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#1 4.2 Exhaust manifold studs
Posted: Thu May 04, 2017 8:30 am
by TrevS
Hi all
Looking to replace my old rusty manifolds and am just ordering all the parts needed to fit the new items. I was going to order all the studs, bolts and washers from SNG but found a full set of fittings on ebay sold by WJ Perry Jaguar spares much cheaper.
My question is why are there 5 longer studs in this set, SNG have just 1 size stud listed so are these correct? Also I noticed the washers are spring washers rather than SNG's plain washers. Again which is correct/better to use
Thanks
Trev
#2 Re: 4.2 Exhaust manifold studs
Posted: Thu May 04, 2017 8:54 am
by mgcjag
Hi Trev.....just beware that the head is alluminium.....so removing you old studs runs the risk of stripping the thread in the head....then you are in trouble.......unless the old ones are broken think about leaving them and just replacing the nuts......its not unknown however to strip the thread just by trying to remove the nuts
#3 Re: 4.2 Exhaust manifold studs
Posted: Thu May 04, 2017 9:10 am
by TrevS
mgcjag wrote:Hi Trev.....just beware that the head is alluminium.....so removing you old studs runs the risk of stripping the thread in the head....then you are in trouble.......unless the old ones are broken think about leaving them and just replacing the nuts......its not unknown however to strip the thread just by trying to remove the nuts
Great tip, will check condition of studs when I remove the nuts.
#4 Re: 4.2 Exhaust manifold studs
Posted: Thu May 04, 2017 9:16 am
by abowie
At least one stud needs to be longer to allow for the dipstick bracket.
#5 Re: 4.2 Exhaust manifold studs
Posted: Thu May 04, 2017 9:16 am
by paulsco
Hi Trev,
From the parts manual, up to 7E6333 there were 3 C2324 studs and 13 C2325 studs; I assume the 3 are longer.
From 7E6333 there were 11 shorter ones and 5 longer ones, presumably to take account of the alternator shield, but I could be wrong on this.
Re what Steve mentions about the removal of the studs; yes I have to agree,there is a risk of disaster. If you are going to do it anyway, the two nut approach is best, i.e locking two nuts together on the stud, then tightening the studs up a fraction to break the seal and then loosen them.
I have found this works like magic and greatly lessens the risk of breaking a stud.
Paul
#6 Re: 4.2 Exhaust manifold studs
Posted: Thu May 04, 2017 9:21 am
by abowie
At least three studs need to be longer to allow for the dipstick bracket and the gearbox breather.
The Parts Manual specifies spring washers. Bronze nuts are correct.
#7 Re: 4.2 Exhaust manifold studs
Posted: Fri May 05, 2017 8:20 am
by TrevS
Right, think I've worked out what the 5 larger studs are for.
2x for alternator heat shield
1x for dipstick bracket
2x Gearbox breather
This picture seems to show the correct fitment.

#8 Re: 4.2 Exhaust manifold studs
Posted: Fri May 05, 2017 9:48 pm
by Series1 Stu
I always find it funny that the alternator heat shield covers every part of the alternator except the part that is exposed to heat.
There is no barrier between the alternator and the exhaust manifold. That's why I made my own heat shield along with my own alternator conversion. Clearance to the connections is tight though.
Regards
#9 Re: 4.2 Exhaust manifold studs
Posted: Sat May 06, 2017 11:59 am
by Mark Gordon
I agree with you, Stuart. I don't show my car in concours competitions so I made a heat shield that curves over the top of the alternator and then runs down between it and the front exhaust manifold so that it protects the rear of the alternator from heat but still allows air to flow over and down behind the alternator. It don't look purty but it works!

#10 Re: 4.2 Exhaust manifold studs
Posted: Wed May 10, 2017 8:45 pm
by Hugo
[quote="Series1 Stu"]I always find it funny that the alternator heat shield covers every part of the alternator except the part that is exposed to heat.
There is no barrier between the alternator and the exhaust manifold. That's why I made my own heat shield along with my own alternator conversion. Clearance to the connections is tight though.
Surely that is meant to be a splash guard?
#11 Re: 4.2 Exhaust manifold studs
Posted: Sun May 14, 2017 8:38 pm
by TrevS
Hi guys
Well getting closer to fitting my new manifolds which arrived this week but forgot to order the downpipe studs so having to wait a few days for them to arrive. I did start having a look though at how the manifolds fit and seems it's 16 nuts holding the manifolds to the block engine and then 4 nuts holding in the downpipes to the exhaust.
As I've not removed one of these before can anyone give me any tips on how to remove. Are there any special tools to use to get the nuts on/off particularly the bottom nuts behind the manifolds where space is tight. Is it a job that needs to be tackled with a lift/ramp and would I be better taking it to a garage to have them installed?
Thanks
Trev
#12 Re: 4.2 Exhaust manifold studs
Posted: Sun May 14, 2017 9:20 pm
by Mark Gordon
You can do the job yourself. You will need a 1/2" open spanner for some of the nuts (particularly those beneath the manifolds) and if I recall correctly, a 1/2" socket with extensions to reach the manifold to downpipe nuts from beneath. It's a bit fiddly, but certainly a DIY job. Like most jobs, it would be easier with the car on a lift, but I did it with the car on ramps (front and rear for safety) and lying on my back.
#13 Re: 4.2 Exhaust manifold studs
Posted: Sun May 14, 2017 9:34 pm
by Mark Gordon
I just checked and I was wrong; big surprise. The manifold to down pipe nuts are 9/16".
#14 Re: 4.2 Exhaust manifold studs
Posted: Sun May 14, 2017 10:23 pm
by Hugo
I got mine off with no problem using normal tools. No problem. 3/8 socket and a couple of wiggle bars from underneath on the lower flange
#15 Re: 4.2 Exhaust manifold studs
Posted: Wed May 17, 2017 8:41 am
by TrevS
Good news, the old manifolds are off the car. Wasn't that difficult at all in the end just a little fiddly in some of the tighter areas getting the nuts off. I am glad I've decided to change the manifolds though as the front one was in pretty bad shape with two cracks in and a chunk missing near one of the mounting points.
So I am now looking at putting the new manifolds on and ordered a pair of sealing/o rings that sit between the downpipe and the manifold. When removing the old manifolds I was expecting to find some kind of ring sat inside the manifold or on the downpipe. I've taken a picture of my downpipe so can someone tell me if the o ring is present as when having a feel around the pipe the top feels like what I thought was the sealing ring at the top is actually part of the downpipe as it is solid. Is it that the ring has set itself to the pipe? Any advice on how to remove and then how to fit the new ones would be much appreciated
Trev