Author Topic: Timing set on 69 Cad 472  (Read 3151 times)

1969 Cadillac Deville

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Timing set on 69 Cad 472
« on: December 08, 2008, 09:56:13 AM »
I have a 1969 Cadillac Coupe Deville.  The timing on the 472 engine seems to be off.  I have attempted to set the timing by turning the screw inside the window on the distributor cap.  When I switch the engine off the motor makes a loud noise and seems to almost crank backwards then makes a loud blowing noise from the carb.  I have attempted to set the timing many times and have had no luck.  I dont know if the adjustment I am working on is the correct adjustment for the timing.  A friend told me that I may be adjusting the points.  I have one more problem.  I took the breather off of the carb yesterday, and when I did there was a fine mist of oil coming out of the valve that links the breather and the valve cover.  Is this normal or do I need to check something?  Could someone please help me with my problems.  I would greatly appreciate it. 

Offline TJ Hopland

  • Posts: 4064
Re: Timing set on 69 Cad 472
« Reply #1 on: December 08, 2008, 10:17:58 AM »
What you are adjusting in the little window is the points.   To set the points correctly you need a dwell meter.  Spec is 28-32*, Ideal 30*.  If they are not set properly or are worn it changes the whole dynamics of the ignition system and can cause all sorts of strange things.  Its not like the timing where you can sometimes 'tweak it for better performance', it pretty much only works properly at the factory spec.

Timing is set my rotating the whole distributor.  Its held down with a clamp that is sort of under the AC compressor.  To set the timing you need a timing light.

For an older motor an oil film in the air cleaner is pretty common.    Clean it up and then install a new air filter and see how long it takes to build up again.  Also make sure the PCV valve is sucking.   If the car has been sitting or its made lots of short trips in its life the rings could be a little sticky.   Several oil change and some longer trips with the occasional stomps to the floor may help get them cleaned up and seal better.
StPaul/Mpls, MN USA

73 Eldo convert w/aftermarket EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Re: Timing set on 69 Cad 472
« Reply #2 on: December 08, 2008, 12:05:58 PM »
What you are adjusting in the little window is the points.   To set the points correctly you need a dwell meter.  Spec is 28-32*, Ideal 30*.  If they are not set properly or are worn it changes the whole dynamics of the ignition system and can cause all sorts of strange things.  Its not like the timing where you can sometimes 'tweak it for better performance', it pretty much only works properly at the factory spec.

Timing is set my rotating the whole distributor.  Its held down with a clamp that is sort of under the AC compressor.  To set the timing you need a timing light.

For an older motor an oil film in the air cleaner is pretty common.    Clean it up and then install a new air filter and see how long it takes to build up again.  Also make sure the PCV valve is sucking.   If the car has been sitting or its made lots of short trips in its life the rings could be a little sticky.   Several oil change and some longer trips with the occasional stomps to the floor may help get them cleaned up and seal better.



I really appreciate your help.  So the PCV valve should be sucking?  The PCV valve is currently blowing a fine mist of oil into the air filter when the engine is running.  Do I need to adjust something, or do I need to replace the valve?

Offline Otto Skorzeny

  • Posts: 3853
  • 1956 Coupe de Ville aka Bismarck
Re: Timing set on 69 Cad 472
« Reply #3 on: December 08, 2008, 12:15:46 PM »
replace thew valve and probably the hose it's connected to.

Check and clean the "pot scrubber" inside the oil filler cap. This is where the fresh air is drawn into the crankcase for the pcv system. You can do this by soaking it in kerosene or gasoline. Get all the crud out, let it dry and moisten it witha small amount of clean fresh oil.

While you're at it, check and/or replace ALL of the vacuum lines on the car - including windshield washers, etc. Cracked leaky vacuum lines can cause all sorts of rough running trouble.

I think it also goes without saying to make sure your plugs, wires, points, cap, rotor, etc. are all in perfect shape and within specs. Change your oil too if need be.
fward

Ask not what your country can do for you, but what you can do for YOURSELF

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Offline TJ Hopland

  • Posts: 4064
Re: Timing set on 69 Cad 472
« Reply #4 on: December 09, 2008, 09:46:33 AM »
I believe the pot scrubber that Otto refers to was on earlier motors like perhaps the 429?  I believe the 69 472 uses a breather filter connected to the air cleaner like most 70's and 80's engines did.

The sucking / valve side of the system should be on the right valve cover.   The valve fits into a grommet on the cover and then has a hose that connects low on the carburetor.  There may be some T's in the line that go to other things which would need to be checked for good hoses and proper function.  I believe the air ride compressor (if you have one) connects to this line.  If its not working properly it could be leaking all the vacuum which means you will not be getting the proper sucking for the PCV system and also have a vacuum leak making the engine run poorly especially at idle.  Same thing would be true for all vacuum devices its just some are pretty small and dont cause as serious problems.   The inlet side of the PCV system is the left valve cover that has that strange tube device that connects.  This device is pretty much an air filter with some baffles in it.  The idea is under normal operation the PCV valve on the other cover will be drawing air through the engine, this device is the inlet for that air.   In a worn engine or under certain loads the blow by (exhaust leaking past the piston rings) is too much for the PCV to draw out so the excess pressure escapes through that filter into the air cleaner housing.  When this happens its common for some oil mist to come with it.  A small amount is normal but if its dripping or pooling you have a problem.   When working properly if you pull the PCV valve out of the valve/rocker cover it should easily hold on to your finger with the engine running.   
StPaul/Mpls, MN USA

73 Eldo convert w/aftermarket EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline Otto Skorzeny

  • Posts: 3853
  • 1956 Coupe de Ville aka Bismarck
Re: Timing set on 69 Cad 472
« Reply #5 on: December 09, 2008, 04:43:47 PM »
You're right. Sorry about that. I wasn't really paying attention to the year of the car - just giving general advice.
fward

Ask not what your country can do for you, but what you can do for YOURSELF

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Art Woody

  • Guest
Re: Timing set on 69 Cad 472
« Reply #6 on: December 10, 2008, 08:46:00 AM »
As far as setting the dwell on points distributor with a cap equipped with adjustment window, you don't need to purchase a dwell meter if you don't have one, or have to replace a failed set while on the road. While engine is idleing, turn adjusting screw clockwise slowly until it misfires or dies. Then turn it back counter clockwise exactly 1/2 turn. You can check it with a dwell meter, but you will find it set on 30 degrees.

Offline TJ Hopland

  • Posts: 4064
Re: Timing set on 69 Cad 472
« Reply #7 on: December 11, 2008, 09:36:13 AM »
You're right. Sorry about that. I wasn't really paying attention to the year of the car - just giving general advice.

I assume that was all an emissions thing?  Functionally they would both work the same except during those overwhelming circumstances when I assume 'they' did not want any of that blow by to escape direct to the air so they fed it back into the engine, sort of a low temp egr?

Were there many years that used that breather cap system (not connected to main air cleaner) and a PCV?  I have a 66 car that has that setup but 67's I have seen have the same looking cap except instead of holes in the bottom it is sealed and has a hose to the air cleaner.  Early 60's cars seem to still have the 'draft tube' setup with often those breather caps on both valve covers.  Im thinking that 67 was the first year that the Fed emissions started using some of the CA parts?
StPaul/Mpls, MN USA

73 Eldo convert w/aftermarket EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

 



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