OM647 intake manifold install in an OM612

jackbombay

Active member
I had the displeasure of removing the high pressure fuel rail from my OM612 recently, and I'm sure somebody has at some point successfully reinstalled a high pressure fuel rail in an OM612, but I didn't want to prove how stubborn I am, so I decided to put an OM647 intake manifold on my 612, which has much, much better access to the high pressure fuel rail.

So, both manifolds use the same gasket, but you do need to get a few parts from the junkyard or your dealer, you need the intake manifold support bracket, this goes from the intake mani to the engine block and mounts to the same hole that the OM612 intake mani mounts to, and you need a different coolant hose that goes from the 647 EGR valve to the coolant pump on the firewall, and you need 4 longer intake manifold bolts that go across the bottom of the intake manifold. The bracket is part number A6470960045, the coolant hose is part number 901 832 8023 C, the longer bolts that fasten the bottom of the mani to the head, well, nobody has a part number for them and they are not shown on any parts diagram, I got mine from a junk engine at a bus shop here in Idaho, the bolt has 100 mm of threads and is 8 x 1.25 I believe, the head of the bolt has some markings KXZ 8.8.

here are pics of all the parts,





The bolt,



There are 2 small 90* brackets that fasten the top edge of the 612 mani to the head, you will need to modify one of those to hold the fuel pressure sensor (I think that's what it is, signals that the fuel filter is clogged) OR you can lengthen the wires for that sensor before you instal the 647 mani, once the mani is in there isn't much room to get down in there to solder and heat shrink the wires...

This is the bracket before I cut and welded it, but if you just lengthen the wires when you have decent access you don't have to do this,



The fuel temp sensor (I thikn thats what it is) that is located at about the mid point of the rail will need just a tiny bit of plastic removed from it to fit with teh 647 mani, when I was removing the plug from that sensor I did break off the retaining clip (due to the terrible access of the 612 mani) which resulted in it just barely fitting, you do have to remove the mounting plate, instal the plug then reinstall the plate that the sensor is mounted to to get the plug on, but it fits fine if you do that.

Lastly, the banjo bolt at the back end of the rail need to be installed before you instal the rail, or mani as with both the rail and mani in place you cannot get the banjo bolt in place.

Yea, EGR, I have a GDE tune, so my van runs fine without it, I do have the old EGR valve hanging from the firewall but I'm working on how to eliminate that...

I now have easy access to the injectors and glow plugs, the manifold cost me $100 off ebay, the bracket was $24, the hose was $5 and the bolts were free.

I did use a sawzall to get the old manifold off, I do have a 3rd degree blackbelt with a sawzall...

I doubt (m)any people will do this swap, but for those for whom it might make sense they can rest assured that it will all bolt up pretty painlessly, with the exception of getting the 612 manifold out...

Here is the mani and fuel rail mocked up, to show it does fit, I can post a complete pic tomorrow.


 

talkinghorse43

Active member
Yea, EGR, I have a GDE tune, so my van runs fine without it, I do have the old EGR valve hanging from the firewall but I'm working on how to eliminate that...
Will you blind the EGR passage in the 647 manifold at the head or at the attachment point of the 647's EGR valve?
 

jackbombay

Active member
Will you blind the EGR passage in the 647 manifold at the head or at the attachment point of the 647's EGR valve?
Right now I've done nothing, looking at the rotary design of the valve I believe it stays closed by itself under all operating scenarios so I don't think I need to mess with it. I could put some JB weld on the top of the rotating assembly, but I don't think there is a need to currently.

The OM647 mani also has a great spot for heating foil wrapped burritos that the 612 mani is lacking :smilewink:
 

Aqua Puttana

Poly - Thread Finder
Interesting modification.

Are you at all concerned that the misplaced EGR may be noticed during an annual compliance inspection, or is annual inspection very basic/not required where you live?

vic
 

jackbombay

Active member
Interesting modification.
When I got the longer intake mani bolts from the guy at the bus company he said to me, "Everyone I have met that owned a sprinter was strange, what do you do for a living?"

Are you at all concerned that the misplaced EGR may be noticed during an annual compliance inspection, or is annual inspection very basic/not required where you live?
Idaho, no inspections of any sort for any vehicle.

The plug for the EGR valve is the same on the 612 and the 647 so there is a chance that I'll be able to get a 647 EGR valve motor and make it work, I sent an email to GDE asking if they know if this will work, I'll post up if I hear back from them.
 

Johnbyrdgates

Vanosaurus
Hoping to hear whether or not you could make the old egr work in the new manifold. Also, I wonder if you could post your pictures in a format other than photobucket, since I can’t view them in that form and they seem really helpful to your article. Thanks for your excellent idea.
John
 

obie

'04 long & tall passenger
Hoping to hear whether or not you could make the old egr work in the new manifold. Also, I wonder if you could post your pictures in a format other than photobucket, since I can’t view them in that form and they seem really helpful to your article. Thanks for your excellent idea.
John
Why would you want to make the old egr work? Isn't the new one less troublesome, and at least a whole lot cheaper?
 
the longer bolts that fasten the bottom of the mani to the head, well, nobody has a part number for them and they are not shown on any parts diagram, I got mine from a junk engine at a bus shop here in Idaho, the bolt has 100 mm of threads and is 8 x 1.25 I believe, the head of the bolt has some markings KXZ 8.8.
Is anyone able to give more info on this bolt? I’m thinking about doing this upgrade, but I don’t know how to find the bolts with this info. The threads are 100mm, but I don’t know how to find bolts online just shopping for thread length. What’s the total length of the bolt?
Mike
 

lindenengineering

Well-known member
Is anyone able to give more info on this bolt? I’m thinking about doing this upgrade, but I don’t know how to find the bolts with this info. The threads are 100mm, but I don’t know how to find bolts online just shopping for thread length. What’s the total length of the bolt?
Mike
These bolts are available from MB.
I buy them fairly often when doing a rebuild and the old bolts are discarded as they sometime won't take a torque.
Dennis
 
Jack, nice work, I think the sawzall is the way to go, after all its going in the s##t can , why not?? When this mod is done is it easier to to get to the glow plugs? I have a 2003 sprinter, OM611 i think?
 

Cheyenne

UK 2004 T1N 313CDi
Oh...since my motor is a 611 , maybe the mani mod wont work?
The mod will definitely NOT work on an OM611.

The OM611 is a 4 cylinder whereas the OM612 and OM647 are both 5 cylinder. There was never a 4 cylinder USA version of the OM611.

I don't think the OM611 suffers from the same lack of access as the OM612 as the OM611 has a simple to remove manifold and then the injector cover can be removed (but I haven't tried on mine).

Keith.
 

Cheyenne

UK 2004 T1N 313CDi
oops!!! I was confused, I have the 5cylinder , OM612 engine, 2003 Freight Liner. lots of motors in the MB vans.
So Yes the mod does work on the OM612 but I believe you need a few other parts as well as the manifold.

Keith.
 

nctrailseeker

Active member
What other parts are needed to do the swap? Fuel rail?
 

Cheyenne

UK 2004 T1N 313CDi
Pardone my ignorance, what is the “Mani Mode”? Thx!
First you have mis-copied the original text - “Mani Mod

And that is short for Manifold Modification or in other words fitting an OM647 manifold to the older OM612 engine. It makes access to the glow plugs and injectors easier.

Keith.
 

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