380SL Diesel Conversion Project - Page 7 - PeachParts Mercedes-Benz Forum

mach4 · #91 12-28-2011, 10:56 PM

Quote:

Originally Posted by jusme

I REALLY want to do this, REALLY WANT TO.

I'm trying to document in as much detail as possible what it takes to do this kind of a swap. Not to say that I'm doing it the "right way", but at least I hope to show that it is possible and provide a map for others to build on. There's a long way to go, but I now believe everything is do-able, and relatively straightforward.

Let me know if I can answer any questions...

charmalu · #92 12-29-2011, 01:38 AM

You are an incredably talented guy and fabricator. You just blew the na-sayers out of the water. wonder where they all are now?

I think you mentioned early on that you were going to use the 85 Cali intake/exhaust with the Turbo sitting up higher for clearance issues.

Are you going to eliminate the trap oxidizer and install a by-pass pipe?

Using a 78 or 79 W116 300SD intake/ex manifold doesn`t have the EGR, and would clean up things. but it would all sit lower.

You are right, looks like it belongs there.

I would like this set up in a SLC.

Charlie

mach4 · #93 12-29-2011, 02:15 AM

Quote:

Originally Posted by charmalu

I think you mentioned early on that you were going to use the 85 Cali intake/exhaust with the Turbo sitting up higher for clearance issues.... Are you going to eliminate the trap oxidizer and install a by-pass pipe?

Actually I needed to use the '85 Cali to meet the requirements of California, specifically the part where you have to have an engine the same year or later and all the emissions equipment that came on the car. Since my 380SL is an '85 I had to go with that year as that was the last year with the OM617 and likewise I had to go Cali (not federal) because that's where I'll be registering it. I don't think clearance would be an issue with the federal intake because the trap ox takes most of the space the turbo would be on the lower mounted federal setup.

Now once I'm inspected and get the title changed from gas to diesel, I can play all the games you other guys play with your setups.

You can see how big that trap-ox is here

charmalu · #94 12-29-2011, 02:52 AM

I hear you loud and clear. forgot about CARB etc....

My 85 300D had all that junk, at higher altitudes, you will have no performance or power. I think my 80 240D could have out performed it, UP HILL.

I kept all the Cali junk, and have a spare cali 85 engine.

Charlie

t walgamuth · #95 12-29-2011, 06:32 AM

That trap ox is like a huge goiter on the side of the lovely 617 motor!

mach4 · #96 12-29-2011, 03:30 PM

I finally got confirmation of my valve cover to hood clearance. Up until now, all I knew that it cleared.

I built a little clearance gauge out of some tape and a piece of paper and a tie wrap. The paper allows the tie wrap to slide and not stick to the adhesive on the tape. I set the gauge at about 1.5 inches and then closed the hood and measured. (I was almost afraid to look) But as you can see there is plenty of clearance - enough so I can add a bit of insulation to the hood without any worries. And could shave about a 1/16" off my subframe shims and still be ok.

ROLLGUY · #97 12-29-2011, 09:34 PM

When you get the car all legal, you are invited to go on one of our So. Cal. cruises. We would love to have you along with us. Check out: Home - Mercedes Benz Enthusiasts Group

PanzerSD · #98 12-29-2011, 09:56 PM

This beast is going to have to be re-badged when it's done... would it then become a 300SLD?

Druk · #99 12-30-2011, 03:47 AM

For the benefit of your British readers

what is a trap-ox and CARB?

Is that the standard fit 617 turbo, it looks huge?

mercmad6.3 · #**100** 12-30-2011, 05:47 AM

I have seen a diesel 107 before ...in India .
In your situation i wouldn't have used a car sump but hunted down a G Wagon sump which is a different shape and in one piece. They have a lot more clearance on the rear where yours is hitting the crossmember.
I have also helped a friend install a M100 6.9 into a 107 and the crossmember was dropped as you have done.
This caused a major problem ,the crank centerline was out of line with the centerbearing on the drive shaft .
Because the shaft must run straight with no bends you have to either keep the crank center line location correct or drop the center bearing and diff to keep everything in line .

DO NO TRY TO USE THE FLEX DISCS AS A MEANS OF RUNNING THE SHAFT THROUGH A BEND.
You will have to either lower the center bearing to realign the shaft as it comes off the rear of the trans or fit a uni joint to the trans . There is a SAE yoke which bolts into the rear of the merc trans to eliminate the flex disc spider. I wouldn't recommend this approach though because you will have harmonics transferring into the car.

I am not sure if mercedes is still selling separate types of engine mounts now as most I buy are the same part ,supplied for all types of engines. The big secret to stop too much engine movement is to substitute one of the engine shocks with a belt tensioner shock from a OM 603 etc.

vstech · #**101** 12-30-2011, 07:16 AM

Quote:

Originally Posted by Druk

For the benefit of your British readers

what is a trap-ox and CARB?

Is that the standard fit 617 turbo, it looks huge?

a trap-ox is a giant can in the exhaust to catch diesel particulate, and I think it needs to be replaced periodically.

C.A.R.B. is the division of motor vehicles dealing with emissions in California.
carb,california air resources board,jobs,employment opportunities,personnel,air pollution,smoke management,mtbe,gasoline,diesel,air quality management,air ...

t walgamuth · #**102** 12-30-2011, 08:40 AM

Quote:

Originally Posted by mach4

I finally got confirmation of my valve cover to hood clearance. Up until now, all I knew that it cleared.

I built a little clearance gauge out of some tape and a piece of paper and a tie wrap. The paper allows the tie wrap to slide and not stick to the adhesive on the tape. I set the gauge at about 1.5 inches and then closed the hood and measured. (I was almost afraid to look) But as you can see there is plenty of clearance - enough so I can add a bit of insulation to the hood without any worries. And could shave about a 1/16" off my subframe shims and still be ok.

Before shaving your shims I suggest you use your tell tale with the car running and driving.

Great work!

t walgamuth · #**103** 12-30-2011, 08:43 AM

Quote:

Originally Posted by mercmad6.3

I have seen a diesel 107 before ...in India .
In your situation i wouldn't have used a car sump but hunted down a G Wagon sump which is a different shape and in one piece. They have a lot more clearance on the rear where yours is hitting the crossmember.
I have also helped a friend install a M100 6.9 into a 107 and the crossmember was dropped as you have done.
This caused a major problem ,the crank centerline was out of line with the centerbearing on the drive shaft .
Because the shaft must run straight with no bends you have to either keep the crank center line location correct or drop the center bearing and diff to keep everything in line .

DO NO TRY TO USE THE FLEX DISCS AS A MEANS OF RUNNING THE SHAFT THROUGH A BEND.
You will have to either lower the center bearing to realign the shaft as it comes off the rear of the trans or fit a uni joint to the trans . There is a SAE yoke which bolts into the rear of the merc trans to eliminate the flex disc spider. I wouldn't recommend this approach though because you will have harmonics transferring into the car.

I am not sure if mercedes is still selling separate types of engine mounts now as most I buy are the same part ,supplied for all types of engines. The big secret to stop too much engine movement is to substitute one of the engine shocks with a belt tensioner shock from a OM 603 etc.

Additional shimming might be needed at the trans crossmember and or the driveshaft center line.

t walgamuth · #**104** 12-30-2011, 08:44 AM

Quote:

Originally Posted by PanzerSD

This beast is going to have to be re-badged when it's done... would it then become a 300SLD?

I would definately do some badging saying diesel just in case someone might be tempted to fill with gasoline in the future.

mach4 · #**105** 12-30-2011, 12:40 PM

Quote:

Originally Posted by mercmad6.3

I have seen a diesel 107 before ...in India .
In your situation i wouldn't have used a car sump but hunted down a G Wagon sump which is a different shape and in one piece. They have a lot more clearance on the rear where yours is hitting the crossmember.
I have also helped a friend install a M100 6.9 into a 107 and the crossmember was dropped as you have done.
This caused a major problem ,the crank centerline was out of line with the centerbearing on the drive shaft .
Because the shaft must run straight with no bends you have to either keep the crank center line location correct or drop the center bearing and diff to keep everything in line .

DO NO TRY TO USE THE FLEX DISCS AS A MEANS OF RUNNING THE SHAFT THROUGH A BEND.
You will have to either lower the center bearing to realign the shaft as it comes off the rear of the trans or fit a uni joint to the trans . There is a SAE yoke which bolts into the rear of the merc trans to eliminate the flex disc spider. I wouldn't recommend this approach though because you will have harmonics transferring into the car.

I am not sure if mercedes is still selling separate types of engine mounts now as most I buy are the same part ,supplied for all types of engines. The big secret to stop too much engine movement is to substitute one of the engine shocks with a belt tensioner shock from a OM 603 etc.

Let me try to address these issues one at a time

Sump: Finding a G-Wagon sump here would be next to impossible. I'm happy with the current sump as it gives me the clearance I need with minimal adjustments

Alignment of engine crank centerline with driveshaft centerline - I have maintained almost perfect alignment because I have made two adjustments each counter to the other. If we consider that our point of reference should be the chassis since both the rear end and the center bearing and the transmission mount are all bolted directly to the chassis (albeit with some rubber dampers in between, but we can pretty safely ignore that) then we have only one variable and that is the position of the front motor mount relative to the chassis. (Parenthetically, since I am using stock MB motor mounts from a vehicle that uses the same 107 sub-frame, and the stock motor mounts, the position of the motor relative to the subframe is not changed) So my adjustments are to move the engine up .5 inches (to gain one-half inch of clearance from the engine sump to the subframe) and down one-half inch (technically .6 inch) to maintain clearance between the rocker arm and the hood.

So the net result is that the engine is in the same relative position to the chassis as stock, and by extension the same relative position to the driveshaft, center bearing and rear end.

Flex Disks - My understanding is that the flex disks are designed to operate up to 2 degrees out of absolute alignment. So assuming for the moment that I didn't make the countervailing adjustments but just made one adjustment of 1/2 inch, either up or down, we can check to see whether we would still be within spec. The distance between the transmission mount and the motor mount is 36". Applying a little trig, a half inch movement up or down at the engine mount would give us a tangent of .0139 which is .8 degree. A full inch would be 1.6 degrees and we could go all the way to 1.26" and still be within spec.

And that makes sense, because there are a lot of people driving around with collapsed motor mounts which is about 1.25 inches (coincidence?? or German engineering) But that's not all, remember that the subframe is also mounted in rubber bushings that can, and do, collapse, maybe even at close to the same rate and amount. So if this happens the engine actually tends to stay in the same relative position as the rubber around it ages. (Which also might be a reason to always change the subframe bushings and engine mounts at the same time)

Because I wanted to take engine mount, subframe mount and transmission mount collapsing out of the equation for maintaining clearance, I filled them with urethane. (We'll see how much additional vibration this creates and whether it is acceptable when I get this thing on the road)

Tensioner - Your idea of using a belt tensioner as an engine shock absorber is interesting. Can you post pictures?