400SE Exhaust Manifold Removal

[h2dca]

Thought this may come in handy after discussions with Andy (AM400)

I have decided to wrap the manifolds in exhaust insulation wrap as it reduces under bonnet heat (Circa 70%) and helps to increase power, also I remember a post about heat shields/starter motors so may also be an option for this issue.

Anyway after a bit of trial and error I managed to remove both manifolds from my 400SE and put together this procedure but as with these things there maybe other ways so please feel free to comment.

I had the car on axle stands as I had already removed the front suspension but I would recommend the removal of both front wheels to gain access through the frame.

1. Disconnect Battery
2. Separate the exhaust manifold to exhaust pipe connection under the car (13mm spanner x 2)
3. Tag & number spark plug leads, remove and lay to one side
4. Remove nearside manifold bolts top/bottom row using a combination of 9/16” spanners, 2nd & 3rd exhaust port bolts are accessible from inside wheel arch of car and through the frame.
5. Lower exhaust manifold down and out underneath the car.
6. Remove offside manifold bolts and rest the manifold against the engine mount to access starter motor
7. Remove starter motor and lay to one side (1/2” AF spanners req)
8. Refit manifold to block with 2 bolts to keep the manifold clear while working on the engine mount.
9. Place trolley jack under the engine sump with a piece of timber to distribute the weight and protect the sump.
10. Take weight of engine on jack and remove engine mount to frame bolts
11. Jack engine approx 6 inches, slowly complete this task ensuring no strain on hoses of wires.
12. Undo remove engine mount bracket from offside of engine ½” AF Spanner for top bolt, 5/8” for the lower two (One maybe a socket head allen key set screw), one 5/8” lower bolt is directly behind the bracket so a small socket was used.
13. Remove engine mounting bracket and lower manifold out from underneath the car.

As it will be sometime before I replace the system I have reinstalled the engine mounts and after checking the manifold for leaks I will paint and tape them

I hope this is of help
Regards
Hamish


>>> Edited by h2dca on Tuesday 15th February 09:54

[gsx600]

Beware, I was told that if I wrapped up normal steel manifolds then they would only last a couple of years as the moisture would also be trapped and actually make them go rusty quicker.

Probably not so bad for SS manifolds, but then you'd want to see the shine on them anyway ?

[adam quantrill]

I wrapped one manifold on my 350i and left the other alone, as I thought it would have to come off soon. The wrapped manifold was brand new, and I also painted it with high-temperature paint which incidentally helped stop the wrap slipping about.

As it turned out the older non-wrapped manifold is still on the car unharmed, and the wrapped one has had to be repaired twice, but is still basically sound.

So there does seem to be some corrosion effect but it isn't very fast - the new one's been on there about 3 or maybe 4 years.

Incidentally don't forget that when removing/replacing maifolds you need 18" clearance under the car to get the bugger out, so be prepared for some teetering jacks and axle stands.

- Adam

[boosted ls1]

You would think that tvr would have made the chassis a bit better in order to allow access to the manifold bolts. This is one of those jobs that's a right royal pain!

boosted.

[jmorgan]

How do they work then? The heat wrap. Just wondering what happens to the heat?

[boosted ls1]

jmorgan said:

How do they work then? The heat wrap. Just wondering what happens to the heat?

The heat just goes down the pipe instead of into your engine bay. I didn't like the wrap on my turbo's. It made them flake quite badly.

Boosted.

[h2dca]

boosted ls1 said:

jmorgan said: How do they work then? The heat wrap. Just wondering what happens to the heat? The heat just goes down the pipe instead of into your engine bay. I didn't like the wrap on my turbo's. It made them flake quite badly. Boosted.

This apparently gives you more power as the hotter the exiting gases the better power delivery or so they say, my main reason is heat reduction under the bonnet. As the bible notes the fibreglass unlike steel retains the heat, heat enters the steel and passes through the steel and subsequently it cools. Fibreglass holds in the heat hence huge build up of heat in the engine bay.

I personally believe that a lot of engine problems stem either directly or in directly from the excessive heat. Fans work excessively to reduce heat, EFi have heat cut off sensor (Previous experience with a Griff), wiring etc will degrade much quicker with higher heat levels so in essence my aim is to reduce under bonnet heat.

I must admit I never thought about the corrosion and I appreciate the insight but as a trade off I will sand blast the manifolds, a good coat of paint prior to wrapping and fingers crossed they last a few years.

Regards
Hamish