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Hi, I am just visiting, I am normally on the gwagen forum, but I think you guys should know the answer to this question.
Are the om603 and om606 engines the same, except for their different heads? So can a 606 slot into a 603 engine bay without too much grief.
I live in Ireland and have a om617 non turbo Gwagen. I need more go and I know that later Gwagens had om603's but I am not sure as to whether an om606 would fit. Om606 engines would be easier to find here than turbo 617s
Bob
 

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Sure Are Same Engines.
Heads Different - 606 - 4 valves per cylinder
603 - 2 valves per cylinder.
Everything you can do with Mercedes.
You are talking about Turbo or normal Engine?
606 have big pipe intake manifold & you need new Air Filter housing.
606 are perfect if you can use on modern way with good lubricants (Synthetic Oils.)
 

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Where can you find the 603 or 606 engines here in the US? I am considering putting them in a Range Rover or Defender Land Rover.
 

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Where can you find the 603 or 606 engines here in the US? I am considering putting them in a Range Rover or Defender Land Rover.
OM603.96: '87 300D/TD (124) '86/'87 300SDL (126)
OM603.97: '90-'92 350 SDL (126) '92-'95 350SD/300SD* (140)
OM606.910: '95 E300D (124)
OM606.912: '96-'97 E300D (210)
OM606.962: '98-'99 E300D (210)




* I probably have the years and nomenclature a little mixed up, but you should avoid the OM603.97 engine, anyway.
 

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Sure Are Same Engines.
Heads Different - 606 - 4 valves per cylinder
603 - 2 valves per cylinder.
Everything you can do with Mercedes.
You are talking about Turbo or normal Engine?
606 have big pipe intake manifold & you need new Air Filter housing.
606 are perfect if you can use on modern way with good lubricants (Synthetic Oils.)
Ok...So are you saying that a 606 engine will fit into where a 603 was? I have a 91 SDL with an engine that is toast. I don't mind spending some cash on a 606 if it will fit in, and mate to the transmission.
 

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I've posted a thread that I'll be updating periodically with my project to install an OM606.962 in my S124. There are a number of differences between the engines and I'll be enumerating those in that thread. It is NOT a simple matter of plug n' play for this swap.
 

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Hi, I am just visiting, I am normally on the gwagen forum, but I think you guys should know the answer to this question.
Are the om603 and om606 engines the same, except for their different heads? So can a 606 slot into a 603 engine bay without too much grief.
I live in Ireland and have a om617 non turbo Gwagen. I need more go and I know that later Gwagens had om603's but I am not sure as to whether an om606 would fit. Om606 engines would be easier to find here than turbo 617s
Bob
G wagens were available with the 606 diesel, at least outside the US. The 606 did not do too well in the G wagen, though, suffering from fuel starvation problems since the engine sits higher than the fuel tank on that vehicle. This caused fuel lock up problems and other fuel related problems especially during off road use.
 

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G wagens were available with the 606 diesel, at least outside the US. The 606 did not do too well in the G wagen, though, suffering from fuel starvation problems since the engine sits higher than the fuel tank on that vehicle. This caused fuel lock up problems and other fuel related problems especially during off road use.
That said: An auxillary electric booster fuel pump placed next to the fuel tank could resolve that problem. Like the one from Mercedes Source: Diesel Biodiesel SVO Electric Fuel Boost Pump Kit | MercedesSource.com

Mark
 

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{I probably have the years and nomenclature a little mixed up, but you should avoid the OM603.97 engine, anyway} why are u saying we should avoid this engine.
 

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The OM603.97 is the notorious 3.5L variant a.k.a. "the rodbender" which is known for headgasket issues, high oil consumption, etc, etc, etc.

Also, bad motor mounts can cause the oil windage tray bolts to come loose, get sucked into the oil pump and thus grenading the engine instantly.

The OM603 in 3L is a fine engine, although it had it shares of issues too such as weak head castings, oxidizer trap, etc.

Given the choice, stick with the 3L version.
 

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{I probably have the years and nomenclature a little mixed up, but you should avoid the OM603.97 engine, anyway} why are u saying we should avoid this engine.
Pay not attention to sbaert. He's just flapping his gums with nothing to useful to say, as usual.

The 3.5L OM603 "rod bender" issues are well documented. Fortunately the vast majority of those engines are off the road by now. What remains are engines that received a replacement short block from MB with much stronger connecting rods. These engines just as solid as any 3.0L OM603 or OM606.

These replacement blocks with the stronger rods can be identified by the tag on the passenger side near the bell housing. Factory original blocks (bendy rods) did not get this tag.

Also keep in mind that quite a few industrious owners swapped older 3.0L blocks into 3.5L engines so don't be surprised to run into OM603.960 when you are expecting to see a .970
 

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Individual members are irrelevant to this discussion, which by the way is an ancient thread. There are still original 603.97 engines on the road, so you'd need to see the factory rebuild plaque in order do be assured that it did indeed have the upgraded rods. For reasons not entirely known, not all of these engines suffered the bent rod issues, and others got tagged early on in their life cycle. Lots of theories floating around, but no confirmed definitives as far as I've heard. A factory upgraded .97 longblock would be an excellent basis for a performance build or an engine swap.
 

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If you're looking to drop a 606 into a 461, then you should check out AGOA or clubgwagen forums. The swap has been very well documented and is absolutely not a straightforward swap. IMO the m117 swap is far easier and much less complicated (except for the big $ amg engine mounts)

But, you can get 603 in without much trouble. look for a JDM Gwagen - 300GD swb would be ideal, unless you need other donor parts.

But at the end of the day you have to ask yourself is it worth it? I've seen a lot of G's falling apart at the seams with rust and huge $ spent on them. SOmetimes a newer 463 g350 would make me feel more comfortable, except down here, they are stupid $ expensive.

So the solution? I bought a 91 Range Rover Classic. and yes, they are sluggish compared to say a 560SL. but I happen to have a spare m117.968 HV engine and with an adapter plate on the ZF auto of the RRC and an EFI conversion, the power upgrade and reliability will be reassuring should I need to do an engine swap down the track.

Unless I could get an LS3 cheap, I don't think I'd bother with that for an RRC. LS1's meh... but an OM606 would be a very nice thing indeed - but the BW viscous transfer case would be the next concern. You'd almost want to pull the drivetrain from a later Disco2 or a manual transfer case from a defender and upgrade the internals with a quaife atb if you want to chase big big torque. ... of course then the issue simply moves further down the drivetrain to uni's and axles... and the cv's.... while a Gwagen will take the pain, I would suggest maxidrive/hy-tuff axles & cv's for the RR and 'pin' the diffs as well as perhaps lockers if you are seriously offroading.
the BECM in the P38 will need a bunch of inputs disabled. They are also not the most reliable bit of electronics (which is another reason I have an RRC and not a p38)

In short, it is all doable, but not without a fair degree of detailed planning and expense. The suggestion would be to thoroughly cost it before even dropping a cent. You know that there will be a bunch of little things to completely bugger your progress along the way, so contingency funds need to be of a suitably substantial amount to prevent the project from becoming a boat anchor, or ballast for a landfill barge.
 
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