Idea's to stop blowing head gaskets at high boost
Turbo Mini Forums

Hi Lads,

Ok, willing to try ideas... I have an 1132 Turbo setup.
Making awesome power at 15psi but blows the headgaskets on the dyno... driving it daily at 15psi is ok, until you give it alot, then the mayo in the oil starts to form (blows HG)

It is blowing on both ends. Between Cyl 1 and the water galley and between Cyl 4 and both water galleys.

A mate (Benjamin) has just done the extra studs and that is keeping his intact - however I am running higher compression than him...

I want to be able to run 15-18psi and not blow the HG

Cheers,
Pete.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

what compression ratio are you running and what head gaskets are you using?

9.4 compression and using ACL Monotorque headgasket.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

and what head?

small bore or 12g940?

if the latter then just drill and add the extra bolts ala cooper S, the gasket even has the holes, not sure how easy this is with small bore heads tho.

Plug off the offending water passages?

The 1275 style gaskets on a 998 block are dangerously close to a couple of coolant passages.

Only other options are a steel laminated gasket such as the Cometic or a custom made anealed copper gasket.

change the the stat for a sleave what they run in the miglias

they don't use them sleave's on the miglias anymore, but 99% of them use electric water pumps

Team Racing

also may be way off base, but have you checked the head studs to make sure the threads are not pulling ? i would go 11 stud and run ARP but that is me i guess :)

finally check all your torques with a different wrench, preferably one which you know to be accurate

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MikeRace, Mini13

Definatley need to 11 stud it mate

Check your torque wrench.

mine failed in this manner for ages until i realised the head was under torqued. i did ass the extra studs too though.

9.4cr and 15psi is surely on the limit anyway.

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

Hi,
I'm astounded it's still got pistons in it at 15psi and 9.4. Everyone on this site has always said 10psi maximum on that CR...
Cheers,
Gavin :)

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Howdy,

Thanks guys, Graham Russell said the same thing - amazed the pistons are holding... but they are.
Ben is running his on 15psi too and its sweet.
Its got ARP studs - I might just have to go the extra studs I guess.
Its a 12g202 (smallbore head) messively worked. Roller tip rockers, Mk1 S valves turned down, k-lined, 8000rpm double valve springs, etc...

Only issue is, the extra stud conversion in a smallbore means i'll have to get new guides and k-lines as it destroys them... but I guess thats ok.

Apart from decompression plate, any other way to bring down my compression (already has dished pistons) but the head is at limit - cant really take anymore out of the chambers.

Pete
Peter

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

Oh, and also, head studs are torqued down properly. Ill go to another place and check with their torque wrench which I know is 100% accurate.

Maybe ill just weld the fu^&er on! lol

Tell you what though, at 15psi the thing is an absolute animal.

Planning to go to Western Sydney International Dragway next month and take her down the 1/4 mile at 15psi to see what she can do... but want to sort the prob first.

Peter

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

Edited by Vegard on 15th Aug, 2008.

Can you get any more machined out od the pistons?

You only need 2cc to drop the CR below 9:1

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

hmmm, not sure about that. They are dished as standard (Hypatec +40) and hastings rings. I would prolly get 1cc out of the chamber and 1 cc out of the piston I guess...

While its getting that done, i'll 11 stud it too.

Or just build a friggin 1275 Turbo ay?

Pete.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

noo smallbore much more interesting!
wont a copper head gasket have a slightly thicker compressed thickness anyway, lowering the compression?
what the hell is k-lined? you mean its linered!?
You could always bash some steel bungs into the block/head water passages, tap the core plug at the end of No4 and drill/tap a hole in the head joined by a bit of nice shiny silicone, heypresto no more probs..
How much charge cooling are you using by the way?

Have you had the head skimmed by a good engine builder's Machine shop when my self and Gary (Spanner on here) started his head work we ended scraping a 12G295 casting as the amount we need to skim out of it to get it flat was craze these heads have a Boeing(spelling the yoke you shoot arrows with) tendency its real also if you do find the head to be 100% flat then get your self a Copper Gasket do a search here I have explained this before to another fellow I am using it on one of my Irish race cars with a N/A compression ratio of + 13.8:1 running 111 octane fuel and mapped ignition this motor makes static compression pressures of 280psi on 3 pushes not to be sneezed at and no head gasket problems it is also running a massively over bored block at +74mm,
regards,
Paul.

998 at 74mm? is that a first paul?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

This could be my hang over talking but I am struggling to find where in my last post that I mention the engine with the 74 mm over bore is a 998

Have you tried a modern Multi Layer Steel gasket like a Cometic ?

never used one on a Mini...they didnt exist back then, but on modern engines, they work !!! Just ensure gasket mating surfaces are very good.

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

i thought you were speciically referring to a 12g295, but re-reading it back, you prob just mean iron mini heads in general?

On 17th Aug, 2008 PaulH said:

This could be my hang over talking but I am struggling to find where in my last post that I mention the engine with the 74 mm over bore is a 998

On 17th Aug, 2008 joeybaby83 said:
998 at 74mm? is that a first paul?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

PaulH, Head skimmed and block decked by Graham Russell... so all good on that front.

Hario, the k-lining is where brone inserts are fitted in the guides but they have a spiral groove in them... wouldnt run a motor without.

What do you mean by charge cooling? Im running intercooler and thats it...

Stevie, have not tried any other gasket types... not sure whats available down here in Aus.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun