1974 Coupe deville questions

Started by Ville, June 30, 2015, 06:12:09 AM

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TJ Hopland

There are still several places around the USA that repair automotive clocks.   I just sent one in.   Repair and restoration seems to run in the $100-250 range.   Quartz conversion when possible $150-250 range.    One thing I did learn is Borg was the most common manufacturer, tended to be the most reliable, and the one with the most parts still available.   Also the one with almost drop in quarts movements available.   Look at the back if it says Borg you should be good.  Any other manufacturer you will have to contact one of the repair places and see what they say.  I guess the Borg movements often interchange between years and models so chances are really good about fixing one.   Other manufactures apparently not so much the same.   

Other than being generally gummed up and un able to move the next most common issue is the coils being burnt up.  Coils burn up from a combination of having to work hard from being gummed up and low voltage (battery going dead from sitting).   The shops can re wind most of the coils for extra cost of course but at least its usually possible. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Ville

Thanks for info! Maybe i just buy one gor spare parts and try do one working one :)


How much headers and/or double exhaust will ad hp/lb ft to stock 472cid?
CDV 1974

35-709

"How much headers and/or double exhaust will ad hp/lb ft to stock 472cid?"

That alone?  Not enough to make any apparent difference except to your pocketbook.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Ville

Yeah alone that was the word.


Ive heard that many oldsmobile engine has poor exhaust manifolds and headers can give 20hp more but cadillac design is okay in stock?
CDV 1974

TJ Hopland

I too would stay in a 74 you are not going to see a big change.   75 you would / could due to the way they did the crossover and early cat but in the pre cat days the stock systems were not that bad.   If you start talking about a different cam and other internal changes then you would want to do some exhaust work but if all else is stock its not likely worth the trouble. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

35-709

Quote from: Ville on July 29, 2015, 04:54:35 AM
Yeah alone that was the word.


Ive heard that many oldsmobile engine has poor exhaust manifolds and headers can give 20hp more but cadillac design is okay in stock?
You would be hard-pressed to notice 20 extra horsepower except at the drag strip --- maybe.  Also, horsepower and fuel consumption tend to go hand in hand.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Ville

Okay so let it be. I got shop manual tomorrow if all wents fine so i can see wirings then.
CDV 1974

Ville

Help.

I cut muffler off because I started exhaust job.

Now exhaust backfiring is better to heard.

Carb is adjusted like shop manual says and ignition timing too.

Every time when I lift foot off the pedal it bangs.


I tried to use more timing, 14deg too but it helped only for engine hesitating on idle. Hesitate wasn't big at all so its not problem.


Loose timing chain was on my mind but more advance would help if its retarded couple degs?


And.. Biggest problem. When engine is hot and I stop the car. About. 20-30seconds and upper radiator hose (intake side) makes noise, like water boils. What is that? More advance didn't help or long idle before shutoff either.
CDV 1974

Ville

Radiator and hoses are pretty new, flushed today and no rust or anything so water flows well i think.
CDV 1974

TJ Hopland

Is the cooling system building pressure like it should?

If you have half the exhaust system missing it will be normal to get a little popping in the exhaust on deceleration but it should not so loud that people are running for cover. 

Does this car have a AIR (called a smog pump in the USA)?  Its a belt driven pump below the alternator that has a hose that wraps around the alternator that connects to a crossover tube between the heads.   If that system is not working properly it will make significant pops in the exhaust.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Ville

#50
Air pump is and it has belt on so it works but i dont know will it work perfectly? How i can see that?


Radiator cap is 16, not so old. I dont know about pressure but coolant reservoir works so it brings there coolant when engine gets warm. Just normal cold to hot you know.


Hot start is also little bit bad and it puffs black smoke when starts and i dont even press pedal to the floor.


But that boiling thing is bad and nasty.

I put coolant temp gauge on tomorrow but it wont fix the problem.
CDV 1974

TJ Hopland

The failure in the AIR system that causes the popping is the diverter valve not working.   I don't remember the details but what is supposed to happen is when you take your foot off the gas the valve operates and for a period of time it diverts the air flow from the pump out a muffler on the valve instead of into the heads.   Most of the time it is pumping air into the heads.  This is done to allow the burning to complete in the exhaust system and lower emissions.   Problem is when you take your foot off the gas the mixture goes very rich and with the extra air added from the pump it really burns.  The fix for that was the valve to temporally divert the air during that deceleration condition. 

When my 73 started doing that real bad I just pulled the hose off that went between the pump / valve and the crossover on the heads.  Removing the system really does not seem to hurt anything on the pre cat converter cars.   With the hose removed there should be no exhaust leak from the crossover.  If there is the check valve is bad and likely what killed the valve and is hard on the pump too. 

Can you get one of those non contact thermometers?    Those are really handy to troubleshoot cooling system issues.   My test procedure is to start with the engine dead cold.   Take the cap off and check the level then re install it.    Squeeze the upper hose to get a feel for what its like with no pressure.  If you are not used to grabbing hot things maybe do this with a glove so later when its hot you will still be used to the feel.  Start the engine and keep feeling the upper hose for pressure.  You should not feel any pressure till things start to really heat up.   If you feel pressure right away you have to suspect a problem like a head gasket which has a different set of tests.   The pressure should start to build as the temp comes up.   With the gun take readings at several locations like the upper hose and the front of the engine around the thermostat.    You should see the temp around the stat start to come up but the upper hose should remain fairly close to ambient till the stat begins to open.   Assuming a stock stat this should be around 190 F.  If the upper hose starts heating at about the same rate as the front of the engine the stat is stuck open or missing.    The stat should be fully open around 200 F and at that point the upper hose should be in that same 200 F range.   It should also be fairly firm at this point but remember its will also be 200 F so this is where the glove may be required.    At idle it should sit around 200 F pretty much all day long.   If it keeps climbing let us know and we can give you more things to check.   If the upper hose is still soft at that point you have a leak somewhere that is not letting the pressure come up which may not be a problem under some conditions but when you shut it down the normal heat soak could push the temps up over the boiling point.  The pressure is the primary thing that raises the boiling point from the 212 F range to more in the 250 range.  With the engine's normal temp around 200 that does not leave you much margin without the pressure.       
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Ville

Thank you! I dont have gun :( Tomorrow when sealant is dry i start engine.
CDV 1974

Ville

Thermostat was ok, i found similar gates in my garage, hah lucky. Its cadillac oe style i checked that.


That brass pipe in radiator where is attached coolant reservoir hose is loose. It drops and now i cant get it tight enought. Any ideas? If i wider it it wont go in the hole.
CDV 1974

Ville

Well, i got the infragun. It gives 140deg on mechanical gauge and upper radiator hose, intake side. Radiatior side couple degs less. Heater hoses give 160. That one which goes to block is couple degs hotter but no big difference.


So the burbing can't be boiling water. It buts air and water in coolant reservoir after shutdown.


But why its not heating? I tested thermostat before installation and it was ok.
CDV 1974

Ville

Sorryn it seems to suck at the reservoir after shutdown.
CDV 1974

TJ Hopland

160 F is too cool but at least should not be boiling even on a hot shut down.   Its not a common issue with these engines but you have to wonder about a possible head gasket issue.  Does it seem to be building and holding pressure?  How quickly does it build?   

What happens when the engine is running with a crack or gasket issue is the compression pressures push air in to the cooling system.   The air causes hot spots which could cause boiling in places even though the overall temp may not be that high.  If and when the bubbles get to the water pump they can cause the flow to stall which then also causes localized hot spots and boiling. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Ville

#57
Upper hose is not stiff,  maybe little loose i think. Ive checked cylinder pressure whit test and coolant wont smell bad etc oil is good. Cap seems working because if i press upper hose, it gives coolant to reservoir.

It just burbs about 20-40s after shutdown but no hot point even then. Inside air is about 135deg on foot when its full hot and def.
CDV 1974

Ville

#58
And gauges needle is stable when it gets 140deg.

Vacuum gauge readings also straight, no wobbling etc so nothing seems not head gasket hopefully?


Heater hose vacuum port is converted to hand switch.

When switch was open and radiator cap open, it gives lots of coolant in radiator. Switch off and it stops. Normal? Engine was just started. I didn't try that in hot engine.
CDV 1974

Ville

Now check radiator level after fully cooled engine. About two inches from cap. So its not so empty that can cause poor heat? I but water on garden hose so i dont know how much it went. I dried system before this job.


CDV 1974