10 replies to this topic

[mini dan 86]

on my supercharged mini blow the head gaskets between 2 and 3 and even melted the decompression plate between 2 and 3 any ideas why!!!

[Tommyboy12]

Your using a decompression plate.

[mini dan 86]

Your using a decompression plate.

iv heard to fit med forged dished 18cc pistons and get rid of the decompression plate.

[mini.cooper998]

i used a decomp plate on a mates turbo for experimental reasons and had lots of problems until we stepped up the torque on the head studs stuck another 15lbs ft on top and then a torqued up again plus a 90deg turn after a drive. been fine since.


Andy

[moke123]

detonation maybe? what ignition system are you using?

[Wil_h]

Definately sounds like detonation. Although decomp plates are not ideal, I can't see it actually being the problem here.

Det is caused by many things, but the main culprets are too much ignition advance, too lean a fuel mixture or too hot charge temps (or a combination there of).

[shellspeed]

de-comp plate let go on mine on the rollers last power run (gutted). Testing a one piece copper gasket I had made shortly and will report back. If that does not hold then i'm going to stop cheating and buy some pistons.

[new_zealand _minis]

mine did the same thing melted the plate and the 2 head gaskets .. ive now gone fully forged and some 16cc dish mini speed pistons

[joe90]

done 3000 miles now with decomp plate & no trouble. i did make sure i used high strengh quality head studs on my build.
My first thought on reading problem was detonaion as will_h has said.
Hope you get it sorted.
On another note i seviced mine today. new plugs, oil etc. Supprise surpprise it goes better
Joe

[shellspeed]

Well, so far so good. Had the engine running for the first time Friday after a bit of fetteling with the webber (blocked jet). Changed some of the tubes and got it a little closer and warmed it up to temperature. Going to re-torque the head and run it up again but seems to work. I guess a nice run on the rollers will tell us more.

[new_zealand _minis]

what dizzy is best . think thats why mine blew when i had ther decompression plat on it .. and i know megajolt but i have not got there yet !!!