rb5037 Posted April 6, 2005 Report Share Posted April 6, 2005 Right. My big end went and i got a recomended company to do the work. Cost £2500 Ran in the engine in for 1000 miles and then got the recomended engine oil changed from a garage the engine rebuilders recomended. Now 150 ish miles later the engine went bang!!! The 1st company picked up the car last Tuesday and got back to me today saying that no.4 piston had melted. This was via e-mail as i've been asking fo news via e-mail, the owner of the garage said he was going to work out how much it is going to cost and get back to me. Now, i got a 6 month guarantee and i feel this should be covered. The car is a Subaru Impreza year '99 I've done a search on "Scoobynet.co.uk" and it seems that a piston melt is due to a poor reading maf sensor. (causes the car to overfuel) Shouldn't this have been checked before letting the car go? Any engine experts please give me some advice. Don't want to post on my normal car site as the company that did the work uses it alot. Thanks Adam Quote Link to comment Share on other sites More sharing options...
barrie0 Posted April 6, 2005 Report Share Posted April 6, 2005 Rb Try this forum http://www.carmechanicsmag.co.uk/cgi-bin/yabb/YaBB.cgi Its the forum off the car mechanics monthly magazine and there are some clever people on there who should know the answer . As an aside if you want cheap new tyres , the price includes vat+deliv try http://www.mytyres.co.uk/start.html It also has links to tyre fitters around the country who will fit,balance etc at roughly £7 a tyre . Quote Link to comment Share on other sites More sharing options...
rb5037 Posted April 6, 2005 Author Report Share Posted April 6, 2005 Thanks AGAIN That's twice in the last 30 sec's you've helped me Now posted and waiting for a reply. Please, anyone on here that has the know give me some advice Quote Link to comment Share on other sites More sharing options...
the last engineer Posted April 6, 2005 Report Share Posted April 6, 2005 Dont buy another Subaru Impreza year '99 sorry guy couldnt help it . selling my grand prix if you want it Martin Quote Link to comment Share on other sites More sharing options...
rb5037 Posted April 6, 2005 Author Report Share Posted April 6, 2005 Dont buy another Subaru Impreza year '99 sorry guy couldnt help it . selling my grand prix if you want it Martin Got to laugh Fisherman mike and Digger.... Do you think i could use my scoob for a bet on the grand national ? Quote Link to comment Share on other sites More sharing options...
Fisherman Mike Posted April 6, 2005 Report Share Posted April 6, 2005 Fisherman mike and Digger.... Do you think i could use my scoob for a bet on the grand national ? 10.00 ew thats £20.00..... you would still have to find a tenner. Quote Link to comment Share on other sites More sharing options...
rb5037 Posted April 6, 2005 Author Report Share Posted April 6, 2005 Quote Link to comment Share on other sites More sharing options...
Fisherman Mike Posted April 6, 2005 Report Share Posted April 6, 2005 The MAF (mass airflow sensor) reduces the amount of time it takes for modern chip controlled engines to adapt to inlet temperature changes and volume. The quicker the ignition equipment reacts to this information the more efficient the combustion process. I must be honest I have never heard of a faulty maf causing fuel overload to the extent that you would get piston melt. I would have thought the car would run extrememly hot and irregular before this happened. That said if there was no reason to suspect a faulty MAF you could be stumped. FM. Quote Link to comment Share on other sites More sharing options...
rb5037 Posted April 6, 2005 Author Report Share Posted April 6, 2005 Not looking good on here i'm "me on my own" poxy car, gonna get a gallon of petrol and do the do's :lol: Maybe not. Quote Link to comment Share on other sites More sharing options...
Fisherman Mike Posted April 6, 2005 Report Share Posted April 6, 2005 Might be a good idea to retrieve the Maf and have it tested. Its normally fixed to the air intake system. This would soon tell you if the unit was faulty. I am a bit suspicious that the maf would fail and cause this problem so soon after a engine big end rebuild......Hope you get it sorted. FM Ps sell the X5 and get the missus a Terrano Goodnight im off to bed. Quote Link to comment Share on other sites More sharing options...
old rooster Posted April 6, 2005 Report Share Posted April 6, 2005 I can sell you a good Fourtrak Quote Link to comment Share on other sites More sharing options...
Tam Posted April 6, 2005 Report Share Posted April 6, 2005 Have you any aftermarket mods (air induction kit) heard this can cause this problem Tam. Quote Link to comment Share on other sites More sharing options...
Deako Posted April 6, 2005 Report Share Posted April 6, 2005 rb, Scoobs are a real worry, loved mine to bits (03 WRX bought new, no mods except afterburner backbox for the lovely flat four burble) and hammered it everywhere, but in the end (18 mths later) I got a bit fed up of having to spend 15 mins warming her up prior to a thrash and 5 mins cooling down... Don't miss every scrote **** car thief in town oggling her either! oh, and the £100 per week in optimax was somewhat tiresome too. but god, I miss that car! Quote Link to comment Share on other sites More sharing options...
Devilishdave Posted April 7, 2005 Report Share Posted April 7, 2005 Same with the motor bikes have to warm em up b4 you take them for a thrash. Dave Quote Link to comment Share on other sites More sharing options...
Axe Posted April 7, 2005 Report Share Posted April 7, 2005 (edited) Its been a while since I tinkered with cars but I do have a freind that works for a certain American company, in the Engine design department. We were chatting the other day about Injectors and the damage that they can cause if they arent right. Basically the injector has a very small gap in it that when the fuel is passed through, it is vapourised before entering the piston chamber. He then explained that if the gap is wrong or closes up to far under heat etc, that instead of the fuel vapourising it actually passes through as a constant jet....'Jetting'. This has an undesired affect as apparnetly fuel does not actually hit the piston before being ignited. Where the 'jetting' takes place the fuel is squirted on to the top of the piston and ignites on it!. The melting point for the piston is around 450 degrees where as the exhaust tempreture gas is normally around 800 degrees. If the injector is 'Jetting' the piston will experience the higher tempreture and literally melt. So maybe, you should get someone to check the injector. Hope this helps. regards, Axe Edited April 7, 2005 by Axe Quote Link to comment Share on other sites More sharing options...
rb5037 Posted April 7, 2005 Author Report Share Posted April 7, 2005 Have you any aftermarket mods (air induction kit)heard this can cause this problem Tam. Mod's Mmmmmm ! ! ! Yep! But they've been done for over 2 years and no problems for 2 years. Car's got (had ) just under 300bhp and run like a dream. Looking at the site i posted in looks to me as though i need bite the bullet Anyone want a limited edition "green house" for their back garden? Steel blue with large potting shelf on rear, does not come with caretaker in side Edited to say "Cheers Axe for that info, didn't think of that" Quote Link to comment Share on other sites More sharing options...
Axe Posted April 7, 2005 Report Share Posted April 7, 2005 (edited) So what time was it running at Santa Pod before the incident? Edit: I normally see my mate after work for a couple of jars, if he's there tonight, i'll grill him on the subject and see what else he can think of. Edited April 7, 2005 by Axe Quote Link to comment Share on other sites More sharing options...
rb5037 Posted April 7, 2005 Author Report Share Posted April 7, 2005 13.4 @107 mph. That was with a dicky clutch as well Didn't take it again but i'm sure it could have done high 12's with a new clutch. :ernyha: I'll never find out now :( Quote Link to comment Share on other sites More sharing options...
barrie0 Posted April 7, 2005 Report Share Posted April 7, 2005 Rb if the Maf was faulty I would have thought the engine diagnostic light would have come on as well , I would also post in the diagnostic section as well on the other forum as the bloke who writes about diagnostic faults etc for the magazine also posts on the forum . I also would have thought with my limited knowledge that you would have had symptoms leading up to this ie unburnt fuel out of the exhaust (black smoke) , uneven and lumpy idle and running etc . Not for it to just happen Still hope your bill won't be to big . Quote Link to comment Share on other sites More sharing options...
lurcherboy Posted April 7, 2005 Report Share Posted April 7, 2005 Right. My big end went and i got a recomended company to do the work. Cost £2500 Ran in the engine in for 1000 miles and then got the recomended engine oil changed from a garage the engine rebuilders recomended. Now 150 ish miles later the engine went bang!!! The 1st company picked up the car last Tuesday and got back to me today saying that no.4 piston had melted. This was via e-mail as i've been asking fo news via e-mail, the owner of the garage said he was going to work out how much it is going to cost and get back to me. Now, i got a 6 month guarantee and i feel this should be covered. The car is a Subaru Impreza year '99 I've done a search on "Scoobynet.co.uk" and it seems that a piston melt is due to a poor reading maf sensor. (causes the car to overfuel) Shouldn't this have been checked before letting the car go? Any engine experts please give me some advice. Don't want to post on my normal car site as the company that did the work uses it alot. Thanks Adam Overfueling is not a piston melting problem with petrol engines. Underfueling (weak mix) is. I would need to see the top of the piston, spark plug and the relevant combustion chamber. A map sensor can do all sorts of things. LB Quote Link to comment Share on other sites More sharing options...
Shotgun-Sean Posted April 7, 2005 Report Share Posted April 7, 2005 Sorry to hear your bad news, but i have some more for you the maf sensor is classed as a ancillary part and therefore not covered in your warranty You can buy an engine be it bottom half, top half, or full motor and it will be just the bulk of the engine things like manifolds inlet and outlet turbos injectors fuel pump etc are from your old unit just transfered to the new one so these will not be covered. the big end is the bearing that connects the con rod to the crank shaft and this is ok so no claim there sorry to bring you more bad news cheers sean Quote Link to comment Share on other sites More sharing options...
Axe Posted April 8, 2005 Report Share Posted April 8, 2005 RB, I managed to speak with my my mate last night and asked the question 'what would cause a piston melt down'. His response was quite simple really, 'Over Fuelling' or the injectors as I mentioned. I then asked him about the MAF and he said that sinse the MAF controls the amount of fuel and over fueling is a possible cause that it may be worth getting it checked. The only other thing he mentioned was piston scuff, but said this would not be mis-diagnosed to a piston melting, by a professional at least. Regards, Axe Quote Link to comment Share on other sites More sharing options...
wabbitbosher Posted April 8, 2005 Report Share Posted April 8, 2005 Why didnt you ask earlyer? Your men that fixed the big end should have re timed the engine ,your garantee should cover the whole engine after major work like a bigend, if you dont get any joy taking it back to them, take it to trading standards (give them a ring anyway for advice) Any problems let me know i still have friends in the institute to lean on them Speak soon WB Quote Link to comment Share on other sites More sharing options...
Shotgun-Sean Posted April 8, 2005 Report Share Posted April 8, 2005 I think you missed the plot WB in the first instance the big end went and he had that repaired the fault now is a piston melt down due to over fuelling cheers sean Quote Link to comment Share on other sites More sharing options...
rb5037 Posted April 9, 2005 Author Report Share Posted April 9, 2005 Thanks guys for all your replies. I've got to wait now for an outcome of what's happening and how much i'm looking at to get it fixed. No one wants a limited edition green house then? Adam Quote Link to comment Share on other sites More sharing options...
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