bloody headgasget.
Turbo Mini Forums

about a month ago when i bought the car i changed the headgasget (amongst other things), as the condition of the engine was unknown. Except the running hot problem, she has been running fine. So with the help of a bleedvalve, actuator and needle/spring, i wound the boost up to 10psi (removing the ecu). I have been running 10psi for roughly a week now n last nite the headgasget blew on my way to work.

when i changed the hg last time i thoroughly checked and cleaned both surfaces befor re-assembly.

Am i unlucky about it blowing or can you not run more than 7psi on standard compression?

Any help peeps.

it may b small but it purfectly formed
http://photobucket.com/albums/v340/1976_mi...roject%20turbo/

I've seen 15psi a few times,just running a 27cc head(instead of 24?)
Only thing I noticed was the studs were pulling out the block when I put it on so I countersunk them a bit

Metro turbo weekend driver,Mini turbo in the making again!

10 psi with standard CR ratio and no intercooler will........ blow the head gasket i can assure you ( detonation rapidly sets in):(

this is the cause

my guess its gone between bores 2&3....correct! ?

if it didnt blow the weak link, the gasket it would melt your pistons in seconds

you want to be lowering the CR ratio to a 28cc combustion chamber.

on a standard motor this will give you a CR ratio in the region on 8.4:1

this should afford you to take it to 10 psi just! without retarding the ignition timing, which has its own pitfalls.
not the way to go realy.

and the intercooler its a must my friend

all the above considering, ............................

the 20 odd year old engine is up to it ??

Edited by BENROSS on 18th Nov, 2006.

cheers guys, i do have an intercooler indoors, just havent got round to fitting it! will have to asap now!

Benross, how can i lower the compression ratio to a 28cc combustion chamber? Is it just by changing the pistons for deeper dish ones?

Cheers, si.

it may b small but it purfectly formed
http://photobucket.com/albums/v340/1976_mi...roject%20turbo/

Think your getting confused!! Benross is saying the cylinder head chambers need machining out to 28cc to give a compression ratio of 8.4-1

-MINI CLUBMAN 1380 TURBO-

oh rite ok, thanks T3Tone. ive got a basic knowledge on turbo engines, never ever looked into machining tho! lol

it may b small but it purfectly formed
http://photobucket.com/albums/v340/1976_mi...roject%20turbo/

Basic chamber size increasing is not too difficult.

IIRC there is a section in the Vizard Bible that covers chambers for turbos.

Every day is a school day ...........

How fast and how expensive ...... the same question...

Just another thought, you are running on a lead replacement with octane booster aren't you?????

Every day is a school day ...........

How fast and how expensive ...... the same question...

my car runs on unleaded, but i use the 97RON. Do i still need octane booster?

it may b small but it purfectly formed
http://photobucket.com/albums/v340/1976_mi...roject%20turbo/

That will be ok I think.

You've got hardened seats in the head then. Maybe I've only had old heads but I have never seen a factory turbo head with hardened seats.

That is a good point actually, what seats are most people running on here?

Every day is a school day ...........

How fast and how expensive ...... the same question...

What gasket do you use?
Is it BK450?
Paul

I seriously doubt it!

yes the BK 450 is well up to the job

you are better running shell V power petrol at 99RON

its a much better safegaurd against the detonation