A few questions re: Engine Bay finishing

[RobSirg]

Guys,

I have poured over the few photo's posted elsewhere of the original engine bays - I think you know the ones. So I now have a few questions :

1) On both these examples the rubber plugs in the side walls of the engine bay are not visible which confirms they were sprayed over. I believe this has been covered before. When I restored my '69 I also noticed my plugs had paint overspray which was flaking off so I simply helped it along thinking it was some previous owners poor work. The question is - if you were respraying your engine bay would you spray over these or not? I'm going to great lengths to give the original appearance elsewhere so why not? My only reservation is that I fear many onlookers (including some judges) may also consider this careless finishing off. (especially when it starts flaking off) Thoughts?

2) What is the finish to the blanking plates on the engine block? I have seen many photos and noticed some have gone with silver (or clear) Cad whilst others have gone with gold Cad. I am even thinking of simply masking and spraying with HT silver paint without removing them as they are barely visible once complete.

3) What is the correct finish to the small diameter brake vacuum lines in the engine bay? Once again I have seen silver and gold examples and it is near impossible to see them on the original engine bay photos.

4) What about the bracket to the ignition Coil and the clamps to the Air Filter Hose? I think silver in both cases.

Thanks in advance

[mbzse]

Number four is silver, yes
/Hans in Sweden

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[Jonny B]

I believe the small diameter braking lines would be the natural finish, dull silver/gray. They would not be yellow cad.

[KevinC]

Hmmm... I don't have holes in the side walls of the engine bay so therefore no rubber plugs. I certainly have seen them on other cars, too but assumed that these were an "after factory" attempt at getting some rust inhibitor inside the inner fenders. Does anyone know for sure?

[BaronYoungman]

I believe only 280sl had the plugs, at least all the ones I owned 230sl no plugs 280sl plugs and not painted.
Bob

[KevinC]

My 280SL from last year...also no holes/plugs. Both cars were initially registered in California. The red car had no rust inhibitor on the undercarriage or anywhere else that we could find. 

[garymand]

Kevin, nice to see a clean original (the white one).  My 250 has no holes or plugs.  It looks the same as yours, except I wish I had a fan shroud and more paint on my booster.

Is that a custome made shroud (on the white one)?  I am inspired to duplicate that.  How is it configured on the drivers side next to the radiator?  I'd love to see a picture of one off the car.  I honestly think mine never had one, but is it possible the 250 shroud was plastic?

Gary

[66andBlue]

Brian at Motoringinvestments has researched this topic extensively. On 280SL with holes:
The inner fender wall rubber plugs were installed by the factory after the primer coat but before the color coat and were painted over. Click on the picture to take a closer look. The "yellowing" is actually the paint aging and reacting with the properties of the rubber. Since the rubber originally had a coat of wax on it the paint didn't stick well and has flaked off over the years.

[KevinC]

So how do we explain the cars with no holes?

[Rolf-Dieter ✝︎]

Hi Kevin,

Dayshift was always pure German workforce they hated holes of any kind ... Nightshift had some Swiss technicians they sneaked holes into the engine bay here and then when the floor supervisor was at a beer break  ... just kidding ... no pun intended 

It is a good question .... just checked mine, I have three rubber plugs along each inside on the inside wall of the fender (driver side anyway, guessing it be the same on the passenger side ~ I park so close together now that I cannot get in there due to a wheelchair lift I had to install for my wife). I'll take some photos tomorrow at daylight

[tel76]

On the last restoration I did a 1968 280sl there were no holes, on the new inner wings/fenders (genuine MB) I fitted there are holes, can I suggest that the holes were introduced on the production line after 1968.

[mbzse]

.../... can I suggest that the holes were introduced on the production line after 1968../..

Yes the holes were introduced in factory production in the beginning of Oct 1968. Subsequently, the factory issued a Technical change document describing where the holes could (should) be drilled on customer's (already produced) cars, in order to increase corrosion protection.

There are very many locations for these holes. On some holes (like the side walls of the engine compartment) rubber plugs were fitted. When a car was manufactured with these, they were spray painted over. When retrofitted (by a M-B workshop) the plugs were bare rubber.
See reply #3 and 4 in this posting http://www.sl113.org/forums/index.php?topic=15001.msg103049#msg103049
/Hans in Sweden
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[KevinC]

Great info gents...thanks! My 280SL was from July 1968 so "no holes" now makes sense.

[KevinC]

Kevin, nice to see a clean original (the white one).  My 250 has no holes or plugs.  It looks the same as yours, except I wish I had a fan shroud and more paint on my booster.

Is that a custome made shroud (on the white one)?  I am inspired to duplicate that.  How is it configured on the drivers side next to the radiator?  I'd love to see a picture of one off the car.  I honestly think mine never had one, but is it possible the 250 shroud was plastic?

Gary

Gary,

I can't tell you much about the fan shroud except that it was on the car 10 years ago when I bought it. A quick look on the SLS site shows it only on the 280SL and labeled "USA". 

Kevin

[66andBlue]

Yes the holes were introduced in factory production in the beginning of Oct 1968. ......

Hans,
do you have a copy of the MB "Technical change document" that you mention?
My 280SL (005600) was produced early in October 1968 and it has the holes. Also there is an entry in the Engelen book indicating that with VIN 5620 (03-Oct-1968) a dip-electrophoresis painting procedure was introduced that required additional drain holes in the chassis:  Zusätzliche Ablauflöcher in der Bodengruppe wegen der Einführung der Eletrophorese Tauchlackierung

[Peter h]

My silver is from mid September 68 and dont have them . Vin  #5480
Peter

[mbzse]

Do you have a copy of the MB "Technical change document" that you mention?

This one is on the VdH webpage. It is in .pdf format
/Hans in Sweden
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[66andBlue]

Thank you Hans, quite a useful document for restorations.

[RobSirg]

Thanks Guys,

A most interesting thread - before posting the question I simply assumed all engine bays had the holes. Possibly because I am mostly looking at photos '69, '70 & '71 engine bays. Just getting back to my original questions - I am thinking :

1) I might get the engine bay sprayed without the rubber with the plugs so as to cover all metal (even though it wasn't done that way originally). IE: Try painting the rubber plugs - if it looks OK, I can leave them painted - if not, it should not be difficult to remove the paint from them (or simply buy more plugs). I would say nearly 100% of the restored engine bays I have seen have the rubber plugs unpainted. As much as I like to have it original looking - I'm not into recreating shoddy work.

2) Still don't know the original finish on the engine block blanking plates and don't really care anymore. I cant imagine I will remove them so I might give them a spray with HT Silver paint in place. Defy anyone to see more tan a glimpse once the engine bay is complete.

3) Will go with natural finish (Clear Cad) on the vacuum brake lines.

4) Ditto on the ignition coil bracket and filter hose clamps

Cheers.

[Garry]

Engine block plates look nice cad plated but of course when the inlet is on you dont get to see much other from underneath

Garry

[RobSirg]

Agreed Garry - your impressive engine pic is already in my file for reference and blatant copying.

I'm also curious about the 280SL in the background. what do you know about it? Looks very similar in colour to my '69. Does it have a two-tone roof?

Cheers

Rob

[Garry]

Rob,

It was in Reinhard Klaver’s workshop where I had my engine overhauled.  I dont remember it being a two tone but it certainly looks so in the photo although it may just be a lighting trick to the eye.

Garry

[garymand]

Curious Kevin, the white car looks to be a 230 or maybe very early 250 (radiator overflow tank)  so no fan shroud would be proper, but it has an 8 blade fan and the shroud looks like it is made of sheet metal rather than plastic.