What makes a diesel motor 'peppy'? - Page 2 - PeachParts Mercedes-Benz Forum

BoostnBenz · #16 08-30-2003, 06:35 PM

After a few more trials the average appears to be in the mid 5s, so I think I will change it. Doesn't look very hard, I'm most of the way there right now anyway. What else will I have to buy though? The price of the chain (& link) doesn't concern me a bit, but the chain, tensioner, rails, ... do. It looks as if with my tensioner rail design I don't have to take out for the new chain, so that keeps things simplier. Do I just remove the hydraulic tensioner then? This expensive little thing needs replacing as well right? It sure would be nice to have all of that power back, gets better fuel mileage I hear as well.

Btw- it is a lot more than $45, it is $101.19 at Fastlane.

samiam4 · #17 08-30-2003, 08:34 PM

Wow prices have changed in the last year!!!

I got my last one for $55. So, I was assuming a couple of off-set keys minus the price of a chain.

On mine I removed the thermostat housing and used a new gasket, a new tensioner gasket, and a new piece of by-pass hose.
I think the earlier style tensioners take an o-ring instead of a gasket.

Michael

R Leo · #18 08-30-2003, 09:53 PM

It's not difficult to install the woodruff key...

After removing the cam sprocket bolt, chain guide and the tensioner bolt/plug, I used a rubber mallet to tap the sprocket off the end of the cam. There's just enough room in the chain gallery to allow the sprocket to come off the end of the camshaft.

Just make sure you know which way to orient the key...

There's enough slack in the chain to allow you to place the sprocket back on the end of the camshaft, align it with the keyway and tap it home with your mallet.

Word of warning:
Drape everything and stuff extra rags in the chain gallery. You don't want to be loosing anything down in there!!! SWMBO walked out when I was in the big middle of the procedure, spotted all that draping and claimed that I was taking Benz mechanicing a bit too far.

I ran out of time that particular day or I would have checked and adjusted the IP timing as well.

Any way you cut it (stealership/wholesale or aftermarket), an armload of woodruff keys is a whole lot cheaper than a cam chain. IMHO, it's a valid fix too. MBZ wouldn't have a procedure for it if it didn't work.

BoostnBenz · #19 08-30-2003, 10:15 PM

As of right now the cheapest I've found is $88, I thought I seen them cheaper before as well. Then again last time I ordered parts it seemed like most of them got a little more expensive. Must be the euro vs. USD fluctuations? Oops, I assumed that the woodruff keys came in pairs, I now see that they don't.

Why did you remove the thermostat housing? Did it help to get to the tensioner or what?

At 4* I probably would of just got a woodruff key, but being I'm nearing 6* I may just as well do the new chain. I just hope that the IP hasn't been readjusted for the 6* or anywhere close so when I get back to 0* it won't be advanced a ways. Did it seem to idle smoother after the new key? I'm surely going to be overcautious about dropping stuff in there while doing the chain. I can almost imagine it already, almost done, just getting ready to crimp the new end link on and whoops.... I hope it is at least metallic so I can go fishin'.

samiam4 · #20 08-30-2003, 10:47 PM

Off idle performance will be better,

I swear with Camshaft and IP perfect(or close) there is not detection of low fuel roughness. Even my non-turbo feels responsive when it's set-up correctly. It was a huge dog when it was out 6 degrees.
I think the chain supplier you want is IWIS. I have a "masterlink" to connect the two chains together. I always zip-tie the chain to the Camshaft sprocket when playing with the chain. It slows you way down if you drop the chain=)

Oh- some people replace the tensioner completely others do only the spring. Not sure how to replace the spring-it's in my tool box somewhere.

To answer your question: I believe the thermostate housing has to come out to remove the tensioner. My car is not close or I could confirm my memory.

Michael

R Leo · #21 08-30-2003, 11:45 PM

Quote:

Originally posted by BoostnBenz
Did it seem to idle smoother after the new key?

I couldn't tell any difference in start or idle after the 4deg offset key was installed. The biggest difference was in the off-idle performance with the a/c running.

now, the engine picks up revs much faster and has significantly better throttle response at low speed.

2 weeks ago, I put about 300-400 highway miles on her and the economy was up to 24 from 21-22mpg. However, when I went to Dickinson last weekend, I only managed to get 23 on the way down and 22 on the way back (220mi each way). Granted, the car was full of dogs, people, luggage and had an 18' extension ladder strapped to the top both ways...maybe this had something to do with it...

For the next couple of weeks, all Marlene's miles will be in town driving. No more touring is scheduled until Sept 20th. Hopefully, I'l have an opportunity to time that IP before hitting the road.

BoostnBenz · #22 08-31-2003, 12:33 AM

IWIS appears to be the only timing chain supplier, at least that is all I have seen so far. The masterlink you are refering to is the same thing as the end link right? Spring? I thought it was a hydraulic bolted to the block with just two bolts pushing on a rail. However I did see in the parts list the spring you are talking about, I just don't see it in the diagrams for the timimg chain. Thanks for the tip, I actually heard of that before on timing belts, I'm hoping I won't have to let go until there is a link there to hold the two together.

Alright, I was hoping for an improvement in the idle too. My cold idle isn't very impresive at times, I believe there is a gold screw to adjust that though. So are you going to do drip timing and start with spec or just keep advancing the IP until it doesn't sound right, then backup a notch? 18' ladder strapped on the roof

, good thing it is a TD!

#23 08-31-2003, 10:35 AM

Recently had my chain and guides replaced at 186k mi and the improvement in performance was quite striking, while the cost (as MB repair costs go) was modest. IMHO, European cars have always been designed with maintenance costs for various adjustments that are not realistic at American prices for car repair. I'm pretty sure you'll find that swapping out the chain and guides has a happy result.

BoostnBenz · #24 09-10-2003, 01:25 AM

As a quick update I got the chain changed last weekend. I measured the new wear at 2-3* which I was less than ecstatic over, the motor seems to react faster now but still doesn't have the power the 84 did. I'm going to advance the IP a little bit now, see if I can get things upto par.

Turns out the thermostat housing is supposed to be removed to get the tensioner out, I don't think you have to but I did regardless. All that needed replacing in there was the spring, very simple and straightforward. I also found big babbo on ebay selling the IWIS for $56 supposedly, however I found this after ordering it.

#25 09-10-2003, 01:09 PM

Quote:

Originally posted by BoostnBenz
Turns out the thermostat housing is supposed to be removed to get the tensioner out, I don't think you have to but I did regardless.

You don't need to do this, Just remove the heat shield and EGR tube. After that you can get a socket, extention and ratchet in there.

BoostnBenz · #26 09-10-2003, 01:21 PM

Agreed it was a pointless waste of time, but I did see rust inside my motor's head which I guess was a nice find. I'm driving it around all week this week with a cleaner in the water to clean a little bit of that stuff out, followed by some new coolant. Which reminds me I have to get to the Mercedes stealership today to buy a new bypass hose, I can't seem to find it online in less than a meter length (only 5cm needed). What heat shield, the a/c line mounting bracket? If you remove the EGR tube and the intake's U bend you have all the room needed with plenty more to spare.

#27 09-10-2003, 05:25 PM

Sorry, I ment the EGR heat shield.

gsxr · #28 09-10-2003, 06:24 PM

Biggest #1 cause of lack of "peppiness" on a Mercedes turbodiesel is lack of fuel off-idle. The typical cure is to adjust the ALDA (turn setscrew CCW 0.5-2.0 turns, stop when you don't feel any more power gains on yourbutt dyno). This is particularly true for off-idle power. For a big loss in top-end power, the usual cause is a blocked banjo fitting for the ALDA line at the rear of the intake, and a blocked switchover valve.

After those 2 things have been fixed, and it's STILL slow, then mess with the timing chain & cam timing. IMO, pump timing affects MPG more than anything else, doesn't seem to do much for power. Advancing my pump timing to the far side of spec increased MPG measurably. Of course we're assuming clean filters, brakes not dragging, etc.

Check your car on a flat road from 0-60 with a stopwatch. It helps to confirm speedo accuracy with a GPS as well, since most speedos are a good 1-3mph off, which can translate into a 10% skew on your results. Factory spec for a 123.133 (82-85 sedan) is about 13.5 seconds with two occupants. Note that above 2-3000ft elevation, times will slow down quite a bit. Data from my car is here:

http://www.meimann.com/docs/mercedes/84_300D_performance.txt

HTH,

#29 09-10-2003, 07:13 PM

It seems like MPG shoulden't change by IP timing alone. When I advanced my IP I found I had to use MUCH less throttle to maintain and reach speeds that before required quite a bit of foot. The IP is still injecting the same amount of fuel, it just does it sooner. Since I don't have a working odometer/speedometer I have no way to acuratly gauge my MPG. I used to fill my tank about once a week, now I fill it about 2-3 days later (I try not to let it get below 1/4 tank, I just don't like it for some reason

).

BoostnBenz · #30 09-10-2003, 10:21 PM

I cleaned the banjo fittings before, it was still slow. I bypassed the overboost valve because it was seriously impedeing takeoff, I tried blowing a cleaner through it which went through fine but it was still lagging badly. I have two freshly rebuilt front calipers, both fuel filters are new. I believe my rear end is the same as the 85s came stock with so it probably won't get the 13.5 in 0-60 anyway. I would like to check the boost, but how does that affect the pre-2k area? The turbo is just starting to spool this low. I think I'll try to adjust the IP this weekend. I'll try the ALDA adjustment tomorrow, do you mean the difference in just low end or on top as well?

I don't like to go below 1/4 tank either, with most diesels you can ruin the lift pump if you get that low and start pumping crud through along with the diesel.