Operating/Running Hints

[Eryck]

I am new to 'old' cars. Please help.

Do these cars require a warm up before taking off with them?

Is it okay to rev them? At what rpm should I be looking to change gears under normal driving conditions? Will revving the engine too much cause undue wear and tear?

For hill stops and starts, is it bad to use the clutch to 'hold' the car?

1965 230 SL White Manual
Hong Kong

[Cees Klumper]

I drive off right after I (manually) close my garage door. As far as I know it's not good to let the car sit and idle right after starting it cold - best to drive off immediately, at a leasurely pace.

Then from my garage it's a short drive to the highway that I usually take to wherever I am heading. Until I get to the highway, I take care not to rev it 'high'; once on the highway I go with the traffic, up to around 3,800 RPMs.

When the engine is at normal operating temperature, I don't hesitate to rev it to, say, 5,500 RPM for short sprints. I don't think I ever hit the red line, but I've probably been over 6,000 at times. I've done some prolonged high-speed (145 KPH) driving to Germany and France and I suppose the engine revs at around 4,800 RPM's then. This goes on for hours. If your engine is in good shape, this should not be a problem.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Richard Madison]

The usual advice is that fuel injected cars do not need a warm up and can be driven off right away.

The shift points as far as I know can be anywhere in the "normal" range of engine operation depending in driving and traffic conditions. The car will labor (lug) if allowed to stay in a gear at too low an RPM and will whine with a loss of power if allowed to stay in gear at too high RPM's.

In my 4 speed manual, the 1st gear is very short...need to shift out almost immediately since it will climb to 3,000 RPM and more at quite low speed...so maybe 20 mph (30 kmh) is max for my comfort.

In the higher gears, I shift according to the sound of the engine and maybe a glance at the tach. After a while you can feel (and hear) when to shift. I guess I shift around 3,000 RPM more or less until I get to 4th gear where it stays, of course.

When stopping, I down shift to the next lower gear until I reach 1st gear to help brake the car if I'm moving at any speed especially when in the city.

Also, 4th gear is not for hill climbing. The car (and the Manual) will tell you to shift down to 3rd to get up a hill of any significant slope. On a hill, a car in 4th will lumber and will have no acceleration if you need it.

You can keep the car at high revs if you want to. Pagodas have maximum torque and great performance at high rpm's. In 4th gear at 4,000 revs or more the engine settles into a Zen-like steady power trip that is wonderful (this is 80 mph, 130 kmh). Can't do this very often with USA speed limits.

To clean engine fouling, city cars (like mine) need to get out for an "Italian tune-up" once in a while. I take the car to a "high speed" road and keep it running in third gear at higher RPM's (maybe 4,000) for a while. This helps clean out any bad stuff on the plugs and in the cylinders...fouling of plugs can occur in these cars when doing slow, stop-and-go driving.  After a run at high RPM's, performance is improved, engine running and idle are smoother.

As for the clutch: I'm told that maximum wear to the cluch will occur when "riding the clutch" (partly engaged.) Since the clutch plate is not completely pressed against the fly wheel, slippage causes wear. A very expensive clutch repair is likely unless the cluch is kept entirely in or out.

Enjoy the ride
Richard M

[Douglas]

I'm interested in hearing more about proper warm-up times, particularly from the engineers here.

My understanding is that it's a good idea to start the car as gently as possible and to let it warm up at least a couple of minutes. I've even heard it's a good idea to wait until the temperature needle moves.

I always thought this was a lubrication issue. I suppose synthetic oils probably help in this regard as they are supposed to provide better "cling" to moving parts prior to start-up.

Douglas Kim
New York, NY
280 SL #016220

[Eryck]

Thank you both for the advice.  I will follow suit. You've answered my questions.

Richard - good metaphor on the 'Italian tune-up'. In fact, the manual on my BMW 840ci says the same thing. After prolonged city driving, it is recomended that the car is driven at high rpms to 'clean' it of soot!  

Cheers.



1965 230 SL White Manual
Hong Kong

[hauser]

When I took delivery of my '69 Alex Dearborn advised to let it reach opperating temp before driving.  This has always been my general practice with all my cars.  I believe that most wear and tear on the engine occurs during cold startups.



1969 280sl 5 spd
Gainesville, Fl.

[Cees Klumper]

Hi Hauser - I've always understood the opposite: that it's not good to let a car warm up idling, that it's best to drive off (without stepping on it of course) without delay. I would suppose that the cold start wear and tear occurs literally within the first seconds, before the oil reaches all places it has to get to. I wonder what's correct now??

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[graphic66]

http://mototuneusa.com/thanx.htm    This may have been posted before. It makes for some interesting reading about engine wear and how it occurs. My car, I just start it up and drive it right away. I drive  easily [under 3000rpm] until the engine is heat saturated. I have found my 230SL will load up if idled to long and skip a little until the extra fuel is burned off.

[glennard]

quote:Originally posted by hauser

When I took delivery of my '69 Alex Dearborn advised to let it reach opperating temp before driving.  This has always been my general practice with all my cars.  I believe that most wear and tear on the engine occurs during cold startups.



1969 280sl 5 spd
Gainesville, Fl.

Question guys.  If 90% of wear occurs on starting (before lubrication to dry moving surfaces) why not have a five second aux. electric oil pump prior to starter engagement.  Trucks and turbine do it, why not cars?  Cost $100 or so.

[hauser]

I had read something about Porches and cold start ups.  The topic was the 911.  It may have been an ad for an engine warmer, I can't remember.  A device placed under the oil pan that would preheat the oil making for better circulation at startup.  It was a long time ago and the details of all this are a bit fuzzy so forgive me if I've left out any other details.   I also remember reading something about a block heater.

1969 280sl 5 spd
Gainesville, Fl.

[ja17]

Hello guys,
Make sure you are using the right weight oil for the weather conditions. Modern oils are much better than what was available thirty years ago.  Driving off gently should be just fine (moderate rpms). This will allow the injection system to cycle at some different rpms and keep plugs from getting gumed up. Harder, brisk drivng should be done only after full warm up.



Joe Alexander
Blacklick, Ohio

[hauser]

Here's a quote from my 250SL - 280Sl english language owner's manual.

"We recommend that you drive off with moderate speed after the engine has fired, since in this way the operating temperatures of the engine are attained in the best way."

I stand corrected!

1969 280sl 5 spd
Gainesville, Fl.

[n/a]

quote:glennard wrote;

Question guys.  If 90% of wear occurs on starting (before lubrication to dry moving surfaces) why not have a five second aux. electric oil pump prior to starter engagement.  Trucks and turbine do it, why not cars?  Cost $100 or so.

You're not just a pretty face!

Neil Rote
'64 230 SL unrestored www.realnoteguitars.com/merc

[n/a]

quote:Originally posted by Eryck

I am new to 'old' cars. Please help.

For hill stops and starts, is it bad to use the clutch to 'hold' the car?

1965 230 SL White Manual
Hong Kong

The ULTIMATE sin! NEVER do this! Either learn to drive or buy an Automatic!

Neil Rote
unrestored manual '64 230 SL www.realnoteguitars.com/merc

[Eryck]

Thanks for the definitve answer. Now I know. For RHD cars (as you know), the bloody handbrake is on the other side! This plus the extremely steep hills (and there are a lot where I live) makes it a bit of a hassle. Alot of practice ahead of me!

1965 230 SL White Manual
Hong Kong

[rwmastel]

What's wrong with using that pesky little brake pedal by the gas pedal?  I have driven manual shift cars for years (but not currently) and I never had to use the hand brake on a hill while waiting my turn to go.  I always used it when parking the car on any surface, hill or not.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[hauser]

Here's what I found out about the warming issue.  Gernold the Pagoda Guru says once you start the car go ahead and start driving it.  To let it idle is the worst thing you can do to the engine.

1969 280sl 5 spd
Gainesville, Fl.

[Benz Dr.]

Here's a story without any jokes in it.

 I used to pre lube my engine rebuilds with a piece of steel rod on an electric drill going into the oil pump drive. One day it was a bit colder than usual in the shop during this operation. I had the drill going nearly full blast when the oil pressure suddenly spiked up as it was starting to pump oil.

I thought I broke my arm, it twisted it so badly. I couldn't work for about a week and it was nearly a month before it quit hurting.
It was then that I quit believing all this crap about dry starts and wear in the engine. Oil companies will try and tell you about all that friction in a cold engine. What friction? The engine I was working on wasn't even turning over.

It's all that cold glue that you're trying to pump through the engine when cold that makes the starter groan a bit. Synthetics have all but eliminated cold start worries these days.

Oil company BS that shouldn't be listened to. Wear occurs because of dirt and it happens slowly over many miles in most cases.

Daniel G Caron