1962 390 - No Start: Guess which plug is Number one?

[midwestisbest]

Still trying to diagnose a no-start.

After one attempt tonight, I decided to take the plugs out and see what they looked like.

Number one is only one of the bunch that looks like its not flooded! Strange.

I took the valve cover off to verify Number one cylinder's valves are moving as they should and they're fine.

So now the question is: Why are all the plugs flooded... except for No. 1 ?

The attached photos show plugs for the drivers side, then the passenger side.



 

[The Tassie Devil(le)]

Looks like that plug has not been firing.

You can check with a timing light to see if it is not firing.

All the others look as though there has been sparking, with carbon deposit on the insulator.

Bruce.

[midwestisbest]

We're not even to the timing light yet.

It won't start.

All the plugs looked wet. Except No. 1. I'm going to clean these up with a wire brush and see about more testing.

[TJ Hopland]

Have you had this running before or is it new to you?

Especially since you have the plugs out I would suggest a compression test.  Even though the valves are moving you could have some sort of seating issues or a cam timing issue.  If you got good even compression on all cylinders you can proceed with the rest of the troubleshooting knowing you have one of of the critical functions required for an engine to run.  If there are issues with compression everything else could be a waste of time.

Also with the bad flooding leaving the plugs out for a while for the gas to more easily evaporate may help things.  After its had time to dry out maybe a little oil down each hole would be good since the gas will have wiped all the oil off the cylinder walls.  Keep an eye on the oil too.  Make sure the level isn't getting too high and that its too thinned out from gas.  With a carb it takes a lot to make bad things happen but if you and possibly others have been working at this for a while who knows how much gas has been getting dumped into this thing.  If its not super thin and gas smelling you are probably Ok to get it started but once it starts you want to change the oil before you really start driving it. 

[midwestisbest]

Have you had this running before or is it new to you?

Especially since you have the plugs out I would suggest a compression test.  Even though the valves are moving you could have some sort of seating issues or a cam timing issue.  If you got good even compression on all cylinders you can proceed with the rest of the troubleshooting knowing you have one of of the critical functions required for an engine to run.  If there are issues with compression everything else could be a waste of time.

Also with the bad flooding leaving the plugs out for a while for the gas to more easily evaporate may help things.  After its had time to dry out maybe a little oil down each hole would be good since the gas will have wiped all the oil off the cylinder walls.  Keep an eye on the oil too.  Make sure the level isn't getting too high and that its too thinned out from gas.  With a carb it takes a lot to make bad things happen but if you and possibly others have been working at this for a while who knows how much gas has been getting dumped into this thing.  If its not super thin and gas smelling you are probably Ok to get it started but once it starts you want to change the oil before you really start driving it. 

I have not had this engine running before. It was sold to me by Rick Raciborski Sr., in Chicago around 2018. I was told it was a running engine. Was not able to start really getting into it until this past year. So far, I've had a valve job done on the heads, new head gaskets, rockers redone, new fuel pump, carb cleaned & re-manned.
New pushrods (two were bent).

I did put about 5 ml of oil into each cylinder last night and I have a compression guage. My first test of cylinder No. 1 was ...not great but I've been told the cylinders can 'come around' after you get the engine started.

[TJ Hopland]

How not great?   A compression test is not an exact science, there are a lot of variables so what is more important than a specific number is that all the cylinders read about the same as each other.  If say the range you are getting is 90-120 I would say keep going.  That is low but for an engine that has had work done and hasn't been running like you said it may come up. It should run that low.  May not run well but should run.   If you are below 90 overall then I would want to try my tools and technique on a running engine to rule out the tools or process as the problem.   If your average is say 150 +/- 10 but you have one or more cylinders that are below 100 you got mechanical issues to deal with.

Do you know how the pushrods got bent?  Was it stuck valves from sitting?  Machine shop should have been able to see that when they took it apart. 

[badpoints]

Hard to unwrap your post. You bought the car with a "running engine" but never tried to start the engine. Rebuilt the top end of the engine and left the old sparks plugs in. Now it won't start. Do you have gas and spark? If you have gas and spark is the car sputtering? Need much more info to diagnose.

[midwestisbest]

Hard to unwrap your post. You bought the car with a "running engine" but never tried to start the engine. Rebuilt the top end of the engine and left the old sparks plugs in. Now it won't start. Do you have gas and spark? If you have gas and spark is the car sputtering? Need much more info to diagnose.

I bought a 1960 Cadillac and then bought a 1962 Cadillac 390 and put the engine & trans in it.
When I rebuilt the heads, I took the old plugs OUT naturally.

Here's a video of the spark for No. 1:

All the other plugs appear to be getting gas, yes.

[midwestisbest]

Compression test results:

1 = 90
3 = 100
5 = 100
7 = 95

2 = 50
4 = 75
6 = 75
8 = 60

Now I wonder if the heads need re-torqued. I felt AIR coming out from the bottom of the passenger side valve cover.

Checking torque next...

[Dave Shepherd]

Spark should be sharp and blue, may have trouble firing under compression.  Compression should be done with the throttle held open,  is the battery fully charged ? Those values are low.

[TJ Hopland]

Before I condemn those numbers I would maybe run the test again at lest in a different order.  Maybe even go as far as setting up a timer and battery charger to make sure you are cranking each for the same amount of time then waiting for the charger to recover the battery for the same amount of time between cylinders. 

If you have air you can feel coming out a head gasket while cranking you have major issues a retorque isn't going to fix.  If its coming out the valve cover that too seems really bad especially at cranking speeds.  Normally you don't get noticeable flow there till you have an engine running with a major issue like a hole in a piston. 

Based on what we seem to be seeing so far I'm thinking a poor mans leakdown test may also be in order.  A real leakdown test takes a leakdown test kit and is a bit of a process.  What I would want to know now is if you inject air into a cylinder with the valves closed where does it come out? 

Some compression tools hoses can easily be adapted to hook to an air compressor hose to do this.  You do want to crank the regulator pressure down when you do this or it will easily push the piston down and kinda wreck the test along with anything that is in the way of the breaker bar that you may have left on the engine.

4 places it could be going.  Intake valve so you would hear the air leaking through the carb/intake.  Exhaust valve you would hear at the tailpipe assuming its got a full exhaust system on it.  Piston/ring/bore issue you will hear in the crank case like the oil fill or breather areas.  Last place is a pretty bad head gasket issue which could come out externally around the gasket or be going into a coolant passage or could be going into the next cylinder so coming out the next spark plug hole or even the crankcase from around an area like pushrods.             

[midwestisbest]

Before I condemn those numbers I would maybe run the test again at lest in a different order.  Maybe even go as far as setting up a timer and battery charger to make sure you are cranking each for the same amount of time then waiting for the charger to recover the battery for the same amount of time between cylinders. 

If you have air you can feel coming out a head gasket while cranking you have major issues a retorque isn't going to fix.  If its coming out the valve cover that too seems really bad especially at cranking speeds.  Normally you don't get noticeable flow there till you have an engine running with a major issue like a hole in a piston. 

Based on what we seem to be seeing so far I'm thinking a poor mans leakdown test may also be in order.  A real leakdown test takes a leakdown test kit and is a bit of a process.  What I would want to know now is if you inject air into a cylinder with the valves closed where does it come out? 

Some compression tools hoses can easily be adapted to hook to an air compressor hose to do this.  You do want to crank the regulator pressure down when you do this or it will easily push the piston down and kinda wreck the test along with anything that is in the way of the breaker bar that you may have left on the engine.

4 places it could be going.  Intake valve so you would hear the air leaking through the carb/intake.  Exhaust valve you would hear at the tailpipe assuming its got a full exhaust system on it.  Piston/ring/bore issue you will hear in the crank case like the oil fill or breather areas.  Last place is a pretty bad head gasket issue which could come out externally around the gasket or be going into a coolant passage or could be going into the next cylinder so coming out the next spark plug hole or even the crankcase from around an area like pushrods.             

I'm going to pick up a Maddox cylinder leak down tester. They're not too expensive. I have a small air compressor that I used for some tile work that I think will work.

FYI: There is no exhaust hooked up, at all. The fenders & entire front clip are OFF as well.

[TJ Hopland]

You don't need a ton of volume or pressure for leakdown testing so anything other than a 'tire inflator' should do the job.

Exhaust off should make it easy if its an exhaust valve issue.  If it does seem to be a valve issue the next step would be to remove the rockers so you know its not some other issue holding the valve(s) open.  With the rockers off you can move or let the piston drop to bottom dead center and not have to worry about it moving while you are doing the test.  I would start out with the rockers in place tho just to try and see what happens.  Like I said note that it will want to move the crank so expect that especially as the pressure goes up. 

[TJ Hopland]

And I would imagine there will be a manual with the leakdown tester but I would not worry too much about it at this stage of the game.  At first you are just trying to inject some air and see where it goes.

[The Tassie Devil(le)]

I would be wondering why the two pushrods were bent, as you say that you were told that the engine was running.

There are two things to consider.   How good was it running, or how bad it was running.

Pushrods don't bend unless there was something really wrong.   Which pushrods were they?   Both from the same cylinder?   Exhaust or Intake?

Back to the compression figures.   They are not good, but try doing the WET check, and then see what the numbers are.

Bruce.

[badpoints]

You can get low compression readings if the valves are too tight

[midwestisbest]

I would be wondering why the two pushrods were bent, as you say that you were told that the engine was running.

There are two things to consider.   How good was it running, or how bad it was running.

Pushrods don't bend unless there was something really wrong.   Which pushrods were they?   Both from the same cylinder?   Exhaust or Intake?

Back to the compression figures.   They are not good, but try doing the WET check, and then see what the numbers are.

Bruce.

I've been told its entirely possible I bent the pushrods, manually turning the engine over. Which is something I tried to do every couple months. There was an incident in which I tried to turn the balancer bolt so hard... the bolt twisted off and I had to use a punch to 'turn it out'.

If its not clear by now... I'm new to all this.

[TJ Hopland]

Keep us posted on how how or where the leakdown test comes out.  That may tell us a lot and what direction to go next.   Like I said earlier the low compression number itself especially on an engine that hasn't run recently doesn't really concern me as much as the range.  Hopefully its a valve not closing issue of some sort that will be fairly easy to fix.

[midwestisbest]

Well, I think the rings are bad.

I tested 1, 8 and 4 and didn't want to test anymore.

Prior to this test, I put in 5ml of oil and let it sit overnight.

I set the air compressor to 100 psi. Next, I opened up the the leak down tester (clockwise) and started letting air in.

For each cylinder tested, I got about 75 psi and the right-side meter only got passed 10-12 psi.

You can hear the air escaping somewhere. If you put an ear near the valves you'll hear it somewhat. It is clearest at the oil breather tube. Not anything out the exhaust that I could hear.

I put a rubber glove over the oil breather tube to see if it would inflate. Nope.

So, its audible above the valves and the oil breather tube.

Thats why I think its likely the rings.

I put about 5-10 ml of Marvel mystery oil in each plug hole to see what it would do

[TJ Hopland]

For oil on the rings you would want to try and squirt it in at the top so gravity would let it run down and coat the rest and give it a few cranks to further distribute and coat things. If your just randomly squirting it in there most of it will likely end up at the bottom so it won't be doing much.

I think a 62 still had a draft tube for crankcase ventilation?  So that is likely were at least some of your air was going and why it didn't seem to be building.  You would also have to seal up the breathers in the valve covers assuming you have the valve covers on.