5 GT Turbo EFI - GT Turbo

[Mark Davis]

On a positive note, stuff is arriving.

 

[DaveL485]

No one has mentioned a possible over-boost situation ...

( have they ? )

Yes but not here flicking back (as many know this discussion has been going on in tandem on a FB page too)

But again, it was cut by the ecu and Mark corrected it quickly with a wastegate tweak.

Mark, was your cut method spark or fuel or both?

 

[Mark Davis]

Ign cut at 29psi, was mapped to 27psi.

 

[Clarkey]

No one has mentioned a possible over-boost situation ...

Had a few over boost situations on our car,
At EFI setting up the VNT, we had 30psi spikes and bent couple pushrods.
Did a head gasket another time, which was my fault, kept going to finish the race........

Cant see it being a factor personally. Had another on carb so no ECU to protect and over boosted until the head gasket went. 2 bar was EPIC

 

[Mark Davis]

I've not called CTM yet, been flat out at work. It was signed for at 10am yesterday morning so now had a good day and a half to inspect. Will call first thing tomorrow to hear what they have to say.

 

[andybond]

Cant see it being a factor personally. Had another on carb so no ECU to protect and over boosted until the head gasket went. 2 bar was EPIC

IF you mapping on the edge , or 9/10 and then that extra 10% boost comes in , it will play a part. Yes the head gasket will eventually go out but you are running leaner , hotter and with more chance of det.

Could have tipped something.

Or not !

 

[Mark Davis]

The boost spikes were a full week before the actual main damage was caused so unlikely to be that in fairness, I guess it could of contributed a small amount. Who knows.

 

[Brigsy]

I think the boost spike issue started the ball rolling to be honest. Usually the headgasket would go first or liner but the mls gasket held out until the rest was shot.

 

[Mark Davis]

Could well be

 

[Clarkey]

mls gasket

Good call Jon, still not convinced though

 

[Fordy]

Timing map could of had the highest row of boost pressure with less timing than what it was tuned too, this would stop any damage if any over-boost occurred after tuning as the car effectively backs itself off naturally or "rolls out timing"

I mean common people we've fed shit loads of boost through these cars for years, a 2psi swing isn't going to cause even a quarter of the damage we've seen, one of the liners would of cracked before that much damage happened.
Detonation signs on 5's
wearing out spark plugs quickly
blow by increase as piston rings are worn on the edges away quickly by knocking
Headgasket starts to leak or pressure up system/air into system
Liner cracks or pistons melt.

There's no real melting of marks pistons unless I've missed a recent stripped down picture and no cracked liners.

 

[Mark Davis]

Morning chaps, so head is all repaired.
I haven't seen it yet as its on its way back to me but Charlie says they have repaired/skimmed squish areas, elongated the push rod holes with the hope it will decrease the chances of push rods bending in the future and then finally they apparently pulled it all apart and replaced the broken valve guide, valve seal etc.

By all accounts the rest of the head is fine, no bent valves or other damage. He didn't really elaborate on the cause but was leaning towards failure of the part itself. I ended up paying £100 which isn't ideal but at the end of the day just happy for a quick resolution and turnaround.

This big question of course now is - will it hold together next time? Let's hope so

Will post pics up when it arrives back tomorrow.

 

[Adey]

Definitely inspect it before anything. I'd be making sure the valves move freely. But to be honest it's a very good result. Shame about the rest of the engine though but the rebuild is off to a good start

 

[Mark Davis]

Good plan Adey, will ask Mark to investigate when putting it all back together.

 

[DaveL485]

Morning chaps, so head is all repaired.

That was fast, considering. I really hope it doesn't happen again! Good result with CTM though fair play to them.

 

[Clarkey]

Glad its all sorted Mark. What was the £100 for ?

Be interested to see the elongated push rod holes when you get it back.

 

[Mark Davis]

New materials, labour and carriage I think mate. To be honest I just wanted it resolved and back so didn't argue too much, I've learnt not to burn bridges with people just in case.

 

[Clarkey]

Agree, easy life and all that....... works both ways though, Goodwill !!

I must remember, next time someone has a problem with my roof work, to charge them.

 

[Mark Davis]

I could of been more of an arse I suppose. Oh well it's done now, if it happens again then that's a different matter of course.

 

[Mark Davis]

Head back, all cleaned up and fixed. They've done a good job on the guide in question, you'd never know it was damaged. The push rod hole have been opened up/elongated too.