I have finally got my car ready and time off work to make the trip from N.Ireland to Perfect Touch in Hoddesdon, the run over went fine and the day on the roller went fairly well too.

My car is fitted with -

Forged pistons
Lightened and Balanced Flywheel
GT28RSR Turbo
SIP
Ramair Filter
Hayward & Scott 3" downpipe GT28 flanged
Decat 2.5"
Milltek exhaust
Greddy Profec B Boost controller
Pro-Alloy FMIC
Walbro Pump
3.8Bar FPR

After a walk up the town of hoddesdon (not much happening there) i went back down to see how the car was coming on.. the peak power output was 299bhp at the Flywheel and 292lb/ft of Torque this was produced using 1.5bar midrange and 1.15bar at the redline, Rob assured me that this was safe to run so i was happy, i though the output was alittle low compared to cars with a simlar setup and running less boost than mine was

Anyways i headed back for liverpool, the car felt great and i got to the boat for a few jars and a snooze, but soon it all went wrong, i was about 10miles from the boat on my final 70mile journey home, pushing on alittle (120ish) in 5th and under acceleration i heard a bang watched the oil pressure drop and the motorway fill with smoke, it had just thrown a conrod out of the sump.. wat a blody expensive and horrible trip, having only done 3k miles on this freshly rebuilt engine

So all in all.. PT? was it their fault? did they dial me in too much boost?

Or was it a dodgey engine component than caused the failure?

I suppose i will only find out when i pull the sump off and see what i can extract

Iain

Oh dear, Sorry to hear that.
So is it a broken rod or broken rod bolts?
When you open it up upload the pics.
Its not boost that breaks rods it’s the torque.
Sounds like a dodgy rod or loose rod bolt as I thought these rods could handle 330ft/lb

fairly unlikely to be PTs fault - With the spec you have, you should be capable of running rather more than the power PT managed to extract

If it was PTs mapping, you would have melted a piston or burnt a valve. If the bottom end has let go, its down to a mechanical failure

However, if the mapping was sufficiently bad, the piston may have failed, causing the rod to flail around in the bore - it wouldn't have taken long for it to find its way out of the block

Can't believe PT could have got it that wrong, not after so many good results

My money is on a failed rod bolt - 300 lb-ft is well within the rod's limits, so it looks like a freak failure.

bad luck

I agree with Nigel the figures seem too low for a healthy engine and bottom end failure is more mechanical than mapping. Who built the engine?

Yeah the car seemed so good but i didnt even get a full tank of juice though it before the Bang..

After a discussion with Rob (who was very helpful) he explained that it was likely to be a machanical failure,

The guy that built the engine is a motorsport minded mechanic and not an actual engine builder, he will be fitting me a std. engine which i think i have sourced, engines are just the kind of thing that you cant really have any comeback on i suppose and i couldnt tell if it was to a loose bolt a broken bolt really i guess

Should be getting the sump off this week and then i should be able to tell if its a rod or bolt failure.. hopefully i can salvage a head at least from the engine and get back on the road again asap

Toss! Really bad luck mate - really feel for you.

If it's any consolation, when I changed the big end bearings on mine I torque the caps up using the 16v settings instead of 20v, not much difference, but one worked loose after 100 yards so no damage done, but if you have a bolt that's worked loose, I guess you'll find it in the sump in one piece as opposed to a broken bolt. Bad luck, hope you get it fixed soon.

Sorry to hear your bad news mate.

Sheesh.. sorry to hear that Iain. My aux belt let go on the PT rollers so I do understand that sinking feeling. Hope you get her back on the road asap.

Really sorry to read this Iain. You're now due about 10 years of good luck, i can't believe the run of bad luck you've had ...

Oh dear, sorry to hear about this Iain . I had a similar experience with mine last year, so I know how you are feeling right now !

Phil

Really sorry Iain, that's really bad news, I can only imagine how you feel. good luck with the new engine.

Joe

Thanks guys I think im going to collect an engine and box tonite

You may want to have a few of the boys keep a look out for someone with a voodoo doll in the shape of a yellow coupe before u fit this one!

Dude. Thats terrible terrible luck.

Not to say anything against your mate, but when an engine isnt running right, the power will be done. Maybe the lack of power from the engine was a sign of the impending failure? Really bad luck but get a diagnose done.

Ross

yeah i intend to..

Im going to drop this lump in on std internals and bolt on my bits and pieces then run it as sensible boost..

I will get the engine dismantled when the engine comes out and get some photos, then some of your technically minded guys can diagnose what the failure was

Iain

bad news mate, but it may not have helped using forged pistons ( these will be usually well balanced ) thus as you kept the OEM rods, these will be BADLY balanced, thus you probably made the crank assembly more out of balance = conrod failure.

the more power, the more you NEED to balance the bottom end, literally to within a gram, get it wrong & kaboom !

soz to hear it mate, hopefully it was a freak failure

New Std engine getting ready for slotting in... then we shall see what we can salvage from the old one!

Wasnt as big a deal as i thot altho my wallet hurts!

I admire your spirit - this would p*** me off enormously

Anymore news?

Ross

nah not yet my mechanic is really busy and he is belting up the engine i got this week nad giving it a quick check over before going in

Iain

nah not yet my mechanic is really busy and he is belting up the engine i got this week nad giving it a quick check over before going in

Iain

just had a report back from my mechanic..

the 5th rod is comeplete shattered, it has broken in the middle Big end is still on the crank and bearing, small end is still up the cylinder.. and the middle of the rod is no where to be found...

Could an explanation of this be the 140mph hard accelleration and the sharp left off? causing Rod stretch?

Iain

Never heard of a Coupe rod letting go in the middle before - its usually the rod bolts that fail

In PT's defence, it now looks like it was nothing to do with their mapping

Yes it does in fairness.. i will have to investigate further, abit worried how to stop it from happening again tho

It´s easy mate. Stop tuning the engine (sorry couldn´t resist joking a little bit )

Will you go to PT again after you finished the engine?

My guess is that it wouldn't happen again - for a rod to let go like yours did, it was almost certainly defective and prior to your mapping session, was running just below its failure point. As soon as you had it mapped, the extra power became the final straw.

I'm running over 400bhp (and more importantly, 340 lb-ft) on balanced standard rods with forged pistons. I've now done over 30,000 miles on them since they were fitted, and occasionally, I still drive it like I stole it.

Cast your mind back to your first post

Did the rod fail while you were still under power or when you lifted off the power?

You've already mentioned the road speed and the gear, which I reckon would be about 6,000rpm, so it would appear that over-revving wasn't the issue

rod failled under accelleration as far as i can remember...

another little question.. car broke/cracked a piston in the 5cyl and thats the reason i did the previous rebuild, i have now acually seen the engine and it is the 5th that failed again?

only thing different on that 5th cylinder is the coilpack.. only realised it has a different part number to the others.. possible an NA one?

The car seems to run fine and i never had problems with it going off a cylinder or anything..

Could the wrong coilpack have caused any of this damage?

Iain