Got the 1956 Cadillac Series 62 running

[Keldridge]

Morning. We just got the Caddy running after a fresh rebuild. She looks great and runs and idles fine. Two items.
#1 after running for 5 minutes or so the generator was hot enough that you could not rest your hand on it. It was charging and the generator light was not on. Is this normal? We took the belts back off and there is no sign of a rough bearing when turning.

#2 the motor seems to run fine and idle fine but it sounds like it could suck a cat down the carb. We removed the carb and checked the gasket, when running and spraying starting fluid around the carb you get no change in idle, and when you place your hand over the carb throat you can kill the motor. Doesn't really run like a vacuum leak but again the intake noise is quite loud. Ideas?

Thanks

Kevin

[jaxops]

I had a catastrophic failure of my generator, and it was a squeak here and there, and then it got hot, and then, that was the end of it.  Do check your voltage regulator as well but it sounds like the generator may need a rebuild.  If you haven't done that already it is a good move for safe driving to get it done.

Your engine sounds like it needs air....a lot of the problems I had were related to the exhaust-carburetor cross-overs.  Hopefully one of the experts can help you further.

[Roger Zimmermann]

#2 the motor seems to run fine and idle fine but it sounds like it could suck a cat down the carb. We removed the carb and checked the gasket, when running and spraying starting fluid around the carb you get no change in idle, and when you place your hand over the carb throat you can kill the motor. Doesn't really run like a vacuum leak but again the intake noise is quite loud.

Kevin, that noise is with or without the air cleaner?

[Keldridge]

Without. Installing the air cleaner may muffle it but I was alarmed at how loud it was.

[Daryl Chesterman]

Was the battery a bit run down?  If so, the generator was probably charging at a high rate for a long period of time and caused it to be a bit warm.  You could check the output of the charging system by starting the engine and just check voltage across the battery terminals--should not be in excess of 15 volts, or it will start boiling the battery and ruin it.  The shop manual will have the exact specs for generator output.

On your newly rebuilt engine: Don't let the engine just idle!!!  It needs to be broken in at a high RPM (1500-2000) for about 20 consecutive minutes to help break in the cam lobes and lifters.  The high RPM ensures that there is plenty of oil for lubrication during this break-in period.  The mechanic who assembled your engine should have coated the cam lobes and the foot of the lifters with a break-in lubricant, and there should have been break-in oil put in the crankcase (oil with ZDDP additive).

As to the loudness of the air rushing into your carburetor, it is probably normal.  The venturi effect makes it sound loud, but without actually hearing it, it would be difficult to tell if it is normal.

Daryl Chesterman

[35-709]

"On your newly rebuilt engine: Don't let the engine just idle!!!  It needs to be broken in at a high RPM (1500-2000) for about 20 consecutive minutes to help break in the cam lobes and lifters."

My 2 cents --- that is absolutely correct and important!  And I would do that without delay!  Might already be too late.

[Keldridge]

Thanks guys. We were hearing this during time setting and dwell setting time. We are now breaking in appropriately.

[cadman56]

What is the @ turns open of the idle air bypass screw?  Those things cans scream if too far open.

[J. Gomez]

Kevin,

For your #1, question, the generator is mounted on top of the exhaust manifold so it would be normal for it to get a bit warm, although not hot to the touch. If I may suggest leaving it off (remove the belts or just remove the wires from it) and run the engine for a few minutes and see if it get hot as you mention.

Would be best to jumper the battery with a booster just for the test to avoid draining the battery.
If the generator stays cool or just a bit warm then recheck all the wiring and connections from it over to the VR, also make sure the ground wire is present between them.

If after reconnecting everything back and rechecking again (don’t forget to polarized the generator before starting the engine) the generator get hot, you would need to have both VR and generator checked.

For your #2, do you hear the same rush air noise going in the carb when you first start the engine (cool engine) or after 5 mins running (warm engine)?

The service manual suggests doing all carb adjustment with the air filter in place. The loud noise of air going in may indicate the idle by-pass screw maybe out of adjustment. This is a major pain in getting the adjustment right it control the air going in while at idle.

Oops Larry beat me to the punch..! 

Good luck…!

[cadman56]

Yep, it is a real 'dance' to get that carb set right.  It is the last thing to do but takes a lot of time to really dial it in.
Then, if you tweak you timing to make the engine run better, like I always have, you get to do it all over again.
Good luck.

[James Landi]

If you have not already done so, I strongly urge you to check the vacuum advance on the distributor.  Often overlooked, if it is ruptured (and they don't last forever), you'll have a substantial vacuum leak, and this will greatly affect engine idle. As well, a non functioning vacuum advance will throw off the engine timing throughout the power range, negatively affect acceleration and smoothness, and cause the engine to use and waste gasoline.  It's a relatively simple replacement;however, if yours is installed as factory shipped, it has a solid pipe, and not a rubber 1/8 hose, so doing I "quick check" requires some work around.  Hope this helps,  Happy day, and be of good cheer, James

[Lexi]

Kevin glad to hear she is running. Short of hearing your car, I can't comment on your carb noise level with certainty. With my car I always thought it was loud when the air cleaner was off as well. Yeah, like it could suck a cat in as you said. LOL.

Agree with comments on not letting her idle right now. Hope break in running with break in oil was used. For around the first 1,000 miles or even 2,000 (opinions vary), I would drive it all over the map speed-wise so to speak. So some days drive it like you stole it, other days drive it like the little old lady from Pasadena. Mix up your driving habits and don't be afraid to drive her hard sometimes. I have been told that once your rings have properly set your engine will run even better. Take a vacuum gauge at idle reading asap. Then after break in take another. I had a couple of old time mechanics tell me that vacuum readings should increase if the engine is broken in properly. I checked mine after rebuild then about 2200 miles later and the engine vacuum readings had indeed risen by around 1.5 to 1.75 inches.

Also change your oil a lot. Depending on how well your engine was tank cleaned, and purged of debris, there may be a lot of contaminants in your oil for some time. Assuming your break in oil is out, I would change again at the first 100 miles. Depending on how it looks you may have to repeat this several times. The mechanic who assisted with my engine rebuild project said you could see odd stuff in there even after 2000 miles. I would also be using oil with approved high levels of zinc, "Dinosaur Juice", to further protect your engine. Clay/Lexi
Clay/Lexi

[Jeff Rosansky CLC #28373]

Ours is a 55 so a little smaller. But the air rushing in is very noticeable with the air cleaner off. We rebuilt our carb too when we 1st got it. I just backed out the bypass screw the same number of turns it was originally and have been able to get a decent idle so I have never touched it again.

Good luck,
Jeff