1947 cadillac

[Larry Moss]

OK, still searching for an answer - have a lot of suggestions, but still problem is unresolved. My 47 Series 62 is losing oil. It doesn't seem to drip, and doesn't blow smoke. However, I noticed that when I start the car, black soot comes out of the exhuast. In fact, after backing the car out of the garage, I stopped to check the oil. When I restarted, there was a streak of black on my grass just below the exhuast. The engine was rebuilt around 2500 miles ago. I've had it checked by our local mechanics and they can't find any major leaks. So, where do you think the oil is going? I've traveled about 150 miles since then, and I'm down a quart. Any ideas?

[Guest]

Hi Larry:

All that oil HAS to be going somewhere ! If you are SURE it is not leaking, there remains two areas I suggest you re-check.

First - the fuel pump. Small hard-to-find leaks in the fuel pump diaphram have frustrated a lot of us down thru the years, trying to find what is causing excess oil consumption. I went thru THREE diaphrams once before I got one that didn't suck oil up from the crank-case. Have you thought of rigging up a electric fuel pump as a temporary "cross check", removing and blocking off all passages your engine driven pump was connected to ?

Secondly - the engine. To put it delicately, I am not overwhelmed with confidence with the typical "engine restorer" these days.....I suggest to all automotive hobbyists they invest (figure about a hundred bucks) in a DIFFERENTIAL COMPRESSION GUAGE. This is what we use in aviation to isolate cylinder problems. The DIFFERENTIAL COMPRESSION GUAGE enables you to blow "shop air" into your cylinders, one at a time, with two pressure guages so you can measure the rate of drop-off. Many times you can actually hear the escaping air (this is a much better way of finding cyl. problems than the ordinary simple "air pressure type" automotive compression guage).

I would NOT be surprised if someone either broke a ring as the engine was being assembled, or put an oil ring in upside down.

Keep plugging away at it - assuming you are using any dard ASTM/SAE approved "meets all maker's requirements" motor oil, you should see oil consumption of not more than 500-750 per qt.

Good luck

Pete Hartmann

[Larry Moss]

Appreciate your post Peter. I did have an electric fuel pump added - a toggle switch that I use when I start the car. Should I just run the electric all of the time? Also, what kind of oil should I use - 30wt etc. I have heard others suggest the fuel pump, but I thought that adding an electric would by pass that, but now I wonder if the electric was just added or is the main pump?

Thanks again,

Larry

[Guest]

Hi Again, Larry:

First and foremost, whenever you have gasoline running around, you have DANGER...treat it as about the most dangerous substance we as ordinary people are likely to be exposed to.

To isolate the problem of your excessive oil consumption..and either confirm or eliminate the possibility that a bad fuel pump is in some way allowing engine crank-case oil to be sucked up thru the fuel pump body, into the intake manifold, I suggest you REMOVE the engine-driven fuel pump completely from the car ( you may note I suggested "plugging" all passages, etc. so you dont have oil and/or gasoline spilling all over the place).

Again, may I suggest a DIFFERENTIAL COMPRESSION GUAGE ? This is about the best engine diagnostic tool you can get. With it, you can usually HEAR with your own ears WHERE there may be excess leakage in the engine.

Should you find that you are still having excess oil consumption with the mechanical fuel pump completely off the car, and even if you do NOT hear excess air leakage when using a DIFFERENTIAL COMPRESSION GUAGE, at that point I would suggest pulling the engine down and giving the ring set-up a look see.

The flat head Cad. is typical of American engines of that era, in that it is easily dis-assembled by the average hobbyist using ordinary shop tools. Read up on what is involved in PROPERLY dis-assembling and RE assembling a motor, and have a friend who is familiar with common automotive shop practice, and you will find it a tremendous learning experience.

Piston rings are relatively inexpensive - you should be able to re-ring the car for around a hundred bucks. Yes...yes..I know..I know...you arent happy about the idea of pulling apart an engine you were told was recently "re built".

But..you see...that's the trouble...I do not know the competency level of the people who actually put your motor together..and..as I noted previously..I do have my prejudices....!

Here's the problem - rings have to "seat in". It is more than likely the cylinder bore wasn't "honed" properly, or a ring was put in up-side down (or broken).....an OIL ring is the most likely culprit, and if the COMPRESSION rings are O.K....that would account for good compression on a "leak down" test even WITH a DIFFERENTIAL COMPRESSION GUAGE.....but still result in excess oil consumption.

I would suspect that if you are in or near a city of any size at all, you will find either thru this web site and/or the Cad. La Salle Club, some fellow car hobbyist with shop training who would be more than happy to give you a hand and some pointers - obviously....while this is a great "medium" for the exchange of ideas...there are limits to what we can do over the Internet. Don't be bashful - ask questions - that is what this "site" is for.

Keep us posted !

Pete Hartmann

If, after a few hundred miles of driving, you STILL have high oil consumption, at that point, I

[Restorer32]

Pierre = Pete Hartmann ?

[Guest]

Hi, Restorer:

Yes, my own personal preference is that we all sign our real names to our posts. I think this is helpful in a number of ways. Obviously, there may be isolated cases where legimate concerns might suggest some kind of secrecy, and I respect that.

As a side-note, in terms of mis-behavior, it dosnt matter whether you sign your name or not to a "post". Those who use vulgar, abusive, or "hate-speech" type of language can easily be dealt with, because EVERY "post", whether signed or not, carries in it, the identity of the sender. There are mechanisms to permanently cut off such abuses, by simply sending a copy of the abusive "post" to the ISP provider. So I think we can be fairly confident REAL LEGITIMATE abuses of good taste and proper decorum would be quickly and severely dealt with.

Now, let's get back to what we are all here for - the exchange of information on how we can enjoy our old car hobby.

Pete Hartmann

[Constellation]

Perfidious Pierre,

You just may have stumbled on to the problem with this 47 Caddy in what you are saying about the fuel pump diaphram. However, being a Packard Man, I also have my prejudices.

There is one thing that I would try with this 47 Caddy. This is an old trick. I did this with my Brothers '53 Packard Clipper which only has 42,000 original miles and was burning oil and was leaving black streaks at the exhaust as well.

Pour a large can of Mystery Oil in the crank case with the oil thats there but do not overfill it and put a can also in the gas. Take that 47 Caddy out on the Interstate and run it hard at 75 MPH for about 100 miles or so. This will help re-seat the rings. This car could very well have some stuck oil rings if it sat idle to long even though the engine was rebuilt. This also will blow the large deposits of carbon out of it also. Change the Oil and Filter and then put some more Mystery Oil in at that time too, it will not hurt it.

That '53 Packard is running fine now with only minimal oil consumption. For the record, this car was so bad that the Man my Brother bought it off of, sold it cheap to him because he thought that the Engine needed to be rebuilt. It even came with all the new rings, bearings and gaskets for a rebuild.

Bob

P.S. Glad to have you back. We all know that Pierre Hartmann is Peter's, French Cousin from Alsace.

[Guest]

Hi, Constellation:

I did not think of a "stuck ring". Of COURSE a "stuck ring" could produce exactly the kind of problem this fellow raises with his '47 Cad.

I should have thought to ask him what kind of oil he has been using. It is certainly possible that if he used a "non detergent" (translation - oil that meets NO accepted standard, and SHOULD NOT BE USED on anything but the blades of your lawn-mower...!) oil, he could, in the only 2500 miles since this engine has been in service, have a "stuck" oil control ring.

This can be dealt with by using ANY standard multi grade oil ( I see the fellow did ask for an oil recommendation...and I over-looked that part of his request).

You can't go wrong on motor oils for ANY automotive power-plant, if you pick an "off the shelf" motor oil of 10W-30 ( 20W-50 if you are going to do nothing but run across the desert at 100 mph+ in the summer....!). No matter what the brand, if the can says something to the effect that it "meets all manufacturer's requirements", it will keep the engine clean, and any "stuck ring" will be freed up in a few hundred miles of driving.

I disagree strongly with your suggestion to him of high speed driving ( without knowing more about how this car has been maintained and prepared). What condition are the front wheel bearings...recently serviced...bearing adjustment correct..? What condition are those rear wheel bearings...have they been changed recently - they are sealed..the grease dries out...no fun to loose a rear bearing (the whole wheel can come off)....differential gear oil been changed?

We dont know condition...what kind of tires, suspension components, etc...etc.

IF this fellow has been using NOTHING but so-called "non detergent" oil, AND the car has stood idle for long periods of time...yes...in that case...there IS the possibility of a "stuck oil ring"...and in that case...NORMAL driving with ANY multi-grade oil, when the engine is COMPLETELY warmed up might free it up.

Sure hope it works out that easy for the guy !

Pete Hartmann

SIDE NOTE TO MILLER - Please...PLEASE grow up and stop interferring with the

legitimate exchange of tech. info. between clasisc car owners.

Thank you

[Constellation]

crosleyracer,

Boy Pete you have more aliases than John Dillinger. You are right about the other mechanicals in the 47 Caddy. I would hate to see this man take his life in his hands without checking it out. I never thought of that aspect.

However, with modern motor oils they will keep the inside of the engine clean as new. My 55 Packard Clipper is testimony to that. That car had a new engine (one of the last crated replacement V-8's that Packard made) put in it back in the mid 1960's. This engine has always had Detergent, Multi Grade Oil in it and its like new inside.

This where I'm going to disagree with you about OLD ENGINES that have always used a straight weight non-detergent motor oil all of their usefull lives and are not burning oil. Do not use Detergent Motor Oil in them, not unless you want to rebuild them. All you will do is loosen up a bunch of gunk that will plug the oil passages and the crud thats around the rings. They will then burn oil and the bearings will start knocking due to lack of lubrication. You are asking for trouble.

I know this is a long story. However, years ago my dad drove a 1949 GMC 1 Ton Truck with a 228 Cu. In. Six for Plumbers' Supply Co. in New Bedford Mass. from new until it was about 15 years old. This truck when Plumbers' Supply traded it in in 1964, had well over 500,000 miles on it. It was running fine, they just felt it was 15 years old and it was time for a new one. It went to Orleans on Cape Cod, doing deliveries along the way and back, some 150 miles round trip the Friday before it got Traded. So much for an Old Truck.

GMC should have used it as a Testimony to their Trucks in advertising. It was probably one of the most dependable Trucks that was ever made. That Truck never had a road problem, an overhaul or any major work on the engine and it always used Non-Detergent Motor Oil that was changed regularly along with the filter. The new owner made a mistake after he got it. He used Detergent Oil. It was sad, as the truck started to leave a cloud of Blue Smoke every where it went, I used to see it all the time and it got so bad he was carrying a 5 gallon can of Oil with him.

I've often wondered how long that little Truck would have been around if it had been using Detergent Oil in it from new. My guess would be, it might still be around.

The lesson here is. If you always have used Non-Detergent Oil keep using it. If you always have used Detergent Oil keep using it. Do not mix it.

Bob

P.S. It must be fun to Race a Crosley.