Author Topic: quiz No. 2  (Read 12012 times)

stickandrudderman

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quiz No. 2
« on: December 12, 2011, 16:18:25 »
CONSTRUCTIVE criticism of how the piicture is posted and the technical merits thereof welcome.....

So, any guesses as to why I would be moved to put up this picture of an air hose as removed from the inlet manifold of a 280SE 3.5?

badali

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Re: quiz No. 2
« Reply #1 on: December 12, 2011, 23:02:12 »
It looks like the hose is missing part of it where it broke off.  Probably caused the engine to have running problems...
Brad

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stickandrudderman

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Re: quiz No. 2
« Reply #2 on: December 12, 2011, 23:12:59 »
The engine certainly had running problems. The hose is something which someone has knocked up as a replacement at some time in the past but on its own is not what I'm alluding to.

Benz Dr.

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Re: quiz No. 2
« Reply #3 on: December 13, 2011, 05:05:56 »
That hose looks like the one used near the auxillary air valve. This valve allows extra air to enter when the engine is cold. I imagine that this particular valve is stuck open on this car so that the engine won't idle below 1,500 RPM or even higher.

  The '' fix '' was to cut two different sizes or hose to restrict air flow to the point that some control could be obtained via the idle air control screw. The auxillary air valve is rather exspensive so blocking it off isn't unheard of, and if you have major vacuum leaks around the plenum chamber, it might be your only option just to make the car driveable without fixing everything. The parts for that fix are not exspensive but it's a lot of work.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

stickandrudderman

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Re: quiz No. 2
« Reply #4 on: December 13, 2011, 08:33:02 »
Benz Dr. does it again!
The owner brought the car to us complaining of hesitation under load.
We quickly discovered that the CO was 9% and there was poor manifold vacuum.
If the CO was adjusted down the engine would become lumpy and start to struggle.
A quick spray of brake cleaner around the inlet manifold whilst the engine was running showed significant leaks in the intake system and the removal of the air bypass hose revealed the washers that someone had installed in order to restrict the air flow and thereby reduce the idle speed.
The owner only recently purchased the car so it looks as though he's been had.
We're now going to remove the intake manifold and replace all of the seals and gaskets.
Well done Benz Dr.!

Benz Dr.

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Re: quiz No. 2
« Reply #5 on: December 13, 2011, 15:28:31 »
Those were washers? I thought they were pieces of rubber hose but the results would be the same.
I just completed a 450SL cylinder head job and since we  did all of the plenum seals, I knew there wouldn't be any leaks. The engine wouldn't idle so I squeezed that curved piece of air hose and it was perfect. I plugged the air hose with a plastic cap and it idled prefectly when hot. This engine has the later CIS system so it seems to work OK, although it's a bit low when the engine is cold.
Since this will be a summer car only, I think it will work OK. If the owner decides to get the new auxillary air valve ( which I doubt will ever happen ) it will be a simple install.

  Don't throw any electronic problems at me - I won't pass.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

Cees Klumper

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Re: quiz No. 2
« Reply #6 on: December 13, 2011, 21:40:36 »
So now we're anxiously awaiting quiz no. 3 ...

But what does spraying brake cleaner around the manifold do?
Cees Klumper
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stickandrudderman

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Re: quiz No. 2
« Reply #7 on: December 13, 2011, 22:23:33 »
It's a useful little trick to discover whether there's any integrity failure in the intake system.
Start the engine and spray a liquid around any potential sources of leak, injector seals, gaskets, hoses etc.
If there is a leak you'll notice a difference in engine speed, stability or note as the liquid is ingested and then a return to "normal" afterwards.
I use brake cleaner just because it's always to hand but you can use WD40 or similiar.
In this particular case it's obvious that someone else has realised that the idle speed is too high and restricted the air flow with the washers to combat it, either because they couldn't work out what the real problem was (leaks to the inlet manifold just about at every possible place), they didn't want to spend the time and effort repairing it properly or they were a professional whose customer didn't want to pay and were instructed to implement a quick fix.

Benz Dr.

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Re: quiz No. 2
« Reply #8 on: December 14, 2011, 01:46:13 »
I'm lucky enough to be able to borrow a smoke tester. This neat little machine pushes a chemical smoke into the intake manifold and anywhere there's a vacuum leak it will produce a small plume of smoke. The smoke disapates shortly after it comes out leaving no smell or residue.
Very handy for finding leaks under the dash in the very complicated heating systems of newer cars. There are a lot of places on a V8 manifold where you won't be able to find leaks in any other way. Some places are impossible to test without this tool.   
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

stickandrudderman

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Re: quiz No. 2
« Reply #9 on: December 14, 2011, 08:07:18 »
I agree that they're a great tool, but they're remarkably expensive and I too can borrow one if needs must...

mdsalemi

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Re: quiz No. 2
« Reply #10 on: December 14, 2011, 12:58:44 »
CONSTRUCTIVE criticism of how the piicture is posted and the technical merits thereof welcome.....

So, any guesses as to why I would be moved to put up this picture of an air hose as removed from the inlet manifold of a 280SE 3.5?

Stick, this photo is significantly better than your past quiz photo.  Though I had no idea of what you were talking about in the quiz, the photo was good! (Oh, and don't be surprised if Dan Caron Dr. Benz "wins" all of your quiz offerings.  He has paid his dues and seen it all...)

You asked for "constructive criticism" so here it is.

1)  Pay close attention to what you are trying to convey, and ensure the photo does that well.
2)  Lighting, focus, sharpness and detail are all important.
 
You control lighting by the use of added light, or reflectors.  Reflectors need not be sophisticated; often a piece of white cardboard will do the trick.  Usually the goal is to fill in the shadow areas.
Focus is from the camera--particularly with point and shoot, you need to allow time for the lens to adjust itself.  Ensure you are within the bounds of the camera's capabilities--if the lens focus is from 1M to infinity, bringing it closer than 1 meter will give you out of focus shots.  Yes, it's that simple.
Sharpness is most often a factor of holding the camera, combined with focus.  Many cameras today have VR (vibration reduction) systems built into the lenses or the camera itself.  While great, they don't replace a steady mount--like a tripod or even a monopod.
Detail is how much information is contained in the photo, and can be a factor of how you compose the shot, and the camera settings.  If you shoot from far away, and have to crop out 90% of the photo, what remains will have less detail.

All that being said, how can anyone (not just you) improve photos of engine bays, or other detail?

1)  Try to avoid a flash--casts too great a shadow.  Most often you'll get the foreground "blown out" (overexposed) while the background/shadow are is underexposed.
2)  Use lights--even a well-placed trouble light will be better than a flash.  JA17 has lights mounted on stands in his shop--and no, he isn't a photographer.  The lights allow a bright illumination to his work area when he needs it.  They are more like lights used by painters than photographers, and they'll do the trick.
3)  Have a big sheet of white covered cardboard around to use as a reflector.  You can often fill in shadow and better illuminate your "working area" by reflecting overhead shop light (or outdoor light) to better light your subject.
4)  The more light the better, generally.  Modern digital cameras, for all their good, don't do a great job in low light situations.  Their built-in flash is often inadequate and really bad for close up work.  Low light often causes the lens to be wide open, or the shutter speed to be very slow, and these together are a recipe for a bad photo--particularly if you are holding the camera!  There will be photographic professionals that aim for wide-open lenses and long exposures--generally on a tripod for a specific look.  They know how to manipulate light.
5)  Most of us are not photographers--I get it.  That doesn't mean you can't understand what you need and improvise.  If you work on old cars, you must be a master of improvisation.  Doesn't take much to make a light stand and nearly nothing to create a reflector.  There are tripods and monopods out there that sell for $500 and more--and also ones that sell for $20.

Great photos of what YOU are trying to shoot are best taken in brightly lit areas with uniform light from all directions, rather than point-source light from a flash.  This isn't much different than the kind of illumination you would like for working!  Shooting outdoors?  Do so on an overcast day.  Specular light from noonday sun on a cloudless day makes for spectacularly challenging photos...

After looking at many thousands of photos, and editing a large number of them for the Pagoda book, I'll all over lighting quality.  In a few cases in the book there were "snapshots" taken by the contributor, of a professional photo shoot in which their car was used as a prop.  In the cases I remember of these shots, you'll see:

1)  Stand mounted lights.
2)  Reflectors
3)  Gorgeous models.

You can get #1 and #2 easily yourself.  For #3, contact Wolfmann!  :D

You can use free software like Picasa from Google to take your photos up in quality, too. http://picasa.google.com/
« Last Edit: December 14, 2011, 13:14:06 by mdsalemi »
Michael Salemi
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GGR

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Re: quiz No. 2
« Reply #11 on: December 16, 2011, 16:53:49 »
I did the same trick on my engine. I have no vacuum leaks and engine idles properly when warm. Air valve closes also properly when engine is warm. My problem is that the Air valve is letting too much air in when engine is cold so my idle is way too high until the engine warms up. I fitted a washer in there to reduce the air flow which does a great job when engine is cold. then idle goes up a bit when half warm, as engine needs less air, and then it normalises when warm. Ideally these air valves should be adjustable. Any idea how to do that the right way?

Benz Dr.

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Re: quiz No. 2
« Reply #12 on: December 16, 2011, 18:04:24 »
Adjust the air valve? It can't be done because it's a sealed unit.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

wwheeler

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Re: quiz No. 2
« Reply #13 on: December 16, 2011, 21:02:40 »
It sounds like you want to change the air/fuel ratio of the WRD during warm up.

I have wrestled with the same issue for awhile. My 111 runs so rich at a cold start that when I add some air, The idle quickly jumps to 1100RPM, which what I desire. Without the extra air, it runs at 900 RPM. Not bad, but not what it should be. However as the engine warms, it leans out. And just as the air valve shuts, the engine is running so lean that it idles around 600 or so and pops a bit. If I split the linkage and add some fuel, it runs perfectly. The engine then runs very well when warm at idle.

So my conclusion is that I need more air with a cold engine and less air just before full warm up. To get less air (more fuel) you would add oval shims at the WRD. BUt that would make the cold running even richer and slower. Adding round shims does not change the mixture, only changing the temperature when the thermostat shuts the air valve passage.

If you look inside the WRD housing where the air valve slides, the passage looks like an upside down pyramid with three steps. When very cold you have the most air and largest opening. It steps down as the engine warms and lets in less air through the passage. My thought was to file part of the opening to let in more air at the very cold stage. This should let more air in only when very cold and raise the idle speed. Once the engine warms, the extra opening will be covered by the air valve and will be the same if I hadn't done anything. In effect, I have changed the air/fuel ratio at very cold running only.

To solve the lean running nearing the full warm state, I simply add more oval sims to the WRD. I have already filed the air valve opening and will install in a month. So I will see if it worked. Other than that, I don't see how you can change the a/f ratio. It is fixed and sealed as Dr. Benz said.
Wallace
Texas
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'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

GGR

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Re: quiz No. 2
« Reply #14 on: December 17, 2011, 03:02:59 »
Thanks. In fact I have converted the D-jet to Megasquirt so I can change AFR at will. But the thing just lets too much air in when cold. I may try to enter data so that advance is retarded by a few degrees when cold then increses to normal while warming up. This may be the way to cotrol rpm when cold in my case.

stickandrudderman

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Re: quiz No. 2
« Reply #15 on: December 17, 2011, 16:22:52 »
If you've fitted megasquirt why not fit electronic idle speed control too?