Manifold Refurbishment

[David's8]

The manifold paint was starting to flake so thought that I should spruce it up a bit. Opted for complete removal rather than spraying in situ around the other gubbins. So after some advice from Mikkijaynes thread ("Hokey Cokey") I decided to go ahead. I first cleaned the area around the injectors/bol heads etc with carb cleaner and a small brush as a lot of cr@p collects there.
The service manual for the Motronic system gives advice and a picture on removing the fuel rail which involves:
1. Remove air supply pipe from filter housing to throttle body.
2. remove vacuum hose from fuel pressure sensor.
3. Unplug connectors for knock sensors and remove cable ties.
4. Detach solenoid for SAI from fuel rail pipe.
5. Unplug connectors to injectors.
6. Unbolt fuel rail from manifold and pull upwards and off the manifold complete with injectors.

You dont need to remove the fuel line as it folds back out the way when released.
Easy huh? Well the removal of the fuel rail and injectors requires a lot of force to overcome the "stiction" of the o-rings on the injectors. I had to resort to a 20" wrecking bar (see photo) suitably protected with rags but its head actually spread the force really well and gentle pressure applied sequentially at the corners and middle got it to pop out. You need to be careful in ensuring that the O-rings come out cleanly with the injectors. One of mine didnt leaving the O-ring and the little brown washer in the manifold cover. I recovered them with a small hook.

You then need to remove the T30 torx head screws holding down the manifold cover as well as 2 shorter T30 torx head screws at the very back of the manifold whcih secure 2 vertical (cooling?) pipes. These can be difficult to access and I used T30 allen keys being v careful not to drop the bolts down the back of the engine.
You also need to remove the ice hockey puck shaped throttle valve control part at the rear (held on by a jubille clip) - and, in my case undo and move out the way a jubilee clip on another adjacent hose - no need to pull the hose off - to allow the rear of the manifold to lift off.
As I was just removing the top section of the manifold, you need to remove or at least pull back the left hand (right as you look at it) manifold flaps actuator mechanism as it is encased in the lower section and the dog mechanism fro the manifold flaps otherwise stops you from lifting the front of the manifold cover. This was quite hard to pull out due to the spring force and stiction. You need to unclip the right hand (left hand as you look at it) vacuum actuator from the mechanism.

Once this is done the cover should be free to move. There is a thin rubber gasket between the top and bottom half of the manifold around the outside which was in OK condition but if you broke it I think you could use some non setting gasket goo. There were traces of gasket goo between the manifold "holes" on the inside linking up with the rubber gasket mentioned above. this broke up on removal and so i used some non-setting gasket goo when re-assembling.
I cleaned the manifold using carb cleaner and wire brushes and gave it a couple of coats of The Laird's (thanks Jim ) HT Ally paint.

Refitting was the reverse etc . But I did ensure that the injector holes were cleaned (there was evidence of alumium oxide around the holes which probably added to the difficulty when removing despite following Mikkijaynes advice to spray with WD40 prior to removal) and also lubicated the o-rings with clean engine oil before pressing the fuel rail home and it popped in as neat as (an analogy escapes me..)

Pleased with the result but it is quite a faff for a cosmetic job.

[MikkiJayne]

Very smart

[Architex_mA8tey]

Nice job David!

[The_Laird]

Push the dipstick back in properly David!

Thanks for the acknowledgement for the paint.

[David's8]

Originally Posted by The_Laird

Push the dipstick back in properly David!

Thanks for the acknowledgement for the paint.

Haha! Good spot - I noticed that just after taking the photo and cussed but couldnt be bothered to go back out in the rain for the re-take!! It WAS fully home for the road test. The car started first time and ran as smooth as silk which I was kind of worried about after messing about with the injectors and fuel rail.

[moltuae]

Nice work David!

Looks great

Of course this means you'll now have a compelling urge to get the rest of the engine looking so clean and new


This reminds me I must get around to painting and fitting the brand new manifold I bought ages ago. When, that is, my car is back on the road and I've finished paying the King's ransom for all the mechanical work I've been having done lately (more on that long story soon, and why my car is presently 200 miles away in Glasgow ...).

[steamship]

Nice job David. I thought of doing mine, but no way on earth would I attempt what you just did. Kudos

[briang9]

Good work David, however SWMBO is clearly not giving you enough to do if you had time to do that

[The_Laird]

Originally Posted by steamship

Nice job David. I thought of doing mine, but no way on earth would I attempt what you just did. Kudos

I did mine the cowards way! Just take off the 'vanity covers', clean it, mask it and spray. Once the covers are back on, it looks just fine.

[David's8]

Originally Posted by briang9

Good work David, however SWMBO is clearly not giving you enough to do if you had time to do that

If only you knew what jobs I had to complete before I could commit to doing that job! I even did a mornings worth of vacuuming and cleaning..