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High School Reunion with 1967 Sedan DeVille

Started by savemy67, December 07, 2014, 11:57:13 PM

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savemy67

All,

If I live to be 90, I don't think I will ever truly be a Cadillac expert.

I think I have a fairly good memory.  I was a Jeopardy contestant in 1991.  I joke with with friends and family that if I get senile in my old age and forget half of what I know, I will still remember more than most because of the amount of what I currently remember.  That said, I did not remember that my '67's parking lights do not stay illuminated when the headlights are energized, so I may have been premature in condemning the headlamp switch.  Someone from this forum kindly brought that fact to my attention a little while ago.  The new switch I ordered yesterday has shipped, so it will either fix the instrument panel lights, collect dust as a spare, or go back to the vendor for something more useful.  Oh well, live and learn.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

57eldoking

I thoroughly enjoy reading this thread, lots of interesting stuff to pick up on. Keep the updates coming Christopher!
1957 Eldorado Biarritz #906
1957 Eldorado Biarritz #1020 http://bit.ly/1kTvFlM
1957 Eldorado Seville  #1777 http://bit.ly/1T3Uo1c
1995 Fleetwood Brougham  http://bit.ly/20YwJV4
2010 SRX Performance

1946 Chevy 1/2 ton pickup
1957 Buick Caballero Estate Wagon (x2)
1960 Chevy Apache 10 Stepside
1991 Jeep Grand Wagoneer (x2)
1992 Pontiac Trans Sport GT

savemy67

All,

A couple of weeks ago, I had my car on the Baltimore Beltway for a couple of miles.  The engine felt like it had a mis-fire, so I knew that eventually I should change the "tune-up" complement of parts.  The car came with a new set of plug wires and plugs, so I ordered a distributor cap, rotor, points, and condenser which will arrive in a day or two.

I noticed that the old distributor cap was loose.  Even though the spring-loaded hooks were seated in the notches on the underside of the distributor, I could easily remove the cap by hand.  It seems as if the spring-loaded hooks have hardly any tension.  Hopefully the new cap will be an improvement.

I am considering removing the distributor for a more thorough look, and possibly a rebuild.  If I remove the distributor gear, what is the correct size roll pin to use when the gear is replaced?

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

All,

Since I am waiting for some tune-up parts, I thought I would clean the ignition coil and the terminals of the wires that connect to the coil.  If I am going to refresh the distributor, I might as well refresh the coil and connections.  Photo 3713 below shows the spot on the manifold where the coil and bracket assembly is bolted to the manifold.  The bolts that hold the coil bracket also hold a bracket to which is mounted the throttle dashpot (this prevents the throttle blades from slamming shut), and the transmission switch-pitch/kick-down switch.

While waiting for the paint on the coil to dry, I dis-assembled the switch-pitch/kick-down switch (SPKD).  An earlier on-the-car test of the switch did not produce an audible click of the solenoids in the transmission, so I thought I might have a broken SPKD.  Photo 3715 shows a square hole in the throttle plate linkage.  Into this hole goes a square shaft that is part of the SPKD.  In the center of photo 3719, the square shaft coming out of the SPKD is broken off.  The broken shaft is one explanation for the SPKD not working.  At this point I had not dis-assembled the SPKD completely, and I thought I might be able to effect a repair.

In photo 3723, the pencil is pointing to one of four peened posts that hold the SPKD terminal board to its housing.  The posts are relatively soft, and a small screwdriver removed the peened heads of the posts (photo 3727).  After the penning was removed, I was able to gently pry up on the SPKD terminal board and remove it from the housing revealing the disappointing contents therein.

Photo 3731 shows that not only is the shaft broken on the part that inserts into the throttle linkage (lower right in the photo), but the upper switch contact is bent (lower left in photo), and the moving switch contact actuator is broken into three pieces (lower center in photo) - it should be one piece.  It is times like this when I wish I had a 3-D printer set-up to make small plastic parts.

I searched many Cadillac parts vendors and found a two-terminal switch for a '69 that uses the same housing as my '67.  I thought I might be able to modify the internal components, but the vendor wanted $200, so I passed.  I found another vendor who has two used SPKD switches for a '67, but this vendor wants $168 for each switch - used.  I found yet another vendor who wants $68 for the switch, but I have not yet spoken with that vendor, and do not know the condition of the switch.

I may explore the 3-D printer possibility as I live close to two colleges that have CAD/CAM, CNC, and automotive curricula.  If by some miracle I am able to reproduce the plastic parts for the switch, I still have to get them re-assembled into the housing.  I mentioned above that the posts holding the terminal board to the housing are soft.  I broke one of them during dis-assembly as is visible in photo 3736.  How to fix?  I can cut off the post and drill out the boss for a small diameter aluminum rod or copper wire, either of which can be easily peened.

I am aware that others have fabricated an SPKD, but although this car will only be a driver for the near future, I would still like the car to appear as original as possible.  Of course, I can drive the car without the SPKD, but what fun would that be?  If anyone has information on an SPKD, or on a '67 parts car (also maybe a '65/66), please let me know.  Thanks.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

All,

In a previous post I mentioned that When I got my car, it came with 8 new ACDelco spark plugs and a set of ACDelco plug wires.  I replaced the plugs today, but before installing the new plugs, I did a compression check of the cylinders.  The engine was cold.  The choke was blocked open.  All old plugs were removed.  The A/C compressor belt was removed.  The belts for the water pump, power steering pump, and alternator were left in place.  For each cylinder, the engine was cranked until the needle on the compression tester rose no further - about 5 to 7 compression strokes.  My compression tester is a Sears Penske tester with an O-ring seal at the threaded spark plug connection.  The results:

cylinder          reading
---------          ----------

    1               185
    4               193
    6               195
    7               188

    2               183
    3               191
    5               192
    8               181

I have listed the readings in two groups based on the intake manifold runners.  The intake is a split-plane type.  One side of the carburetor (primary and secondary bores) feeds cylinders 1, 4, 6, and 7.  The other side feeds cylinders 2, 3, 5, and 8.  The lowest reading is 181, and the highest reading is 195.  The difference (14 PSI) represents a variation of less than eight percent between cylinders.  The car shows 90,000 miles on the odometer.

If the readings are grouped by bank, the following relationship appears:

cylinder          reading
---------          ----------
    1               185
    3               191
    5               192
    7               188

    2               183
    4               193
    6               195
    8               181

The cylinders at the ends of both banks (1, 7, and 2, 8) read with a variation of less than four percent of each other, and the cylinders in the middle of both banks (3, 5, and 4, 6) read with a variation of about two percent of each other.  The average of the four end-of-bank cylinders is 184.25.  The average of the four middle-of-bank cylinders is 192.75.  The difference of the averages represents a variation of less than five percent between end-of-bank and middle-of-bank.

The shop manual describes the intake runners as being approximately equal in length.  However, approximately does not equal exactly, which is why performance engines strive for equal length intake runners.  I hypothesize that the end-of-bank cylinders are slightly starved for air.  Given that all cylinders have the same amount of time within which to draw in air (the pistons travel the same distance in the same amount of time in each cylinder), the volume of air in the end-of-bank intake runners has less time to reach those cylinders due to the longer path the volume of air has to travel.  The end-of-bank cylinders do not get quite the same volume of air as the middle-of-bank cylinders.  Since pressure is a function of volume, less volume of air in the end-of-bank cylinders would result in a lower reading for those cylinders.

Another consideration is that the exhaust cross-over passage in the intake affects the cross-sectional shape of the middle-of-bank runners in such a way that the volume of air in the runners for those cylinders has its velocity increased resulting in more volume in the middle-of-bank cylinders, and higher readings.

When I removed the old plugs. they were all uniform in color and appearance.  I am OK with the results of the compression check and I am reasonably confident that I can eliminate compression issues when it comes time to tune my car's engine.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

corey raub

Mr. Winter,
Your writing skills are fantastic and your attention to detail is unmatched.  Thanks for taking the time to share your knowledge and observations. 
Corey

savemy67

Corey,

Thanks for the kudos.

All,

In a couple of previous posts I indicated that I planned to do a thorough tune-up on my car.  I got around to that chore the other day.  The tune-up included the replacement of sparkplugs, sparkplug wires, distributor cap, rotor, points, and condenser.  I also removed, dis-assembled, and cleaned the distributor, and adjusted the carburetor.

The first thing I did was remove the left side valve cover and rotate the engine so that cylinder #1 was at top dead center (TDC) on the compression stroke.  The valve cover was removed so I could keep an eye on the valves to verify the compression stroke.  The timing mark on the harmonic balancer was aligned with the zero degree mark on the timing tab.

With the engine in this position, the distributor rotor firing tab points to cylinder #1.  Before I removed the distributor, I made a mark on the distributor to facilitate its replacement with the rotor in the same position.  When the distributor is removed, it will rotate slightly in a counter-clockwise direction due to the helical cut of the gear at the bottom of the distributor.  When the distributor is replaced, it is necessary to have the rotor pointing a little counter-clockwise so when it rotates clockwise when the distributor is replaced, the rotor will align with the mark made before removal of the distributor.

My distributor was dirty after decades of being in the car (photo 3743).  I believe it to be the original distributor based on the painted vacuum advance canister, and the number on the aluminum band wrapped around the distributor (Delco Remy 1111682).  In order to completely dis-assemble the distributor, I had to drive out the roll-pin that secures the distributor gear to the distributor shaft.  I used a 3/16 inch punch (photo 3748).

Between the gear and the bottom of the distributor is a thrust washer which limits the end-play of the distributor shaft.  I could not find any Cadillac specification for the end-play measurement.  A Corvette forum had a reference from Delco Remy indicating that production end-play measures .025 to .096   My measurement is about .035 (photo 3750).  How important is end-play?  Some might argue that excessive end-play causes the distributor shaft to move up and down (due to the helical cut of the gear) and thereby rotate the rotor and slightly advancing or retarding the timing.  In theory this may be true.  In practice, I think, since the gear on the camshaft that drives the distributor gear rotates only in one direction, there is a constant upward thrust on the distributor gear regardless of engine RPM and regardless of whether the camshaft "walks" back and forth.

Photos 3751 and 3752 show the holes in the gear through which the roll-pin is driven.  One hole is chamfered and the other is not.  The chamfered hole is aligned with the firing tab on the rotor.  There are 15 teeth on my distributor gear.  If the gear is installed 180 degrees out of alignment, the timing will be off by a half gear tooth or 6 degrees at the crankshaft timing tab.

One of the last parts I removed was the vacuum canister.  One of the two screws holding the canister to the distributor would not come out even with a large screwdriver (photo 3759).  I used a grinder to grind the screwhead (photo 3761) which relieved enough tension so that I was able to remove the screw without having to drill it out.

The distributor was cleaned, inspected, and painted.  There are two bushings in the distributor housing within which the distributor shaft rotates.  There was no detectable side-play between the bushings and shaft in my distributor.  Excessive side-play may cause the distributor shaft to wobble as it rotates.  This could affect the position of the rotor and possibly affect timing, but it is probable that this might only occur at high RPM, and if the bushings are excessively worn.

In my next post, I will describe the assembly of the distributor.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

All,

Photo 3769 shows the top of the distributor.  In the center is the hole and bushing for the distributor shaft.  The breaker plate fits around the outside diameter of the bushing boss.  Also around the outside diameter of the bushing boss is a groove (photo 3773, just above the breaker plate collar).  Into this groove fits a split-spring washer (photo 3774).  This washer is very small and easy to lose, but it retains the breaker plate as seen in photo 3776.

After installing the condenser and points, and the shaft with a new roll-pin, I found it easier to install the mechanical advance weights and springs, and to preliminarily adjust the point gap with  the distributor in a vertical position.  A scrap piece of 1 1/2 inch schedule 40 PVC pipe, held in a vise sufficed (photo 3784).

Photo 3788 shows the distributor cleaned, painted, and assembled.  I left the vacuum canister in its natural finish after cleaning it, but I did spray it with a coat of clear enamel.  The only vacuum pump I have is my lungs.  I sucked on the vacuum canister and the canister stuck to my tongue, so for now I am giving an OK to the canister.

Photo 3790 shows the distributor back in the car next to the refreshed coil.  The coil was cleaned and painted.  All terminals and connectors at the coil and distributor were sanded until shiny, and sprayed with contact cleaner.  When the final connections were made, a coat of di-electric grease was applied.

I do not have a timing light, so the only way I can check the vacuum advance and the mechanical advance is with a vacuum gauge and by how the car runs.  To set the base timing at 5 degrees before TDC, I connected a test light to the positive battery terminal and probed the coil negative terminal while turning the distributor.  When the light changed in intensity, the distributor was in the correct position for 5 degrees advanced base timing.

I put the new wires on the new cap and double checked all my connections.  I have an oil pressure gauge and a vacuum gauge installed in the engine bay, so before starting the car I hooked up my dwell/tach meter and started the car.

The car started immediately and the dwell registered at 29 which I adjusted to 30.  I let the engine warm up and used the vacuum gauge to adjust timing.  I used the vacuum gauge and the tachometer to adjust curb idle, the throttle return dashpot, and the idle mixture screws.  I was able to get a rock steady vacuum reading of 21 inches Hg, but I think my idle is still a little too high.  I took the car for a drive and was satisfied with its performance during the short trip which included two miles on the beltway at 60 MPH.

So far, so good, but I will need to revisit the carburetor adjustments in the near future.  In addition to another round of carburetor adjustments, I have to drop the fuel tank and inspect the sending unit.  Earlier testing indicated my gas gauge is OK, but the sending unit may be bad.  I also have to check the relay for the power windows, all of which work from the master switch, but none of which work at the respective door switches.  I also have to finish installing a new headlight switch.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

All,

Considering the number of Cadillacs that rolled off the assembly line on a daily basis in 1967, I wonder how many cars were delivered with manufacturing errors?

In a previous post I indicated that I removed the left side valve cover in order to view the valves to confirm that cylinder #1 was on its compression stroke.  Another reason for removing the left side valve cover was noise.  Since I purchased the car, I noticed that there seemed to be some valve noise coming from the left side valve cover.  The noise can be described as a clattering sound, typical of loose valve rocker arms.  The noise was present, although not quite as loud, when the engine was warm.  My mechanical oil pressure gauge always shows good pressure when the engine is running.

When I removed the valve cover, everything looked correct, but the rocker area was dirtier than expected (photo 3766).  I wiggled each of the eight rocker arms by hand.  Some were snug, which would be expected if the valve spring was under load.  Some rocker arms could be wiggled just a little, but the last rocker arm, the one for the exhaust valve for cylinder #7, I could shake easily - it was very loose.  I suspected that this rocker arm was the source of the noise, but what was causing the rocker arm to be so loose?  Was there a bad lifter?  Was the valve stem excessively worn?

I decided to remove the bolt that holds the rocker arm pedestal to the cylinder head.  For '67, Cadillac changed how the rocker arms were attached to the head.  Instead of a common shaft, each pair of rocker arms is mounted on a pedestal.  The bolt that holds the pedestal is also a cylinder head bolt, so before removing this one bolt holding cylinder #7's pedestal and rocker arm pair, I torqued all the other head bolts, none of which budged indicating that they were all OK.  The pedestal holds two rocker arms but the pedestal is not symmetrical.  One arm of the pedestal is for the exhaust rocker, and the other pedestal arm is for the intake.  Each pedestal arm is stamped with an E or an I (photo 3794).  Due to the arrangement of the intake and exhaust manifolds, the valves are arranged in the head thusly:  E I   I E   E I   I E.

When I removed the bolt holding the pedestal for cylinder #7's rockers, there was excessive wear at the side of the exhaust rocker that bears against the end of the pedestal arm.  Upon closer examination, I noticed that the I and the E stamped on the arms were oriented opposite of how they should have been oriented.  The intake rocker was operating on the exhaust pedestal arm, and the exhaust rocker - the one that was very loose - was operating on the intake pedestal arm.  I took photo 3794 after I reversed the orientation of the pedestal.  Of course I could not swap the rocker arms so I still have some noise due to the different wear patterns on the two rocker arms relative to the pedestal.  The noise may subside as the pedestal and rockers arms adjust to their "new" orientation.

Based on the history of ownership of the car, and the condition of the engine, I do not think the engine or heads have been rebuilt.  That leads me to suspect that the pedestal for cylinder #7 was installed incorrectly at the factory.  Has anyone  had a similar experience with their engine?  Or any other assembly?  Does anyone have a pedestal and rocker pair that are in good condition?  Does anyone know if the 472/500 pedestals and rockers will fit the '67 429 (are the rocker arm lift ratios the same)?

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

6262

Thanks for the interesting and detailed posts!
1962 Cadillac Series 62
1965 Pontiac Bonneville

DeVille68

Interesting cause of liver noise! Could well be - where humans work, failures are made!
1968 Cadillac DeVille Convertible (silver pine green)

savemy67

All,

My gas gauge has not indicated any fuel level since I purchased my car despite the fact that twice I have put 10 gallons of gas in the tank. The gauge always reads Empty.  A few months ago I used the procedures in the shop manual to determine if the gauge or the sender was the most likely culprit.  At that time, the gauge functioned properly based on the tests, so I figured it must be the sender causing the gauge not to register.

I recently dropped the gas tank and removed the sender.  I noticed that a small portion of the ground wire was wrapped in tape, and I discovered broken insulation under the tape.  My first thought was that this might be responsible for the gauge not registering, but alas, when I tested the wire with an ohmmeter, the wire had continuity.  I then noticed that the ground wire was attached to the same terminal post as the sender wire (the wire that goes to the gauge).  This arrangement did not seem correct.  Every illustration or video I have seen that shows a sender being tested, shows the ground wire attached to the sender flange or a separate ground terminal or post, not the sender terminal or post.

I configured some jumper wires and my meter to see if moving the float arm would indicate varying resistance values between 0 and 90 ohms.  I connected one lead to the sender post, and the other lead to the mounting flange.  When I moved the float arm I got a reading between 0 and 2.5 ohms.  The sender does not appear to be original.  It resembles many that I have seen for sale on-line for about $80.  There isn't much to the sender assembly, mechanical or electrical, so I removed the cover of the resistance wire housing, sprayed contact cleaner on the wires and bent the wiper for firmer contact with the wires.  I checked for and found continuity between the rivet at the end of the resistance wire assembly and the sender post, so that seemed to be OK.  I put the cover back on the resistance wire housing and tested again for values between 0 and 90 ohms.  Despite my efforts, the meter displayed values between 0 and 1.5 ohms.  In other words, cleaning the resistance wires with contact cleaner, and thoroughly drying them with compressed air, and bending the wiper for firmer contact did nothing to improve the functioning of the sender.  I can hear the wiper rubbing across the resistance wires when I move the float, but essentially the sender is not indicating any resistance.

As I mentioned, the sender does not appear to be original.  In fact it looks to be only a couple of years old, and I suspect the previous owner was the one who replaced it.  Before I shell out $80 or more for a new sender, does anyone think I have overlooked something, and does anyone know where a replacement sender might be purchased for less than $80?  Rock Auto doesn't carry this sender, nor could I find a listing at NAPA, Pep Boys, or Advance.  USA Parts has one at $80.  Caddy Daddy and OPGI are in the $115 to $120 range.  Thanks for any suggestions.

One positive note is that the inside of my gas tank is nice and clean.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

mgbeda

I think you found the problem in the first place- the sender wire should NOT be connected directly to ground (and the flange is ground).  Connecting the wire straight to ground will cause the gauge to read at E.

The tests you've done also make sense if the sender is shorted to ground.  The short conducts at 1.5 ohms and when you vary the resistance by moving the float you can get it  down to 0 with the added conduction through the sender.

-mB
-Mike Beda
CLC #24610
1976 Sedan DeVille (Bessie)

savemy67

Hello Mike,

Thanks for your reply.  The photo showing both wires attached to the sender post is to illustrate how I found the wires.  When I tested the sender, the wires were removed and I had one lead of my meter on he sender post and one lead on the flange.  You are probably correct in your second assertion that the sender is shorted to ground, meaning that the resistance wire assembly is grounding.  I will take one more close look at the assembly to see if I can locate where the short to ground might be occurring before I open up my wallet.  If and when I purchase a new sender, I will test it prior to installation.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

mgbeda

Very interesting.  That second wire connected to the sender post has to be wrong, but since you took those wires off before testing, that can't be part of the problem.

I bet you can fix the sender- they aren't very complicated and you've done the hardest bit (taking it out and apart).

Did you try testing it with the sender taken apart, like in pictures 3881 and 3882?  There should be no conduction between the sender post and the flange with that shell taken off like that.

-mB
-Mike Beda
CLC #24610
1976 Sedan DeVille (Bessie)

Dan LeBlanc

0-30 ohms is the proper resistance range for the sending unit.  If you're only getting 0-1.5 ohms, the sending unit is fried (likely from the misconnection of the wires).
Dan LeBlanc
1977 Lincoln Continental Town Car

savemy67

More fun with fuel gauge sending unit!

Hello all,

Since my Cadillac restoration budget is very small, I tend to evaluate the opportunity cost of any parts purchase.  My fuel sending unit was malfunctioning.  A replacement costs about $80.  That may not seem like a great deal of money in the grand scheme of things, but I am sure I will run into a situation when that $80 will be better spent on a piece of "unobtainium" for some other part of my car.

I took a second careful look at my fuel sending unit, and did some more testing.  In answer to mgbeda's post about testing the resistor assembly without the metal housing attached, I did test the resistor assembly without the housing attached (picture 3885), and I got near perfect readings on my meter.  The results of this test indicated that when the metal housing is assembled over the resistor assembly (which is plastic), either the housing or how it is positioned caused the resistor assembly to short to ground, thereby providing no resistance value to the gas gauge in the dash (always on E).

With my meter attached I removed and replaced the metal housing over the resistor assembly (picture 3889), and moved the float arm between its empty and full positions.  If the metal housing was located in the position where the small metal tabs that hold it could be bent over to hold the metal housing in place, the resistor would short to ground.  If the metal housing was slightly out of place relative to the small metal tabs, the resistor would work.  I was finally able to determine that when the metal housing was aligned with the small metal tabs, the conductor from the resistor assembly to the sender post was being pushed to the side and making contact with the pick-up tube.  The conductor is a flat piece of copper that is coated with insulating material.  Apparently, at some microscopic level (I cannot see any break in the insulation with my naked eye), the insulation must be broken just enough (electrons are very small after all) to cause the resistor assembly to short to ground.

My fix for this problem was to cut a short length of nylon tubing, slit it, and position it over the conductor so that the conductor is insulated from both the pick-up tube and the vapor return tube (picture 3895).  When I reassembled the parts, and tested with my meter, I got readings of about two ohms with the float arm in the Empty position (picture 3896), and about 91 ohms with the float arm in the Full position (picture 3897).  Dan LeBlanc posted that 0 - 30 ohms is the proper resistance range for the sending unit, but my research (several sources) indicates that in 1965, GM changed the resistance values from 0 - 30 ohms to 0 - 90 ohms.  The 0 - 90 ohms scale was used until the late 1990s when GM changed the scale to 30 - 250 ohms.

Before the sending unit is installed in the tank, I will connect it to the gauge using the wiring at the back of the car, and see if the gauge in the dash works properly.  If so, the sending unit and tank can go back in the car.  My only concern is how flimsy the sending unit seems to be.  When moving the float arm from the Empty to Full positions, there is enough looseness in the float arm to cause the meter readings to jump.  I am hoping that when the sending unit is submerged in the tank, the gas in the tank will stabilize the action of the float arm.

I adjusted the float arm to a little less than the measurement called for in the shop manual.  The manual states the arm should drop 5 1/4 inches.  My drop is at 5 inches.  The effect of this will be that I will have about one gallon of gas left in the tank when the dash gauge is on E.

Christopher Winter

Christopher Winter
1967 Sedan DeVille hardtop

mgbeda

Brilliant detective work, Christopher.  Now you not only have a working sender but a good story to tell.  Well done!

-mB
-Mike Beda
CLC #24610
1976 Sedan DeVille (Bessie)

savemy67

Hello all,

1967 Sedan DeVille, 429, TH400, A/C, 90,000 miles.

Over the past several months I have done many repairs on my car - wheel bearings, brakes, exhaust, power antenna, lighting, distributor, and most recently I repaired the fuel tank sending unit which is now back in the tank, and the tank is back in the car with a working fuel gauge in the dash.  I replaced all the ignition components except the coil, but I am confident that the coil is OK.  My timing is set to factory spec, and my timing light indicates that my mechanical and vacuum advance are working (when I rebuilt my distributor, my lung-powered vacuum pump sensed that the vacuum advance was working but weak, it ultimately failed, so I replaced it).

My car starts immediately, and it idles very well.  When the engine is warm, and the choke is off, the curb idle speed is a little above the factory spec.  Vacuum and oil pressure are steady at about 20 inches of Hg and 30 PSI respectively. Even after I removed and replaced my gas tank, the car started in less than 5 seconds.  This indicates to me that my fuel pump seems to be operating OK.  My car has air conditioning, so it has a fuel return line from the fuel filter bowl to the tank, and the tank is vented.  I believe the fuel pump was replaced by the previous owner, and I know the previous owner had the carburetor rebuilt.  Typically, when I start my car, I let it run at idle for about a half hour or more.  The temperature gauge moves to about the first quarter hash mark and stays there.  When I tested the coolant temperature without a radiator cap, the coolant temperature was about 150 degrees F.

I put my car in a dead-level position and checked the transmission fluid after the engine had warmed up, and after shifting the car through the gears.  The transmission fluid level as indicated by the dipstick was where it should be.  The parking break vacuum release works as it should.  When I put a new exhaust system on the car (from the Y pipe back), I fished a stiff wire up the Y pipe to see if the heat riser was stuck in the closed position.  The wire penetrated the pipe a few inches further than the location of the heat riser, indicating to me that the heat rise, even though it is stuck, is open.

Despite all my good efforts, my car has a problem.  When I drive the car (after it has warmed up in the driveway for a half hour or so) it accelerates smoothly and shifts smoothly through all three forward speeds.  After about 5 to 10 miles of driving, either on neighborhood streets at about 30 to 40 MPH, or on the highway/beltway at 50 to 60 MPH, when I come to a stop-sign or traffic light, the car stalls.  Downshifting is relatively smooth, but when the car has down-shifted to 1st, and as it almost comes to a complete stop, the car bucks - sometimes a little, sometimes a lot.  The bucking reminds me of driving a standard shift car and forgetting to step on the clutch when coming to a stop.  If, before the car comes to a complete stop, I shift into neutral, I can usually keep the car running.

When the car stalls, if I immediately try to start it again, it will either restart and stall, or it wont restart.  If I wait a few minutes (about five), the car will restart but I have to put the car in neutral and keep the RPMs slightly elevated to get going.  This problem has occurred 4 times.  The weather was not particularly hot on the days when the car had this problem (much to my chagrin, one of the 4 times was when I was on my way to a meeting of the CLC Potomac Region).

I have considered that I might have a fuel problem (including the possibility that the carburetor was not correctly rebuilt), and that I might have a torque converter or transmission problem.  I have considered vapor lock, but the fuel lines are in good condition and they are well away from the exhaust, and the car does not get terribly hot.  If anyone has any thoughts about my predicament, I would appreciate hearing from you.

During the upcoming Winter, if there are a few mild days, I am considering rebuilding several of the car's components including: alternator, starter, power steering pump, steering gear box, exhaust heat riser, and maybe the carburetor and transmission if these last two components are indicted as the possible cause of my stalling issue.  I may post this message as a separate thread in the Technical/Authenticity portion of the forum in the hope of getting more viewers and responses.  Thanks for reading.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

I want my car to be as mechanically sound as I can make it.  One task yet to do is the repair/replacement of the heat riser valve located between the passenger side exhaust manifold, and the exhaust Y-pipe.  I have replaced the entire exhaust from the Y-pipe back.  I did not replace the Y-pipe because it appears to be in good condition without any holes (there were several holes in the rest of the exhaust system).  When I replaced the exhaust system from the Y-pipe back, I fished a long, stiff wire up through the Y-pipe towards the heat riser valve.  The wire penetrated the Y-pipe several inches beyond the location of the heat riser valve, so I concluded the heat riser valve is open even though it does not move.  However, when I was doing this work, I noticed that the heat riser valve is cracked along the side of the stud that goes through the heat riser valve, on the side close to the engine block (photo 3919).

When the car is running, and I have my head under the hood, I notice a slight ticking sound.  This sound could be valve train noise, or it could be a small exhaust leak.  I want to eliminate the cracked heat riser as a possible source of noise.  This should be a simple task - undo the nuts holding the Y-pipe flange to the heat riser/exhaust manifold, remove the Y-pipe, remove and replace the heat riser.  As most of you know, this is easier said than done.

Photo 3922 shows the nut at the driver side exhaust manifold/Y-pipe flange.  The flats on the nut are very distinct, and it looks like I should be able to remove the nuts (on this side of the car they are both in the same condition) with some penetrating fluid, some patience, and a good breakfast.  Photo 3914 shows the nut on the passenger side of the car - the side on which the heat riser is located.  Notice the lack of definition of the nut.  I think Euclid would call this shape a circle instead of a hexagon.

Aside from penetrating oil, plan A is to try to find a special deep socket designed for removing rounded nuts.  Plan B is to grind or cut off the stud as close to the nut as possible, and drill out the stud.  Both actions will be difficult.  The nut is recessed in the flange and space is limited.  Also, one nut is on the other side of the pipe making it more difficult to get tools into the space.  Plan C is to disconnect the Y-pipe from the resonator, unbolt the exhaust manifolds from the cylinder heads, remove the starter (which I was planning to do anyway), and with the car high enough off the ground, see if I can maneuver the Y-pipe with the exhaust manifolds attached back and down and out from under the car.  Plan D is to cut the Y-pipe near the exhaust manifolds, and spend about $100 for a new Y-pipe.

Once I have the heat riser in hand, I will see if I can locate a local welding shop that welds cast iron.  If the heat riser - I will remove the valve - can be repaired for less than the cost of replacement, that is what I will do.  I recall reading on this forum about someone who fabricated and sold a spacer to replace the heat riser valve, but I also recall that the individual is no longer providing this service, and I do not remember if the spacer was available for a '67.  Knowing that I may need to repair or replace the heat riser, or find or fabricate a spacer, I am hoping not to also have to spend money for a new Y-pipe.  If anyone can shed some light on how they removed their heat riser, I would enjoy reading your reply.  If anyone has a source for a replacement heat riser or spacer that is in stock (other than eBay), please let me know.  Thanks.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop