Clio R27 #241

[S24NRC]

PROJECT THREAD: Five Years of Ownership… Four Engines Later

Having owned this car for five years now, I think it finally deserves a proper build thread.
Mainly so I can share the pain… but also so I can remember what I’ve actually done to the thing.

The first two years of ownership were bliss.
Then I decided to Megane swap it.
That decision opened the gates to an entire universe of engine-related misery.

Engine History (aka The Hall of Shame)

May 2023 – June 2023 — Engine #1

• Melted a piston thanks to a weak fuel pump.
• Completely stock power.

July 2023 – October 2023 — Engine #2

• Thrust bearing failed at Anglesey on an outlap.
• Crank walked itself out of the block like it was trying to escape.
• 250 bhp — mapped on 630cc injectors at EFI.

April 2024 – September 2024 — Engine #3

• Unknown failure (yet to strip).
• Bottom-end bearing definitely destroyed itself.
• Same power and setup as before.

February 2026 - Engine #4 (The Current One)

Thrown a bit more at it, now at 315 bhp and 290 torques - atleast its meant to be…

Spec list:

• 225 engine — fresh belts, gaskets, coil pump (far better than Renault OE)
• 250 15T turbo
• 250 5-bar rising-rate fuel system, 630cc injectors, Sytec 300 LPH pump
• Forge intercooler
• 3" decat
• 3" bumper cold-air feed to an open filter for all the wooshy noise.
• R26 ND0 gearbox with LSD and R26.R spec single mass conversion

I would love to say it’s been perfect… but obviously it hasn’t.

Teething Issues

Being off the road for 18 months meant the car woke up with a full cast of mechanical gremlins.
Highlights include:

• Boot opening every time the brake pedal was pressed (beautiful).
• No power at the BCM (expensive)
• Over-boost issue that only surfaced after mapping — sorted with a return trip to EFI.
• OE Renault spark plugs all gapped wildly differently from the factory, causing breakup and horrid drivability — also sorted.

After all that, it was time for a shakedown on track before it went bang again (I have full faith in this car I promise)

Oulton Park - The Humbling

Stormy day.
Car felt decent, was getting into the groove nicely. I’d recently had a tuition day at Donington with some GT3/Formula drivers and had picked up a lot of new techniques and had more confidence than ever in my own ability.

Then I came across an 318 E36 Compact race car.

Caught him in traffic, sat behind him, fully expecting to walk a low-power NA car on the straights.

Cue the Renault Moment™:

I’m not any faster. At all.

Had a mint run with him though carving through slower traffic and being relatively level pegged. I made a point of finding him in the pits for a chat as I was curious if the car was actually a 318 as the badge implied.

“It’s a 2.8 that races in Tegiwa Club Enduro. 180 bhp/tonne class.”

I’m ~240 bhp/tonne.

At this point I overlayed my lap telemetry with a mate’s Clio 182. I drew a conclusion that I’m massively down on power, mainly based off the fact that I’m barely +5 mph quicker than a factory 182 on the longest straights on the track.

Fantastic.

Currently preparing myself to compression test it… then cry accordingly. If compression is good, then we’re likely dealing with a boost leak somewhere.

Fingers firmly crossed.

(I’ll keep this updated as the saga undoubtedly continues…)

[DaveL485]

@S24NRC

Mainly so I can share the pain…

[DaveL485]

@S24NRC

Boot opening every time the brake pedal was pressed (beautiful).

Thats such a Renault fault

[DaveL485]

@S24NRC

Cue the Renault Moment™:

If it makes you feel any better I paid £600 for a track day at Monza, drove all the way there (900 miles) and my turbo failed after 4 laps…

[Adey]

ouch, not having the best of luck are you

[S24NRC]

Threw it in my unit Tuesday night and got to work. Benchmarked it against an Diesel Insigina Estate up a slip road enroute and got comprehensively humbled. Not a happy boy.

First job was track down the “dead good” compression tester my mate had left on the shelf.

“Dead good” if i was testing diesel injectors. That was a non-starter so [I]I’ll just rip into it then.

[/I]

So I figured whilst I was down there I may as well check everything else. Smoke tester was MIA so went through and checked every single joint in the boost system, Found a few dodgy looking Jubilees and some couplers that looked a bit rough but nothing too scary. Made note of sizes and ordered some nicer-than-jubilee clamps for future improvements.

After this I tackled the PCV and Vacuum lines. This has all slowly been changed over the years and there was a couple of redundant one way valves and lines that really only serviced the fuel breather and didn’t need to be there, they got chopped out and simplified with fresh lines. Also found the top breather had a one way valve that functioned as a goose call when tested via sucking/blowing into it, so swapped that out for a known good one, as that would’ve 100% been bleeding off boost.

Finally, I went through all the coil packs and tried to pick the ones that looked the “cleanest” - a couple of the springs that carry the signal to the sparkplug looked slightly corroded/full of s*** so spent some time taking the 3 sets that I have apart and making the best possible ones from them.

Took it out for a quick test and the difference is night and day. Was barely spinning up 1st gear and now it was flashing the traction light at me throughout 1st 2nd and into 3rd. Not 100% certain exactly what the fix was but had noticed some hesitation/occasional misfire when loading up 3rd and 4th gear so I’m in the camp of a combination of boost leaks and coil packs being on the way out had been contributing.

Fingers crossed/touch wood/3 daily prayers it stays like this for the foreseeable - bored of doing engines, I want rudeboy racecar bits like coil overs now!

[Brigsy]

It will have been a boost leak. Id still smoke test it or pressure test, can miss loads of issues without.

[S24NRC]

Fair few months down the line now. No issues to report, really starting to refine it now. High level of the past few months -

• March: Kind of settled for there being nothing wrong with the engine. Picked up some BC Coilovers brand new in box for 500 quid and slammed it.
• April: Various snagging
• May: Engine came back out after the drivers side brake line corroded and burst, and failed welds on the downpipe. Did a load of changes and general tidying up of the fit and finish of the conversion
  • New AN-8 Fuel line from the firewall forward with Torques adapter for the rail.
  • New nimbus firewall heatshield designed to be a bit more serviceable than the stock 225 one.
  • New anti rotation links - the before and after for how the car drove was borderline embarassing
  • Smoothed the drivers side of the bay. Removed spire clips for all the daft OE connections for AC, fuel and PCV lines and replaced with rivnuts and P clips, Halfords finest rattle can finish to round it all off.
  • Forge Solid boost pipe from IC cold side - hot side is going to require more thought with regards to packaging.
• June: Bridgestone Potenza Sport EVOs fitted all round. Cracking fast road tire.
• July: Chassis hit 150k miles
• August: Few more improvements towards the end of the month:
  • New Thermostat - one in it was smoked and basically constantly open. massive difference in mid range and drivability
  • New crash bar - the one fitted to the car was about 3 inches shorter at each end (not asking any questions, its hpi clear and that’s all I need to know…) bumper now goes on and doesn’t pop off at the edges for the first time in my entire ownership!
  • Posh constant tension clamps on the boost pipes as the cheap Halfords jubilees were looking a bit ropey.
  • Studied Visu and managed to piece together a working Xenon levelling system - just cornering lights to tackle now and we should be good. Headlights have been a bit of a pain ever since fitting the Megane set up.

Hopefully now trackdays aren’t £1,000,000 to enter and the cars feeling a bit better we should be getting out for some laps this winter. Few outstanding jobs to get sorted (Brakes, rotten radiator fan) and we should be ready to go. Maybe.

[S24NRC]

Made some changes last week, cars ripping now.

Had a week off work so went ahead and threw a new oil and filter into the rig and finally made use of the cornering lights post Meg conversion.

For some reason, and I’m guessing its something to do with the Megane ECU and loom, the Clio cornering light system simply do not work for love or money. I’ve spent a good few hours on a few occasions metering out the loom and checking things but I can’t seem to get it to work. Decided to fit some nice PIAA bulbs in the high beams and the cornering lights and dump them all into the same circuit so I essentially have a 6 bulb high beam. It’s absolutely mega at night, and just in time for winter commutes.

On Thursday, Chris at EFI posted some last minute availability for the weekend. I jumped on this as it would be nice to know where we currently sit with everything.

Roll on Sunday afternoon and we had a chat about the economy being a bit weird, the car not feeling particularly fast top end and some general weirdness with part throttle. First run and Chris aborted it at 4k as he could already see the fuelling was out-of-range rich and the power was already tailing off at 238bhp.

Oh.

So we went back in and had a look over the bay. A lot has been changed since Feb, but nothing huge, and nothing that Chris thought would be causing the fuelling to be so wrong. We decided to start from scratch and finished at 300ish and 280 torks, not bad considering it pulled 310/290 at -2 ambient in Feb.

Because I’m also a massive child and had been at the Woodpecker stages on Saturday listening to Rally 2 cars farting about, I had also asked for some mild bangs on gear change. Chris said he was limited with what parameters he could change for that kind of thing but said he would add the mildest option possible. Never really heard them during the post dyno road test, but on the way home discovered it basically has full bore anti lag now if I let off above 4k. I imagine the novelty will wear off in the next fortnight as its been approximately 4 days and the constabulary have already had words…

Absolute missile now though. Buzzing with it.

[Brigsy]

I had the same 4k pops on my kangoo on overrun on stock meg ecu to help with engine braking whilst in gear as the canbus/vss did not work as good as megane.

Was savage, flames all the time on high rpm liftoff​

[andybond]

Had some major banging going on my r26 as well.

Lasted 2 weeks I think!

[S24NRC]

My glowing 15T is visible from space at the moment

Deffo needs revising, got a trip into Wales tonight/tomorrow so will enjoy the B5105 and A5 into Snowdonia then sort some suspension issues and get it booked in for a tweak in a few weeks time. Shouldn’t have fked with it

[S24NRC]

This aged like milk.

Bottom ends went 15 minutes after leaving the house. 99% certain this is thrust washers again.

Time to build the 5th engine.

[andybond]

Ah man, no!

Any idea of the cause?

[S24NRC]

I’m putting good money on thrust bearings.

This is my 3rd engine failure in a similiar way. Engine 1 had completely worn the thrust bearings and side loaded the shell bearings, this one seems to have gone in a similiar way.

Had just set off to camp out tonight before hiking Snowdon in the morning and noticed the engine start rumbling at 50 mph on cruise control. Dived off the A494 to be greeted with a lovely knock on decel.

I really don’t think R26R spec clutches and SMF are a good shout on these engines for daily use.

[andybond]

I ran a SMF + Helix for about 35k on my f4r 774. No issues at all.

What were the other failings caused by?

[S24NRC]

Engine 2, im unsure of, never stripped it down after it died as i tried limping it back a bit too far so it probably wouldn’t yield much information.

Engine 1 was interesting because the thrust washers were very clearly worn, and it failed on a gear change. Big ends look to have been the next thing to go but thrusts were by far the worst.

The only constant across the 3 engines with bottom end failure has been the unsprung clutch set up.

Recovered the car today with the trusty 400 quid Discovery. Will start ripping into it and see what we can find.

[S24NRC]

Rolled the Clio back into the unit after giving the place a proper clean and clearing some space at one of the workbenches. All our cars have been working, so we’ve got out of the habit of tidying up and lost a few hours to that in the morning.

Gave the Clio a wash and got chatting to the landlord. He’s done everything: chassis development with Bentley, VW Cup cars, Porsche Cup—the list goes on. He mentioned having trouble with a VW Cup car where the helical gearing in the gearbox was loading the crank, which I’d never considered and might be worth checking. I noticed some horrible gearbox noise when the car was on the dyno, and the ND0 interfaces directly with the crank through the pilot bearing. The box is probably approaching 200,000 miles now, so there’s a good chance some wear items are past their best. It’s also the only component that’s remained unchanged across all these engines. It might be a long shot, but it’s worth investigating.

I started cataloguing my spares, too.

A head I thought was good turned out to have some nasty gouges in the inlet cam journals, so that’s no use. Pulled another head that looks good, has undamaged journals, but needs a few helicoils where the threads disintegrated while removing the rocker cover. They don’t take much torque, so provided I’m accurate, it should be fine.

I also had a block acquired quite cheaply from Facebook, containing a crank that had covered around 500 miles after a rebuild before a piston melted. The crank was mint, as were the bearings but unfortunately, there are some nasty scratches in the bores. It would suit a forged build with oversized pistons, but I don’t think I’ll get away with using it in a stock Mk3 bottom end. That one can be shelved for a rainy day.

Checked another spare block that has been on the shelf since 2023 because it was too heavy to scrap and that ones a lot better, will likely go again with a hone and some gentle WD40 and Scotchbriting on the journals. I still have the engine in the car and another assembled bottom end sat there, so will crack on disassembling those two and go from there I think.

Cams and pistons are pretty simple - I’ve got 225 cams that will go again, and I’ve got a set of 874 rods and pistons out of a 250 that will be fine to go in with new rings and bearings.

After this, my mate decided to absolutley fkin nail his 172 bottom end. Worst knock I’ve ever heard coming out of one. Discovery 3 once again saving the day…

I hate F4Rs.

[S24NRC]

Spent Monday/Tuesday night investigating previously destroyed engines and blocks.

Stripped the bottom end of engine number 3 and found number 2 big end and number 3 main had spun. So most of the bottom end is scrap, but the head is still usable.

Then whilst speaking to my mate and fiddling with the oil pump chain drive, I noticed the sprocket was free spinning on the crank. Penny dropped. Went to check over engine number 2’s crank and sprocket that I’d kept together and confirmed that the crank and sprocket had witness marks suggesting the pump sprocket was spinning in place on the crank. I’ve seen various reports of this happening on diesel M9Rs which use a similar architecture.

I will probably admit I’ve been a bit lax in torquing the crank bolt to to spec in the past, probably erring more on the side of ‘FT’ than the exact angle tightening on the presumption that a keyed crank pulley would prevent most issues… Will have the engine in the car out this weekend and that will be the first thing I check.

[Brigsy]

No luck with engines mate! Be interesting to see whats failed on the current one.

Thrust washers seem to fail quite often on higher milers. My mate has just narrowly escaped a fail after finding one in his sump. I dont think its smf related, maybe heavier clutch though.

Oil pump sprocket needs clamp force of pulley. Definitely torque to yeild crank bolt as per manual. Ive had no issues personally, oil pressure is always rock solid.