Blown Headgasket
Turbo Mini Forums

So the other day at Donington my head gasket blew.

I pulled the head off last night and the gasket has blown in strange place. Never mind it will be replaced and straight back on. What I was surprised was the bent pushrods.
Has anyone got any idea how these have ended up bent? Valves are all fine. Could this be part of the failure from the head gasket.

Thanks
Andy

is there a valve head mark on the piston i can see ?
if so i would say the valve siezed in the guide .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

No I don't believe there is any marks on the pistons.

I have cleaned the surfaces and didn't see anything unusual.

Extreme coil bind at full lift?

If something is worth doing, it's worth doing half of.

What springs are you using ? And what cam/rockers ?

Phil.

WWW.TURBO-MINI.COM

What is extreme cool bind john?
Phil not sure on the springs it's a Benross head maybe 280lb? Just a guess.
It's a phase 2 cam and med 1.3 rockers

seen this on a 1293 with high sporty cam combined with high lift rockers ( 1.5) and skimmed head. the dude didn't believe me it would not match and he bent 4 of those before he listened to the fact that his springs couldn't be pushed in that far.

you can do anything if you set your mind to it...
i rather blow it up winning than keep it together losing.

finish date set for project 1... march 2018

The head gasket failure is caused by under torquing. Check your torque wrench.

It would benefit from being 11 studded.

As for the pushrod. As above, check that the coils aren't binding when you have it all back together. Simple check with a feeler gauge.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Are you on about the coils of the valve springs?
I'll look into it. I've ordered a new set of Minispares performance push rods to replace the full set.

yeah there is a point where the valve springs will compress no more as the coils are touching each other, this is coil bind, and something will "give" be it bending a rocker or a pushrod. On another note cant quite see where the gasket has failed :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I had to run shims under the med 1.3 rocker posts or the rocker arm would catch the top cap just before the roller made contact with the valve stem

Edited by gr4h4m on 4th Sep, 2015.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

which camshaft you using?

EDIT: didn't see this...

Edited by PhilR on 5th Sep, 2015.

is that push rod from cylinder 4 with the blow out?

maby the gasket blew out hydro locking it jaming the valve into the seat?

why would only one push rod bend? surely 4 or 8 would as the valves and springs should have been a set? unless the installed heights where different?

WWW.TURBO-MINI.COM

If I recall the springs were 180 pound ones on the nose, so not over sprung, check your torque wrench compare it to another one.

Its "lots of revs" and maybe detonation, poor fuel and fueling incorrect timing, engine not set on the rolling road.

Would like to add, you say you were at donnington. . . That's a race track. .lol and there is only so much an engine will take before something fails as we all know, I suspect! You have been trying so to speak

Edited by BENROSS on 5th Sep, 2015.

Thanks BENROSS for confirming the valve springs fitted.

I know it's all guessing as no one knows exactly what the failure is on a forum but there wasn't loads of revs as it doesn't need to be revved and the limiter is set at 6.5k anyway. Fuelling is pretty good now and afr gauge has been confirming this for a while. Timing is spot on.

Congratulations on identifying donington as a race track. Unfortunately I'm not rich enough to race miglias so I was participating in a track day. The conditions were soaking and it was hardly being pushed hard. The engine has maybe done 3000 miles max since being built and well looked after.
I don't know what you're trying to say with your emoji but feel free to expand on that as it may help me ensure this doesn't happen again for any reason.

On 5th Sep, 2015 BENROSS said:
If I recall the springs were 180 pound ones on the nose, so not over sprung, check your torque wrench compare it to another one.

Its "lots of revs" and maybe detonation, poor fuel and fueling incorrect timing, engine not set on the rolling road.

Would like to add, you say you were at donnington. . . That's a race track. .lol and there is only so much an engine will take before something fails as we all know, I suspect! You have been trying so to speak

Edited by PhilR on 6th Sep, 2015.

What head gasket was it? Maybe 11 studding would be an option. How much boost were you running?

Matt W

classic under torque HG failure, had a few before buying a good torque wrench
classic advert for 11 stood also

edit: bit slow like, at least we all seem too agree though

Edited by Brett on 6th Sep, 2015.

Yes i moved to the darkside

Instagram @jdm_brett

so the gasket seems an easy fix check the block/head are still flat and check the torque with know wrench possibly 11 stud it

but what hasn't been figured out is why did the push rod or rods bend? we still dont know how meany rods are bent??

im still convinced a significant amount of water fulled the cylinder hydro locking it forcing the valves closed bending the push rod after all the cooling system has about 16psi pressure depending on rad cap

Off head I'd say 4 or 5 push rods were bent

I'm also sure Andys torque wrench is a snap on item

Yes i moved to the darkside

Instagram @jdm_brett

Any chance this was one of those bad BK450 HGs produced quite some time ago?

Dazed and Confused....