[joeblack5]

Howdy folks, Happy 2021.

Have been thinking about diesel conversion for a while and think I have read most threads and posts on this and other forums.
We are attempting a camper with our second 404 and would like the fuel efficiency of the diesel. For that reason the TDI above the OM617.
In this camper the 404 cab will be hard connected to the camper shell.. all on pivoting frame...and the front seats of the 404 will have swivel so that the cab becomes part of the living space.
For that reason I do not want to reduce the cab area or modify the engine dog house unless it is going to be smaller.
The cab will be raised about 2" to make space for 12.5-R20 tires

Looking at the available picture and taking some measurement it seems that if I pull the TDI engine to the front of the mog and remove the alternator and oil filter then it all could fit with out interference.
The front of the 404 engine bay is wider ( 22") with space for the original distributor. This would help with space for diesel pump. With alternator removed less then 20". Worst case would be to use the pump duse engines BEW and so on.

The 5 speed transverse manual transmission of the TDI can be split and the engine / bell housing section can be used as spacer / adapter.
This would have several advantages:
-TDI flywheel / clutch assembly can be maintained, power upgrades are available
-Clutch cylinder is already attached to bell housing.
-Starter is attached to bell housing. along the transmission
-readily available.
- the lighter weight TDI engine slid to the front gives max pressure on the front axle.

Another adapter / spacer has to be manufactured to adapt from the TDI bellhousing / half transmission to the bell housing of the 404.
M180 engine length 31" with pulleys... without fan.
TDI ALH 18"
TDI 5spd bellhousing / half transmission 5"
TDI ALH with transmission 32"

Problems:

Depending on that exact space the original TDI starter will not interfere with the 404 bell housing. unknown

The TDI ALH 5 speed has no pilot bearing and the input shaft no stub for a pilot bearing.

The TDI ALH longitudinal transmission has a pilot bearing so a shaft swap with bearing might need to happen.

The TDI transmission shaft has to be extended and adapted to the 404 input shaft , probably nicest with the spline of the clutch.. It looks like the 404 shaft's spline id long so for best alignment maybe two clutch centers could be welded together

The differential housing has to be cuttof from the TDI transmission.
ideas.

ideas??
The TDI with 5 speed is about as long as the M180.
Potentially the cover 5th gear steel cover of the 5 speed can be removed, the transmission gutted and an adapter flange from the back of the transmisisson can mate to the 404 bell housing.
The splined old 5th gear can be welded to the clutch spline of the 404.
Bearing would have to be replaced with enclosed ones or if pilot bearing/ new shaft is used then both tdi transmission bearings can be removed.

In the pics of the TDI / 5 spd.. the starter motor is removed.

Anybody has tried / see this approach?

Johan by

 

[MicMoor77]

I’m very interested to see how this works out for you. Be sure to post lots of pictures. Where are you located?

 

[joeblack5]

Hi MicMoor77,
I am in State College,PA
This is going to be a very slow thread and sofar mainly research.

Today back with measuring tape.

The distance from the 404 bell housing to the front cross member with motor mount is 28"
The rough distance of center of crankshaft above the cross member is 4-1/2" .

The overall length of the TDI engine from front of pulleys with complete transmission is 32"
I did not measure the distance from the front of pulley to the oil pan or the distance from the center of crankshaft to the bottom of the engine. Tomorrow back to the junk yard and see what those dimensions are.

The TDI engines come is several variations.. the first are the AHU, then the AHL and the pump duse engines. BEW, BRM etc

For the the unimog conversion the oil pump location is interesting because of steep inclines/ declines.

The oldest engine, AHU has the pump at the rear end of the block with a steel oil pan.
The newer AHL and BEW have a chain oil pump at the front of the block. I believe that the newer version are better engines but a rear oil pump means more clearance up front, a steel oil pan that can be easily changed to a deeper one at the right location.

The starter motor of the TDI ends about at 25 " so if I can make the end of the TDI tranny mate to the 404 bell housing then that would make life easier.

OK , now I am going a little of the deep end... I have not made gear calculations yet.

Assume I leave the 5 speed TDI transmission intact and weld a shaft to the the 5Th gear on the primary shaft,, effectively deleting the 5 gear I could use the complete TDI gear box and delete the low gears / reverse and first gear of the 404.

My reason not to increase the max speed of the 404 but lowering the engine RPM

That means that the I would have to modify the 404 transmission and adapt a new input shaft directly to the 4 and 5th gear , resulting in 4 speeds from the TDI and three speeds from the 404. 12 in total.

The VW transmission is very universal and available with different gear ratio's depending on what gas engine or diesel engine. So my hope is that a good match would still have an over drive in 4.
Another option would be to make a new gear set an adapt from the TDI intermediate shaft. These extra gears are required to reverse rotation and recenter the input and out put shaft...A lot more complicated

The normal 404 input shaft likely cannot handle the torque from the TDI in first and reverse gear but the 4 and 5th gear of the 404 are pretty stout so they might..

So the key here would be if the TDI 4Th gear with the the 5th gear could still be configured as an overdrive.

The VW 4 speed transmission GP/ GL had a 4 th gear ratio of 0.71. That linked to the 5th gear of the O2J transmission rati0 0.844 would result in a reduced overdrive of 0.84. Still not bad
the question here is if the gears of the 4 speed tranny would fit in the 5 speed tranny?
I put the question up at the TDI forum but hope there are some knowlegeable people here.

Your thoughts please!!

Johan

 

[tmodler]

You need to ditch the TDI gearbox.

C.

 

[joeblack5]

why?

 

[tmodler]

Why do you want to lower engine RPM? An ALH will run up past 4K rpm no issues. You are just setting the 404s gearbox up to fail sooner by increasing the input shaft speed.

If you want lower RPMs, best option on a 404s is to drive slower.

C.

 

[joeblack5]

Hi C.

No, the input speed of the 404 transmission stays the same...but the engine rpm would go down. Yes the alh can run up to 4500 but that does not mean that you should for noise or fuel consumption.
I am not sure at what speed the ahu engine is happy but it is an older design. The advantages of the ahu are the oil pump and easily modifiable steel oil pan.

I am just trying to go thru solutions people already attempted and some actually finished, see their hangups, and a different approach with I hope less hangups... Use the vw transmission as a spacer so that the engine get further to the front and avoid the trouble of starter motor location and flywheel clutch combinations flywheel adapters, cab modification and such.

A second opportunity... Not great by any standards... is use the vw transmission and gut the 404 transmission leaving the 4,5,6 gear in place. Some of the sleeve bearings might not like the potential of higher potential input speed but on the positive side many bearings and gears would be gone so noise, heat and wear would be reduced. What that would mean about the sleeves in the 4 and 5 gear , that I do not know.. not many pics around of worn out 404 sleeve transmission bearings.
Some people have tried to modify the 404 transmission but I have not read much about result.

Anybody know what sleeves in the 404 transmission are worst affected with higher input speeds?

Thank you,

Johan

 

[tmodler]

Still don’t understand:

1. The desire to move weight forward.
2. The desire to lower the input RPM if the goal is not more top speed.
3. The desire to pair #2 with an engine that has no low end, and makes its best power over 3K rpm.
4. The money saving angle.

C.

 

[joeblack5]

Hi C.

Sorry that my arguments in post number one was not clear, your question 1 ,2 and 4 have been discussed no.
# 3 torque at low engine speed. I do not have the numbers in hand but I have no doubt that the the TDI run circles around the M180.


Johan

 

[tmodler]

Oh, right on then. Carry on.

C.

 

[joeblack5]

Hi C,
Just coming back on your question about torque / power.
copied from Staying Ahead in an Ever-Evolving Field
M 180: 2.2 liter gasoline engine (2196 cc displacement)
6 cyls inline, 4 stroke
with standard 7.0:1 compression:
82hp @ 4850rpm, 105 ft-lb @ 3200rpm
With high compression heads:
8.7:1 single carb 105hp
8.7:1 dual carb 124hp


According to malone tuning
The AHU without tune is 90 HP and 155ft-lb @ 1900 RPM.
with a stage 1 tune the HP can go up to 109HP @ 4300 RPM and 188 ft-lb @ 2500 rpm. ( Malone tuning about $300)

So even in stock the TDI would be an improvement.

I am waiting on a friend that is going to measure the length of the o2o transmission in the hope that it is slightly shorter.

The AHU engine has a turbo that can be disconnected from the exhaust manifold and potentially lowered/ angled below the floor level.

Johan

 

[Mark D]

Joeblack5,

I like the idea, and look forward to reading how you resolve the fitment and drivetrain issues.
But before I get too invested in this, can you clarify which motor designation you are planning on using - I see ALH in the thread title and AHU in your last post.

Mark

 

[joeblack5]

double post

Johan

 

[joeblack5]

Hmm, something went wrong here ( post 13). My intended post disappeared and an earlier got copied ??

Hi Mark, sorry for the confusion.
I am no expert on VW . so original the ALH looked the best but now with more reading I think I better opt for the AHU.
That is the oldest TDI version with the simplest computer.. Main reason the oil pump is in a better location ( rear of engine) and the oil pan is made of steel so it easier to modify. The HP with a stage one tune is acceptable and reliable.
If I later want to change it then both engines fit to the transmission.

My friend did sent me the length of the o20 transmission ..13" about a welcome 1 " shorter the O2A but the clutch mechanism is unfavorable with the actuation going thru the main shaft.. Also the flywheel is a bit of a surprise. see pic
So in first instance I will focus on the 02A or 02J transmission. The cases are the same.

No takers on the which sleeves wear in the 404 transmission?
Johan

 

[joeblack5]

well there has been a shortcut. I was going to use our second 404 for this experiment....the one I had intended for camper conversion.. Then Tgreening , member here , put his project 404 up for sale.( facebook, unimogs of North America) His truck has no engine besides a brand new M180 still in crate. Originally I was hoping to by his remaining pivot subframe ( from a radio box) but after some good conversation it became clear that I should buy his whole rolling chassis without the engine.
With help of a good friend we have scheduled pickup next Saturday. ( if you need a new crated engine, then contact him)
Also I acquired a VW AHU TDI diesel motor with a good 5 speed. Since I am going to gut the transmission I am looking for a more shot transmission in the local junkyards.
These unimogs are scary.... it started 3 years ago with one fLU419 and know they have epanded to 2x flu419 and 3 x 404.

Here is our oldest daughter (14) photoshop attempt for our unibody camper plans.

Johan

 

[MicMoor77]

That’s photoshop? It looks so real!

I really like where you’re going with this concept. It seems massively complicated, but I’m eager to see how it shakes out. Keep the pictures coming!

 

[joeblack5]

Today with help of a friend we picked up the 404 from tgreening for this project. It has no engine.( He still has a new engine in crate).

The original interest was the pivoting radio box subframe but the taller tires, painted frame and the absence of the motor all played a roll.

It was a long drive and we left it on the trailer. Tomorrow unloading with daylight. If time allows we will take a look at the VW motor.

 

[joeblack5]

Help needed..
Wanted, DEAD, broken 404 clutch. actual the only part that I need is the spline . I have read ( choprboy) that most unimogs have the same spline..26x32-10N.
Anyone has something with that spline on it.

It is going to be attached to the VW transmission shaft so the clutch itself is not required.
Broken fingers pads of clutch, is it laying in the way please let me know.

thanks
Johan

 

[choprboy]

I have an old 404 clutch plate, It was worn down to the the minimums and just starting to touch the rivets on one side. I drilled out the rivets experimented with the possibility of using MB 250S clutch friction pads (250S clutchs were readily available and cheap at the time) but it didn't work out. I had some other thoughts, but it has mostly just been sitting in my projects pile for the last few years. Send me a PM with your address and I will mail it out.

 

[joeblack5]

Wow, great, thank you, PM sent

Johan