Cleaned, new studs inserted with anti sieze paste awaiting the coated manifolds and heat shield.

the other side.
Also I replaced the core plug that was looking a little dodgy!


This was the sorry state of the heatshield! I expect to see a different sight on Wednesday!
Be back soon with update!
Kind regards, Danny.

 

yes those shields can get nasty. I never liked them. Earlier engines like the 3.8 litre don't have those shields.

 

Dear friends, I am collecting the bits from the ceramic coating firm later today. I would like some advice on torque settings to the manifolds to the head, I am using mild steel studs and brass nuts. I seem to recall that between 25 and 28 ft/lb was advised somewhere.
I know it is going to be impossible to get my torque wrench on the nuts underneath, but I thought it might be possible to use a 1/2inch combination spanner by using the ring part on the nut and the torque wrench to the 1/2inch open ended side of the spanner. I appreciate that the 6inch length of the spanner will influence the torque. Any thoughts will be greatly appreciated. Kind regards, Danny.

 

I'm in the midst of a very similar project where I am having my manifolds and Y pipe ceramic coated also. And I found that if I took the fan belt off the A/C compressor, loosened all the bolts for the compressor and rocked it as far to the outboard driver's side that I could get in to all the underneath, hard to get to nuts, to take the manifolds and Y pipe off - all in one piece. That's how I intend to put the whole thing back together again, when they come back from the ceramic coating. I'll be using SS nuts though, when replacing. I'll torque the upper nuts, but not really going to worry about the lower nut torque pressure. Just going to do what I think feels right. In addition to the ceramic coating, I'm fabricating from Mr. Gasket 77A exhaust manifold gasket material ,a heat shield that will mount between the two manifolds and the block to further knock down the heat radiating from the manifolds to the block. I'll attach pics next time.

 

The large hole on the heat shield will be covered by new large stainless steel washers, above and below as suggested by Jose.

I am pleased with the ceramic coating on these manifolds, although I am not sure that the mating surfaces should not have been masked.


A very improved heat shield!
As promised, here are some images of the manifolds and heat shield after ceramic coating.
I will get them onto the car over the weekend. I will post more images then.

 

Wow looks awesome. I would not worry about the mating surfaces Danny, quite the opposite, the parts will not rust where they meet.

Yes I used washers under and over my shield holes. Never any problem. I did mine in 1997 and the parts are still like new. The coating is permanent.

 

Thanks Jose, you have made me feel better about the mating surfaces. Can you confirm the recommended torque settings for the manifolds to the head please? Am I correct with 25 to 28 ft/lb?

 

Danny, I don't remember the torque figures by memory. They are in the Service Manual, Engine section.

if you don't have the service manual, go to my website and download any section you need, including the Parts manual sections, gratis.

Jag Upgrades Home

 

Many thanks Jose for your introduction to your wonderful site. Unfortunately, your service manual is the same as mine, there is no mention, (that I can see) of torque settings on the exhaust manifold. I am going to tighten to 22ft/lb, the last thing I need is to overtighten and risk any damage to these now smart cast iron manifolds.
Once again Jose, I am most grateful to you, and all the other members here for their thoughts and suggestions. I will post the finished job soon, hopefully!
Danny.

 

Danny I searched the Service Manual too and the only reference I found is "tighten the nuts".

I have removed and reinstalled exhaust manifolds in both my Jags but never torqued them to any given ft.lb, just tightened them enough without stressing the studs. Never had a failure.

are you using lock washers? I did and essentially once the washer is locked down, whether partially pressed or fully pressed, the nut will not back off.

 

Thank you Jose, yes I am using all new stainless steel spring washers and brass nuts.
I agree, once the spring is compressed, that will be very close to being tight enough!
Many thanks once more, Danny.

 

Both manifolds are back on.

Heat shields back in place with SS washers above and below as recommended by Jose.
What started out as a small job to replace the sealing rings at the manifold to pipe junction, ended up with both manifolds ceramic coatings along with the heat shield. New studs, SS spring washers, brass nuts and SS nuts on the manifold to pipe clamps. I did not use the torque wrench after all, I just tightened them all up in a sequence starting at the centre, by hand using a combination spanner, it is very difficult to get anything else on the nuts below. It runs really nicely now with no exhaust blowing!
I am really glad I did the extra work, and I am very grateful to Jose and other members who have offerred help and encouragement.
I am a TV engineer by trade and this work is a very pleasureable distraction! I dare say I will be back on this forum seeking advice on the next project, thank you all once again, regards, Danny.

 

looks awesome Danny.

I didn't do the manifolds in my car but now I will have to ! I am a believer in ceramic coatings. I did do the washers below the shield and not being in direct contact with the manifolds it remains cooler. The slight separation from the manifold surface allows air to circulate between both parts.

TRIVIA: the manifolds seem to be the same in the 3.4, 3.8, and 4.2 litre engines. Different part numbers for the same part?

I have pairs from each engine, no difference except for that huge bolt in the 4.2 rear manifold. Frankly, I don't even know what that bolt is for and it seems it is not needed except to fix the shield in place, but the shield could be fixed in place by other means.

 

That "large bolt" is actually a screw that not only secures the cover to the rear manifold, but plugs a tapped hole in it. I suspect some piece of emissions apparatus went in there, probably for the US market,

 

Fraser, in my car there was never any fixture attached to that large bolt, mine looks just like Danny's.

Earlier S3 XJ like 1979-1983 don't have anything there either. I always thought it was some kind of "drain" or "test hole" for exhaust gas before it reaches the O2 sensor?

no clue.

 

I quickly need to find where to do this ceramic coatings in Ghana so I can turn mine into a such nice pieces.

In fact your car looks superb.

 

I quickly need to find where to do this ceramic coatings in Ghana so I can turn mine into a such nice pieces.

In fact your work done looks superb.