Author Topic: Removal of Compensator, etc. from Fuel Injection Pump (Read 3141 times)

Harry · « **on:** December 28, 2019, 03:27:49 »

I would like to remove some “appendages” from my FIP to paint them, then reattach to the FIP. This includes the barometric compensator, the coolant tower, etc. some of the things that were anodized when new.
Is there anything to be cautious about? I don’twant to regret a slight cosmetic improvement.
Thanks,
Harry

1966 230SL

doitwright · « **Reply #1 on:** December 28, 2019, 05:22:31 »

I think you mean Cadmium plated rather than anodized. Most people have painted the baramotric compensator (once referred to as the tuna can) rather than dip in a plating solution.

Harry · « **Reply #2 on:** December 28, 2019, 13:23:45 »

Yes. But I would like to remove them rather than mask in place. I just want to be sure that they can simply be removed and reinstalled. The compensator, for instance, contacts/positions the rack. I don’t want to have follow an involved reinstallation procedure and risk a faulty installation and leaks/poor performance just to improve appearance.

doitwright · « **Reply #3 on:** December 28, 2019, 14:38:43 »

You will likely find one or more washer-like shims under the compensator. It can be removed, just be sure to put the same shims back. Other parts can be removed also. You just have to be careful when you get to linkages attached to internal parts. Just photograph everything as you go. Remember that the pump is in time with the engine just like a cam sprocket.

Pawel66 · « **Reply #4 on:** December 28, 2019, 14:57:59 »

I am not a mechanic, but have some practical observations.

I would not remove the lever connected to linkage rod. I would not touch it.

When removing the barometric compensator be sure not to lose any shims (they have the tendency to fall down from the compensator threaded stud). You may find most of the spanners too long to easily unscrew the compensator. I cut a spanner to have an easy way to screw and unscrew the compensator.

If you decide to remove the WRD "tower", I think (just my view) it is better to remove it as one piece with thermostat housing, then detach the thermostat housing (otherwise you may spill coolant inside the WRD valve). Be sure not to lose oval shims - at certain moment of unscrewing, the spring will kick the "tower" up - this is the moment you may have one or more shims fall down. If you are doing it, you wil need to detach three hoses. Prepare that some coolant will drip from the coolant hoses, the bottom one particularly. Prepare some plugs to plug the coolant hoses and the air hose while they are waiting to be re-assembled.

When putting back the thermostat on the WRD, use sealant between thermostat housing and the large thick base shim.

Harry · « **Reply #5 on:** December 29, 2019, 02:35:05 »

Thanks all. I failed to note that the FIP is not installed on the car at this time. The figure below shows the 4 items that I would like to uninstall and paint, then reinstall. And I am not about to touch ANY linkages.

Additional thoughts?

Harry

Pawel66 · « **Reply #6 on:** December 29, 2019, 08:00:37 »

Well, then, by the look of it, I would send it to professionals for reconditioning of the whole thing and check up.

Harry · « **Reply #7 on:** December 29, 2019, 13:35:08 »

I have read many times on the forum, and certainly have experienced it myself on this and other projects, that one thing always leads to another. The line on when enough is enough is very hard to find, and it is super easy to continue to spend money. I began this exercise really just wanting to recondition my head and freshen up the engine compartment. I now have a rebuilt engine, rebuilt front suspension, cosmetically refinished "everything" under the hood, new front brake calipers, etc., etc.
And I would love to send the FIP off for a rebuild. But it was running fine when I began the job and prior advice on the forum said don't touch it if that was the case. Also, the FIP can be removed later for that purpose if it appears it is warranted at the time. So, for now, I just want to do a few things to freshen up the appearance - and get this sweet ride back on the road!

Thanks for the advice though!
Harry

Pawel66 · « **Reply #8 on:** December 29, 2019, 15:34:43 »

Sure, if it was running fine on a running car, I understand, of course. Then, as previously advised, timing is important. All three marks need to be lined up. If you decide to work on the housing - make sure you plug all the screw holes.

Minerva · « **Reply #9 on:** December 29, 2019, 18:20:09 »

Here's the pump on the 230 I'm doing, spent days with a toothbrush and petrol cleaning it, I wasn't sure of its condition but took a chance on it being ok, the only thing that lets it down is the compensator as I didn't want to send it for plating. The air filter is new and the stat housing is re-plated. I didn't want to send the pump for vapour blasting for obvious reasons.

doitwright · « **Reply #10 on:** December 30, 2019, 06:21:41 »

The smaller item (below and to the right in the photo) has a paper filter inside. Most people just replace it with a new one.

Harry · « **Reply #11 on:** December 30, 2019, 16:22:51 »

The red canister has the paper filter?

Pawel66 · « **Reply #12 on:** December 30, 2019, 16:29:47 »

The paper insert is in the air filter, the tin attached to the WRD tower below the thermostat, the far right side on the picture. It is good to buy the filter new if the paper insert in yours is gone or clogged. The air goes from there to the inlet manifold. I do not suppose you can replace just the paper insert.

Harry · « **Reply #13 on:** December 30, 2019, 16:56:58 »

Thanks. I have actually replaced that already.

Harry · « **Reply #14 on:** December 31, 2019, 01:51:04 »

I was able to remove most of the pieces/parts that I was talking about (see photo of one part). This part appears to have a perforated screen and maybe element behind it - like an air filter. It is the small part indicated by the third arrow from the top. Should I remove the circlip and clean, replace, reinstall or what do you think?

The coolant tower on the other hand is quite stubborn so I am soaking the two screws overnight to see if I can encourage those to free up.

Thanks again,
Harry

Pawel66 · « **Reply #15 on:** December 31, 2019, 12:05:01 »

If you have the pump out with no coolant and there is difficulty with unscrewing and WRD was working fine on the car during cold start and warm up - for cosmetic reasons you may want to just unscrew the thermostat housing, not the hole tower.

The part you ask I am not so familiar with (early pump, I have the late one), sorry.

I just thought I would add this: I read in numerous posts on this Forum that the early style thermostat housing is very hard or impossible to buy and the early style thermostat - hard to get or expensive ($800-900 at MB dealers). The housing can be a bit rusty, etc., so one needs to be really gentle, I think...

Harry · « **Reply #16 on:** December 31, 2019, 12:09:33 »

Thanks Pawel66. Yes - I am leery of getting into more than I bargained for just for cosmetic purposes. I am only trying to remove the housing, i.e. the uppermost portion that the coolant lines fit onto, held on by two screws.

Harry

Harry · « **Reply #17 on:** January 02, 2020, 13:24:23 »

I have successfully removed the few items from the FIP - just took patience and care. So this includes the Cold Start Valve (CSV), the Warm Running Device (the tower with fittings for coolant attachment), Barometric Compensator and the smaller "can" in the photo of my Dec 31 post. I had replaced the air filter some time ago.

Interestingly, there were no shims under the Compensator.

My only concern is being sure that the WRD can be reattached without leaking. The brass WRD inside the coolant tower has a copper washer between it and the FIP mount. I'll replace it but there is also a deteriorated rubber gasket between the tower and the FIP mount, and it looks as though the two screws clamp both of these seal surfaces simultaneously. I did find a small amount of sealant around the copper washer - which I will probably repeat.

Pawel66 · « **Reply #18 on:** January 02, 2020, 19:03:11 »

You have the housing of the thersmostat, thermostat inside, then going down is that thick ring and further below the WRD (air valve). You need to use the sealant between the thermostat and housing, if I remember correctly (I do not know your type of FIP very well).

Take a look at the drawing here, you will see where coolant is: https://www.sl113.org/wiki/Engine/WarmRunningDevice

Do not lose any shims - there are some round shims there in the WRD.

Harry · « **Reply #19 on:** January 05, 2020, 16:00:02 »

Here is another question. I am reinstalling the WRD and I want to be sure that I am not missing a gasket - it doesn't appear that I am. The photo below shows the mount for the coolant housing. I have scribbled a couple of pointers in red that identify an upper surface with the two threaded mounting holes and a counterbore (recessed surface) below that.

The thermostat has a lip that seats within this counterbore on the bottom and against the housing on the top. The mating surface with the housing has a copper gasket. So it doesn't look as though there are any other gaskets involved although as I noted in disassembly, I did find a small amount of sealant on the thermostat lip.

What is the correct arrangement?

Thanks,
Harry

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Author Topic: Removal of Compensator, etc. from Fuel Injection Pump (Read 3141 times)