Engine Failure - Reasons/Causes - Fiat Coupe Club UK

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Re: Engine Failure - Reasons/Causes [Re: ] #581791 05/04/2008 19:14 05/04/2008 19:14
J jamie3 Unregistered
jamie3 Unregistered J	if we wanted an engine rebuilt, who would do it? and where would we get the uprated internals from?

Re: Engine Failure - Reasons/Causes [Re: ] #581806 05/04/2008 20:05 05/04/2008 20:05
T TurboJ Unregistered
TurboJ Unregistered T	Because your pistons are new. This coating has worn off don't know how many miles they have done. Anyway that coating aint gonna mean jack as it is applied to the skit and no amount of any coating it gonna save a cast piston from destruction. As people have said and I show proof the ringlands are the weakest point.

Re: Engine Failure - Reasons/Causes [Re: ] #581825 05/04/2008 20:21 05/04/2008 20:21
Joined: Dec 2005 Posts: 3,158 Near Reading JohnS I need some sleep
JohnS I need some sleep Joined: Dec 2005 Posts: 3,158 Near Reading	Quote: If the car has been mapped properly, i can't see why the knock sensors should have to retard timing - detonation should not occur! That's not really how a knock circuit works. It is true that if the max advance is some way off any pinking it should be ok, but that's not always the case particularly when people up the boost and are running larger turbos than std.

Re: Engine Failure - Reasons/Causes [Re: JohnS] #582943 07/04/2008 15:02 07/04/2008 15:02
T Trickymex Unregistered
Trickymex Unregistered T	JohnS is correct in saying its a matter of time.... the reason for this is that a piston with ringland damage will be down to fatique but will have little to do with detonating if you run any engine lean eventually the pistons will fail but forged pistons have more tollerence to it than cast items. Lars_DK you are wrong and you are right at the same time, yes a cast piston will take the same amount of BHP as a forged piston(to a degree)the problem is fatigue, they will fail What you need to do is have a word with a metalurgist (spelling?) he will be able to explain better than i can via a forum but if you told him the enviroment that a piston has to work in and then told him that you think a cast piston could do the same job as a forged piston i am sure he would burst into laughter Trick

Re: Engine Failure - Reasons/Causes [Re: ] #583079 07/04/2008 17:39 07/04/2008 17:39
S Squid Unregistered
Squid Unregistered S	Thats OK Jay. I looked through the invoices and it does indeed appear that I had only done 3700 mile on the GR28RS with the remap.

Re: Engine Failure - Reasons/Causes [Re: ] #583091 07/04/2008 17:57 07/04/2008 17:57
L Lars_DK Unregistered
Lars_DK Unregistered L	Originally Posted By: Trickymex if you run any engine lean eventually the pistons will fail but forged pistons have more tollerence to it than cast items. Trick But why would you run your engine lean? That is my point excactly. It seems that alot of you have slapped on a Gtech2, had the fueling checked (Through the exhaust backbox?) and then drove with that. That cant be the right way to do it, and hard to calculate for different fuel qualities, weather conditions etc. etc. I'm not saying my engine will hold up to the 350-360hp - but there is a good chance. I believe it'll work, and others have shown it works - but only with a very good tuner that knows what he is doing. My tuner has shown that, with 3 hours of work got the 20vt ECU running with 440cc injectors! No UK tuner has been able to do that yet? Last edited by Lars_DK; 07/04/2008 17:58.

Re: Engine Failure - Reasons/Causes [Re: ] #583094 07/04/2008 17:59 07/04/2008 17:59
H h2ypr Unregistered
h2ypr Unregistered H	Although im not posting (apart from this) im watching this very carefully. Ross

Re: Engine Failure - Reasons/Causes [Re: ] #583134 07/04/2008 18:49 07/04/2008 18:49
E eldinho Unregistered
eldinho Unregistered E	my car had been on many RRs to check the fuelling including mapping, was running WI and also had a egt gauge to check cylinder temps! but the pistons still went!

Re: Engine Failure - Reasons/Causes [Re: ] #583147 07/04/2008 19:08 07/04/2008 19:08
T TurboJ Unregistered
TurboJ Unregistered T	@ Lars I personally think you are running a risk, as mentioned earlier the cylinder pressures are extremely high so you run the risk of piston or rod failure. I think the mapping does play an important part but any tuner/engine builder should know that you really should be forged at that level of tuning. The mapper should not have to worry about these things whilst mapping you should be able to take the car to them and just say “Map this please”. Look at what happened to yellow coupe although it was narrowed down to rods bolts and possible a bad build. Whilst were on the topic of engine failures it has also been known that the EGT of a certain cylinder think its number 4 can cause heat build up causing the spark plug to fall into to bore anyone know any more info on this?

Re: Engine Failure - Reasons/Causes [Re: ] #583152 07/04/2008 19:19 07/04/2008 19:19
H h2ypr Unregistered
h2ypr Unregistered H	Originally Posted By: eldinho my car had been on many RRs to check the fuelling including mapping, was running WI and also had a egt gauge to check cylinder temps! but the pistons still went! How long did the car run like that tho? Thinking back, it was a testiment to the way it was mapped and maintained that it lasted that long. Ross

Re: Engine Failure - Reasons/Causes [Re: ] #583160 07/04/2008 19:26 07/04/2008 19:26
E eldinho Unregistered
eldinho Unregistered E	probably about a year or so I think!

Re: Engine Failure - Reasons/Causes [Re: ] #583189 07/04/2008 20:10 07/04/2008 20:10
S sparco Unregistered
sparco Unregistered S	I have had my standar ecu mapped for 440 injectors now too but it does take a good bit of time and perserverance on the dyno and a very knowledgable tuner to do it. I don't really want to post in here but i reckon if the engine is tuned properly then you should be able to see more power for a longer period of time before failure occurs than if you just bolt bits on and up the boost. All engines that are in ahigh state of tune by their nature unless being built purposely for a sepcific BHP will be liable to a failure iinternally of some sort sooner or later.

Re: Engine Failure - Reasons/Causes [Re: ] #583259 07/04/2008 21:30 07/04/2008 21:30
T Trickymex Unregistered
Trickymex Unregistered T	Im not saying that you should run a engine leaner or even that you would What i am saying is that its quite evident that the common failure in the 20vt engine is the ringland breaking up and that has nothing to do with tuning/running lean, its down to metal fatigue and this is where the forged pistons come into there own. Remember that fatique does not happen when you start the car for the first time, it takes time, this is why F1/WRC engines have a hourly life for each component, E.G: piston 20 hours, rod 10 hours, rod bolts, 5 hours and so on, in most cases you cannot even measure wear on the formentioned components but they can and do fail after there life cycle To put it simply if you want the engine to last then you are going to have to improve the matierial/design of each component in the engine or it will eventually fail form fatigue and the more BHP you put through each component the shorter that life cycle becomes you also keep going back to saying that a good tuner (Mapper) will be able to make this work, i dont know the Mapper your talking about but im afraid it doesnt matter, he will not be able to bend the laws of physics no matter how good he is. Tricky

Re: Engine Failure - Reasons/Causes [Re: ] #583378 07/04/2008 23:27 07/04/2008 23:27
V Vas Unregistered
Vas Unregistered V	I generally agree (although I did mention of some Greek cases running extreme power on stock internals - mind you few failed on ringlands in the meantime...) but another issue has to be counted (and I've not seen anyone mention it) Length and frequency of abuse! I mean you may have an engine that on dyno produced 420bhp on stock internals (don't laugh we have a few...), if you're more or less driving miss Daisy (on the fear that something will break) then yes, engine may last an eternity! If you only go for short blast of 3-5sec at 6+rpm and then relax, then I guess it will last $;\)$ I've also notice that a few of the failures happen on new owners (short after they bought a car already prepared/mapped/dynoed etc) Maybe the fact that on the enthousiasm of the ownership you're overdoing it a bit, pushing trying to find the car's (and their) limits and failures occur... V.

Re: Engine Failure - Reasons/Causes [Re: ] #583393 07/04/2008 23:47 07/04/2008 23:47
T Trickymex Unregistered
Trickymex Unregistered T	Agreed, the life of the engine is very much dependant on how its driven, if its a road car you are far less likely to damage it compared to a drag car unfortunatly its almost impossible to tell how long the life cycle of each engine component is as differing power levels and different driving styles change it a lot

Re: Engine Failure - Reasons/Causes [Re: ] #583401 07/04/2008 23:52 07/04/2008 23:52
H h2ypr Unregistered
h2ypr Unregistered H	Originally Posted By: Trickymex Agreed, the life of the engine is very much dependant on how its driven, if its a road car you are far less likely to damage it compared to a drag car unfortunatly its almost impossible to tell how long the life cycle of each engine component is as differing power levels and different driving styles change it a lot What if you'd had an engine built by barbz with brand new pistons and rods that were balanced and lightened? Ross

Re: Engine Failure - Reasons/Causes [Re: ] #583437 08/04/2008 00:22 08/04/2008 00:22
S sediciRich Unregistered
sediciRich Unregistered S	Originally Posted By: Trickymex Im not saying that you should run a engine leaner or even that you would What i am saying is that its quite evident that the common failure in the 20vt engine is the ringland breaking up and that has nothing to do with tuning/running lean, its down to metal fatigue and this is where the forged pistons come into there own. Remember that fatique does not happen when you start the car for the first time, it takes time, this is why F1/WRC engines have a hourly life for each component, E.G: piston 20 hours, rod 10 hours, rod bolts, 5 hours and so on, in most cases you cannot even measure wear on the formentioned components but they can and do fail after there life cycle To put it simply if you want the engine to last then you are going to have to improve the matierial/design of each component in the engine or it will eventually fail form fatigue and the more BHP you put through each component the shorter that life cycle becomes you also keep going back to saying that a good tuner (Mapper) will be able to make this work, i dont know the Mapper your talking about but im afraid it doesnt matter, he will not be able to bend the laws of physics no matter how good he is. Tricky Unlikely, unless severly over reved or used for a lifetimes racing the ringland damage is due to detonation. IIRC the pistons are hyper eutectic which are fairly brittle, detonation spike is like a center punch hitting the piston easy to see why such a small bit of aluminium could break off. Heat and pressure causes the detonation, higher boost on a lean setting will increase both significantly. As for fatigue, kept at normal rpm the loads will be well within spec for the pistons, damn sure fiat didnt miss that step out in the design. Materials dont fail humans in their design and application do. Change the engine spec -> change the material spec/design, look at an S/N curve for alloys or any metal (aluminium alloys dont really have a defined fatigue limit like ferrous alloys), increasing the loads severly reduce operating life(cycles vs load) - I'd attribute rod damaged after ruling our oil issues to that, but for cracked pistons - detonation for sure.

Re: Engine Failure - Reasons/Causes [Re: ] #583447 08/04/2008 00:28 08/04/2008 00:28
V Vas Unregistered
Vas Unregistered V	btw, do we have any case of forged pistons failing in the ringland or elsewhere in that matter??? After all it pays to have forged pistons of decent(ish) quality installed... V.

Re: Engine Failure - Reasons/Causes [Re: ] #583494 08/04/2008 01:11 08/04/2008 01:11
Joined: Dec 2005 Posts: 286 Germany Stichl Making a profit
Stichl Making a profit Joined: Dec 2005 Posts: 286 Germany	Hello, I myself drove about 20tkm with an engine with stock internals and about 400HP Boost with "big" GT2871R (and head work) was 1,6Bar at top power. Only modification of the parts: - lightening and shot peening of the rods After 20tkm I dismantled the engine (installed a 2,4l). I could not see any signficant abrasion... the engine was ok! I think you have to look for a good tuner who creates a good map... Moreover the original rods are quite heavy... better to lighten them. Note: The original rods ARE FORGED ones! Juergen 20VT coupegrale 4x4

Re: Engine Failure - Reasons/Causes [Re: ] #583512 08/04/2008 01:19 08/04/2008 01:19
Joined: Dec 2005 Posts: 3,158 Near Reading JohnS I need some sleep
JohnS I need some sleep Joined: Dec 2005 Posts: 3,158 Near Reading	look at this pattern and tell me what is wrong take a chip with a more aggressive ignition map Run more boost generate more heat The answer is that with more boost generally you can run LESS ignition particularly at the top end. but a lot of people using a chip with the same or more advance then standard. Yes there is some leeway because of decent quality fuel but running a chip with more advance takes some of that leeway out. So the knock circuit is probably working all the time backing off when it sees pinking or at least you aren't far off it. Bearing in mind the temp sensor is extremely slow to react to inlet temp differences there is a good chance that you car will have pinked at some point.

Re: Engine Failure - Reasons/Causes [Re: ] #583614 08/04/2008 03:17 08/04/2008 03:17
Joined: Jun 2007 Posts: 1,035 Carlisle Rob40 Club Member 1717
Rob40 Club Member 1717 Enjoying the ride Joined: Jun 2007 Posts: 1,035 Carlisle	Originally Posted By: Vas btw, do we have any case of forged pistons failing in the ringland or elsewhere in that matter??? After all it pays to have forged pistons of decent(ish) quality installed... V. Yeah, me. Burnt 5 lovely holes in 5 lovely CP pistons $\:D$ Cause? Quality det! This is how it should have come out of Torino!

Re: Engine Failure - Reasons/Causes [Re: Rob40] #583634 08/04/2008 03:31 08/04/2008 03:31
P paul205 Unregistered
paul205 Unregistered P	sorry to jump in but would a 252bhp coupe be in any danger of being to hot inside and melting/cracking???????

Re: Engine Failure - Reasons/Causes [Re: ] #583637 08/04/2008 03:33 08/04/2008 03:33
Joined: Dec 2005 Posts: 17,917 J JimO Forum veteran
JimO Forum veteran J Joined: Dec 2005 Posts: 17,917	Its all to do with gettin adequate fuelling Paul, have you had your fuelling checked on a RR? What are you running to get 252? 252 is not pushing the car too much, but thats not to say if its not done properly its safe!

Re: Engine Failure - Reasons/Causes [Re: Rob40] #583648 08/04/2008 03:43 08/04/2008 03:43
V Vas Unregistered
Vas Unregistered V	Originally Posted By: Rob40 Originally Posted By: Vas btw, do we have any case of forged pistons failing in the ringland or elsewhere in that matter??? After all it pays to have forged pistons of decent(ish) quality installed... V. Yeah, me. Burnt 5 lovely holes in 5 lovely CP pistons $\:D$ Cause? Quality det! nice one! how can you possibly have 5 holes? All happened together??? can we have photos plz? Was it long after fitting? did you have a custom chip or somesort of mapping? cheers V.

Re: Engine Failure - Reasons/Causes [Re: ] #583658 08/04/2008 03:53 08/04/2008 03:53
Joined: Jun 2007 Posts: 1,035 Carlisle Rob40 Club Member 1717
Rob40 Club Member 1717 Enjoying the ride Joined: Jun 2007 Posts: 1,035 Carlisle	There was a hole in each one, couldn't have done as good a job with an oxy/acetelene torch $\:D$ No pics, think i sent some back to Barbz to turn into ashtrays or sommat $\:D$ It turned out that the problem was caused by ECU not reading crank position sensor properly and as soon as it hit boost, it was 25deg out. All sorted now though $;\)$ If you ask Ross nicely, i'm sure he'll post up a nice pic of a remaining piston with some rather unique markings! $;\)$ This is how it should have come out of Torino!

Re: Engine Failure - Reasons/Causes [Re: ] #583667 08/04/2008 04:08 08/04/2008 04:08
T Trickymex Unregistered
Trickymex Unregistered T	in normal cercumstances i would probably agree but in this i do not you see i have pistons removed from a 20vt that had ringland failure on piston no:4 and none of the pistons showed any signs of detonation here are some pics i have of one of the pistons from that very engine [img]http://img2.putfile.com/thumb/4/9717551946.jpg[/img] [img]http://img2.putfile.com/thumb/4/9717551934.jpg[/img] as you can see there are no det marks what so ever this engine was live mapped and was absolutly spot on. I agree that the extra heat and pressures that are present in a tuned engine would be a contributory factor.

Re: Engine Failure - Reasons/Causes [Re: ] #583673 08/04/2008 04:14 08/04/2008 04:14
Joined: Jun 2007 Posts: 1,035 Carlisle Rob40 Club Member 1717
Rob40 Club Member 1717 Enjoying the ride Joined: Jun 2007 Posts: 1,035 Carlisle	Originally Posted By: Trickymex in normal cercumstances i would probably agree but in this i do not you see i have pistons removed from a 20vt that had ringland failure on piston no:4 and none of the pistons showed any signs of detonation here are some pics i have of one of the pistons from that very engine [img]http://img2.putfile.com/thumb/4/9717551946.jpg[/img] [img]http://img2.putfile.com/thumb/4/9717551934.jpg[/img] as you can see there are no det marks what so ever this engine was live mapped and was absolutly spot on. I agree that the extra heat and pressures that are present in a tuned engine would be a contributory factor. But you never saw mine! you could clearly see where the det had started to hot spot and then concentrate the heat til it totally melted through the crown. This is how it should have come out of Torino!

Re: Engine Failure - Reasons/Causes [Re: ] #583674 08/04/2008 04:14 08/04/2008 04:14
P paul205 Unregistered
paul205 Unregistered P	just a gtec1, bacbox k&n 57i, and turbosmart boost tee set to 16psi. the main reason of my rr was to check fueling, he said it was fine but a little lean around 3-4k, but he personally wouldnt bother changing it as its spot on further up he rev range all the way over. but my grap only has bhp&torque curves.

Re: Engine Failure - Reasons/Causes [Re: Rob40] #583675 08/04/2008 04:14 08/04/2008 04:14
T Trickymex Unregistered
Trickymex Unregistered T	cp pistons are good quality, i would guess that your problem was caused by an extremly lean mixture but i have never heard of all the pistons failing at once, very odd

Re: Engine Failure - Reasons/Causes [Re: ] #583676 08/04/2008 04:16 08/04/2008 04:16
P paul205 Unregistered
paul205 Unregistered P	that was in response to JIM O.

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