48 DeSoto engine start up after 40 year ago rebuild

[MarcDeSoto]

This car has been garaged for most of that 40 year span.  What was done on the rebuild?  Everything about.  Machine shop work: crank and cam reground, engine bored out .030.  New rings.  New pistons .030 over.  I reground the valves according to manual.  New bearings.  New valve springs.  The cooling system is working.  Smoke is coming out of the exhaust pipe to exhaust manifold connection.  Spark plug electrodes are turning black quickly.  Does this engine start look normal?  

 

 

[Sam Buchanan]

That sounds pretty good! The stumble may very well have been due to not giving the engine time to come up to temperature. Fine tuning the choke should make it run smoother when cold.

 

The new rings are going to need some time to seat, the tailpipe smoke doesn't alarm me on first starts with fresh rings. Did you replace the valve guides? Idle that thing down to about 450 rpm and let us hear it tick over. 

 

Congratulations on turning gasoline into noise!

Edited January 18, 2023 by Sam Buchanan

[Los_Control]

You want to look at the draft tube .... whats coming out there? .... Just let it run it looks fine.

 

When you put oil in the cylinders it gets pushed out into the exhaust pipe.

One forum member ran so much oil through the engine into the muffler, took 2 hours driving to clear it out.

 

Also metal will absorb moisture from the air ... this includes your engine block that has been stored for 40 years. You will get white steam from the engine as it warms up.

I recently bought a used engine that sat for 8 years. Took 1 hour before all the white steam...smoke went away from the tail pipe.

JMHO, I would let the engine clear itself, then I would dump the oil & add fresh .... treating it like a "break in oil"

 

What is coming from your road draft tube imho is what you should be concerned about ... If your rings were leaky you would get a lot of blue smoke from the tube.

A modern PCV system eliminates the road draft tube and runs the stoofs back through the tail pipe.

Your road draft tube will tell you the story on your engine.

 

 

[junkers72]

Congratulations 

[keithb7]

It sounds pretty decent to me.  Congrats on getting it running. 
 

Tell us what you sealed the joint with, between the exhaust pipe and the exhaust manifold flange. How long ago did you assemble this joint? Are the bolts tight? Does it have a gasket? Or some type of goop?  Are both iron mating surfaces of the joint true and square?

 

If you have good engine oil pressure, I’d plan to move forward with car reassembly. Break the engine in later. If the engine has to come back out after extensive break-in time, so be it. You won’t need to take the body off the frame to do so. ?
 

How’s your coolant look? Any air bubbles? Any oil in coolant?  

 

 

[Jerry Roberts]

Re torque the head bolts now that things have warmed up . 

[JerryinTx]

I remember my first start up after overhaul and know how great it makes you feel to hear that engine run.  Big congratulations!

 

Jerry

[Marcel Backs]

It seems that your flanges are not seating themselves properly at the manifold outlet. A flat heat resistant gasket should be enough to seal up the exhaust pipe/ manifold flange junction. The engine sounds pretty good. It is important to have your fuel-air mixture right before extended periods of running to avoid carbon build up in combustion chambers and plugs. The plugs should be tan at the electrodes and not black. You should have a good feeling of accomplishment at this point! M

[MarcDeSoto]

The exhaust manifold gasket was put in a few months ago.  Maybe somebody sold me a bad gasket?  I did not use putty or goop.   I did tighten it more and for awhile there was no burning until the engine got hot.  Nothing is coming out of the draft tube, it's all from the manifold to exhaust pipe gasket.  Spark plugs turn black pretty quickly from burning oil.  I did put a lot of Marvel M.Oil in there while I was getting the engine ready to start.  And the rings haven't seated yet.  I'm using 10 W non-detergent so the rings will seat easier.  

 

 

Edited January 19, 2023 by MarcDeSoto

[keithb7]

I like that flathead 6 rumble. Made my day.

[Cannuck]

Congratulation Mark  It sounds really good.

[MarcDeSoto]

A Model A friend of mine said to use Permatex Copper gasket maker on the exhaust pipe gasket.  It is made for exhaust and other high heat applications.  

[kencombs]

JMHO, but no sealer should be needed at the pipe to manifold connection on a new installation.   If it fits correctly, it won't leak.   Double check the flange.  Is it flat?  If not correct that first.

 

Does the pipe project slightly into the manifold?  Or is the pipe flush with the flange?  A projecting pipe was original on every old Mopar if my memory is any good.  That makes the gasket last longer and reduces stress on it.

 

 

[wagoneer]

It does sound fantastic! Congratulations! It's also very pretty.

[Bob Riding]

very cool! Good work!

[MarcDeSoto]

For some reason, the engine remains hard starting.  I think I'm going to follow LeRoy's troubleshooting tips one at a time to see if I can correct this.  All I did to my carburetor lately was put in a new carb kit.  I didn't take it all apart and soak it in carb cleaner and blow every orafice out.  I just put in a new dashpot, accelerator pump, metering valve, etc.  The engine only seems to start when I squirt in gas from a sqeeze bottle.  Not when I pump the throttle a few times.  It is squirting gas though.  So after I rebuild the carb again, if that doesn't solve it, I will put in new points and condenser, and go from there.  

[MarcDeSoto]

I looked down the throat of the carb. as I pulled on the accel. pump.  The squirt comes out mainly on one side and just dribbles on the other side.  That could be a problem if it's supposed to come out of both sides with a strong stream?  

[wagoneer]

1 hour ago, MarcDeSoto said:

I looked down the throat of the carb. as I pulled on the accel. pump.  The squirt comes out mainly on one side and just dribbles on the other side.  That could be a problem if it's supposed to come out of both sides with a strong stream?  

 

I found the rebuild to be trickier than expected. There is definitely an order of operations, and you have to be careful about blowing out those holes and the check balls are the right size for the right hole. I had to open mine up several times, and how the linkage connects is funny too. Everything is super precise, and for some reason takes me 3 times to set it right. 

[MarcDeSoto]

I know what you mean.  I'm going to watch the MTSC filmstrip again on carburetors to understand the workings, and then put it together.  Does anyone know if the acc. pump is supposed to squirt out of both sides of the wall in the carburetor?  I took my carb all apart today and will assemble it back together tomorrow.  If the engine is still hard starting after that I will work on the distributor.  New points and condenser.  I checked the throttle body, and didn't see any looseness in the throttle shaft.  

[Sam Buchanan]

If the ignition is in good enough condition to run the engine smoothly I doubt it would contribute to hard starting. I suspect you may not have yet found the sweet spot for choke and throttle to start the engine easily.

[MarcDeSoto]

I took Wagoneer's advice and pulled the carb.  I took it completely apart and cleaned the parts with Chemtool 12 carb cleaner and soaked the jets in acetone.  Then I blew everything off with compressed air.  I made sure the accelerator pump holes were blown out so I could feel air coming out strongly on both sides of the divider in the venturi.  Right now, I'm reassembling everything.  If you get lost assembling your Carter B&B carb, Mike's Carburetors has a good two part video showing you how!  

 

 

[wagoneer]

 

I had problems with carburetor performance both in the accelerator pump and the dashpot,  I would say there are important and very subtle differences between OEM parts such as the accelerator pump spring length that require careful attention.

 

Here's a short video clip my son took of me testing the accelerator pump springs that come with the kits (old and new), and the springs control the flow through those holes.

I watched his video a number of times but Mike's kit doesn't replace all the relevant parts for our Chrysler B&B such as the dashpot. I found things very tricky like the triangular base that controls the choke can easily be put on backwards. 

 

I ended up reading the Carter B&B documents (original) AND the shop book. Both are written, as it turns out, very precisely and done in specific order. Once the system is put back together precisely then it really works flawlessly. I also purchased most of the Carter original tools like the float level measure, accelerator pump tool, and several other small parts that helped.

 

Many people are 'old hands' at putting these carburetors together, but I think we just have to go through that trial and error phase to get it right, and then we too can put them together in no time at all!

 

I ended up buying an original Carter rebuild kit and using parts from it. Those Carter kits are much more comprehensive including the accelerator pump spring!

 

 

 

 

 

Edited January 23, 2023 by wagoneer

[Sniper]

 

[LeRoy]

My car uses a Stromberg carb, even with the dashpot it's a pretty simple in the grans scheme of things. Looking at a completely disassembled quadrajet and its thirtyeleventy billion pieces compared to mine is a joy. I hope I never see another metering rod.

[MarcDeSoto]

That was an amazing difference between the new spring and the original spring.  I'm going to look at that closely.  Luckily I have two other EV2 Ball & Ball carbs that I can take original parts from.  I'm having trouble right now putting the kick down switch together.  When I do, the push button won't go in, so something's wrong.