new hole in firewall for alarm wires?

[rutger kohler]

As mentioned in my embarrassing post re the "mystery" bolt i am doing a makeover around the firewall in my enginebay. When a past owner had an immobiliser fitted, a two wire cable was jammed into one of the grommets that already carries the hood release cable, and the tube for the windscreen (windshield) washers.  This is unsightly and I can't make a neat job of it with a new grommet. How acceptable would it be to make a new hole in the firewall and fit another grommet with a single entry for the two wire cable, or has someone got around this some other way?

[66andBlue]

If I understand you correctly you have a two-hole grommet for the washer hose and the hood release cable but need a third hole for some thin (?) electric cables.
Why not use a 3-hole (or even 4-hole) grommet with the same OD? I would send an inquiry to SLS and ask whether they have one of the correct size:
http://www.sls-hh-shop.de/en/230-280SL-W113/54-Elektrical-Equipment-at-Body/54-d-Rubber-Grommets/?_artperpage=10&listorderby=oxstock&listorder=desc
Check out items "15" and "22".
IMO, drilling a new hole through the firewall is a BIG no no ... but it is you car not mine.

[rutger kohler]

Hi Alfred, thanks for that. Yes I guess I know that a new hole and grommet would be treated with horror by the cognoscenti. I will go to SLS, looking at your suggested number it would do the trick but, by eye, looks a bigger diameter where it goes though the firewall. Andy Burns suggested replacing a small blind grommet that already exists up on the drivers side where the firewall pad just covers it.  This could work but would mean running the two wire cable round three sides of the engine bay. Will try sls first, thanks for the tip.

[66andBlue]

Blind grommet? Is your 280SL have a RHD or LHD?
You could also use the fitting 2-hole grommet that you have and using a hole punch cut another hole through it. But the hole should be smaller than the combined diameter of the two electric wires to get a better seal.