now there's a thought...

well the new gasket has a bigger hole to allow for oil. im also running head studs so this may make the difference

I used to swear by acl gaskets - but a couple of years back a friend had an 'ezy-fit' (I think was the brand, it was a subgroup under the ACL banner in any case) and there were numerous issues - pushrod holes cut crooked, so they lined up one end, but not the other, and other issues too. I dunno what happened there, but it certainly made me sus on the whole thing.

Their original gaskets were good, so they almost certainly must have moved production elsewhere for it to 'suddenly' stuff up.

Since then I've gone with genuine head gaskets on anything i could actually get them for.

It's a shame if ACL goes under totally, their pistons and bearings were definitely good quality. I know guys who put more than 30psi boost on top of their holden pistons in drag engines without a meltdown.

Quote:

I shouln't make a difference [head studs] as there are two variants of the a-series ARP head stud kit available for early and late engines. Hope you have the right one for your engine Hope you get it back on the road soon.

cheers
benny

i did get the right ones ... difference i think is the late set has one long bolt for where the oil feed is and the early set has all the same size

I realise this is resurrecting and old thread however it is still a relevant topic today.

Has anyone had recent experience with the Monotorque head gaskets?

We are using one on our Junior Sedan and suspect a failure after only 3 meetings. We experienced some overheating due to mud on the radiator core and reached about 225 deg.F ('ken hot!)

Now, we can't get it to idle properly. Changed carbs and no difference so that is eliminated from the range of possibilities. No vacuum leaks. On raising the RPM it runs smooth.Still investigating at this stage and need to eliminate valve lash as a possible problem. I am now inclined to the view that the head gasket is the source of the problem.

Any suggestions or comments?

Test gasket- oil in water water in oil? Or do co2 test in rad coolant.

225 not that bad if short time only. Might have detonated or similar

225F is not bad. The engine can run at that temperature all day if the radiator has a 15psi cap. As long as the water didn't boil out, it should cause no harm.

212F thermostats are very common.

It might handle that temp fine without mechanically seizing or blowing the head gasket (as DD says, if the cap held pressure and it therefore didn't allow steam pocket formation etc).

BUT - and this is a 'maybe' - presumably it is running a comp ratio/timing/cam duration (even if the cam was stock, there's still a max timing/cr you could run, so I'm trying to cover all bases here by saying that) that is closer to the detonation/pre-ignition threshold than a lot of street driven motors might be.

That would then be, relatively speaking, more sensitive to a rise in coolant temp above whatever it was tuned/setup to run at in race trim.

If the gasket is blown bad enough to affect the idle massively, it is at least likely you'll see bubbling in the radiator at idle (or whatever revs you can keep it going at) with the cap off. Sometimes they can just blow between cylinders and that won't see any coolant loss/contamination. Same deal with water in oil and or oil in water.

It's probably worth the time to pull the head and get it checked out if the usual tests (as mentioned in this thread) show nothing up.

It totally depends on the type of racing and so forth, but on a couple of mates cars, they've deliberately run stock head gaskets instead of copper ones, on the theory that they are fine to cope with normal pressures/usages, and will only blow (acting like a fuse of some sort) with abnormal combustion - too hot, detonation, preignition etc. Sure it meant they were replacing the gaskets every few race meets (this was entry level speedway racing, so whilst the combinations were pretty tightly regulated and modest, the amount of punishment the engines had to take was still higher than moat people could likely ever put them through on the street)

Thanks to all who responded. All useful stuff.

Jmac, I like your thinking about the use of stock type gaskets and the "relief valve" approach to them.

The motor we are running now has flat tops and .060 over bore so we are getting quite good compression now compared with our old motor which only had those standard dished jobbies. That motor was more a set and forget type setup that was reliable meeting after meeting. Now it is making more power so everything is a bit more stressed including the head gasket.Once Ive checked the valve lash we'll decide what to do but I'm about 95% convinced at this stage we will pull the head to make sure all is well.