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Oil in #3 cylinder after a rebuilt

Started by Jose Gomez, July 10, 2005, 04:29:22 PM

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Jose Gomez

G’day Cadillac enthusiasts,

After a long delay in getting my “baby” altogether, this weekend I finally got back to it with one more disappointed surprise.

Everything is back in; tuned, adjusted, and calibrated, after warming the engine I’ve notice “white” smoke coming out on the driver side tail pipe during high revs or after shutting it off and restarting (larger plume of smoke). I pulled number 1, 3, 5, and 7 spark plugs and found the one from number 3 cylinder was foul with oil. Also, I’ve noticed a small residual of oil inside the chamber (enough quantity to be noticeable).

Since the oil is only present in the number 3 cylinder, my first thought was possible a bad valve seal (I’ve used the “cap” type instead of the “O” ring ones).

After removing and re-installing both seals on number 3, re-torque all bolts, I started the engine, once again after it starts to warm out the “white” smoke starts (during high revs). Again I pulled number 3 plug and same condition foul plug and small residual of oil in the chamber.

Compression test indicates all cylinders are approximately the same reading on all (except of course #3 which it is a bit higher due to the oil), and applying compressed air to each cylinder pressure holds (all piston at bottom and all valves closed).

I’m not at a standstill with this problem, after a complete machine shop rebuilt. Where is this oil coming from? Assuming it is not from the valves (since the seals were replaced), could it be a bad/defective piston oil ring? Could it be other place i.e. oil passages in the head, between the head and block, at the block itself?

At this stage, I may need to disassemble the engine, pull the head out, take the number 3 piston out and inspect everything. These would be drastically unless there are other alternative that I maybe missing.

I’m extremely disappointed at this stage after a long time in getting the engine put back together.

Any help/suggestion is appreciated it.

Regards,

FAQ Engine is a 365 with new .030 over pistons and new rings, heads are from a ’61 390 with several new valves. Camshaft and crankshaft were not machined were within specs same size bearings were used as the old ones. Push rod, lifters, and rockers are from the old original 365 heads. Oil pump was also rebuilt.

Bruce Reynolds # 18992

Gday Jose,

Well, looks like you tried everything, but pulling the piston out might reveal that you have damaged, or missing oil control ring or separator.

It is possible for oil rings to become damaged when installing pistons into the bore due to both the rings not being assembled correctly, and poor use of the ring compressor.

The compression test will not identify bad oil rings as the compression rings are designed to hold the cylinder pressure.   The oil rings only scrape the oil from the cylinder walls on the downward stroke so that it cant contaminate the compression rings.

It ius also possible that the No. 3 piston might have been incorrectly machined, and the relief slots or holes that allow the oil to escape behind the oil ring may be blocked.

Stranger things have happened but did you assemble the engine yourself?

Bruce,
The Tassie Devil(le),
60 CDV

P.S.   White Smoke usually indicates burning Transmission Fluid, and as some have said, also Antifreeze.  

Jose Gomez

Bruce,

Thanks for your info, as you stated it is the only obvious thing at this time after isolating the basics and unfortunately it seems what I was afraid of being the piston “oil” ring.

The installation of pistons and rings were done at the machine shop, the shop owner also installed all pistons, bearings, cam and crankshaft. I did however assemble the rest of the engine after the heads were done.

Oh well, it is back to square one with my project…!

Thanks for your help.

Regards,

Bruce Reynolds # 18992

Jose,

I would be going back to the engine builder with your symptoms, and see what he says.

If you pull it down, then he could say that you broke something, if something was found to be wrong.

Bruce,
The Tassie Devil(le),
60 CDV

Bruce Reynolds # 18992

Jose,

I have also heard of rings being completely missing from a piston when an engine was put together in a rush, and the assembler got called away during the rebuild.

Bruce,
The Tassie Devil(le),
60 CDV

Roger A. Zimmermann #21015

What is the year of your engine? I had the same problem as you have with cylinder 3 & 4 on a 1956 Sedan de Ville, after a complete rebuild of the engine. It smoke like hell when warm, nothing when cold. I checked all the pistons (I removed the heads), nothing wrong. I installed the heads again with new gaskets. It was the same. I began again to put the engine apart. When I removed the intake manifold, I noticed oil at the vacuum tube for the wipers. Then I did know where the engine oil was coming from!
1954 to 1958 Cadillac engines have a vacuum pump under the oil pump. There is a vacuum tube coming out of the engine block, behind the starter motor. At this location, there is a check valve; this valve should avoid that the oil is coming into the intake manifold when the vacuum is high. (its a one-way valve)The small plate inside this check valve was stuck open, therefore, the high intake manifold vacuum could suck the engine oil!
If your engine is from this period, have a look at this check valve. You have to remove the starter motor to see it.
Please report!

Roger

Jose Gomez

Bruce,

Thanks for your comments.

Per your previous posting, I already had discussed the problem with the machine shop owner who did the rebuilt, and he stated to take the easy route in changing the valve seal first. Im not to concerned with him covering any damages cause by him doing the job, as long as I’m careful in the dismantling, he and I have a good relationship.

As humans we are allowed to err once in a while, so there is possibilities he may have miss this one, or as you mention he may had been distracted during the assembly.

Again, I appreciated your feedback..!

Regards,

Jose Gomez

Roger,

First the block is a ’56 365, so it fits your criteria.

I know what you are talking about, since I did clean and burnished the vacuum pump walls before installing it back in the oil pump.

You must excuse my ignorance in my question.

Also, the valve you mention is located on the right side above the starter directly on the side of the block, however on mine there is no mechanical plate as you stated. The best I can describe on mine is just an expansion of about 3/4” cylinder and the inside has a piece that looks like a round ^^^^ (a picture is worth 1000 words), there is no other piece or plate.

Is this a flat plate or a ball i.e. similar to the PCV valve?

I have both the soft (parts and shop) and hard (shop) copy of the manual and I can’t see to find any details on this valve. So, I’m at a disadvantage as to the specific for this type of valve.  

I’ll give it a try to visually inspect the connections and possible removing/tapping the vacuum hoses to see if this is the problem. Without this vacuum the engine may be idle/rev rough but if this valve is the cause it will be only for a short time.

Thanks for your feedback; I’ll keep you posted of the results…!

Regards,

Paul Flykt # 18899

Jose

I had what sounds like a similiar problem on my 57. The check valve was stuck and oil was being pulled into the intake manifold. As I recall the main difference was it was going to the second cylinder on the right (passenger) side, #4 not #3. To verify the problem I cut a clear plastic fuel filter for a lawn mower into the vacuum line coming from the auxilliary vacuum pump, started the engine and sure enough the filter filled with oil. I had switched to an electric wiper motor so I just plugged the connection to the auxiliary vacuum pump.

The check valve on my 57 was a flat disc held by a coil spring.

Paul

Jose Gomez

Paul,

Thanks..!

Ill try this weekend to check if this valve is feeding the oil into the cylinder. As I stated on my reply to Roger, mine lacks the plate and as you stated yours also has a spring. So, Im missing both pieces, and it is a good possibility the oil is being force up the vacuum hoses.

I’ll keep the board posted of my findings.

Regards,

Bob Hoffmann CLC#96

Well, here we are 50 years later still dealing with the possibility of problems stemming from vacuum w/s wipers. Trico must have had GM(especially Cadillac) by the ba$$. They just couldnt, repeat COULDNT get OFF those vacuuum wipers. The very fact that they spent money to develope the vacuum booster in the oil pan of ALL places,is insanity! Even Chevrolet had ELECTRIC wiper motors in 1955 as an OPTION of course! Cant irritate the Trico gods too much. If you think this tirade is bad, dont get me started on hydralic windows in 1954 & later GM cars! LOL Bob

Roger A. Zimmermann #21015

Hi Jose!
Dont look further, you have the solution to your problem! You may also do a quick test, with the engine not running: take a rubber hose, insert it at the end of the vacuum tube. You should be unable to suck air (or oil) but you should be able to blow air into the engine.
Somebody took this valve apart, loose something (probably the spring) and installed it that way. Criminels are everywhere!
You can either plug the vacuum port (it will have no incidence on the engine) or search a complete good used valve. I cannot help you; I have no spare and Im located in Switzerland. Not the ideal country to search for such parts in a junkyard!

Roger

Paul Flykt #18899

You are right on the mark. According to my Hollander manual the electric wiper motor for a 57 Chev fits the 57 Cadillac. I found this after buying a Newport Engineering unit.

Jose Gomez

Folks,

First able, thanks to everyone for providing a feedback, comments on this problem, I sure appreciated it everyone’s help!

I could not wait until the weekend to get started with the troubleshooting on the mysterious oil in the number 3 cylinder. Yesterday after work, with tools in hand (and a cool drink to fight the 98 degree plus afternoon weather), I put in place the suggestions provided it regarding this check valve.

I knew that mine did not have the spring and plate mention on Roger and Paul’s comments, I decided to directly cap the hose connecting this feed to the main vacuum manifold at the firewall; the same was done at the port on the manifold. I then started the engine, waited to warm up (only took a minute or two), and after several high-revs cycles “hallelujah” the smoke was GONE..!

It only took me a few minutes to do the test, so I’m 95percent sure the problem was/is this check valve (which it is missing the plate and spring) connecting the internal vacuum booster pump.

Since there is no information on the manual on the function of this valve, I had no clue on what it was and what its use. Now that I know, my dilemma is how this valve functions and were the spring and plate are place inside if I tackle fixing it.

Any help will be greatly appreciated it.

Regards,

Paul Flykt # 18899

I am glad the forum was able to help.
The only real advantage to having the auxiliary vacuum pump is so your windshield wipers do not slow way down when you are accelerating. Some car had the auxilary pump to provide additional vacuum for their brake booster. I do not think this was the case with Cadillac. If you feel you still need it check the vendors in Hemmings for an original part or McMaster-Carr for a general purpose one.  

http://www.mcmaster.com/ TARGET=_blank>http://www.mcmaster.com/

Either way you can still drive your car while waiting for the part.

Paul