1958 Cadillac Vacuum Leak - Solutions and More Questions

[Matt I #21633]

First off, I want to personally thank everyone who offered input and suggestions as to why my 1958 SDV was running so poorly.  With your help, I was able to diagnose the problems, so I thought I would offer a small narrative on the solutions.  Hopefully, this can help some fellow Cadillac owners in a similar situation.  Of course, with old cars, with every problem you fix, 2 more pop up.  As such, I have some more questions following the summary.

For those who were not aware, my Cadillac was running terribly - it felt like it was running on 5 cylinders and the power brakes were practically non-existent, despite the fact I had the power booster rebuilt.  The vacuum on the car was reading 15" Hg, indicating a huge vacuum leak.  After days of chasing, the source of the vacuum leak was the heat riser tube for the choke and the control switch for the windshield washer.  Making a secure connection for both of these pieces brought the vacuum up from 15" to 21" and a much smoother running engine.  Also, the brakes are 100 times better now that I have full vaccuum!

Now for more problems.  My washer was not working before (obviously) as the control vacuum line became disconnected.  Now that it is connected, it is still not working.  When I push on the button inside the dash, I hear air coming out, so I know it is holding a vacuum.  How do these old washer pumps (that mount on the lid of the washer jar) work?  Can they be cleaned or rebuilt?  Any idea what is wrong with mine?

Second problem - once I corrected the vacuum leaks, I had to re-time the car and re-adjust the fuel mixture.  If I set the car to factory specs, which is 400 rpm in "Drive", it wants to stall.  The Generator light starts to come on when I come to a full stop, so I have to feed it gas to avoid a stall.  Is my idle set too low, or can this be a problem with the voltage regulator?  When the car has gas, or cruising down the highway, the Generator light goes out.  The voltage regulator is about 10 years old, whereas the generator and battery are rebuilt and new, respectively.

As for the timing, I time the car by ear and vacuum gage.  I think John Washburn wrote a good article in the Self Starter a few months back on setting timing and mixture with this approach.  I set the timing to give me the highest vacuum (about 21 inches) and back out the idle screws accordingly.  However, with the timing that gives me the optimum vacuum, the starter motor struggles when the engine is hot, indicating it is too far advanced.  Should I sacrifice precious vacuum for a hard start once the car is warmed up?  Any suggestions?

Thank you in advance for any insight on the windshield washer information, idle speed and timing!

[Porter]

Matt,

I dont have a car with a generator but have read here the light will go on when idling because the system is discharging, 400 rpm seems too low for me anyway.

You dont want the timing too advanced, that can create problems starting the engine when cold not to mention engine pinging.

http://www.type2.com/library/engineg/ping.htm TARGET=_blank>http://www.type2.com/library/engineg/ping.htm

Tell us what you have learned about troubleshooting, funny, in the previous thread I think I said never assume anything.

Porter

[Matt I #21633]

Porter,

     Thank you for the reply.  I would like to add "unless proven otherwise, its broken" to your motto of "dont assume anything".

     Gang, I swore up and down my carburetor was shot.  My engine went to the crapper the other day.  At best, it was running on 6 cylinders.  I refused to think the points were the culprit, being they had onyl 1500 miles on them.  Yet, Porter insisted I change them, as a set of points is alot cheaper than a rebuilt carb and a nervous breakdown.

      Sure enough, after a new set of point, it is running like brand new!

     Lesson learned - points indeed can make an engine run terrible even though they onyl have 1500 miles on them and are less than 4 years old.  Porter, thanks again and I hope some others can learn from my experience!

Matt

[Porter]

Matt,

We discussed the points resistance test mode on the tach dwell, there is a reason why its there.

If you have strong compression and it was running strong look for the obvious vacuum leak and then start with the igntion system, work your way up the food chain then you can blame the carb if you cant adjust the idle, typical carb problems are a worn accelerator pump; weak acceleration but good idle, or just plain dirt, stuck needle and seats, etc.

Make sure you have a steady timing mark and check the vacuum/centrifigul advance with your timing light.

I rebuilt my 66 Carter and that thing was a complete mess, float level and float drop way off, the last person that touched that carb was an idiot, all started with a stuck needle and seat with flooding.

The old breaker point ignition and carb engines are very fussy, get out of tune after 10K mileage or so easily, once you foul the plugs from lack of highway driving they will never run right.

The fine tuning is the icing on the cake, seperate the men from the boys or shall we say the shadetree mechanics from the old pros.

John Washburn would have wheeled out his antique SUN diagnostic machine and nailed the problem in 5 minutes.

LOL,

Porter ( just rambling )