Converting 280SE from IP to Carb

[Fano]

Hello all.

I've been struggling to get my 280 SE engine going as the pump needs a total rebuild that costs atleast two of my limbs. I've been considering changing the delivery system from IP to carb. Is there anyone here who has succesfully done it; or knows of someone who has? So far, I understand I'd have to change inlet manifold, exhaust gaskets, cylinder head, and obviously have to get a carb. But I know that it's not always so simple to convert. I'd appreciate any tips/instructions

Thanks,

Fano

[cth350]

Fano, I know you're far from a good supply of used parts, but here in the states a used pump is alot easier to find than the engineering expertise to switch to carbs.

The conversion's been done before.  Alex Rozzi has a 250SE with a carb'd FI motor. He likes it better than having a dead motor, but he'd rather have the FI back. He's in Argentina, another place where spare parts are not easy to come by.

This forum exists to help guys like you find what you need.

-CTH

[hands_aus]

Have you thought of sending the IP to the USA for rebuild?
The database here has their contact details
http://www.sl113.org/data/show_table.asp?table_name=usr_parts_and_service_suppliers

look for Pacific fuel injection and H&R injection.

I notice there are no web addresses but there are 'phone numbers

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[psmith]

I can vouch for Pacific Engineering, and all reports are that H&R is as good or better.  

However if you really want to switch, you might look at this post  http://www.mercedesshop.com/shopforum/showthread.php?t=62202 and ask for help there.  It's possible that a manifold from a carburettor equipped 250 S may fit your 280 SE, but you'd better ask the experts first.   Also try JAM Engineering at     http://www.jameng.com/ for Webber conversions.

Or you could modernize with aftermarket fuel injection.  Take a look at Karl Middlehauve's site here http://www.mbgrand600.com/  He puts modern fuel injection (and sometimes superchargers) in MB 600's

Pete S.

[glennard]

'Total rebuild'?  Please describe the symptoms???  Hard to believe it needs a 'total'.  FI pumps have a longer life than the engines- in general, if they have lubrication.

[Fano]

Problem is that there are only a handful of workshops left in South Africa that are willing to work on older petrol FI's. I had to search two weeks to find just ONE in Johannesburg. The ones that are willing to do the work charge quite a lot for the labour. The fellow at the workshop I eventually found also told me that there are no more parts available for these pumps In South Africa. Even if I were to fix the pump (The equivalent of USD 550.00 here), I would be unable to replace any parts that would require replacement in future. Fitting a carb would make it easier for me to use the car as a daily driver.

Changing over to a carb at this point seems the most sensible option in the long run in the RSA (Republic of South Africa).

As for the sympoms, The pump doesn't pump ANY fuel at all into the injecors. I printed and followed the instructions on the entire FI pump tour on this website. It's delightfully comprehensive; yet despite all wealth of info, I am still unbale to get the pump to turn.

Thnaks again for all your input. i look forward to more of it.

Fano

[glennard]

Hi, The first and only symptom you present is 'no fuel into the injectors'.  Some questions-Is the electric fuel pump circulation gasoline from the tank to the FI pump and back to the tank?  At what pressure and flow?  Will the rack in the FI pump rotate the FI pistons?  When you remove the cap on the front of the FI pump and screw in the 5 mm screw, can you move the rack rod?  With these answers, we're on our way!

[rwmastel]

Don't forget pulling the lines off the top and trying to push the plungers down manually to see if they are "stuck".  I'm sure this is detailed somewhere!

Rodd
Pagoda Technical Manual
please contibute: http://www.sl113.org/wiki/pmwiki.php
1966 230SL
2006 C230 Sport Sedan

[Fano]

Thanks gents. I'll try your suggestions again. Perhaps I have missed something basic on my earlier attempts. Will get cracking on these suggestions.

I'll get back to you with the results.

Thanks,

Fano

[Fano]

Hello again gents.

I believe I may have good news. I went through the tour again. Joe's been helping me along quite a bit with trying to sort the IP out, instead of converting to carb. I have removed the check valves and doused the plungers in the IP with carb cleaner and lubricant. They seem to be moving freely now, and the rack also seems to be moving the way it should. I will try get the pump back onto the engine by tomorrow, and will let you know what the results are. Hopefully not too much adjustment will still be required.

thanks again for the help. I do believe y'all have saved me plenty time, money and hassle. You'll hear from me soon.

Fano