Advance/Retard?

[Guest J446]

The Dusey manual (which is a reprint and may be wrong) states that you should use midpoint to start and Adv. for highway and Ret. for low speed power. When I do this I find my car runs much hotter than when I leave it Adv. all the time except to start which also seems to start better on full Ret. What do you think?

Thanks

[Guest BillP]

Jim~

It sounds like a calibration problem. There would be a couple ways to tackle it. The initial advance setting may be listed in your manual. You probably know how to set this by manually turning the crank until points just open (as revealed by a test light) and then verifying the (presumed) mark on the crank pulley or flywheel. This would probably best be done with the manual advance linkage disconnected.

I prefer to achieve final timing on the road by ear. Under a series of low speed, full throttle pulls in high gear, incrementally advance the timing by turning the distributor until you hear the rattle of preignition, then retard it a whisker until silent. Of course, this assumes a well-muffled engine; the racecars can't be done this way. After you've acheived optimum timing, adjust the cockpit timing adjustment to correspond to the highway setting. The other settings should fall into synchronization by virtue of the original design.

I'm not familiar with a Duesenberg, my prewar cars are Cadillacs and Packard but the same thinking should apply.

Advise how this goes. WP

[Guest J446]

Bill

Thanks very much. I bet you're right. Would the higher oct. gas I'm using vrs. CCCA period gas effect this as well?

[Guest BillP]

Jim~

I doubt the gas would have much effect on this problem. It does seem to be more volatile and therefore easier to vapor lock but that's a separate deal. Because of the relatively low compression ratio on these thirties cars, I just use the lowest octane available, figuring that it is higher than what was available back then. They seem run OK; I also use it in my farmall snow plowing tractor which has about a 4 and a half to one C.R.; no problem.

Originally you related the timing issue to running hot which I didn't really address. In addition to timing, you want to avoid a lean mixture which can be read by looking at the plugs. If you have the correct carburetor and it's running OK (i.e. no lean surge or bucking), you might assume the mixture is the fairly good. The big hazard with these old cars is, as they sit around year after year, the radiators and engine water passages get fouled up. Don't know how yours are.

Just some thoughts. WP

[Guest J446]

Bill

Your right about the rad and water passages and pump. Cleaned and fixed all of that. I was wondering if higher octane would be able to use more advance and if so would this be a good idea? Engine seems to run cooler with more advance. (does this make sense?) Mixture is ok slightly rich if anything.Thanks

[Guest BillP]

Jim~

<runs cooler with more advance> is of course also saying runs cooler with less retard which does make sense. You may find after some experimentation that the spark timing you eventually achieve isn't so much overly advanced as it is simply correct, which makes for a happier engine. Mixture a little rich is a good thing. I think that the idea behind more octane was to be able to increase the compression ratio which was an easy avenue to more horsepower. Separately, they also found that running the engines faster made more power and naturally required more total advance. Advancing the timing beyond its 'natural' setting on an otherwise stock engine running within its design speed doesn't seem to have much benefit. Also, engines with a lot of static advance are kind of cranky to start which would be cause for embarrassment on the show field.

This reminds me of centrifugal advance mechanisms. In that you have operator-controlled spark timing, your car probably has a fixed, immovable points mount in the distributor. However, if there is a moving, centrifugally adjusted points arrangement it'd be well to ensure its proper motion. WP

[Guest J446]

Thanks. Timing control in this car is manual. I think I was running with improper ADV. After some more driving I'll report.

Best

[Guest stude8]

I would check the distributor point cam drive before I would say that Deusy only has manual advance control. My 1930 Studebaker had manual advance but the Delco 668C distrib also had centrifugal motion with weights and springs below the breaker plate. I would bet a car the caliber of Deusenberg had the same.

Just grab the distributor point cam and try to rotate it CW or CCW, if it moves that is the centrifugal weights moving. Another way is hook up a timing light and observe the timing indicator then rev engine, if it appears to change position that is the centrifugal weight motion. You calibrate your damper with a hotrod shop degree tape and calculate the degrees right from the timing light indications. Stude8

[Guest J446]

Stude 8

Thanks. You are quite right. The automatic advance is 40 deg's and the manual advance is an additional 20 deg's. The problem we were having was the owner's manual vrs. where the previous owner had set the timing. I think we have it sorted now but need to put on a few miles before I'm sure. Another part of the overheating prob was that the cockpit controlable exhaust back pressure valve was vibrating and sticking shut.

[Restorer32]

In the fully retarded position the charge in the cylinder ignites while the piston is lower in its' bore, thereby exposing more of the cylinder wall to the heat of combustion. In very early, marginally cooled engines, especially those with thermosyphon cooling, the degree of retard is especially critical to engine cooling.

[Guest J446]

Thanks. This is all very helpfull. Now that I running more advance it seems to run much cooler.

[Guest Ken G]

I hope my 1925 Rover 16/50 phaeton (the only one in North America and possibly the only one in the world actually running at present, see http://mywebpage.netscape.com/rover1927/index.htm) qualifies for this forum.

I have similar questions about ignition timing (with purely manual running adjustment). The lever on the steering wheel moves the timing through about 25 degrees. At present, in the absence of any precise guidance in the original instruction book/service manual, I have it set so that it goes from about 5 to about 30 degrees before top dead center, and checked with a timing light. (I may say it's a pain to change the range, involving removing the magneto and using a puller on a plate at its bottom).

To my surprise, at any speed, the engine pulls best with the ignition lever at full advance i.e. about 30 degrees advanced, and it even starts and idles perfectly well like that. At idle, if I retard it, the engine slows. What am I missing? I might add that the engine is noisy enough that I don't think I would hear noises resulting from excessive advance!

Although I have been round the loop several times, I must try yet again to confirm that the timing mark showing TDC is correct (I had to make it myself).

Anyway, should I be surprised?

Ken G, 1925 Rover 16/50 (San Francisco)

[Guest J446]

Ken

I found the same thing! I'm going for a long drive this weekend and will report.

[Guest J446]

Ken

Went for a long drive today. Ran very well at full adv. water temp on highway 180 in town slightly cooler. What temp does your car run?

[Myron Williams]

Hi Bill P,

I hate to change the subject, but it sounds like you have some knowledge about Packards, so here goes...

I'm in the process of ressurecting a basket case 1935 Super 8. I have it running, but the rebuilt carburetor seems to be WAAAAAAY rich. It starts, idles, and runs fairly well, but the plugs are VERY sooty, and it puts out a black cloud of smoke SOMETIMES when it is idling.

Do you have a recommended procedure for setting the mixture on the carburetor that you would be willing so share?

Thanks in advance,

Myron <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" />

[V.Milke]

Jim:

If it helps in any way, or better say, to reinforce what you've found, I have two cars with timing control on the steering column. First one, a 1928 Stutz, has no other timing thing, that is, only the control on the steering column. Second one, a RR 25/30, has centrifugal advance and also a steering column control. Both cars run better with the manual control in the most advance position. The RR manual states that you can start it with the timing retarded but then pull it up almost all the way for regular driving. The Stutz also starts better with timing retarded, but as soon as it starts, I push it all the way up to full advance, as the car is much happier this way, even at low speeds. Of course, I have no idea about a Duesy, but it has been and will probably remain my whole life's dream to find out and...

Victor.

[Guest BillP]

Hi Myron

My experience with Packards consists mainly in standing in the barn and admiring mine so take my thoughts with a big grain of salt.

Is the choke opening fully and completely and staying open.

Sometimes when these (or any) engines sit, the float bowl leaks and sinks. You could take off the top of the carburetor and see if it has perforated.

Also, the fuel inlet needle and seat may be sticking, particularly if they used a neoprene tipped needle. Fiddle the float up and down to make sure the needle is utterly free in its' travel.

Check the float level to specifications.

I think the main jet was supposed to be .060, see if someone drilled it. Such was a common but misguided shade tree fix for the ratio of low horsepower to high weight. Of course, verify what the jet is supposed to be b4 you change it.

Has the car been fitted with an electric fuel pump. If so, the fuel pressure may need reducing.

Hope this helps, advise your findings.

Bill

PS not only looking at it; driving it, sitting in it, waxing the chrome, cleaning the engine, reading the owner's manual for the thirty-seventh time, adjusting the valves, winding the clock.....you get the point.

[Guest J446]

Victor

Thanks! It's been a long haul but I think I've finally gotten this trailer queen to start, stop, and run. This is a great time of year to drive in NY!

[Guest Ken G]

Dear J446 (that seems a very strange greeting).

I don't know. I have a Motometer which doesn't actually indicate, that is, the radiator doesn't get hot enough for the red spirit to become visible, although immersing the end in boiling water does produce a display, so the (new) Motometer works. So all I can say is that the engine is certainly not overheating. Apparently this model was renowned for its not being possible to boil it, and at present I have a six-bladed flex-fan in place of the original two-blade cast aluminum one (a long and painful story!) which may I suppose mean that it runs even cooler (but there is a thermostat).

I was, and still am sick (nothing serious), so I haven't done anything more to the car, and in particular to checking yet again that my previous measurements of the degree of ignition advance are correct. Anyway, many thanks for your comments.

Ken G, 1925 Rover 16/50 (San Francisco)

[Guest J446]

Hope you feel better. Thanks

Jim