Valves...

[DodgeDan]

Was wondering if I could get a little help.  I've been plagued with an an engine issue in my '39 Dodge D11 for a while now and I have slowly been trying to diagnose it so that I can fix it.  The car has an intermittent popping noise when idling, you can hear it out the tail pipe and see the engine shake under the hood.  It has gotten worse over time to the point that it is non driveable.  It will be smooth for few seconds then rough and popping, then back to smooth.  It does not go away when the engine warms up, and like I said it has gradually worsened.  I have been told it is a sticking exhaust valve, or a collapsed valve spring or broken spring.  I tried all the liquid remedies in a can to no avail, so I'm going in.  Before I pull the head, I figured I'd remove the inspection panels on the side of the block under the manifolds.  I have it lifted on a stand, pulled the right front wheel and the inner fender panel so that I have a straight shot now to the two inspection panels.  I have not pulled them yet.  They are held on with thumb screws.  Once I have them off, what am I looking for?  A broken spring should be pretty obvious, but anything else?  Also, when I go to put them back on any gaskets, or just some hi-temp RTV sealer?  Any help appreciated, next step will probably pulling the head.  Thanks.

 

Dan

Edited July 29, 2014 by DodgeDan

[greg g]

before you do that, can you do a vacuum gauge test?  Hook the gauge to the line on the intake manifold that feeds the wiper motor. readings from the gauge will help you figure out what is likely going on inside the engine.  Go to Secondchance garage website for a how to on readig vacuum gauge results.   Aslo you can isolate the cylinder that might be causing the fault, by removing and replacing the the spark plug wires one at a time with the engine at idle.  Use a properly insulated pair of pliers or rubber gloves.  When you pull a plug wire, does the engine run rougher or not change.  If there is no change that is likely the culprit. Then you can narrow down what you are looking for in the valve gallery.  By the way when you put the side covers back on DO NOT over tighten them, getting the thumb screws too tight will warp them and cause a worse seal not a better one.

[DodgeDan]

Thanks Greg, good info indeed.  My wipers are electric not vac, so I'll have to see if there is another place to tap into engine vacuum.  I'll try that with the plug wires too.

 

Dan

[Ricky Luke]

I had an issue on a Lucas distributor (yes, yes I know - Prince of Darkness, etc...) where the vac advance diaphram had a small leak, which gave me all sorts of odd issues. Don't know if it could happen on the superior Chrysler unit, but it's something to consider if your are starting to get really frustrated.

 

Cheers

 

Rick

[Don Coatney]

First thing I would do is a compression check.

 

[Robert Horne]

Don is right, the first thing to do is a compression test.

Hook up a vacuum gauge, dwell meter, timing light.

Run some test before pulling a head, or other parts.

How many miles on the timing chain?

[plyroadking]

I had the same symptoms, the brass throttle shaft was worn to the point that i was sucking air in around it, i swapped the base of the carb out with one that wasn't worn completely out. That solved my issue

[james49ply]

another scary culprit could be valve guides, had that problem with mine, bought new guides, pulled the head and no matter what could not get the guides out, so I knurled the bad ones, reground the seats and valves. I will wait until I rebuild the engine at a later time to have the guides replaced.

[DodgeDan]

Thinking I'm going to do a quick carb swap and go from there.

 

Dan

Edited August 8, 2014 by DodgeDan

[DodgeDan]

Did a compression test today, here is what I found:

 

in psi...

 

#1 - 100

#2 - 105

#3 - 95

#4 - 100

#5 - 105

#6 - 105

 

This was with all the spark plugs removed.  Going to put the vacuum gauge on her tomorrow and see what it looks like.

 

Dan

Edited August 12, 2014 by DodgeDan

[DodgeDan]

So the only spot I can find to hook up a vacuum gauge is the steel vacuum line that runs to the vacuum advance on the distributor, if I pull the line at the base of the carb to hook up the gauge, do I need to make a T fitting so that the vacuum advance is still connected? Or can I measure the vacuum without the advance?

Dan

[Niel Hoback]

Put your gauge on the wiper hose connection under the carb on the manifold. You will get no vacuum from the advance connection on the carb at idle.

[DodgeDan]

I'll have to see if I have one, my wipers are electric not vacuum. The '39 Dodge has electric motor driven wipers. I'll see if there is still a capped off vacuum port?

Dan

[DodgeDan]

Actually I can see threaded plug in the manifold under the carb, that must be it. I need to make a threaded line now that I can screw in and connect the rubber line from the gauge. Thanks for the help.

Dan

[Niel Hoback]

I think you can use a 1/2" to 1/8" pipe reducer and a 1/8"  pipe to hose barb fitting to hook you gauge on.  When you are done, just leave it there and put a rubber cap on it for future use.   Lucky you, electric wipers and all.

[Don Coatney]

If what I have pictured below is the threaded plug you are referencing that is actually the heat riser spring stop. I believe it will be very difficult to remove. I wonder what the factory recommended for vacuum  gauge connections on your car? Another very difficult option is to drill and tap a hole in the intake manifold. If you go this route find the thickest portion of the manifold to drill and tap.

[DodgeDan]

Here is the plug I am talking about...

 

 

 

Having a hell of a time getting it to crack loose though.  I sprayed it pretty good with penetrating oil, letting it soak now.

 

Dan

[Don Coatney]

Do you have a hammer driven impact wrench as pictured? Might make removal easier.

 

[Frank Elder]

I briefly thought of that also Don, but don't you think you would be running a chance at starting a crack somewhere?

[Don Coatney]

I briefly thought of that also Don, but don't you think you would be running a chance at starting a crack somewhere?

That is a possibility depending on how hard one slams the hammer.

[greg g]

You say you are located in CNY, me too. If want pm your contact info, we might be able to get our heads together in person at your place. I know cny is a pretty broad area, I am near Mablius.

[DodgeDan]

Hey Greg, I'm originally from East Syracuse so I'm very familiar with Manlius, but my job currently has me living near Cobleskill right now.  I do get back home pretty frequent to visit my mom so it is still a possibility, but the car is out here with me.

 

Dan

Edited August 12, 2014 by DodgeDan

[TodFitch]

Hey Greg, I'm originally from East Syracuse so I'm very familiar with Manlius, but my job currently has me living near Cobleskill right now.  I do get back home pretty frequent to visit my mom so it is still a possibility, but the car is out here with me.

 

Dan

Hmmm.

 

Sunnyvale to Clements for a BBQ: 95 miles each way. A nice little day trip in the '33.

 

Cobleskill to Manlius: 88 miles each way. "But the car is out here with me. . ."

 

I guess distances in the west are different than distances in the east.

[Lloyd]

Most times if I just turn it one way I found it will snap off.

When I'm trying to get a stuck bolt out I go both ways with it. Tighten and loosen just to try and get it to wiggle. If you can get it to turn just a little either way its a big step to getting it licked.

Heating and tapping help a lot as well.

[DodgeDan]

Lol, 88 miles is a long distance the way she's running right now, I wouldn't take her to the corner store lol.

Dan