bk 450 gaskets blowing at opposite ends of the head?
Turbo Mini Forums

Hi
I have had recent problems with the famed never go wrong bk450 head gaskets
The car was on the rolling road at 4000 rpm BANG! FLAMES! POP POP POP SHEITE!
Head removed, gasket blew out either end of the head removing a 5mm wide piece of the gasket
at either end out side 1 and 4
New gasket fitted (bk450) new set of ARP bolts fitted,tightened and torqued down correct sequence 55lbs, back on the rollers 4000 RPM BANG! POP POP POP NO FLAMES
head gasket popped destroyed on no 4 cylinder again blew out the end of the head but not as bad
Am I doing something wrong? head was skimmed and tested block was decked
Standard Metro Turbo motor running low boost
should I go geg 300 full copper gasket from mini spares? or scrap the car?
cheers
Roy

Are you warming it up and doing the second tightening? Have you put a straight edge on the block and head to confirm they are flat?

Edited by metroturbo on 24th Apr, 2017.

Check the torque wrench is correct, most cheap ones are poorly calibrated. You're torturing to lbft and not NM, right?. Just checking as I've made that mistake.

Otherwise the only way I fixed this on mine was to 11 stud the block and head.

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

www.twin-turbo.co.uk

40ft/lb with ARP studs, not 55. You're over torquing the bolts and pulling the block around the stud holes to.

Phil.

WWW.TURBO-MINI.COM

Post a picture. But either it isnt tightened correctly or the block/head is not flat.

40lbft sounds very low though ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Thanks All
Will post some pictures as I have never seen anything like it before
Am I right in saying there were some faulty/defective bk450 gaskets on the market not so long back?
Is the geg300 copper gasket from mini spares any better?
cheers
Roy

Just a couple of answers to the questions posted

Head pre tested for flat before fitting

block decked

Snap on wrench with calibrated certificate in date

55lbs not newton meters

did not know that ARP bolts only need 40lbs? is there a reference for this?

cheers
Roy

Yes, ARP website. 40ft/lb with the supplied moly lube.

Phil.

WWW.TURBO-MINI.COM

too much ignition advance ?

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

That certainly is odd...

Just for future reference what's low boost?
And when you fit the head gasket are you doing it dry or with oil?

Edited by Will on 24th Apr, 2017.

I blew the end out of one of mine when running on 9 studs and 97 octane fuel instead of the 99 it had been set up on.

Back to 99 octane and fitting the extra studs and it has never happened again.

I would say that the majority of us are running BK450s without issue.
The problem batch was many years ago now.

Check your torque wrench against another, just because it has a certificate doesn't mean that something has gone wrong.
Check your ignition timing
What's your compression ratio? You say that the head and block have been skimmed? That could be where your problem lies

I am thinking along the lines of what Nic said and going 11 stud , the blow occurred along the lines where the extra 2 studs would fit , I will also check ignition,compression ratio again and try another wrench against the one used, to answer another question I used no oil on the gasket
Still leaning towards a copper gasket geg300 it has better thermal conduction than a fibre plus more tensile strength , Its also first choice for most top fuel dragsters in the US
cheers
Roy

that extra 15 ft/lb on the torque could easily be the cause,

over torquing can colape the fre ring so it will let go.

I had at least 3 go when overtourquing. I also wanted to go 11 stud, but the last one I fitted (at the correct torque) has lasted 2 years and 2000 (fucking hard) miles.

In the 13's at last!.. Just

Don't forget the extra stud at the thermostat end has a lower torque figure.
I can't remember it off my head though, it's been a while

25ft/lb iirc ?

Phil.

WWW.TURBO-MINI.COM

25ft/lb iirc ?

Phil.

WWW.TURBO-MINI.COM

approx half,

although TBH I have been using the same size stud on all 11 and torquing them all to 40...

I have started posting on Instagram also my name on there is turbomk1golf

Nothing is impossible it just costs more and takes longer.

Ok all thanks for the comments, I will look into them and do more checks at the weekend.
I have been advised to try a Cometic MLS gasket as sold by Burton power and also advised
that it will lower my compression ratio any thoughts?
cheers
Roy

If a standard engine is blowing the gasket there is a problem, fitting a different gasket will not solve the underlying issue.

I'd have to echo the same points the guys have already picked up on. Work out what your compression ratio is first. Most of us are running the BK450 without an issue so this is all suggesting something else is an issue.

ok back to the drawing board then , so what if I am using the latest batch of bk450 gaskets and this batch is faulty? if I use an alternative and this cures the problem then surely the bk450 is either inferior or faulty?.I emailed Rob from mini spares and told him of the problem, he said that their geg300
all copper gasket is now the preferred choice for high performance engines not the 450
Other contributors have fitted extra studs to cure the problem, so why not give another type of gasket a go?
cheers
Roy