old fuel pump to new conversion, and IP start up

[Ron]

Hi all, I have a 1966 230SL, not running, that I'm putting back together, from an engine rebuild by the PO.  The engine is still out of the car.  

All the fuel hoses, the rubber parts, are getting changed now.  The car has the new type, short electric fuel pump installed by the PO, before the engine was removed.  The line from the tank feed and the line to the injection pump are there, but the fitting for the fuel bypass hose is not used and sealed with a small machine screw and washer.

In a Haynes manual, the '68-'72 version, it says that that a return line from the pump should be placed into a tee on the IP to tank return line.  That has not been done.  

1. Should I do this?  I think this car has been running without it.

The Haynes manual also says the fuel regulator (damper) under the injection pump should not have a hole in the back cover.  This car does not have a hole in that regulator, so I guess this thing is ok.

Also, as near as I can determine, this car has not run for 12 years.  I took about 6 gallons of rotten gas out the tank, but it flowed freely, and the tank was replaced 12 years ago, with a new one.  The M-B inventory tag was still on it.  I'm hoping it's good to go.

2.  Should I take the side cover off the IP and turn the engine to check if the pistons are free.  Or just wait until I get it started and see what's needed then?  (I read about stuck pistons on some other posts.)  Will I need a new side cover gasket, and where would I get such a thing if I do?  It seems easy to play with the IP now, but scary for me to open it.  It looks like it'll be difficult to address if in the car.

Thanks in advance,  Ron

[George Des]

Ron--On the 230Sl you do not use the tee fitting. This arrangement with the tee is for the later version fuel injection pump equipped models only.

George Des

[al_lieffring]

The later style fuel pump will work with the screw plugging off the bypass, but the pump will prime its self more quickly at low fuel levels with the bypass opened and a hose and T fitting installed.

Have you removed the drain plug from the bottom of the tank? there is a strainer screen in the plug that should be cleaned after long a long storage.

The easiest way to check for stuck plungers in the Injection pump is to remove the plug from the front of the pump and install a 5mm screw into the threaded fitting at the front of the rack, if the rack moves freely with only a small amount of spring resistance and freely returns by its self the plungers are OK. Never force the rack if it does not move freely. This will not free up the plungers, but will severely damage the pump.

Do a search, I'm sure you can find a photo of where this acess plug is located.

Al

[lurtch]

Hi Ron,

I purchased my 230SL after it had been rotting away in a Texas warehouse for 5 years. The gas tank was severely contaminated with rust particles and putrid old gasoline.

I had the same concerns about injector pump pistons that you are having. I removed the injector lines,  filled the piston cavities with penetrating oil and let them soak for a couple of weeks.

After fuel system corrections were made , it started right up and has been running reliably for 4,000 miles or so. These injection pumps are not as fragile as you might think.

Good Luck with yours,  Larry in CA

[Naj ✝︎]

quote:Should I take the side cover off the IP and turn the engine to check if the pistons are free. Or just wait until I get it started and see what's needed then? (I read about stuck pistons on some other posts.) Will I need a new side cover gasket, and where would I get such a thing if I do? It seems easy to play with the IP now, but scary for me to open it. It looks like it'll be difficult to address if in the car.

You can do the "Blacklick Test" on the Inj Pump



naj