Hi all I was asked to look and sort out a damaged (forged)265 Meganne engine. This engine was built by someone (i'm not going to say who, so don't ask, that is going to be down to the owner) they were supposed to have forged the engine, at a cost of £8k, they had the car for quite a while apparently as the owner didn;t want a rush job. Owner told me it has done less than 4000 miles since the build, its had 3 oil changes since the build and was just about to have it's 4th when it started knocking. the car was only the owners daily, never tracked but on occasions driven spritely. The car was trailered to me, i never ran it as i didn't want to do any more damage causing more expense for the owner. With the engine and box removed from the car, i drained the engine oil and it was black, almost as black as the oil from my 175Dci after 3 trackdays and about 1500 miles, very suppressed at that. My Forged R26 does 3 trackdays and a good few miles to and from tracks and is nowhere that black, so i really think something isn't right. With the gearbox removed, the sump was removed. Found these in the bottom https://flic.kr/p/2pjDMMV https://flic.kr/p/2pjyaEo There was also a real gritty mess in the bottom https://flic.kr/p/2pjCTZK checking the big ends by hand, found that the #2 big end was rattling around, 1,3 and 4, felt okay, so a full engine strip was needed.
There was evidence of oil vapour around the rocker breather outlet pipe, checked the end float of the standard turbo and there is about 3mm in and out movement, so that's knackered as well. The head was removed, after taking off the cambelt etc. Pistons didn't look great, more carbon than i expected due to the mileage. https://flic.kr/p/2pjDPTP Also noticed that i could see the top ring of piston two, hard to see in the pic https://flic.kr/p/2pjCV7z also hard to see is the signs of hard rubbing of the pistons against the cylinder wall https://flic.kr/p/2pjEysc was quite suppressed that there were no markings on the top of the pistons https://flic.kr/p/2pjCV36 this engine was supposed to have had Wosner pistons and Wosner rods fitted, just saying. the combustion chambers don't look great considering the mileage. https://flic.kr/p/2pjCUgG quite oily
So flicked the engine over to undo the conrod bolts, can see some discoloration to the cap of number 2, so poped it out and the reason for the knocking becomes obvious https://flic.kr/p/2pjydxc Also these don't look like Wosners forged rods https://flic.kr/p/2pjydtj Further inspection of the pistons there were no markings except for a couple of letters etched in the top of the piston, the markings look nothing like the markings on the inside of the pistons taken from my Forged 250 that another builder so called, built, (that's another story ) there also didn't look like there was coating on the skirts, unlike Wosners own pistons, so these pistons in my opinion are Wosner copies. https://flic.kr/p/2pjydxc https://flic.kr/p/2pjDQSC The rest of the pistons were removed, all the big end bearings are in a bad way Also the crank is toast as well, last crank i had this happen to it had 100 thou runout, my engineering company refused to try and straighten it, so guessing this is the same. https://flic.kr/p/2pjFedj
With all the pistons removed, another thing i noticed was how tight the pistons are on the conrods, they should flop from side to side, these were no way slack enough, this then causes the piston to rub on the side of the bore on the way up and on the other side on the way down, think this is why the bores are so marked up. The crank w=as moving fore and aft by a good amount, maybe 4mm+ as you ca see in the pic, the flywheel was touching the block when the clutch was depressed, https://flic.kr/p/2pjFdZ3 Was quite surprised on the amount and type of sealer that was used on this engine build by this builder. this gunge is everywhere and in way to big a quantity https://flic.kr/p/2pjFerk removed the main bearing caps and ....... Think this is where all the problems have come from, this has obviously restricted the oil flow to the bearings, crank journals and big ends. https://flic.kr/p/2pjFeub another main bearing https://flic.kr/p/2pjDRRG The recess where the crank thrust washers fit on one one side of the main bearing, has been worn away, so basically the whole block, crank, rods and pistons are scrap. For this £8k+ build, the owner didn't even get uprated valves and springs, the head hasn't even been touched. I removed the valves as there is no way i'm leaving the standard ones in there, hate to have one break once the engine is built, the owner does intend to track it in the future, so there is no point taking chances. A replacement block and crank are on the way to me some tine this week, so i can start to build this engine for the owner. Parts list Wosner pistons Catcam rods Supertec valves Catcam Gold valve springs King big end bearings King main bearings Crank thrust bearings Genuine head set lower gasket set. Already started cleaning and painting parts for when it starts to go back together. Thats it for now, will keep adding info and pics as it progresses.
Hi Ian, I had 2 turbos fail from the same tuner, last one at 960 miles, and 10 months use, and of an unknown origin, and would only repair at my cost. Have also spoken to several people who have had turbo failure from the same tuner, one with a forge build that's 3 months old, smoking very nicely, and gone back to be looked at. Keep us posted. If response is poor on here, post on Megane Facebook forum.
Not much to report today, apart from some tasty bits that have arrived to do the build. Catcam Conrods with ARP bolts https://flic.kr/p/2pk2jxy Supertec valves and keepers https://flic.kr/p/2pk2jst Catcam Gold springs https://flic.kr/p/2pk2koG Valve guides https://flic.kr/p/2pk4Ae8 Uprated oil pump, having a higher pressure and a higher flow, also bough one for my 250 build. https://flic.kr/p/2pk3e6G King racing big end and main bearings No pic forgot Head will be dropped off at my local engineering company to fit the valve guides and recut the valve seats
Picked up the block and cylinder head today, the blocked got bored out first oversize, it was borderline if it was needed, but as it needed new pistons anyway, i thought it was better to be safe than sorry. https://flic.kr/p/2pnsNZT The cylinder head had new valve guides, as the exhaust guides were a little worn, so as a precaution they were all changed, the seats were cut back to make sure the valves seat properly, they will be lapped in as well to finish the process off and the head had a very light skim, just to make sure its flat. https://flic.kr/p/2pnxx93 And it got a good clean https://flic.kr/p/2pnzfRY Obviously the pistons arrived a couple of days ago, as they were required for the boring process, as this engine will eventually be used on track it had another thou taken off, mine had 3 thou extra as it will have a big turbo and basically be a track only car. https://flic.kr/p/2pnxx6s Genuine Wosner pistons have markings on the crown, unlike the ones i took out. https://flic.kr/p/2pnxwZk I have cleaned the block, it was cleaned after it was bored, but just getting the odd bits off, then a good coat of etch primer and a couple coats of black gloss. https://flic.kr/p/2pnzMrg Well this is it for now, more progress at the weekend
Also today i modified the main bearing shells, genuine Renault ones don't have locating tangs on them, aftermarket ones do, especially race ones https://flic.kr/p/2pnzMJW After I very gently ground the tangs off with my cordless angle grinder, i put the grinder in the vice to hold it still and kept checking after each second of grinding, it takes time but then you don't cut too much off. https://flic.kr/p/2pnsNYA
Hi Arthur Sorry some how i missed this post of yours. I've have 3 hybrid turbos fail now, there is no way i'm going to spend that sort of money on one again, this is the reason i have been running a Borg Warner 6758 Twin scroll turbo, the low end response is great, starts to boost at 1800-ish and i had full boost by 2400, the 6758 is rated at 500hp, i don't think there is anyway this can be achieved on a Megane, but it did make 436 on the dyno but was pulled back to 405hp for other reasons than the turbo, i suppose what i'm saying is this turbo can potentially run 500hp so it's not being pushed to the limit, where as the hybrids are pushed beyond there design. The last turbo i had was sent back to the supplier to be checked out, as the car was smoking, but as it turned out it was the engine itself, so with a clean bill of health i bought it. Had the car mapped, drove there and back, around 600 miles, time on the dyno (there was a problem with air intake temperature) the turbo was working to hard, so the power was brought back down till it was safe. I drove then to Cadwell another 280 miles, i got blacked flagged on my second sighting lap due to excessive smoke. Got home driving really steady, stripped off the turbo and it was toast, hybrid never again. Hope you are well and have a great Christmas and a happy new year young man See you sometime soon
Hi Ian. my car went into my local garage 31 August, got it back today!!.First turbo sent, was the wrong one, second one had play in a bearing, also sent back, third one was the wrong one, but a local engineering firm made a part, and it all works!! It's a new crated Garret T20, so we will see how it goes. Out of curiosity, my intake is down behind the N/S wheel arch, so always get cold air, and been through downpours, standing water, and never had a problem. With my driving ability, the Turbo will never be near its limit!!. Am booked on Anglesea 17 June, Oulton 18 June, more to come I am sure. Nice to meet up sometime. Hope you have a peaceful Xmas, and a Happy new year.
It shouldn't be a problem with your air intake there, but i've never had a problem with mine at the back left hand side of the engine bay, you could run a pipe from down at the front up to the filter in the engine bay, that will stop any serious moisture getting into the intake. I'm in the process of building a Mk3 250, my R26 was becoming a problem child. Once this 265 is finished i'm straight on to mine, hopefully will be ready for a trackday before Easter
Is there an option on a better turbo that can still run stock manifold? Hybrids are always ticking time bombs and I hate non cast manifolds
Yes there is, i started off with a Borg Warner 6758, if you search on the project thread theres my 265 forging pages sure its there somewhere. The 6758 was a T4 twin scroll unit, i made an adapter for it to start with, but there is a company in the USA that make stainless adapters, i have a spare new one, bought one and found i had a new one already, when i start on my 250 i'm going down a slightly different route. https://flic.kr/p/2kxM6sQ https://flic.kr/p/2kxRkUG You will have to get a down pipe made, it's not that hard, i fabricated it and got someone to weld it for me. That set up was on my car for a good while, then i sold the car (really shouldn't have) the guy that bought it tracked it all the time, he then took the engine out and sold it on and by all accounts it's still going, the engine must have 50+ trackdays and driving to and from the tracks. This will all be explained once i start my 250 build.
Cool was that on a standard engine or forged? Do you think it’s even worth stressing a standard engine with it being hammered on track?
Its was a forged engine, standard engines are okay ish if you track them, i've heard of standard engines throwing conrods and i know someone that is running 330ftlb of torque(R26) on a standard engine and tracks it a lot, there is no way you can work out what the breaking point is with these engines. This is why they need to be forged, it's the conrods that are the weak point, i have it on good authority that the pistons are good for 400hp, the valves on a 250 etc that can also be a problem, there two piece valves and prone to breaking if reved hard. My Forged 250 broke a valve, the reason it was cheap
... another issue with stock engine are the top ring gaps. are set from factory @ 0.25mm / .009 on high EGT due to boost / load sustain on track / lean AFR and so on, the top ring is at risk to block in the cylinder and broke the ringland of the piston. there are several cases of this issue. this is a brand new factory block + brand new oem ring .009 gap (are from my spare engine ). .... I think the gap is very tight for the car`s spec.
I've just done the ring gaps on the 265 engine, with the information from Wosner, the gap of the top ring was set at 18thou and the second ring at 21thou, if your talking about the F4R774 engine (225 and R26) most of there problems with ring land failure comes from the fuel rails shit design, fitting a Mk3 fuel rail is going to be probably the best upgrade you can do, even on a stock engine. It will be even better if you do the raising rate fuel setup as on the mk3's, a in tank pump and different FPR valve is also required., use a set of 250 injectors as well, but you will to get it mapped.
No. i don't have that tool, i have an angle grinder with a thin cutting disc on it. as long as you are gentle and take your time, i've done at least 6 engines this way without an issue
So did the 250 onward have a bigger ring gap or was it all down to higher cylinder temps of the 225’s
I think if it's forged then the heat level goes up and a bigger gap on the rings is required, i.m sure that the R26 with forged pistons was the same gaps, there basically the same engine, apart from the vvt and a slight combustion chamber shape change
so the piston rings were gapped yesterday ,today i fitted the pistons to the forged conrods and the rings installed onto the pistons, used my ring compressor, fitted the pistons into the block. https://flic.kr/p/2po6Guf Then to build up the head, assembly lube used in the guides to help on start up, the catcam gold springs fitted, the exhaust valves they need the single groove keepers as the standard one have 3 grooves so can't be used. Head then fitted using Victor Reinz head bolts, https://flic.kr/p/2po7vtB Part number https://flic.kr/p/2po183p head then torqued 40nm then 180degrees Put the pistons half way down the bore before, so the cams can be turned without the possibility of the valves touching the pistons, turn the cams till the locking tool can be fitted, undo the cam pulley bolts leave them loose by one whole turn, fit the cam belt, turn the crank till you can put the crank locking tool in. Tighten the cam bolts to the spec required. Remove the cam locking tool and the crank pin, turn the engine over at least two whole turns, refit the crank pin and recheck the cam timing, if it lines up then all good to go. Then fitting the cambelt covers and start putting all the other bits back on, will finish it off tomorrow. https://flic.kr/p/2po7v36
Well sorry i didn't take many picks yesterday or today, fairly basic work really, fitted the flywheel, clutch, gearbox etc etc Then to fit all the coolant pipes, wiring harness etc. The owner text me asking if i could do a short shift mod for him, good job the engine was still out, although it can be done with the engine in, it's a bit easier with the engine out. https://flic.kr/p/2poqyK7 Then is was fitting the engine back in the car, i wanted to get this done as i need to get this finished as i want to get mine in the workshop asap, time is running as i'm going to book Zandvoort and Bilster Berg, there at the start of March so time is in short supply. https://flic.kr/p/2poqyS1 doubt i will be doing much tomorrow or Boxing day, but we will see
It's staying with the standard turbo at the moment, the guy lost all confidence in the car after the last build and problems, but keeping him up to date with progress seems to have sparked some enthusiasm again for the car. Said it would be best to drive it to run it in and get the love back, he's already talking of a different turbo, but that's for later.
My Garage removed manifold, fitted original cast one, and had a stainless steel part made by a local engineering firm to fit the T20, Standard 250 crate turbo.car is running very well now
I have a spare one of these, standard manifold to T4 twin scroll or could be used for a single scroll turbo. It's made from stainless steel. https://flic.kr/p/2kxM6sQ https://flic.kr/p/2kxRkUG
Cool I was toying with a different turbo eventually but suspension and belts 1st. Will keep you in mind when the time comes for sure
