Which Head Gasket Compound? (Or not bother?)

[56Lotus]

Hi all

I'm rebuilding my all alloy FWA using a competition steel head gasket, which is very thin. My liners aren't protruding the best and in the very old manual they say use a sealing compound with a gasket. Now they wouldn't be referring to a steel head gasket but an older thicker type. I'm thinking of using a gasket compound in addition but have no idea what to use.

Both head and block are alloy and the gasket is steel. What would be the best compound to use? Compression ratio should be about 10:1 so does that count as high compression? I'm looking for something that would be best for metal to metal sealing.

What does the great collective think? Can't currently get hold of the experts for pro advice.

Thanks for your help

Jon Adams

[E-bmw]

You shouldn't need anything on a gasket under as much compression as a head gasket to aid sealing, however just in case it ever comes off again I tend to smear a little silicone grease on any fibre/metal gaskets just in case I come to take it apart again to ease surface cleaning.

I am sure many will disagree, but never had an issue doing it like that.

[GreenV8S]

I'm used to fitting gaskets with reinforcement around the fire ring which ensures the clamping pressure goes where it's needed - these are fitted dry. It sounds as if the gaskets you're describing are much thinner. I haven't used that style myself, but I understand these sometimes have a surface treatment that looks like varnish, in which case they should also be fitted dry. You might find gasket cement necessary if the sealing surfaces are flat but not very smooth, it's not practical to remachine them for a better fit and you want to help the gasket seal to them. The goal here would be to make it easier to seal the oil/water passages, not seal the combustion chamber. Some people even take the opposite approach and use anti-seize to allow the gasket to move against the mating surfaces to help it flatten out as it is clamped up, and to ease disassembly.

If you don't think the fire ring has enough clamping pressure, I don't think sealant or gasket cement is going to solve that problem.

[99hjhm]

A very light stipple of old fashioned wellseal works well on most head gaskets, silicone tends to shim as it's not easy to apply evenly but found it to be ok around water ways etc.

[Mignon]

What exactly do you mean by "steel head gasket"? A multi layer MLS one coated with something "rubbery" or something else entirely? I'd just ask the gasket manufacturer what they suggest to be honest.

[paintman]

Late reply & you've probably resolved it, but you need to wait & speak to the suppliers of the gasket. Nothing worse than fitting it only to have it go shortly after & you would void any comeback.
IME of compound, MLS or shim steel gaskets (the last being on the Rover V8 & LR factory workshop manuals have 'NOTE: Gasket must be fitted dry' in bold in the replacement sequence)sealant is not normally recommended or required.

Edited by paintman on Tuesday 22 November 11:27

[56Lotus]

Thanks all

I've spoken to the experts and its a thin coating of wellseal. To me the gasket is a thin piece of steel with raised ridges around all the holes. I believe the raised lip of the liner will cut into the gasket and create a seal, not enough lip not a good enough seal so the gasket doesn't work. Now off to measure the liners.

Thanks

Jon Adams

[paintman]

56Lotus said:

To me the gasket is a thin piece of steel with raised ridges around all the holes

Sounds familiar!
http://www.rimmerbros.co.uk/Item--i-GEG340
http://www.ebay.co.uk/itm/CYLINDER-HEAD-GASKET-GEN...

Edited by paintman on Tuesday 22 November 20:18

[227bhp]

Makes you wonder how you would get an accurate torque setting with sealant blathered all over the place....

[exitwound]

I remember watching the drag racers at Santa Pod painting head gaskets with aluminium furnace paint. The suspended particles were supposed to fill in any imperfections in the gasket.