Head Gaskets ?

[nheather]

A question about head gaskets. I have a Hobao\Mach 28 but I guess this question is quite generic.

When I got my 2nd hand car, the previous own had cross-threaded a glow plug (he told me about this up front). So I got a new head button, but when I removed the old one, I found that there were no head gaskets fitted.

I found the Hobao Mach 28 instructions and this shows two gaskets

a brass 0.1mm which goes next to the button.

an aluminium 0.3mm which goes on top of the liner

so liner > 0.3mm alum > 0.1mm brass > button

Also when googling I found the Dynamite Mach 28 instructions and this also shows two gaskets but these are

0.1mm copper

0.2mm copper

Now my question as a newbie is "Should I fit both gaskets or just one?"

I was wondering whether you just fit one depending on what power fuel you intend to use?

If just one, which should I fit for 20%

Can anyone advise please.?

Cheers,

Nigel

[cerbrus2]

I only have 1 on my SH engine. It doesnt need one seperating the button from the heatsink. And yes. when going to a higher nitro content, say 30% most engine manuals will tell you to put in enougher Gasket/shim. to rais the head a bit.

[nheather]

Many thanks,

It doesnt need one seperating the button from the heatsink.

Agree, that isn't where it shows. The manual shows

Heatsink (Cylinder Head)

Button

0.3mm aluminium gasket (shim)

0.1mm brass gasket (shim)

Cylinder lining

But it doesn't make it clear whether both should be fitted or just one.

I've been researching a bit more and found that you should put an extra shim in if you are using >25% or sometimes when breaking the engine in.

So if I need only one, should it be the 0.3mm or the 0.1mm ?

Cheers,

Nigel

[rogersden]

check you old button gasket probably still on it

[danniuk]

sometimes the old ones are compressed beneath the heatsink and engine block they simply stick to the heatsink or head. i found this happend on an old MT2 T-15 engine. if not im sure you can buy some off the iinternet for a very low amount of money.

[nheather]

No not stuck on top of liner or on old button - that was the first place I checked.

The problem is not which ones to buy but which ones to fit. As you say, they are cheap and I actually have the full range

Brass 0.1mm

Copper 0.1mm

Copper 0.2mm

Aluminium 0.3mm

I have the copper ones because at the time there were none to be had in the UK at all so I ordered from the US. They supply the Dynamite parts. WHilst they were in transit the UK stock became available so I also have the Hobao parts.

The problem is that I don't know which ones to fit?

The dynamite exploded diagram shows 0.1mm and 0.2mm copper

The hobao exploded diagram shows 0.1mm brass and 0.3 mm aluminium

What neither of them show is whether they should both be fitted or just one. And if just one, which one under which conditions.

Cheers,

Nigel