NA head on turbo block?

[Rashakor]

Here is the dilemma,

would a NA head from a pre 1981 300TD would fit on a post 1983 617.xxx turbo block ?

The idea here is to resucitate a 1979 300TD that has a shot block with a turbo 617.XXX block from a sedan. because complete TD engines are really hard to come by contrary to their sedan counter parts. The head on the wagon is fine and has the pump necesary to the hydropneumatic rear suspenssion.
what to do? any other suggestion how to get that wagon the turbo treatment besides getting the much prized turbo wagon engine?

[t walgamuth]

i am not sure what if any differences there are in turbo/na heads. i would check with my mb parts specialist to see if heads have a different number, then if they do i would look at valves guides etc to pin down the differences. are you planning to make the engine turbo or na?

tom w

[boneheaddoctor]

Turbo heads AFAIK have sodium filled valves....for temperature resistance. Don't think the non-turbo heads have them. Also the NA heads have a slightly higher comression ratio. THere MAY be other differences but now having compaired them side by side I can't say what they are.

[Rashakor]

Originally Posted by boneheaddoctor

Turbo heads AFAIK have sodium filled valves....for temperature resistance. Don't think the non-turbo heads have them. Also the NA heads have a slightly higher comression ratio. THere MAY be other differences but now having compaired them side by side I can't say what they are.

that is was i was afraid of that the na head could not take the heat and boost.
Then the question would become how do you transplant the suspenssion pump from the TD in to a sedan's 617.XXX turbo.

[Bajaman]

The valves can certainly be upgraded with sodium valves if you want. As far as compression ratio goes, it should be easy to reduce that as well. the head is actually flat, so any differences in compression ratio will be in the prechamber or top of the piston. My guess is the turbo piston has a larger releif- resulting in a lower compression ratio. If that is the case, the only real differece would be valves. On the other hand, I have a TD NA engine that will be coming out of an 80 wagon shortly if your interested.
BB

[Rashakor]

Originally Posted by Bajaman

The valves can certainly be upgraded with sodium valves if you want. As far as compression ratio goes, it should be easy to reduce that as well. the head is actually flat, so any differences in compression ratio will be in the prechamber or top of the piston. My guess is the turbo piston has a larger releif- resulting in a lower compression ratio. If that is the case, the only real differece would be valves. On the other hand, I have a TD NA engine that will be coming out of an 80 wagon shortly if your interested.
BB

I am looking for the turbo 617 from a TD. I am getting rid of the NA.

[boneheaddoctor]

Well you aren't moving that pump to a regular OM617.950 or 952 engine...and you just hit upon why the egnines from the wagons bring a premium in price.

If the valves interchange or not is anyones guess. THe real key issues are block differences between the turbo and non-turbos.

Can the prechambers swap? and the valves? you are beyond my ability to answer on this.

[dieseldiehard]

Originally Posted by Rashakor

I am looking for the turbo 617 from a TD. I am getting rid of the NA.

I hope you have a good source for parts. The following items will need to be swapped into the NA wagon:
A 617 turbo engine with the TD head (hydro pump)
A larger exhaust line all the way back from the down pipe to the rear muffler (larger ID)
The Vac manifold line from the vac pump to the brake booster is different than in NA cars.
New radiator with fan shroud to fit the 617 turbo fan. And the overflow reservoir is nice if you have a donor car swap that over too. Rad hoses are different also.
Pivot at the firewall for the accelerator linkage.
Transmission is different, plan on getting a pre-85 transmission too! A trans w/ the six bolt pan is best.
New driveshaft to fit the different yoke on the new tranny. It may be possible to change the yoke. This is the last thing you want to face without a connection to the rear end!
Speaking of rear ends, a 2.88 or 3.07 differential wil be highly suggested. I don't think you'll enjoy running with the engine all revved up with the 3.46 that is in the car presently - unless you plan on drag racing
Add a switchover valve and the boost line that runs from the intake manifold to the ALDA.
You can keep the series connected Glow Plug configuration but the purist might want to convert to the independant connected plugs to make checking them easier, in such case the later style GP timer and wiring harness needs to be installed.
Good luck with the conversion!

[300SDog]

ALL MB's both gasoline and diesel have sodium filled, self-rotating valves going back to 1973 at least.... And regarding cylinder head swap - just compare head gaskets for each at the dealership parts counter. If head bolts, oil and coolant passages line up then go for it, says me.

And definitely skip the turbo and treat it like an NA longblock if you want to follow the path of least resistance. Turbo's are over-rated anyhow. Either the car will do 90mph or it wont, acceleration is NOT the critical factor. And how many long steep hills do you have to climb in Texas? I think its an American 'hotwheels generation' phenomenon where everybody gets all goo-goo/gaa-gaa over having a TURBOCHARGED engine.

[Rashakor]

Originally Posted by dieseldiehard

I hope you have a good source for parts. The following items will need to be swapped into the NA wagon:
A 617 turbo engine with the TD head (hydro pump)
A larger exhaust line all the way back from the down pipe to the rear muffler (larger ID)
The Vac manifold line from the vac pump to the brake booster is different than in NA cars.
New radiator with fan shroud to fit the 617 turbo fan. And the overflow reservoir is nice if you have a donor car swap that over too. Rad hoses are different also.
Pivot at the firewall for the accelerator linkage.
Transmission is different, plan on getting a pre-85 transmission too! A trans w/ the six bolt pan is best.
New driveshaft to fit the different yoke on the new tranny. It may be possible to change the yoke. This is the last thing you want to face without a connection to the rear end!
Speaking of rear ends, a 2.88 or 3.07 differential wil be highly suggested. I don't think you'll enjoy running with the engine all revved up with the 3.46 that is in the car presently - unless you plan on drag racing
Add a switchover valve and the boost line that runs from the intake manifold to the ALDA.
You can keep the series connected Glow Plug configuration but the purist might want to convert to the independant connected plugs to make checking them easier, in such case the later style GP timer and wiring harness needs to be installed.
Good luck with the conversion!

wuuuu!! that is sobering. Let get that donor wagon then!!!!!

[t walgamuth]

i believe the compression ratios on most of the turbo motors is the same as the na ones.

if not the difference is very slight.

tom w

[boneheaddoctor]

Originally Posted by t walgamuth

i believe the compression ratios on most of the turbo motors is the same as the na ones.

if not the difference is very slight.

tom w

The difference is slight...with the NA one ever so slightly more. Not enough to make a huge differnce on its own.