V12 Engine - Difficulty Removing Exhaust Manifolds - Inaccessible / Seized Nuts

[PJAB]

Hi

I am taking a Jaguar V12 engine to pieces and will then put it all back together again having refurbished various parts.

This is one big learning exercise for me - and I am loving it.

However, I am a bit stuck at the moment - in a fairly predictable place. Each exhaustion manifold is attached to the engine block on 6 studs - each of which has a washer and nut on it. I have been able to loosen the nuts on the four most accessible studs - but cannot do so on the two least accessible ones. These are on the underside of the exhaust manifold - see photo.

I have tried my best - using a 1/2” spanner - but not even a hint of joy.

Does anyone have any advice about how I might loosen these pesky nuts, please?

Thanks and all the best


Peter

[almcl]

In similar circumstances I find heat usually works.

My weapon of choice was a small nozzle on an oxy-acetylene torch applied just to the tip of the stud for a few seconds.

A small blow lamp might also be effective and then a ring spanner, with a tube over the end to allow more leverage, always worked.

Good luck!

[PaulGover]

The other thing is to use the best sort of spanner you can get over the nut in the space available. With clearance to the top, a hardened impact wrench socket will be best, but of course you won't get one in there. Flat ring spanners or flat ratchet spanners are far better than anything open-ended, provided you have the clearance. Open-ended ones splay under high torque, and if you've used heat to loosen the nut (which, as almcl says, is highly recommended as long as there's nothing flammable nearby) it's easy to round the corners of the nuts.
This sort of thing from Halfords looks suitable, but you need imperial and they are metric.
https://www.halfords.com/tools/hand-too ... acement=10

[PJAB]

Hi Al

Thanks for that. I am not experienced at using heat to free up rusted nuts - but I’ll give it a go. I bought a propane gun the other weak - I am not sure if that will be able to generate enough heat to expand the nut sufficiently to break the rust seal.

I would use a ring spanner if I could - but I only have an open ended imperial spanner (ratchet ring on the other end - wouldn’t take the torque without being damaged I think). I might look for some Imperial ring spanners online - I think I have seen a technique where you can link two spanners to increase your leverage.

All part of the fun - thanks for the advice.

Peter

[PJAB]

The other thing is to use the best sort of spanner you can get over the nut in the space available. With clearance to the top, a hardened impact wrench socket will be best, but of course you won't get one in there. Flat ring spanners or flat ratchet spanners are far better than anything open-ended, provided you have the clearance. Open-ended ones splay under high torque, and if you've used heat to loosen the nut (which, as almcl says, is highly recommended as long as there's nothing flammable nearby) it's easy to round the corners of the nuts.
This sort of thing from Halfords looks suitable, but you need imperial and they are metric.
https://www.halfords.com/tools/hand-too ... acement=10

Hi Paul

Spot on - I follow exactly what you are saying. I’m off to Amazon to hunt down some Imperial ring spanners.

Thanks

Peter