LCGB Forums

Hi ,
What are you guys using to seal your cylinder heads down, running with no gaskit? thanks

Loctite 638 on mine (rapido 225) packer plate & no head gasket.638 on the head - clear silicone on the base. Leak tested recently all good.

used various products, from the Loctite mentioned to the cheap clear silicone sealent from b & q and never had a leak from any.

+1 on the cheap silicone, although i find B+Q too dear , Wickes or Wilko for me

Many silicone sealers are not petrol and oil resitant and will break down. It is best to stick to products that are made for the motor trade, hylomar is an excellent sealent for heads without gaskets. IMO of course.

Tractorman wrote:Many silicone sealers are not petrol and oil resitant and will break down. It is best to stick to products that are made for the motor trade, hylomar is an excellent sealent for heads without gaskets. IMO of course.

This is true.Silicone will turn to jelly when in contact with fuel/oil.I personally would'nt use it,but if you have to,use it sparingly.Just remember,what squeezes out on the outside,the same is happening on the inside .Having said all that,what is squeezed out on the inside will more than likely get burnt up anyway.

usualy use loctite 270 stud lock on the head with or without gasket . on a side note please be careful if using 638 as thread or stud lock we used it on a job at work as thread lock and had to scrap the job as we couldn't move the screws even after 24hrs in a stoving oven it is a high strength retainer I use it for sticking bushes in ( ie lever pivots if worn )

I second the last post regarding 638. I never thought of 270 as a gasket replacer though.

Stag Wellseal on my mugello with no head gasket.Works well and can be removed easily if need be later

Loctite 5290

270 studlock on the head, the cheaper the better silicone on base.

maybe a daft question but if you are using 2 or 3 packers to get the right squish on the head which faces do you put sealant on?

I run three Casa kits and never used any cylinder head sealer on any of them.

^... I agree. The whole idea is that the surfaces are flat and that is what provides a seal, if people get too hung up about the agent added to ensure a gas-tight seal then they are already focusing too much on the sealant and not enough on the surfaces.

Likewise, if you have more than the tiniest amount on there, so that you end up with a significant amount squashing out when you tighten it down, then you've put too much on and are expecting too much of the sealant. The sealant is an aid to the surfaces sealing, not to form a gasket of sealant.

Adam

Stag-well seal or Three bond, agree that surfaces need to be well prepped before hand, never really got the loc-tite theory as heat is what is required to undo loc-tites grip?

As above +1