Author Topic: 1968 DeVille Convertible - Restoration  (Read 17368 times)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #140 on: March 27, 2017, 02:56:36 PM »
Hello guys

Not too much progress in the last weeks but I managed to completely wet sand, puff and wax the car. It now looks way better.
But unfortunately I now know every rust bubble and imperfection! And there are a lot of tiny imperfections. Damn...some day I might need to repaint the car...but that shall wait another 5 years!

So, otherwise I completed the restoration of my vacuum system. It is all fixed and leak free. Exept for the power brake booster.
I did put the A/C dash control back into the dash and startet the calibration as outlined in Tim's manual.

But something I must do wrong.
I says to disconnect the dash interior temperature sensor. Then to jump the yellow to green wire on the amplifier connector with a 150 ohm resistor. Then the voltage to the transducer (black and white wire) should be about 6V

Well, I measure 12.9 V!! (to ground)
The yellow wire (power supply) has about 12.97 - 13 V.   (to ground, that is batterie voltage)

When I measure the resistance on the amplifier I measure (between the two terminals) I get about 160ohms (ignition off) but I measure about 650 ohms when the ignition is on.

When I plug all the sensors back in I measure about 180 ohms. But still the voltage is way off. (around 12 V)

So then you should be able to hold the potentiometer with a screw driver and move the temperature dial until you get 6V. Well I can set the dial completely to max (with no travel on the potentiometer left) or to full cold. And the voltage at the transducer only varies by about 0.4V, still being around 12V.

I must be doing something wrong?
Any ideas?
Should I remove the A/C Dash unit again and test it on the bench? How could I do that?

Thanks!
Best regards,
Nicolas
« Last Edit: March 28, 2017, 02:54:13 PM by DeVille68 »
1968 Cadillac DeVille Convertible (silver pine green)

Offline 6262

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Re: 1968 DeVille Convertible - Restoration
« Reply #141 on: March 29, 2017, 07:00:01 AM »
Nicolas, is there no woodgrain on your dash? Is this standard for the De Ville convertible?
« Last Edit: March 29, 2017, 07:03:09 AM by 6262 »

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #142 on: March 29, 2017, 08:32:26 AM »
Nicolas, is there no woodgrain on your dash? Is this standard for the De Ville convertible?

Hi, no a DeVille Convertible has real rosewood veneer as standard (because it has leather as standard).

But, mine was cracked and in bad shape, hence I sanded the wood and sprayed new clear coat on it.
Refer to
post http://forums.cadillaclasalleclub.org/index.php?topic=130360.msg334363#msg334363
so see the restored wood veneer.


The Calais only had cloth inserts and a brushed aluminum instrument panel insert. (I think it is aluminum?)
The standard DeVille (closed car) had no wood when outfitted with cloth.
If the optional leather was ordered, then it would also receive the rosewood veneer on the doors and in the instrument panel.

--> Detailed information can be found in the data book of this year (available on the gm heritage website).

Best regards,
Nicolas
1968 Cadillac DeVille Convertible (silver pine green)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #143 on: March 29, 2017, 02:04:28 PM »
I refer again to my post about the A/C amplifier board.

So suddenly, I realized that my problem of measuring about 12V at the transducer wire (black and white) could be of a miss calibrated vent switch. I checked that the switch only sends 12V in vent or off position and sends 12V to the violet wire (which then goes the compressor clutch) only when the lever is in lo, auto, hi, fog, ice position. Also the lever should be in the auto modus for making this temperature dial adjusment.

So, the switches on the unit are not my problem. I even disconnected them - no difference at all.

What is strange is, that when I measure the resistance of the potentiometer of the temperature dial I measure reasonable values when the ignition if of.
I measure between 100 ohm and 850 ohm.

But as soon as I switch on the ignition I measure -200ohm or open loop. Very strange. I do not understand this.

How can I measure and verify the amplifier on the bench?


Best regards,
Nicolas
1968 Cadillac DeVille Convertible (silver pine green)

Offline 6262

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Re: 1968 DeVille Convertible - Restoration
« Reply #144 on: March 30, 2017, 12:11:43 PM »
Hi, no a DeVille Convertible has real rosewood veneer as standard (because it has leather as standard).

But, mine was cracked and in bad shape, hence I sanded the wood and sprayed new clear coat on it.
Refer to
post http://forums.cadillaclasalleclub.org/index.php?topic=130360.msg334363#msg334363
so see the restored wood veneer.


The Calais only had cloth inserts and a brushed aluminum instrument panel insert. (I think it is aluminum?)
The standard DeVille (closed car) had no wood when outfitted with cloth.
If the optional leather was ordered, then it would also receive the rosewood veneer on the doors and in the instrument panel.

--> Detailed information can be found in the data book of this year (available on the gm heritage website).

Best regards,
Nicolas

Nicolas, thanks for the extensive answer. I have been following your thread from the beginning and know about your efforts on the wood veneer. It was the attached picture which got me thinking. I did not recognize that it was taken before the re-application of the veneer. Therefore I assumed you had left it out with good reason.


Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #145 on: April 01, 2017, 02:09:51 AM »
Hi Nils

Ah, oke. Very good. Thanks for reading my thread. I hope it helps others with the same restoration jobs. Or that it is just interesting to read. I myself read other restoration blog too, just because I think it is interesting.
I will add some more content over the next few weeks.

Best regards,
Nicolas
1968 Cadillac DeVille Convertible (silver pine green)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #146 on: April 09, 2017, 08:43:23 AM »
So my mistake was that I did not check for proper ground at the transducer. There is a insulation material with a quite big "bulge" with some more insulation material stuffed in it.

I accidentally but some screws in for mounting the transducer and I wanted to just mount it loosely to be able to calibrate it.
Well by putting it in loosely I accidentally screwed into the insulation material making no ground connection of course.

So, what I measured with my multimeter was basically the voltage drop across the multimeter itself. Since it has very high ohm a very very small current was flowing giving almost no voltage drop.

I then mounted the transducer correctly and now the amplifier along with all the sensors and temperature dial works perfectly.


One last issue that I have is with my rebuild vacuum valve. It lets a small amount of vacuum by in the vent position. Somehow the planes are still not perfectly flat. When holding the valve against a light source I can see a little light coming through, but only on the perimeter. Hope I can sand the valve half some more...
1968 Cadillac DeVille Convertible (silver pine green)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #147 on: May 11, 2017, 03:02:54 PM »
A little update:
- Since I grounded the transducer the mixing of heat and cold worked fine. I adjusted the voltage at the transducer according to Tim's manual.
- However, the blower would only work in A/C mode. (dial turned to 60)
- The reason was the power servo on the firewall. I had to resurface the valve again. I did this before but apparently not good enough. This time I used a 5000er grid wet sand paper and a piece of glass such that I had an absolute flat surface. I checked the surface of the valve halfs against the light using a straight edge.
- After that I replaced the rubber insulation around the base of the power servo.
- Now everything seems to be vacuum tight.

- To be able to test the system without running the engine (ignition not yet reinstalled) I used an external vacuum pump. However the blower would still only work in A/C mode. Until I realized that the heat sensitive valve in the heater valve is still open thinking that the engine water was still cold, and hence not allowing the vacuum blower switch to close. So I heated the valve a bit with my heat gun and voila everything works now. All flaps and all blower settings.



Since I already removed the dash, radio and ducting I decided to replace the insulation on the dash and firewall. I also glued new rubber around the A/C outlets on the ducting. Here are some pictures.

The last picture shows the new insulation. It is a special glass fiber material with an aluminum foil on one side. I did glue two or three sheets together. 
1968 Cadillac DeVille Convertible (silver pine green)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #148 on: May 11, 2017, 03:07:42 PM »
Found some factory markings!

1) On the passenger floor pan under the carpet under the dash - there is a large yellow "A"

2) On the insulation of the firewall under the dash. There is rubber molded piece that holds a pocket of insulation material against the firewall. On its side there is a large yellow "29"

1968 Cadillac DeVille Convertible (silver pine green)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #149 on: June 21, 2017, 02:17:54 PM »
wow, how time goes by!  Haven't posted any progress in a while.

Since May I have finished the A/C restoration, the car drives again. Had to repair the kick down switch (I will write something later about this). Had the repair the heat riser valve. The replacement unit is well made but something with the spring rate or weight does not match. Have to make some adjustments.

I also studied and totally rebuild the ignition system, new plugs, new wires, new condensers all around.
An advice to all: change your condensers! I have measured them using a proper capacity measurement device and they were only about 10%-15% lower than the rated capacity, but now with new ones (about 5% higher) I have a totally clear radio signal!

One question about the ignition system:
I have a later model HEI ignition system (do not know from which year)
But it seems that the centrifugal advance does not advance far enough.

The information in the show manual tells me that at 2000 rpm I need between 29 and 33 degree of advance at the crank.
The vacuum needs to be 0 at 8'' and between 22.60 and 25.20 at 14'' vacuum. (in degree of crank)

My vacuum advance canister seems to be correct, but my centrifugal advance only gives me about 23 at 2000rpm (with 10 of base timing)
So, with the factory recommended 5 of base timing the centrifugal would only add about 18 of crank degree instead of about 25.

I have attached pictures of my centrifugal advance. The weights are labeled 130, the center plate 370 and the base plate 128

Can anyone help?
« Last Edit: June 21, 2017, 02:19:36 PM by DeVille68 »
1968 Cadillac DeVille Convertible (silver pine green)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #150 on: July 02, 2017, 02:37:37 PM »
Can anyone provide some pictures or inside regarding the weights and springs for a 68 distributor?

Should I buy some generic HEI weight kit?
1968 Cadillac DeVille Convertible (silver pine green)

Offline cadmium

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Re: 1968 DeVille Convertible - Restoration
« Reply #151 on: July 08, 2017, 10:15:08 PM »
Hello.  Brief intro - I used to hang out here a long time ago but haven't been here for years.  I couldn't remember my user name so I have a new one.

By the time the HEI came out, the spark advance curves were quite a bit different than what your '68 had.  You can start with the stock curve in the HEI and see how it works for you.  Have you tested the distributor and verified that the centrifugal advance tops out at 2000 rpms?  If it does, then set the distributor so that you have 32 of centrifugal spark advance (just for a place to start) at that rpm with the vacuum advance unit disconnected.  Let the initial advance fall where it may.  It's not that important and should really only be used to set the timing when you know where the total spark advance tops out.  Drive the car a little bit with the vacuum advance unit disconnected and see if you have any pinging under various rpms and engine loads.  If you do, then retard the timing 2 at a time until it goes away.  If you don't have any pinging, you might try advancing it 2 at a time until you hear it, then back it off 2.  That will be how much maximum centrifugal advance you want.  If this gives so much initial advance that the engine starts hard then you may need to get a weight and spring kit and design a curve with more range to it so that you have less initial advance while leaving the maximum where it is, but start with the stock curve and see how it works out.

Now connect the vacuum advance unit and see what happens.  The specs on your unit look like a good place to start.  If you have pinging under a moderate load that then goes away under full throttle, then you probably need to get an aftermarket vacuum advance unit that is adjustable.  You want the most advance it can give you under a light load but you want it to start taking out what it adds in pretty quickly under moderate throttle load.  By about 10" of manifold vacuum the vacuum advance should be all gone.  Also, I recommend not using the temperature controlled vacuum switch for the vacuum advance, but instead run the vacuum advance unit directly to a source of manifold vacuum.  In stock form there should be a vacuum line coming from a port on the back side of the carburetor and going to the temperature controlled vacuum switch.  Simply pull that line from the vacuum switch and connect it directly to the vacuum advance on the distributor.

Give this a try, see what happens, and go from there.

On another note, you may be interested to know that I have two '68s, a Coupe deVille in Silverpine Green with a black vinyl top and dark green cloth interior, and also a Deville Convertible in Grecian White with white top and red leather interior.  The coupe was purchased by my father in '73 and I purchased it from him in '87.  That car has been in my life for 44 years and I can never sell it.  I purchased the convertible in '91.  Both cars run and drive fine but are patiently awaiting new paint.  To see your particular car which is kind of a combination of my two is very interesting.
« Last Edit: July 08, 2017, 10:31:08 PM by cadmium »
1968 Coupe deVille
1968 DeVille Convertible

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #152 on: July 11, 2017, 02:00:53 PM »
Hi Lynn

Thanks for your suggestions! I have not yet tried to drive without the vacuum advance. I have added about 5 of initial timing. Maybe need even more. I have created an excel sheet that displays the timing for speed and vacuum. Unfortunately the forum does not allow it to be uploaded. I will buy an advance curve kit and start modifying.

Send me some pictures of your two 68s!

Best regards,
Nicolas
1968 Cadillac DeVille Convertible (silver pine green)

Offline DeVille68

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Re: 1968 DeVille Convertible - Restoration
« Reply #153 on: July 11, 2017, 02:37:43 PM »
Hi guys

You won't believe what just happened!

Past Sunday I was on the drive back from looking at an 80 Eldorado Biarritz (check out the thread here http://forums.cadillaclasalleclub.org/index.php?topic=145873.0). After an highway junction I again stepped on the gas and heard knockings from hell.
I immediately hit the brakes and left with squeaking tire sounds the last possible exit ramp! At slow speeds the knocking also stopped, so I carefully nursed the car the next 10 miles home. I could hear it knocking while accelerating.
At home I checked under the hood but I could not find anything wrong on the outside but heard a loud knocking coming from the back and down low of the engine. My immediate guess was a connecting rod knocking.

Luckily I already had taken Monday off of work and had an appointment with my mechanic to finally try to find my vibration problem. In the morning I drove the few miles over to him and we we able to locate the knocking from under the car (car on lift) with an stethoscope.
We were sure that one of the rear connecting rods must had come loose or some similar damage.

While doing the listening I noticed that the rear passenger side wheel was wobbling real bad --> So I had finally found my vibration problem!
We removed the wheel and brake drum and the drive axle would still wobble! I must have damaged this drive axle two years ago when I blew a tire on that exact side! I was chasing tire balancing problems since then!

So as always in life there is good and bad very close together. I have found my vibration issue but ended up with an damaged engine! :-D
And I have learned a ton in just a few weeks about 80's Cadillacs - unfortunately, I know have to spend my money on the engine rebuild.


So then I figured let's just pull the pan and see! I removed the pan (steering linkage, exhaust, starter and transmission cover) and removed all connecting rod bearings and sure enough Nr. 8 had a problem: it had spun the bearings!


Here are some pictures!
Pic 1: this is one of the pieces I found in the oil! There are some more trapped in the filter of the oil pump pick up!

Pic 2: Engine from below. I think it looks real good. No dirt or other damage.

Pic 3: Check out the bearings of the connection rod nr. 8 The surface is very bad and maybe seized too. The bearings seem to have been replaced once before, they are 0.010'' over.

Pic 4: This is the Nr 7 & 8 crank journal. The surface is quite bad. You can feel the grooves with your finger.

Pic 5: This is the Nr 3 & 4 crank journal - for comparing how a good surface may look like.



Now I have a lot of questions for you :-)
  • I will have to pull the engine or the transmission to remove the crank. Which is easier?
  • I found that 500cid.com sells bearings up to 0.030'' over. When I buy the bearings I do need to temper the journals?
  • Or should I buy a new crank. Who sells good cranks?
  • When i remove the crank do I have to replace the crank bearings too? Or just measure with Pastigauge and then decide?
  • Any other suggestions or inputs? Have you done this before? Where should I be especially careful?
1968 Cadillac DeVille Convertible (silver pine green)

Offline The Tassie Devil(le)

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Re: 1968 DeVille Convertible - Restoration
« Reply #154 on: July 11, 2017, 07:41:15 PM »
You are one lucky fellow.   Could have been worse.

Now, The engine will have to come out, and be stripped down completely.   There is no getting over this.

The Crankshaft will need machining, and don't purchase any bearings until you have been advised by the machine shop as to the condition of the crank, as in straightness, and what amount of machining will be required to bring the journals to perfection.   You might only need .020 undersize bearings.   One of the problems with spun bearings is that there is always the possibility that the crankshaft is damaged more than a simply bearing replacement, and in many cases, the shaft is cracked, so that needs to be checked as well.

Plus, the Connecting rod that suffered the spun bearing will need to be re-sized, so the piston will have to be removed, which means removing the head and therefore, I would recommend all rods being re-sized.

You will end up replacing the big end bearings, and the mains, as this much damage as shown in the pictures will have come from grit that has passed through the main bearings before getting to the big ends.

Plus, when you pull the pistons out, you might be surprised at the condition of the bores, and the wear, because the oil that contained the grit that caused the journal damage has been scraped up and down the bores by the cylinders.

Bruce. >:D
« Last Edit: July 11, 2017, 07:49:33 PM by The Tassie Devil(le) »
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Offline cadmium

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Re: 1968 DeVille Convertible - Restoration
« Reply #155 on: July 13, 2017, 06:39:28 PM »
Wow, what a rotten bit of luck.  Sorry to hear of your catastrophe.  Yeah, the engine will have to be pulled and completely gone through.  You don't want any debris left setting in oil passages anywhere.

I would let your machine shop inspect the crankshaft and tell you whether it can be reused or not and how much the journals will have to be turned down.

When you have the engine completely apart, one good thing to do is drill a " hole through the lifter valley at the back of the engine.  That will prevent the lifter galley being half full of oil and sludge that never gets changed because it doesn't drain out and reduce it to a small puddle at the very back of the block.  I think in later blocks the valley was opened up more for this reason, but in the earlier blocks it's a good thing to drill the hole, and the only time that can be done is if the engine is completely apart.

I've rebuilt a couple of these engines and can help you out with any other questions.  Good luck with your rebuild.

Here are some old pictures of the cars.  The convertible is still in 75% original paint.  The paint on the coupe is so oxidized that it's not a good representation of the color.  Both cars need fresh paint now and are waiting very patiently.
1968 Coupe deVille
1968 DeVille Convertible

Offline nolacaddy1960

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Re: 1968 DeVille Convertible - Restoration
« Reply #156 on: July 13, 2017, 10:33:14 PM »
Those are the best tips.  When someone knows a hack to get more oil going.
    Sadly like others have said, to do this right, you have to pull engine and likely that affected piston at minimum to do it right.     Sure you could get by with minimum parts but when you have a serious issue like this, the total repair is the better option.   You never want a repeat issue.
   
   

Offline Jeepers Creepers

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Re: 1968 DeVille Convertible - Restoration
« Reply #157 on: July 16, 2017, 03:46:32 PM »
Yep, Bruce is on the money.

Engine out and a full once over. :'(
Kevin and Astrid Campbell
Tin Can Bay,
Australia
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64 Fleetwood.

Offline 2manycars

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Re: 1968 DeVille Convertible - Restoration
« Reply #158 on: July 16, 2017, 06:11:36 PM »
Yep, another vote for full rebuild. Years ago I spun the front most rod bearing in my 67 Camaro (327). Debris went *everywhere*. The machinist just kept finding problems. Everything got redone. The crank and that one rod had to be replaced, in addition to everything else that was done. Fully balanced while I was at it. It's been good ever since.
1964 Coupe de Ville
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1957 Ford Thunderbird
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Offline savemy67

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Re: 1968 DeVille Convertible - Restoration
« Reply #159 on: July 16, 2017, 08:54:13 PM »
Hello Nicolas,

So sorry to hear of your mis-fortune.  I agree with the other posters who suggest rebuilding your engine.  If you do not have the measuring tools needed to determine the dimensions of the rod and main crank journals, cylinder bores, cam journals, etc., I hope you can find an excellent machine shop that has the staff and equipment to rebuild your engine.  You (and the shop) may never determine what caused the bearing to spin, so you may want to consider the rebuild with that in mind.  Ask if your shop can straighten cranks, and do align-honing.  Also ask what equipment does the shop have for re-sizing the crank end of the rods, and how they examine the block to make sure it is rebuildable.  You need to be confident that the shop knows how to look at your rebuild holistically.

This task will be relatively expensive, but if done correctly, you will never have to worry about the engine in your lifetime.  Good luck.

Respectfully submitted,
Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop