engine popped - advice for future.

[The Baron]

Hi,

took the 5gt for a track session and all was going very well up to the point we had a quite sudden failure at speed.

first sign was expansion bottle blowing water up through the side of the bonnet at which point we immediately slowed and stopped.

a large plume of white smoke from the rear of the car followed.

car still starts and runs - turbo seems ok.

it's breathing a bit from the engine and its blowing a LOT of water vapour (white smoke) from the exhaust.

so are we talking head gasket or worse cracked liners?
we were running about 15 or 16 psi carb base (fuelling spot on though - professionally rolling road set up)

we hadn't had this GT long so were never sure about the head and gasket in the car.
engine ran very sweet though.

now-a-days what head gasket do people run for high psi?

what other mods does anyone recomend for head or liners?

the planned future spec is to build to allow circa 20psi @ carb base and it will receive mostly track abuse.
we look after our car but we push pretty hard on track too.:)

we need to rebuild so it is as tough as we can make it within reason, the budget is NOT unlimited but we want to do it right.

PS: we took some scalps on track so still came away smiling. :D

[Fordy]

what turbo you running chap?

If your giving it large on track it may of got a bit hot and induced some det.

I put in a bottle of octane booster on top of tesco 99 when i go out on track for safety with my lil alloy double cap intercooler :laugh:

blue seal headgasket from gsf, 12.9 head bolts and a freshly skimmed head are good for a fair amount of power aslong as its not detonating or running lean.

You could go crazy with bigger valves, seat angles and port work but it depends how deep your pockets are :agree:

Strip it and find out why it popped i bet its just a headgasket blown :)

[The Baron]

what turbo you running chap?

If your giving it large on track it may of got a bit hot and induced some det.

I put in a bottle of octane booster on top of tesco 99 when i go out on track for safety with my lil alloy double cap intercooler :laugh:

blue seal headgasket from gsf, 12.9 head bolts and a freshly skimmed head are good for a fair amount of power aslong as its not detonating or running lean.

You could go crazy with bigger valves, seat angles and port work but it depends how deep your pockets are :agree:

Strip it and find out why it popped i bet its just a headgasket blown :)

thanks fordy :agree:


turbo is a T28 .49


i think our issue was

we ran a 'fair' amount of boost possibly on a standard gasket and got knows what skim on the head.

it was very hot weather though - we are running an uprated intercooler but not a big lad, so maybe charge temps were a wee bit high? :innocent:

we were running shell 99 and never seemed too hot...
it was set up spot on for fuel on the rr. we have a stack afr just didn't get it fitted in time.

it was all an unknown and a shakedown day really... could have gone either way i guess

[The new Bill J]

The standard head gasket is fine with a bit of boost through it, as long as it's not det'ing.

[Tony Walker]

shouldnt really of det'd at that sort of pressure if you've had fuel mods, id check your tdc loom isnt reversed, and check head thickness when its off, possibly had alot skimmed off? perhaps starved of fuel supply on a long corner? blocked fuel filter/lines/carb float filter? faulty reg? dodgy fuel pump? all could cause leaning off and detonation. or maybe split actuator pipe, overboosting?