Rusty front wings on S2

[charles.y]

I have had very bad rusts (big holes) on both side sills and the wing panels. I only discovered how bad they are when I had the car looked into by a local welder for some other problems to fix where the MOT failed. He discovered that (by bloody peeling the rust off the sills in front of me []) the sills were badly rusted and the previous owner probably covered it up by filling them with plaster and then painted over them. He couldn't fix them and even if he can it could cost me at least £1200 (labour) + parts etc [&o].

So I ran up Richard of Porscha in the Midlands to get them looked into. The reason that I ran Porscha is because there was an article re 944 sills repair in the 911 & World mag sometime ago I read that they do custom made stainless steel sill and wing panels for the 944. I finally got it booked into to have both the rusty side sills and wing panels cut-off and replaced by their own ones (incl. welding, sandblast, rust proof underseal proxy and match-up paint) for a merely £500 + vat. Porscha has done a superb job and I strongly recommend 944 owners with rusty sill and wing panels problem. They also sell the sills and panels only if you prefer to do the works yourself. Check them out on http://www.porscha.co.uk/ and scroll down halfway on the main page right pane until you see the hyperlink
944 sill repair panels page £40
and then click to find out.

According to Richard of Porscha and he had seen a LOT porsches, the rusts are the worst in the S2 and turbo (and particularly the cabriolets - maybe something to do with manufacturing process) but the earlier 944 models are not that bad. He thinks it could be to do with the black plastic skirts under the sills which trap water and dirts that overtime rottens the sill area. I have removed them since after the repair job is done.

 

[zcacogp]

Phil (Alpine) - thanks for the geeky help! Yes, I was referring to the plastic trims on the bottoms of the wings, and your answer confirms my findings. I can only guess that the debris of old clips that I found in my trims was misleading as to the way that they were put together.

Charles - interesting page about those wing repair panels. Thanks. The photos are a little unclear as to what they actually are - are they simply fibreglass pacthes which fit over the remains of the existing wings, or are they tin which is welded in place? I am thinking the former ...


Oli.

 

[charles.y]

They are actually stainless steel panels that Porscha made and they are welded over the existing sills (or whatever leftover).

 

[zcacogp]

ORIGINAL: charles.y

They are actually stainless steel panels that Porscha made and they are welded over the existing sills (or whatever leftover).

Oh, thanks. Stainless steel? Really? It will mean that they won't rust, but what are the implications of wending stainless steel to the mild steel of the rest of the wing? And can you paint stainless steel with normal vehicle paint?


Oli.

 

[Fen]

I have to say I kinda doubt they are stainless also. I don't think you can successfully weld stainless to mild steel.

 

[sawood12]

Welding the dissimilar metals is not necessarily an issue for those trained to do so but there are potential problems wherever dissimilar metals come into contact with one another. This is because whenever dissimilar metals are in contact you set up a galvanic cell which can promote corrosion. This is effectively the concept behind galvanising in that the zinc coating provides a sacrificial coating over the steel panel such that the zinc will corrode instead of the steel which will only start to corrode once the zinc has significantly corroded away to expose the steel - i.e. you wont get the steel corroding underneath the zinc coating like you do with steel bubbling under the paint with non-galvanised cars. I'll have to dig up my old material science text books to understand the effect of welding stainless steel to mild steel. But weld repair patches are the way to go I think for repairs to the bottom of wings to avoid the cost of wing replacement.

 

[charles.y]

Sorry for the incorrect info. I think they are galvanised steel.

 

[zcacogp]

Chaps,

To complete the saga, I did the other side in the same way on Saturday, and am pleased with the result.

Once again, liner out, black plastic trim off the bottom of the front of the sill, and clean the whole area with a high-pressure hose. Dry with rags then a hair drier, then a thick coat of waxoyl over the whole lot (suspension unit, brake pipes and all) and refit everything.

The wings were in good shape. There was ALOT of anti-rust stuff on the 'shelf' already, which was good. (There is now a whole load more!) There is slight rust forming at the edge of them, where the paint is peeling back a little, but nothing more than that. All is covered with waxoyl, and I'll take it apart again in the spring and treat it properly.

So, I'm pleased. BUT, one question. There is some large zinc-yellow passivate component in the front wing behind the wheel (drivers side) which has a load of brake pipes going into and out of it. I am guessing this is something to do with the ABS ... is this so? I cleaned it carefully with the high-pressure spray and waxoyled it, and the cars runs fine. (I was worried I may damage it with water/wax, but this seems unfounded.)


Oli.

 

[Fen]

Yes, that's the non electronic part of the ABS. The ECU for it is inside the driver's kick panel.

 

[zcacogp]

ORIGINAL: Fen

Yes, that's the non electronic part of the ABS. The ECU for it is inside the driver's kick panel.

That's interesting - there is an ECU for the ABS? And it's inside the drivers' kick panel - where? (I am familiar with the engine ECU, on the passenger side, but you couldn't put anything in the equivalent place on the drivers side, surely?)


Thanks for the info.


Oli.

 

[Fen]

It's up the side of the dash, behind the carpet trim. By "kick panel" I mean the side, not under the floor.

These cars were quite new when electronics came in so the "main" ECU just manages the engine. On a Turbo there is even a second one for boost. There is also the ABS one, one for the central locking, various alarm ones etc. dotted around the car. Basically anything that is electronic (as opposed to just electric) has it's own dedicated ECU.

 

[zcacogp]

OK, thanks.

I guess part of the issue is to decide what is an "ECU" and what is not. I have come across the central locking control box - clipped to the bottom of the steering column. But I would call this a 'Control Relay' rather than an ECU.

In fact, come to think of it, what does "ECU" stand for anyway? Engine Control Unit, Engine Computer Unit, Electronic Control Unit or something else?

Fen - thanks for your answer BTW.


Oli.

 

[Fen]

I use ECU to mean electronic control unit and hence anything beyond a relay really qualifies - usually a silver box with a multi-connector plug in it.

Specific to engine control I would tend to use EMS I would use as engine management system. Of course that's just me and others may have different understanding of the ackronyms.

 

[zcacogp]

OK, hence an ECU can control the central locking or the ABS (another acronym!). Therefore, would term the ECU that controls the engine on a 944 an EMS?

(I think of ECU as being Engine Control Unit, hence my confusion - apologies.)


Oli.

 

[Fen]

I would consider what Porsche term the DME (not DME relay) to be an EMS for the 944, but also it's an ECU that could be referred to as the ECU when talking about the engine - again that's just my personal understanding and others could disagree.

 

[zcacogp]

Hmmm, and DME is the german acronym for ECU in english - non? (Or 'Nein', to be more correct!)


Oli.

 

[Fen]

I think the M is for (German for) motor, hence it's more like EMS than ECU I think.