Gents,
I know the GEMS does not "need" a gasket between the inlet manifold and the lower plenum/ trumpet section. But on the other hand is there any harm in fitting one? Whenever i've unbolted the section (ok, so only 3 times) there seems to evidence of the inlet galleries talking to one another (though not that there is leaking to/ from the outside) ie i can see a brown oily film between galleries, where there wd only have been blue hylomar on assembly. I though I could nail it with the ERR6621 gasket ? Thoughts?
I always put a thin circular smear of Hylomar Blue around each port when I put them back on. The same goes for the plenum to upper inlet manifold joint too.
Ok, so the answer to this is, that the bores on the Thor inlet manifold are laid out as two flat pairs and two diagonal pairs, whereas the Gems is 4 diagonal pairs, so the Thor gasket won't fit.
I missed this sorry - but as you've found out, the Thor gasket doesn't fit unfortunately. RAVE doesn't call for one either I don't believe - just the use of a sealant like Hylomar.
No worries Sloth. Rave suggests Loctite 577 which is a specific "pipe sealant". I've used Hylomar twice now and it has dissolved/ disappeared. I'm going to go and find some 577
Isn't the Loctite 577 used to glue the trumpets into place rather than between the two parts of the manifold? Hylomar will disappear as you are using it on two smooth machined surfaces but it will fill any irregularities. In theory, nothing is needed, or wasn't when it was new and you had two perfectly flat machined faces but as it isn't new any more you might have slight leakage so the Hylomar will seal that.
Nope, 19.22.46 no 49, "apply Loctite 577 to mating surfaces". 577 is also spec'd for plumbers as pipe/ thread sealant, i was hoping I would have some in my plumbers kit, but sadly no.
Hylomar Blue has been my go-to gasket sealer for a very long time, but now i'm starting to think more about when to use it. It hasn't worked at all well on the plenum mating faces, and it's a new tube.
I always use wellseal, it’s used at most engine rebuild shops
That's for the plenum chamber (the bit with 4.6 cast into it) to the upper manifold, not the upper to lower manifold. For some odd reason, the upper plenum chamber lives under the Fuel System section, whereas the manifold lives under section 30, Manifold and Exhaust System. No mention of putting anything on that joint except for the Thor where it just says to fit a new gasket (as the Thor has one but GEMS doesn't).
Richard, as you say, no GEMs reference for ram housing to inlet manifold - I'm just assuming that if they recommend 577 for the ram housing to plenum chamber then you can/ shd use the same.... bit of a stretch, but both joints will operate under the same temperature/ pressure conditions, bolts are torqued the same, and both are ali/ ali joints
Interestingly though - if you go to the Defender V8 supplement, there IS a separate section for ram housing where it recommends Hylomar for the inlet manifold to ram housing, and Loctite 577 for the ram housing to chamber
I normally use a bit of RTV on the plenum but I've taken cars apart where people have used RTV on the ram housing to manifold and the intakes have been partially blocked when it's all oozed out.
My Loctite 577 arrived. It's yellow, and quite viscous. The packaging is great, standard loctite top, and a concertina-type tube for easy application. The bead it creates is nice and small, so perfect for the narrow mating face on the top of the ram housing, and also for the lower join to the inlet manifold. Beats smearing hylomar out of a tube. At £25/ 50ml it's also "reassuringly expensive". I guess I won't really know how good it is until i next pull the plenum off and can see how it fared.
There was a comedy moment as the usual white loctite top disappeared out of sight down bore no 2 of the inlet manifold - my life flashed before my eyes as I imagined having to pull off the inlet manifold, but fortunately i managed to fish it out with a coat hanger and a bore scope
I like your idea of comedy!
It's only plastic, the engine would have eaten it and spat it out the exhaust.......
I was changing my spark plugs one day and one of the middle ones slipped out of the socket and was hanging down between the head and the exhaust heat shield. Missus was there who offered to fish it out as her hands were smaller. She got hold of the top, started lifting it out and it slipped out of her fingers and disappeared! It wasn't on the ground under the car so the bore scope came out to see if I could see it. Nope, no sign of it from above. From under the car looking up I still couldn't see it. After the best part of an hour, I eventually found it sitting on top of the engine mount. She hasn't volunteered to help since for some odd reason..