Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
41
Jaguar recommends the use of Hylomar on the tappet block-to-head joint, and to seat the cylinder liners in the block. Both are poor applications for Hylomar. Michael Neal told us a good steam cleaning would blow the Hylomar out of the joint under the tappet block, and from then on the engine will leak oil onto the exhaust manifold forever. The tappet block joint calls for Loctite 518 or similar, an actual sealant that won’t hold the parts apart, will squeeze down to basically nothing during assembly.
The joint under the ledge on the cylinder liners rarely leaks – at least, nobody knows if it leaks – but that’s primarily because it’s an iron liner pressed onto an aluminum shelf with full head bolt loading, so it’d seal dry. I recommend Loctite 518 there, too, although other sealers would probably work as well. Nice to have something that doesn’t glue the liners in, though, in case it ever needs to come apart again.
Once Jaguar changed over to gortex gaskets – which are to be assembled dry – I don’t think there was much use for Hylomar on the Jaguar V12 any more. Of course, it seems harder and harder to get the genuine gortex gaskets any more, too many suppliers ship paper gaskets, and if you’re willing to use those at all you might as well use Hylomar on them.
It began in my Model T days. Permatex black for joints not likely to need service soon. it goes hard.
Permatex red remains softer. We used a lot of it.
I was pleased that the T engine I built was leak free and clean and painted!!!
A couple of OHV engines along the way. Permatex red for the cover side of the cork gasket. Dry on the head side. Gasket remained in place when replacing the cover. Great… Running the valves a normal maintenance item!!!
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
44
Are you talking about the air injection ports? Those go into the exhaust tract. They are always coked up on any engine that’s got more than a few thousand miles on it.
So, does that condition result in any harm, Palmdude? I was wondering too whether it would be O.K., now that I have new one-way valves on Superblack’s air injection system, to just disconnect that line that leads to them from the air injection pump. ? The (new intact) one-way valves should prevent the hot exhaust/manifold gasses coming up through the air injection ports (assuming they are not “coked” up) from going past that point and frying things under the hood (correct?). No idea how the old valves got fried in the first place (perhaps b/c the injection pump wasn’t/stopped working, and therefore not holding those hot gasses at bay in the exhaust manifold 24/7?), Strange though that the “y” hose was not fried or even slightly melted, or anything else on the way back to the pump.
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Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
46
The air injection system only works while the engine is cold. If it were to operate when the engine was hot, the injected air would confuse the oxygen sensors. So if the system doesn’t work, theoretically you’d pollute a bit more during the warm-up period.
Yes im talking about the little hole that comes from the air rail, most of those holes almost blocked with some kind of plastic/rubber staff.
Should i clean this or its should be lime that ?
I’ve seen the “recommended” way of blocking the holes up with miniplugs. I’m wondering why a person couldn’t just carefully (spatula?) in them and cover them up with some of that metal putty stuff (e.g. Quik Steel)? It hardens as hard as steel, as it is made of it.
Now I’m confused … So they how do the one-way valves get fried, typically (and as with Superblack’s)? Is it just a matter of “wear and tear” over the years?
The only reason to block them would be if you remove the entire air injection system. Some do this to reduce the clutter under the hood. If the system is intact, no benefit to removal other than that.
It does allow installing a larger alternator in the former air pump location, but you also have to reconfigure the air conditioning compressor drive, and change the wiring to the new alternator location.
Does it run smoothly? Red catalyst are an indication of unburned fuel/excessively rich mixture. Check the condition of the vacuum line that goes from the center of the balance pipe (at the back of the engine) to the ECM in trunk, must not leak or will affect fueling. Check the vacuum line to the transmission; must not be full of oil. Check for failed fuel pressure regulators; must be no liquid fuel in the vacuum lines- also check fuel pressure (should be about 30 psi at idle).
Retarded timing can cause excessive heat in the exhaust.
So today i sew that i forgat to connect thise 3 ground wires (those that goes at the back of the B bank), after doing that the right cat convertor stop glowing and now only the left cat convertor is glowing red.
i also notice that the spark plug wires was not where they should be on the distibutor so i fix this
( nothing change).
Robert, you said that there is a vacuum line that goes from the balance pipe to the ecu, how can i trace it ?
With the engine off - take the vacuum line, at the back of the balance pipe off - now go to the ECU in the boot and take the vacuum line off - now using something for an air source, blow air through the vacuum line, and with a helper, test for the air coming out at the other end.
It connects to the engine at the balance pipe directly behind the throttle capstan; the other end connects to the ECM in the trunk, right side above the wheel well. There is a black plastic vacuum damper in the black rubber tube just before the ECM. Start the engine, immediately go the the vacuum line in the trunk and disconnect it and feel for vacuum.
If you think that there isn’t proper vacuum, get a vacuum gauge and do the same test measuring vacuum at the balance pipe and then in the trunk- should be the same.
If fails test, trace between. I think it runs inside the car along the right sill. Don’t run the car with it disconnected for long, only to test.
Generally, a glowing catalyst means it is still working. Need to find out why that side is running rich or misfiring.
You can remove the oxygen sensor to relieve the back pressure if you suspect the catalyst. But first, compare the flow from each tailpipe, obviously should feel the same. I suspect you will feel a misfire in the side with the red catalyst.
Also, couldn’t he just remove the cats and replace them with straight pipes, being that his XJS is too old to need passage of emissions tests anyway (if like here in TX)? That wouldn’t affect the source of the “excessive fueling” (or “lack of fire”?) issue though …
I was wondering too whether it would be O.K., now that I have new one-way valves on Superblack’s air injection system, to just disconnect that line that leads to them from the air injection pump. ? 
That wouldn’t affect the source of the “excessive fueling” (or “lack of fire”?) issue though … 