g g g gaskets
Turbo Mini Forums

An old trick but a good risky probably crappy and worrying one but her goes

Anyone ever tried two head gaskets to get the compression down ?

Did it work ... or POP !


Steve

TurboLessTosser

a guy in brewsters pub the other night told me to do this! I told him hes talking rubbish. Have i made an arse of myself!

He said you can do it instead of getting a turbo mini head tho, and just use a normal mini head with two head gaskets.

Previous Engine: 1040cc Morespeed engine, 1275 turbo head T2 Turbo Mirage Manifolds Megajolt
Previous engine: STD metro turbo, megajolt
Drives: 399bananahp (flywheel) Honda Civic Vtec b18c4 T28 Turbo 1968 Mini

Megajolt maps to download: http://www.jamesfawcett.co.uk/cms/index.ph...&gid=3&Itemid=3

Turbo heads and std heads will most likely have the same chamber volume, hence compression. The important part about the turbo head is the good quality valves, better coolning distribution in the casting etc.

Would fancy 2 head gaskets myself, a thicker one or possibly a spacer plate but to be honest i wouldnt bother with either, its not expensive to have the chambers made larger to get the CR down.

I thought the metro turbo head was 9.4:1 which is the same as most other metro 1300's
ie nothing special !!

I had a supercharged Rover v8 in a 53 Anglia and if my memory serves me correct was running 8:1

S

TurboLessTosser

2 head gaskets is a no no..it is very easy to scoop out the head yourself, i've done it with an electric drill before.

Lets face it boosted turbo head gaskets weep at the best of time, 2 will make it worse. Do it properly by using a bigger dished piston or increasing the head chamber volume.

giallofly
Am interested in your head modifications
HOW is it possible to do this and be accurate ?
or am i being a silly ol' billy ?

Steve

TurboLessTosser

Turbo head chamber volume is the same as the other Metros, 21.4cc or so.

Phil.

WWW.TURBO-MINI.COM

turbo heads also have larger 3 groove collets on , as i know as i have loads of larger ones and can`t find any smaller ones for my head.

Everyone knows that instructions only have to be read if the thing doesn't work....

Enlarging the chambers is not to difficult, this is what i've used in the past for head mods -
You can measure the volumes with an accurate syringe to keep them equal.

Phil.

WWW.TURBO-MINI.COM

phil any pics of your head??

Everyone knows that instructions only have to be read if the thing doesn't work....

Head off, strip it down, get a couple of old valves put the old valves in to protect the valve seats and start grinding into the chamber. smooth out the beak shape or even loose it totally. Before grinding use he old head gasket as a template so you don't grind too far into the head face onto where the firering sits.

Measure as you go with a seringe bought from the chemist, or if you are a junkie like me you'll get then on perscription(jesting).

Find the CC required to give the lower compression ratio needed, 8.5:1 is decent for a mild set up.the maths are another story, Vizard has covered it and a link to a CR tool is on this site somewhere.

This is bargain basement head work but it does work.

I can get syringes free too if anyone needs them, i work for Cartridge World part time, we throw them all away after filling a certain number of cartridges would be better to suggest rather than throwing them away.

Previous Engine: 1040cc Morespeed engine, 1275 turbo head T2 Turbo Mirage Manifolds Megajolt
Previous engine: STD metro turbo, megajolt
Drives: 399bananahp (flywheel) Honda Civic Vtec b18c4 T28 Turbo 1968 Mini

Megajolt maps to download: http://www.jamesfawcett.co.uk/cms/index.ph...&gid=3&Itemid=3

ive got two head gaskets on mine, and its absolutely fine. however it has only been running for about two hours and not been driven anywhere yet!

i have every intention of getting a thick copper gasket made up before it goes on the road. i forget how much i chopped out of the chambers, but it was a reasonable amount and i still calcultaed that it wouldnt lower the compression low enough. i didnt want to pull the rest of the engine apart so i just chucked two head gaskets on! :)

Pete

And on the 7th day........... God created turbochargers!