Thats bad.

Yep clean out mate and covered my nice freshly painted engine bay in hot oil
I knew it was wrecked by then so covered the electrics and just got the hot jet wash out and blasted it clean.

 

[Trophyboy2017]

i'd be tempted to get the injectors flow tested, always nice if you can find out what's killed it. presume the injectors have a filter in them? was this replaced and were the flow tested or where they just cleaned?

Yeah i might do that once its built back up to figure out what went wrong.
They were just ultrasonic cleaned as far as i know and opened up with a small amount of voltage. Nothing was replaced as far as i could tell bud.

 

[NorthloopCup]

@NorthloopCup
Yeah that would be great if you could let me know what the upper bore level is buddy? I can measure with a vernier in morning or does it need to be lower down in bore?
Don't suppose you have bolt torque settings have you? Gonna need these when building her back up.

I'll have a think about the injectors but as the OEM ones are shite i may opt for 630's and map them to suit. What are standard pistons good for BHP wise as i know there obviously made of chocolate as are the rods haha.

With the mods i already have im prob looking more towards 280 but I'd never go over that without getting forged pistons & rods.

The induction kit was done when i detailed the engine so prob 5 weeks ish. It never threw any codes up but i did have a throttle body fault code and I can't remember for the life of me what it was. Also boost pressure sensor code which ive now replaced with 2 new ones.
I was also running a blanking plate for chatter and im now wondering if this has wrecked the turbo as id heard conflicting stories about it wrecking them. I've now got a properfekt to install instead of the blanking plate.

Mate that would be a massive help with regards to rings, seals & gasket kits etc. I was gonna order Victor Reinz top & bottom complete sets as i heard Victor Reinz make all seals & gaskets for Renault but how true this is i dont know buddy.

Im gonna need the usual:
Cylinder Head Set - 7701475375
Lower Engine Seals - 7701477218
Piston Ring Set - 7701474725
Thrust Washer -
End Crank Case Gasket - 8200760071
Front Crank Seal - 7700103245
Rear Crank Seal - 7703087224
Sump Gasket - 8200282199
Dipstick - 8200962990
Oil Pump Chain Kit - 7701472674
Water Pump Kit - 7701479043
Thermostat Hous Gasket - 7700104129
Exhaust Mani Gasket - 7700105843
Turbo to Mani Gssket - 8200392165
Turbo Stud/Nut Kit - 7701473143
Turbo to Cat Gasket - 7700115198
Cam Seal Kit - 7701471372

Think thats all I can think of for now buddy. Thanks so much for all your help. Really appreciate it.

Yeah I'll sort all that out when I'm back home mate. Currently on holiday! Lol!

Regards the gaskets and seals, I'm pretty sure that everything comes in the bottom end and top end gasket sets. Thrust washers and stuff are separate obviously.

Drop me a pm next week and I'll get on all of it for you. :up:

 

[Trophyboy2017]

Yeah I'll sort all that out when I'm back home mate. Currently on holiday! Lol!

Regards the gaskets and seals, I'm pretty sure that everything comes in the bottom end and top end gasket sets. Thrust washers and stuff are separate obviously.

Drop me a pm next week and I'll get on all of it for you. :up:

Cheers pal will do.

Just spent the last hour reading your engine build thread. Fu##ing fantastic attention to detail buddy. Seems you have OCD like me haha.

Enjoy your hols mate

 

[R3k1355]

Yep clean out mate and covered my nice freshly painted engine bay in hot oil
I knew it was wrecked by then so covered the electrics and just got the hot jet wash out and blasted it clean.

The dipstick flew out because of excessive blow-by, caused by the piston and rings being fucked.

 

[Silent_Scone]

lol, aye it's gotta go somewhere

 

[Trophyboy2017]

Haha don't i know it. Enough to make a grown man cry his fu#*king eyes out

 

[Trophyboy2017]

Can anyone tell me the best way to remove this cog wheel from the crank end? Need to remove it in order to get the end casing off but it just aint budging.

Cheers

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[bloke]

puller.

 

[AlexW]

Don't use King racing bearings.
Check the Renault ones & replace like for like.

 

[STEVE.M]

Can anyone tell me the best way to remove this cog wheel from the crank end? Need to remove it in order to get the end casing off but it just aint budging.

Cheers

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@Philpooma tackled this recently.
I think the answer is in this thread http://www.cliosport.net/threads/timing-belt-please-explain-this-to-me.809671/#post-11433222
but basically invert the crank & fill up the pulley with WD40/Plus gas for 24 hours and then carry on as you are.
If you have access to a slide hammer, so much the better.

With regard to the piston damage, have you checked that all the vanes are present on the turbo impellor?

 

[Philpooma]

The way I removed the pulley was to lock the crankshaft using a crankshaft locking tool or 8mm drift.
I used an aluminium paint stirrer with some holes drilled to accept the small bolts that screw into the pulley.
I basically then started turning the pulley clockwise and anticlockwise, initially using a hammer, it then got easier and I gradually got more movement until it came off.
The pulley basically rusts onto the the end of the crankshaft, once you break this it will come off.
Good luck :up:

 

[bloke]

the meg pulley is keyed though so you need a puller or slide hammer if it's rusted on.

 

[Philpooma]

the meg pulley is keyed though so you need a puller or slide hammer if it's rusted on.

Bloody hell Bloke.
You are the man with the knowledge :up:

 

[JamesBryan]

Yeah you won't turn it with the keyway in there.

 

[Trophyboy2017]

Don't use King racing bearings.
Check the Renault ones & replace like for like.

Any reason why Alex just out of curiosity as i know Engine Dynamics & KTR use and sell them.
Cheers

 

[Trophyboy2017]

Yeah you won't turn it with the keyway in there.

Yes there is definately a woodruff key on the meg as i can see it.
I just can't get a puller on it as the back of the cog is sat flush with the casing.
You must have to use those M4 bolt holes somehow on the pulley.

 

[Philpooma]

Those threaded M4 holes are definitely for pushing the pulley off the end of the crank. I did try this initially but I didnt have and suitable bolts which had strong enough threads to take the strain. I'm sure that suitably hardened bolts would push the pulley off the crank.
Its a real pain when such a stupid thing like this causes problems with a job on a car. I hope that you get it sorted.

 

[Trophyboy2017]

Those threaded M4 holes are definitely for pushing the pulley off the end of the crank. I did try this initially but I didnt have and suitable bolts which had strong enough threads to take the strain. I'm sure that suitably hardened bolts would push the pulley off the crank.
Its a real pain when such a stupid thing like this causes problems with a job on a car. I hope that you get it sorted.

Cheers buddy. Managed to get the b*****d off with brute force haha