Final Questions on Engine Swap - PeachParts Mercedes-Benz Forum

diesel don · #1 09-23-2003, 08:57 AM

A huge thanks to the collective wisdom on this forum that enables a rookie to get 95% of the way through this project. We have swapped a 300DT into a 240D chassis. If interested, read below to see what has been done to date. But I need help with some final issues:

FINAL QUESTIONS:

1. The clear line that runs from the rear of the manifold to the top of the IP and then to some type of switch on the firewall. What does one do as the 240 chassis had no provision. Is this the overboost sensor? And if so, I can swap it to the new chassis but I don't have the plug in cord???

2. Will the line running to the clutch master cylinder automatically fill with fluid as I bleed the brake lines?

3. The bowden cable setup is different. There appears to be one from the 240 chassis, but its out of place, etc. Any help here?

4. Since I didn't mess with the IP, I should have no worry in attempting to start the beast right? I'm going to drain the fuel and work with fresh stuff anyway.

DONE TO DATE:
1. Swapped engine
2. Mated engine with 4 speed manual tranny
3. Pilot bearing
4. Modified transmission crossmember support bracket
5. Calipers, hoses, pads
6. Had the axle shafts and differential torn apart to inspect
7. Replaced driveshaft with shorter one from euro parts car
8. Reduced 3 transmission linkage rods by 4" and reinstalled
9. Exhaust from 300 moved to 240 chassis
10. Shroud from 300 moved
11. Oil cooler
12. Radiator
13. Modified coolant resevoir and installed in 240 chassis
14. New belts
15. Diff fluid, tranny fluid, oil, coolant, ps fluid

Thanks again to the forum

Don

kerry · #2 09-23-2003, 09:24 AM

Yes, you will need to move that sensor to the new car (I think.)

Bleeding the brakes should have no effect on the clutch system. It must be bled separately. If there was air in the line joining the clutch master to the brake fluid reservoir, the clutch will need to be bled.

P.E.Haiges · #3 09-23-2003, 10:05 AM

Diesel Don,

#1 That is the boost sensor. It causes tha ALDA to add more fuel as the turbo boost increases. Without it the engine will like a non turbo engine I.E. less power. I don't know what you mean by the plug in cord.

#2 NO. You must bleed the clutch hydraulic system separately. One way is to connect a line between the front left wheel brake bleed screw and the bleed screw on the slave cylinder and pump fluid thru the clutch system by pumping the brake pedal. Make sure the resorvior on the master cylinder stays full.

#3 Not sure about this one but isn't the Bowden cable for an auto trans? Maybe you don't need it.

#4 Don't drain the IP. Diesel fuel does not deterioriate like gasoline. You might have trouble getting the air out IP and injector lines. I've used 10 year old fuel and it ran as good as new fuel, couldn't tell the difference.

P E H

Stevo · #4 09-23-2003, 10:10 AM

diesel don

Good show on your switch project. On the clutch.. hook the hose from RF brake slave to clutch slave and pump brekes like crazy. that should fill the line.

engatwork · #5 09-23-2003, 10:21 AM

#1 - no you do not need that - you can just run the intake manifold pressure line to the IP ALDA. The switch is an overboost protection switch that cuts the boost signal down to the ALDA if the intake pressure reaches 16 psi (or somewhere around there). I would recommend running the engine and "teeing" off of this line to ascertain how much boost you are getting with the existing wastegate setting. You can safely run up to around 12 or 13 psi. I have bypassed this switch on my 300D but have confirmed the wastegate setting. The only issue is if the wastegate fails closed then you can mess up the engine if the pressure goes over 16 psi although you should be in for the ride of your life for a few minutes

. Personally, I would not worry too much about it.

#3 - Get rid of the Bowden cable stuff - you don't need it anymore.

mplafleur · #6 09-23-2003, 11:30 AM

Good work Don. I can't wait to see it sometime.

When I had trouble bleeding the clutch slave on the 240D, no one told about the brake caliper method. I bought a power bleeder and used it to bleed the clutch slave. But first I had to buy a new brake fluid resevoir because the old seals couldn't take the pressure of power bleeder.

diesel don · #7 09-23-2003, 12:09 PM

Wow. Thanks for the great help. I have a couple of follow up questions in you don't mind.

1. I understand now that the line going from the Manifold to the ALDA handles the boost and that I can avoid the overboost sensor if I'm sure that my PSI is around 12-13. In order to test that I just put a T in the line and measure it with the mighty vac right?

2. Regarding old fuel. The car itself has sat for over a year and the engine has sat for 3 months. You wouldn't have a problem with the fuel in the tank being too old?

Again, thanks for all the tips (brake bleeding, etc)

Don

engatwork · #8 09-23-2003, 12:36 PM

#1 - you are correct. The way I do it is to tee into the line and run the plastic line through the drivers side water drain, out behind the front left tire and then just bring it up through the open window. The MV gauge may just read vacuum and not + pressure so you may have to find a 0-15 psi gauge to use for this purpose. You will have to get on the steepest hill around (I have to drive pretty far to get to it around here) and then floor it going up the hill. Works best if you can find one on an interstate somewhere where you can get some speed up.

#2 - I would try to fill up with new fuel at the first opportunity and probably dump a bottle of some type of diesel additive in there.

Ken300D · #9 09-23-2003, 02:06 PM

An interesting point from the literature (I have not done this yet on Cindarella - she still needs some welding first) is that you bleed the clutch system from the bottom up with pressure - thus pushing old fluid out the top. You want to pull the top clutch line OUT of the brake reservoir and flush the bad stuff into a jar, not into the brake reservoir. With the number of cars you have I'd strongly recommend the Motive Products PowerBleed.

Ken300D

kerry · #10 09-23-2003, 02:27 PM

I have successfully bled a Mercedes clutch system from the top down without any problems.

As you may know, the system is designed so that the hose which takes fluid from the brake reservoir to the clutch master cylinder is higher up the side of the reservoir than where the brakes are fed. This means that if the fluid gets low, the clutch will go out before the brakes. An ingenious system.

Rick Miley · #11 09-23-2003, 03:37 PM

And that also explains why my brakes didn't go out when the supply hose came out of the clutch master cylinder. Only a small amount of fluid was lost.

But I still say it's easier to bleed from the bottom up.

#12 09-23-2003, 05:05 PM

With most hydraulic clutches you need to open the bleeder, then depress the clutch pedal, then close the bleeder, then release the pedal. (that is without a power bleeder). Otherwise it takes forever to get the air out of the line.
Does an MB work the same?

P.E.Haiges · #13 09-23-2003, 06:41 PM

Diesel Don,

The old fuel is no problem. Its not gasoline so it doesn't deteriorate. There could be a problem with algae but you have to cure that with Diesel Doctor additive. But if you didn't have a problem with algae before, you won't now.

PE H

kerry · #14 09-23-2003, 07:05 PM

Yes, MB hydraulic clutches are bled that way.

Stevo · #15 09-23-2003, 07:42 PM

"With most hydraulic clutches you need to open the bleeder, then depress the clutch pedal, then close the bleeder, then release the pedal. "

Old Deis

I just did two of them in the last week by hooking a hose between the RF brake slave and clutch slave , opening both bleed fittings and then pumping vigorously. I use a clear hose and you can see that its full of juice. then close both bleeders. Done, easy and quick