@DirtSniffer and I have been talking a lot about different options for the OM606 engine. Power goals, transmission options, transmission controllers, etc. After looking how long our conversations have gotten we figured we should start a thread on this motor since I am sure we aren't the only ones who have the same questions. I will say I am new to this motor, I am not sure why it has not come up on my radar until I saw @DirtSniffer start talking about it in his build thread. I am hoping @LA Z will add some of his knowledge as we get going. Thanks in advance.
OM606 Thread/Info/Discussion (1 Viewer)
- Thread starter fjdiesel
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We are both still learning about these engines, but here is a quick summary of what we have found.
The OM606 is considered by many to be the “2JZ of the diesels”. It is a 3.0 liter, DOHC, high revving straight 6 turbo diesel that is capable of making quite a lot of power on the stock bottom end with not a whole lot of effort. A simple turbo swap on the stock manifold and upgraded injection pump can yield around 300 or so HP and 400 lbft torque, with the capability to go much higher. These engines came in the Mercedes E300D from 1996-1999 here in the US. However, the desirable turbo variant was only available in 1998-99. The NA version came with weaker connecting rods and a mechanical injection pump. The turbo versions came with electronic pumps, which are largely swapped out for a modified mechanical pump with larger elements from either the mechanical NA OM606 or predecessor OM603 pump. The engines are not the easiest to come by, but they are out there. I thought long and hard about importing a toyota diesel, but have found a very happy compromise in this engine. May even be more satisfied in the long run with the performance this engine is capable of.
The two big names for getting these built IPs are Dieselmeken and DieselPumpUK (DPUK). Both appear to be good options, but for those of us in the US, Benzforce in TX is a partner with Dieselmeken and will build your pump using Dieselmeken parts and specs. Mechanical pump cores can be a bit tough to source here, so you may not have the option to just pay the core charge when ordering from them. DPUK seems to have a steadier supply, and you can choose to just eat the core charge which may be worth it anyways due to shipping likely being pricey.
The OM606 has a front sump oil pan and pump. Fortunately, the later OM648 rear sump oil pan and pump are a bolt on replacement. However, the rear of the oil pan forms part of the bellhousing mount, and the bolt pattern is slightly different.
Most transmission options require the use of a bellhousing adapter. DPUK, Doomsday Diesel, and Speed Gems are a few. The DPUK adapters all seem to have both the 606 and 648 oil pan bolt patterns in the adapter plates for you to choose from. The other options do not appear to, but may be an option if you ask or in the future. Some say the added strength from using the oil pan bolts is not needed as the strength is in the block holes. I will leave that for you to decide.
Cooling. These engines have a tendency to run a bit hot when turned up. The two biggest things you can do to combat this is to keep the mechanical fan, and to add a smaller water pump pulley to turn the pump up. There is also a water pump housing mod where you run a new line to the rear of the block to add a cooling circuit and improve circulation.
The OM606 is considered by many to be the “2JZ of the diesels”. It is a 3.0 liter, DOHC, high revving straight 6 turbo diesel that is capable of making quite a lot of power on the stock bottom end with not a whole lot of effort. A simple turbo swap on the stock manifold and upgraded injection pump can yield around 300 or so HP and 400 lbft torque, with the capability to go much higher. These engines came in the Mercedes E300D from 1996-1999 here in the US. However, the desirable turbo variant was only available in 1998-99. The NA version came with weaker connecting rods and a mechanical injection pump. The turbo versions came with electronic pumps, which are largely swapped out for a modified mechanical pump with larger elements from either the mechanical NA OM606 or predecessor OM603 pump. The engines are not the easiest to come by, but they are out there. I thought long and hard about importing a toyota diesel, but have found a very happy compromise in this engine. May even be more satisfied in the long run with the performance this engine is capable of.
The two big names for getting these built IPs are Dieselmeken and DieselPumpUK (DPUK). Both appear to be good options, but for those of us in the US, Benzforce in TX is a partner with Dieselmeken and will build your pump using Dieselmeken parts and specs. Mechanical pump cores can be a bit tough to source here, so you may not have the option to just pay the core charge when ordering from them. DPUK seems to have a steadier supply, and you can choose to just eat the core charge which may be worth it anyways due to shipping likely being pricey.
The OM606 has a front sump oil pan and pump. Fortunately, the later OM648 rear sump oil pan and pump are a bolt on replacement. However, the rear of the oil pan forms part of the bellhousing mount, and the bolt pattern is slightly different.
Most transmission options require the use of a bellhousing adapter. DPUK, Doomsday Diesel, and Speed Gems are a few. The DPUK adapters all seem to have both the 606 and 648 oil pan bolt patterns in the adapter plates for you to choose from. The other options do not appear to, but may be an option if you ask or in the future. Some say the added strength from using the oil pan bolts is not needed as the strength is in the block holes. I will leave that for you to decide.
Cooling. These engines have a tendency to run a bit hot when turned up. The two biggest things you can do to combat this is to keep the mechanical fan, and to add a smaller water pump pulley to turn the pump up. There is also a water pump housing mod where you run a new line to the rear of the block to add a cooling circuit and improve circulation.
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Some somewhat loose measurements of the OM606:
-Length, front of fan to bellhousing mount- 32.25"
-Height, bottom pan to top valve cover- 26.5"
-Fan diameter- 18"
-Fan offset- 4" to passenger side from crank.
For reference, here are measurements from my 2F:
-Length, front of fan to bellhousing mount- 36"
-Height- 28"
-Fan diameter- 16.5"
-Fan offset - 0, but engine is offset 2.5" to drivers side.
So, for example. On a stock FJ40, the fan is offset 2.5" to the drivers side due to the engine being offset. If you were to offset the OM606 the same (Assuming you are running an offset output split case), your fan would be offset about 1.5" to the passenger side. More centered than stock. Just offset to the opposite side.
Also, the 2F weighs roughly 700 lbs whereas the OM606 weighs around 500 lbs, maybe a little less.
-Length, front of fan to bellhousing mount- 32.25"
-Height, bottom pan to top valve cover- 26.5"
-Fan diameter- 18"
-Fan offset- 4" to passenger side from crank.
For reference, here are measurements from my 2F:
-Length, front of fan to bellhousing mount- 36"
-Height- 28"
-Fan diameter- 16.5"
-Fan offset - 0, but engine is offset 2.5" to drivers side.
So, for example. On a stock FJ40, the fan is offset 2.5" to the drivers side due to the engine being offset. If you were to offset the OM606 the same (Assuming you are running an offset output split case), your fan would be offset about 1.5" to the passenger side. More centered than stock. Just offset to the opposite side.
Also, the 2F weighs roughly 700 lbs whereas the OM606 weighs around 500 lbs, maybe a little less.
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View of offset fan for reference.
My initial planned transmission was the R150/151F. It is a fairly strong Toyota 5 speed with a few transfer case doubler options. Either dual marlin cases, or Northwest Fab EcoCrawler to RF1A. This transmission choice limits you to a centered rear output, and to center the engine. This would cause the engine fan to be pretty far off center, require a centered rear axle, as well as push the shifter about 10" back from stock 40 location. This also lengthens the driveline to the point of needing a wheelbase stretch. If you are putting a 606 into a stock length 40, you will want to stick with an offset case and axles.
I want to stick to 80 series axles, which are offset, so I am considering a different path that will allow me to run an offset split case. The control advantages of an auto are also attractive to me for my intended use of my build. We are currently looking into the available options including:
-NV3550/3500/4500 (Another manual option) - can adapt to split case and more. Needs bellhousing adapter.
-700r4 - can add a full manual valve body, no computer/controller. Need to manually shift every gear. Can adapt to split case and more.
-4l60/80 - can add manual control, 60 still needs computer, 80 can be full manual. Can adapt to split case and more.
-NAG-1 722.6- This is a Mercedes transmission that also came in a number of Mopar vehicles and will bolt directly to the OM606, which saves a good chunk of money and shortens the driveline a bit. We are currently researching transfer case and controller options. Input appreciated.
There are other options out there, but these are the main contenders.
It should be noted that depending on your transmission choice, your starter bolts will be inside the bellhousing. Starter replacement would require removing the transmission. The Doomsday Diesel adapters give you the option to add threaded inserts to the starter bolt holes on the adapter to be able to bolt the starter on from the outside. This uses smaller sized bolts, and is a bit weaker. But probably not a big deal. The OEM starters are considered pretty robust, but if you abuse your vehicle like some of us on here, a starter replacement may be something that will inevitably happen. Most likely on the trail, in the middle of nowhere. So something to consider. DPUK does suggest drilling holes in your bellhousing to access the starter bolts, which would stay in place while you replace the starter.
Relevant information we are looking to gather include:
-Ideal cruise speed RPM at 70 mph (Stock E300D is at around 3000 rpm at 70, is 2000 rpm too low?)
-Torque converter stall speeds for various power goals (300, 400, ??) I have heard 3000-3500 rpm for around 500hp.
-Controllers that monitor boost. Apparently the 722.6 NAG-1 transmissions don't like to work well with the mechanical pump 606. Options?
I want to stick to 80 series axles, which are offset, so I am considering a different path that will allow me to run an offset split case. The control advantages of an auto are also attractive to me for my intended use of my build. We are currently looking into the available options including:
-NV3550/3500/4500 (Another manual option) - can adapt to split case and more. Needs bellhousing adapter.
-700r4 - can add a full manual valve body, no computer/controller. Need to manually shift every gear. Can adapt to split case and more.
-4l60/80 - can add manual control, 60 still needs computer, 80 can be full manual. Can adapt to split case and more.
-NAG-1 722.6- This is a Mercedes transmission that also came in a number of Mopar vehicles and will bolt directly to the OM606, which saves a good chunk of money and shortens the driveline a bit. We are currently researching transfer case and controller options. Input appreciated.
There are other options out there, but these are the main contenders.
It should be noted that depending on your transmission choice, your starter bolts will be inside the bellhousing. Starter replacement would require removing the transmission. The Doomsday Diesel adapters give you the option to add threaded inserts to the starter bolt holes on the adapter to be able to bolt the starter on from the outside. This uses smaller sized bolts, and is a bit weaker. But probably not a big deal. The OEM starters are considered pretty robust, but if you abuse your vehicle like some of us on here, a starter replacement may be something that will inevitably happen. Most likely on the trail, in the middle of nowhere. So something to consider. DPUK does suggest drilling holes in your bellhousing to access the starter bolts, which would stay in place while you replace the starter.
Relevant information we are looking to gather include:
-Ideal cruise speed RPM at 70 mph (Stock E300D is at around 3000 rpm at 70, is 2000 rpm too low?)
-Torque converter stall speeds for various power goals (300, 400, ??) I have heard 3000-3500 rpm for around 500hp.
-Controllers that monitor boost. Apparently the 722.6 NAG-1 transmissions don't like to work well with the mechanical pump 606. Options?
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Here's my adapter for the Toyota transfer case and 722.6 transmission next to an a440f from an fj62.
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Nice, what did you do for the output shaft?
Bellhousing to rear driveshaft flange is 37.75".
That puts the NAG-1 front to transfer case length at about 29". May be able to adapt without that long factory transfer case adapter housing and shave off a good chunk of length.
@LA Z , what did you do for the output shaft? I read somewhere you had it custom made, could not find details. Thanks
By comparison, the 4L80 is about 26", but needs a 1.5" spacer. And potentially a split case adapter, unless you are running a NWF black box to adapt to split case anyways.
@LA Z , what did you do for the output shaft? I read somewhere you had it custom made, could not find details. Thanks
By comparison, the 4L80 is about 26", but needs a 1.5" spacer. And potentially a split case adapter, unless you are running a NWF black box to adapt to split case anyways.
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For those interested in putting one in a stock wheelbase 40, the H42 front of bellhousing to transfer case mount is about 18.5". An auto may be a bit too long. You can either run an nv35550/3500/4500 to cruiser case, or run a Chevy bellhousing adapter and a Marks 4WD bellhousing to retain the H42/55.
You can shift the engine forward about 3.5" if needed because it is shorter than the 2F. The shifter is further back on the GM transmissions. For the H42/55, you can shift it forward and run an FJ60 transmission top plate which moves the shifter back pretty close to where it was. Just some ideas.
You can shift the engine forward about 3.5" if needed because it is shorter than the 2F. The shifter is further back on the GM transmissions. For the H42/55, you can shift it forward and run an FJ60 transmission top plate which moves the shifter back pretty close to where it was. Just some ideas.
I did make a custom shaft for the transmission to transfer case. It was made from an OEM Toyota transmission output shaft.
You can’t make the drivetrain shorter because the 722.6 transmission output shaft and hub is as short as it can be. The output shaft on the 722.6 transmission is the same length on the 2wd, or the one that has the provision for the transfer case. The only difference in length is the engagement between the output hub and the input shaft for the transfer case. ( about 2” ) I didn’t want to make the engagement lengh any shorter because of the power that gets transferred through it. We all familiar with the transfer case input gear getting sloppy on the transmission output shaft.
You can’t make the drivetrain shorter because the 722.6 transmission output shaft and hub is as short as it can be. The output shaft on the 722.6 transmission is the same length on the 2wd, or the one that has the provision for the transfer case. The only difference in length is the engagement between the output hub and the input shaft for the transfer case. ( about 2” ) I didn’t want to make the engagement lengh any shorter because of the power that gets transferred through it. We all familiar with the transfer case input gear getting sloppy on the transmission output shaft.
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Do you have any pictures of that? Just curious how it all goes together. Do you sell them as well?
![IMG_20240130_2011125[1].jpg](data:image/svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg' width='1280' height='1920' viewBox%3D'0 0 1280 1920'%2F%3E "IMG_20240130_2011125[1].jpg")
I've driven these cars for about 10 years now, and worked on many customer's cars. I've fitted some big pumps and turbos. My current daily is a 99 e300 240k miles, tune, 1.5gph water meth kit (comes on at 3PSI) and HE221 6cm turbo, no lag at all, I'm guessing it doubles the stock torque but it does choke at high RPM, it's great for what we use the car for and I feel like if it was in a heavy truck it would work well. that being said I'm building a stroker motor to swap, using a om603 3.5 crank, The pistons hit the oil squirters so needs a little notch in them. also need to run a thicker head gasket. it'll be awhile before it's driving.
also Dpumpuk has rods that let you use a om648 crank, not as much of a stroker as the 0m603 3.5 crank but should help with the bottom end and i dont think piston machining is required.
i have the doomsday r150 kit, very nice. a splitcase can be mated to a R150.
also possible: take a jeep NSG370 rear half and mate it to the front half of a Mercedes 716 transmission (there are 2 sizes must use the larger of the 2) you can then take all the money you saved from not buying any adapters and buy an atlas transfer case that fits the jeep transmission and has Toyota driveshaft flanges if you can deal with a centered rear output.
Good info and thanks for the input. As far as I know the only way to get a split case behind an r150 is to use an hzj79 r151f tail housing, which used a variation of the split case. Unless there is an adapter I am unaware of?
AussieHJCruza
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What sort of torque do these make? I'd be concerned about the longevity of an R1## transmission. Have seen 3 broken behind hopped up 1HD-T engines, circa 150kw, 550-600 nm at the tyres.
Ideally, cruise RPM would or you about midway between peak torque, and peak power.
This gives decent fuel economy, gives you some room to lug it up hills without dropping down a gear, and leaves power and torque in reserve for evasive manoeuvres, or to power out of an "Oh Shìt" situation.
My experience with changing gearing on Toyota diesel cruisers is a change in final gearing of 10%, cruising RPM drops below about 2500rpm, you end up down shifting far too often on insignificant hills or for passing on the highway etc
I found you need to change down as revs drop through about 2250rpm. If you wait to 2000rpm to downshift, you're often losing too much steam and shifting down two gears.
The 1hd-t 4.2 litre toyota turbo diesel I had definitely did not suffer as much from taller gearing, but it still was noticeable.
Similar with my TD VW work ute, below 2500RPM, it's not getting out of it's own way when you need to step on it. Not without dropping a couple of gears.
I HATE the way it downshifts
but that's a whole other story, and is partly about the transmission!The 1hd-t, peak torque is at 1650rpm, peak power 3600rpm. ( maybe 3800? memory may be off)
Cruising rpm wants to be around 2600-2700rpm, which is right where the factory gearing and 5 speed puts you.
I'm in the same camp as @AussieHJCruza on the r151 5 speed.
They aren't well regarded in Cruisers in Australia.
5th gear failures are well documented, among other things.
I'm not sure I'd invest in one.
Comparing the R151, and H151F used in 80 series, and vdj79s etc, side by side, the H151F is built STOUT!
They aren't well regarded in Cruisers in Australia.
5th gear failures are well documented, among other things.
I'm not sure I'd invest in one.
Comparing the R151, and H151F used in 80 series, and vdj79s etc, side by side, the H151F is built STOUT!
Indestructible 47
SILVER Star
I'll be the third aussie here to say a hard pass on the R151. One of our old work N/A 1hzs broke one when it was let of the clutch a little aggressively. Same with the H55f. POS of a transmission in all honesty (yes I'm a toyota man).
