Top end saga. . . - Page 6 - PeachParts Mercedes-Benz Forum

79Mercy · #76 09-04-2008, 10:19 PM

10W-30, isn't that a bit thin ofr a M117. Im running honey in mine(20W-50).

Lexxani · #77 09-04-2008, 10:22 PM

Quote:

Originally Posted by 79Mercy

I haven't check the vacuum output in a very long time so it maybe differnt now. It also depends on how high the motor idles, mine idles at 950 in P.

950 RPM??? WTF? mine idles at like 500 RPM. .dude your idle is way high. . .I think 750 is about at the highest end you'd want. does your car slam into gear?

Lexxani · #78 09-04-2008, 10:24 PM

thanks al. .Im going to go and have me a look at my local napa. . .

yeah, 10/30 is a little light, I really should be running 20/50. . .next fill-up in a couppla weeks.

79Mercy · #79 09-04-2008, 10:46 PM

Quote:

Originally Posted by Lexxani

950 RPM??? WTF? mine idles at like 500 RPM. .dude your idle is way high. . .I think 750 is about at the highest end you'd want. does your car slam into gear?

In park yours is only 500, what is it in D?? You idle is to low. No wonder you have rough idle. Mine is like 950 in P and 750 in d.

No it doesn't slam into gear.

79Mercy · #80 09-04-2008, 10:54 PM

I found the PDF file for the M110. It says a good speed is 850, and no lower than 750. Mine is only about 900-950 in P. I turned it up alittle bit because at idle in gear it seemed to shake alittle, now since I turned it up I can't even tell its running.

http://pauldrayton.com/uploadfiles/merc/Service/W123/w123CD1/Program/Engine/110/07_3-100.pdf

alabbasi · #81 09-04-2008, 10:59 PM

20w50 is fine but for break in period either 30w non detergent or the oil i mentioned earlier. Thats critical

Lexxani · #82 09-05-2008, 10:17 AM

Quote:

Originally Posted by 79Mercy

I found the PDF file for the M110. It says a good speed is 850, and no lower than 750. Mine is only about 900-950 in P. I turned it up alittle bit because at idle in gear it seemed to shake alittle, now since I turned it up I can't even tell its running.

http://pauldrayton.com/uploadfiles/merc/Service/W123/w123CD1/Program/Engine/110/07_3-100.pdf

Al- I used to run 30 weight, however I as the consumption issues became more significant I steped it up to 50 weight. Ive always liked straight 30 weight over multi-grade.

Stewart- Mi idle is around 700 RPM in park and sits at the low peg on the tach (like 500RPM) in drive. Ive thought about turning up the idle, however It was always this way and I figured it was correct, I didnt want to have transmission issues arise. I really need to get rid of the lumpy idle Ive always encountered ( Ive attributed it to many things, top end wear being one of them)

This afternoon Ill adjust the idle and play with the mixture. Thoes are about the only two variables left in my quest for an efficient M117. Now that Im back on the road its time to complete my emissions delete campaign. I already got rid of the cats now for the EGR, I have the schemtic and plumbed all the new vaccumn lines so dissassemly (now that I know how it goes together) should be a snap.

79Mercy · #83 09-05-2008, 10:34 AM

I think you should turn the idle up to about 850-900 in P. That should solve your rough idle. You shouldn't have any tranny problems, its not like your idling at 2K.

todds · #84 09-05-2008, 02:08 PM

I think it all depends on the cam right? Theoretically the smoothest idle would be the lowest that the engine could do while still being able to suck in the right amount of fuel and air and retain proper momentum. A v8 would have more rotating mass and more momentum than a six due to the balance weights on the crank and extra cyls. Manifold/fuel system design would effect it too. I think that's why hotrods with wild cams and light flywheels and rotating assemblies idle like crap. Perhaps the m110 has a different cam design than the v8 and thus a different recommended idle? They wanted it to breathe at the top end where it typically be cruising and revving. Also, I'd think the stall speed of an auto and the ignition timing play a part as well. Heck, even the motor mounts! Idle is a complicated thing, especially in light of emissions stuff.

I might be wrong about some of this, just trying to make discussion really. Perhaps someone who knows more will chime in.

Lexxani · #85 09-05-2008, 09:29 PM

Todd- Excellent insite. Im actually thinking of swapping my cams for euro 500 cams (waiting on one to show up in the yard, I missed the last one). All that about engine design is valid, however someone with more insite then I needs to comment on thoes theories.

Stewart- I advanced my timing and brought the park idle up to 750, things smoothed out a little bit however I think I need to 1) let things settle and drive a little more 2) Run 93 octane as opposed to 89 (and quality gas, not Racetrack) 3) Track down vacumn leaks, I think some degraded contour hoses might be the culprit.

Now Im not saying my car is running like crap, it is just not as smooth at idle as I'd like. . .I seriously think im too much of a perfectionist.

Tomorrow im going to play install the servo and install a new thermostat and some MB coolant I snagged from Pierre.

Oh BTW-Pierre and Chris (113 280SL) are going to be at the GTG. Chris's car was over at Pierre's getting some work done, I saw it today.

alabbasi · #86 09-05-2008, 09:31 PM

The rough idle could be related to your fuel injection system. Quite common for k-jet systems to get lumpy with age.

Lexxani · #87 09-05-2008, 09:39 PM

Quote:

Originally Posted by alabbasi

The rough idle could be related to your fuel injection system. Quite common for k-jet systems to get lumpy with age.

Any suggestions on a rebuild Al? You definately know more about fuel injection I do.

alabbasi · #88 09-05-2008, 09:46 PM

I managed to smooth the idle out on mine soaking the injectors and hard lines in parts cleaner then spraying them down with brake clean.

That said, what appears to be the most common cause to me is the fuel distributor. You can find these rebuilt for about $500 but I would take a quick read of the CIS to Megasquirst article on the web.

The guy reported a drastic improvement in idle after the conversion.

http://www.merccismegasquirt.britautorepair.com/

Lexxani · #89 09-05-2008, 10:17 PM

hmm fuel distributer aye?. . .Im certain my lines are clean and I soaked my injectors in brake cleaner, they're clean. My idle isnt bad, its just not "new car smooth" (its kinda like new 4cyl smooth) Mabye im just looking too far into things. . .I should probally look at some motor mounts and new tires. .

A front suspension rebuild in in order for perfection, thoes rubber bushings could stand to be attended to. . . I sense another project comming on. . .

I've reviewed that megasquirt conversion in the past, the only downside for me is all the electronical work, which I have no desire to take a stab at this time. Electronical stuff and machine work are two things I do not excel at.

79Mercy · #90 09-05-2008, 11:38 PM

tell me about front end work. Im taking the 280CE to the dealer and have them "try" to line it up, and tell me how many thousands of works needs to be done. Drive it home replace everything they said was bad and have them re-algin it. I can fix anything on the front end as long as I don't have to pull the springs out. Im way to scared of that, even if I had a klann spring compressor.

I'll have to see at the GTG what you mean by rough idle. Are you talking vibrations, or missing.