Er Silly question maybe? Valve Seats

[Malc]

Hi,
Probably a silly question that has been answered before...

Will a 1965 230SL cope with unleaded fuel or will I have to get the valve seats changed, bronze guides fitted?
In addition does the modern unleaded petrol have any effects on the fuel pump.
My old lady runs a 1974 BMW 2002Tii and so far there has been no problems with the cylinder head or the klugeflischer mechanical pump (I think Bosch bought them out afew years ago)
Thanks
Malc
Scotland

[Cees Klumper]

Hi Malc - the common opinion is that all W113's run on unleaded gasoline without problems straight from the factory. There should not be a problem with the fuel pump either.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[JamesL]

I asked the bloke who sold me mine (a dealer) about unleaded

He insisted that you'd be fine - but better with the higher octane "performance" unleaded (ie, EVEN more expensive for the UK).

His argument was to do with the age of the head/valves and their being hardened simply by years of use.

I did doubt that (as he's trying to sell me a car, after all) but am encouraged by Cees' post

While we're on the subject though, anyone ever fitted a catalytic converter? I know there's some performance loss but I like trees!




Jan 1970 blue 280SL...mmmm

[Ben]

My '64 230SL had 110,000 miles on it when I got it. I always used unleaded and put up 12,000 miles of daily driving over the next 6-8 months. It broke a piston ring and when I pulled out the engine and opened it up I paid particular attention to the valve seats.

There was absolutely no valve seat recesion and no damage due to unleaded. My engine machinist confirmed this and said he would never install so called "hardened" valve seat on one of these engines because they would simply not be as hard as the original ones !

I had my valves refaced and the seats recut and a full rebuild and now I still use unleaded all the time with no ill effects !

Regards,
Ben in Ireland.
'64 230SL 4sp.
'03 CLK Kompressor

[Cees Klumper]

I understand that in Germany catalytic converters are (sometimes?) fitted to older cars. Maybe someone in Germany can comment? I may want to do this myself for the sake of the environment.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[George Davis]

Tosh,

your catalytic converter question is interesting, I've wondered the same about an older pickup truck I have.  For both of us, the answer is probably no.  Catalytic converters get too hot and fail early if the air/fuel mix is too rich, and these cars are set up to run on the rich side.

Cars equipped with cats typically have carbs or injection systems with O2 sensor feedback control, or an air pump which supplies extra air to the cat to prevent overheating.  The Pagodas, of course, have neither.  With some effort, expense and additional equipment it might be possible, but it's not as simple as just putting a cat in the exhaust system.



George Davis
'69 280 SL Euro manual

[JamesL]

Thanks George

Thought that might be the case. There are some cars being advertised here in the UK as having had an "unleaded conversion" but not sure if that runs to the converter. I also found one on my recent search for a car that was converted to run on LPG. Gotta love that for green

Jan 1970 blue 280SL...mmmm

[kns]

Hi Malc.

For what it's worth, here's how the two previous owners of my 230 dealt with the question. The first (a golf nut) kept five golf tees in the ashtray. Each time he filled up, he did so on unleaded, and then moved one golf tee from one side of the ashtray to the other. When he got to the last tee he put in a tank of LRP, then started over.

The second owner kept a bottle of lead additive in the boot (trunk), and each time he filled up on unleaded, he added a capful of the additive.

For mine, the engine 'pinged' on the lower octane fuels (perhaps curiously?). My mechanic took the same view as mentioned here by one or two others (see Ben below) - you won't get better modern valve seats, and you don't need them. I took that as a licence to run on the highest grade unleaded available, and couldn't be happier. As for the environment: I'll have to make up by recycling my garbage and composting!

Cheers,


kns.
1965 230SL, Manual
[1965 220SEb Coupe, Man.]

[Klaus]

Cees/George,
at least five years ago MB Classic developed a "G-Kat" catalyst for the W113. This is not a TWC (three-way-catalyst) as all of today's cars have, and which would have to include oxygen sensors to run the engine at stoichiometric fuel-air ratio, but this is a two-way catalyst that reduces hydrocarbons (HC) and nitrogen oxides (NOx) under rich conditions.
The kit can be bought from MB Classic, or there are companies that install them; e.g. in Germany Gilles Autotechnik GmbH in Frankfurt.

Klaus
1969 280 SL