Could The Exhaust Heat Riser Be Installed Backwards & Causing Running Problems?

Is it possible that the rebuild shop put the heat riser valve in backwards, causing excess back pressure in the manifold, causing the engine to skip and cut out and then stall when it is fully warmed up and under load? Also to run very hot- in terms of heating up the car like it never did before, and to be sluggish?

One thing I noticed when the car came back from the shop was that I no longer heard the "tick-tick" sound that the heat riser made when the car was running. The shop also complained about difficulty reinstalling the exhaust connection and that the muffler was touching the floor, which it never did when they got the car.  This could be a clue. 

It seems to me that the fuel, exhaust, cooling and electrical systems were the only peripheral systems that the shop had to touch to remove and reinstall the engine.  These were all in perfect working order when they received the car, and the only issue was the oil fouling in the no. 1 cylinder.  When I cleaned the plug, the car ran with smooth power and acceleration, because the engine was in perfect tune, and with all 8 firing, it ran like a new car. 

The ignition system was now replaced twice and the symptoms are exactly the same: starts and cold idles good, but when engine warmed up and under load, intermittent cutting out, stalling, and lack of power and  abnormal amount of heat through the floor.

We gotta figure this out. It has to be something very basic that was not put back correctly by the engine shop.

What do you think?

Jeff K.

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Comment by Jeff Kinzler on July 10, 2016 at 2:53am
Thanks for the good wishes.

Because an old upper control arm bushing popped, we also did a Kanter front end kit, plus new front and rear springs.

I was also able to get a set of rear shocks from Pep Boys for about $42.00.

Also, handy to know, Espo Springs in Pennsylvania (570-672-9413 ) had the front and rear coils for about half the price of anybody else.
Comment by Clovis on July 9, 2016 at 11:14pm
I suggest going to a flamethrower 2. All these issues with points, dwell and so on, evaporate into thin air. A little hidden modern technology goes along way to letting us just enjoy our babies!!!
Comment by David Thomas on July 9, 2016 at 3:33pm

Great news!! Thanks for letting us know the fix. Improperly adjusted points may not saturate the coil sufficiently, for a strong spark. A weak spark will not adequately fire the plugs under compression.

Comment by Tony and Ginny 429 on July 9, 2016 at 3:02pm
So glad the car is running good ,after you ordeal
Like to point out that ,points and timing were my first suggestion
It was because that was the same way my shop sent me home after some major freshening up of my car
I found my problems quickly and corrected both
Your heat issue had to be retarded timing ,to run hot ans blow the muffler
Changing the dwell ,changes the timing ,directly
So if the dwell is changed from its correct setting , while the timing was set correctly to begin with ,the timing is now not correct ,as well
This is standard mechanic BS ,to get you back to the original shop ,to pay for what ever it is they tell you was the issue ,when they caused the issue
Amazing how bad a car can run ,when ignition spec are off
The more you drive ,the worse the car performs
Welcome your car , back from the dead
Comment by Jason Edge on July 9, 2016 at 8:24am

That is fantastic news! I would replace the muffler and enjoy the car and keep the points adjustment issue in the back of your mind for future reference.  I've never heard of points dwell affecting a car like that but crazier things have happened. Whether or not this was solely responsible for everything, I guess you will never be completely sure, but you are at the point the car runs good which is what matters. Congrats!

Comment by Jeff Kinzler on July 9, 2016 at 12:59am

Wonder of wonders, miracle of miracles, we got it!

My friend and mechanic buddy Bill Gonzalez, who had the engine tuned like a top after the last partial rebuild, got it running properly today.  He tinkered with the point dwell, having had a defective reading on the previous meter he used. He showed me that the stable reading while revving the engine indicated the distributor was likely ok.

Afterward, he asked me to drive the car.  No cutting out, no stalling no issues, and only normal heat behind the engine, except for the blown out muffler that is touching the floor. Gunning the engine and downshifting produced only normal (if slightly tight) responses. I think we are good for a decent run-in test drive, finally.

We also checked the heat riser valve and it was free and the spring looked good.

Could this whole problem have been nothing more than a failure to set the distributor points properly?

Frustrating as heck, because I would have done this myself, but I had a long and miserable (16 month) bout with a serious chronic sinus infection followed by surgery.  My energy is not quite back to normal, and working around the car- which I always did myself-has not been an option for a long time.  Hopefully, we have turned a corner and me and the old Caddy will be back up to cruising speed real soon!  (Next up- the new gas gauge float and upholstery!)

I would like to humbly express my deepest gratitude for my friends and fellow members of this group who offered help and encouragement during this most difficult and frustrating challenge.

Like those guys said in the song:

     "You can't always get what you want, but if you try some times,

       you get what you need."

Bill cleaning the gasket surfaces back in 2010 when we did the heads, cam and lifters.

Comment by David Thomas on July 7, 2016 at 7:12am

Jeff, sorry to hear that your car is still miss behaving. I know it is frustrating, but a methodical diagnosis of each system is about the only way you can find the culprit. You have made sure the ignition circuit is correct and the adjustments are to spec. Ignition supply voltage is sufficient at  both cold and hot conditions? Fuel delivery is to spec cold and hot? Are the rubber fuel lines new both at the tank and on the cross member under the engine? Cracked or collapsed lines could be letting the pump draw air or a reduced amount of fuel causing a vapor lock condition when the engine is warm. When the engine miss behaves after warm up, is the filter bowl full of fuel? Is the fuel pickup in the tank restricted?

These are just a few of the possible issues that may be causing your problems. Bottom line, thoroughly  check out each system to be sure it is functioning so you won't waste time and effort bouncing around trying this and that. Inspect, diagnose, then repair if necessary. Once a system is correct you can move on to the next one, confident it is not the issue. Good luck, keep us posted on your progress.

Comment by Jason Edge on July 7, 2016 at 6:00am

Did you confirm the heat riser is functioning properly? If it is staying closed engine will run like crap when it heats up.

Comment by Jeff Kinzler on July 6, 2016 at 10:31pm
Jason and Tony
Thanks for your help. We will keep working on this.

Why would the engine cut out intermittently under load and then stall when it heats up? The cold idle, choke pull off and initial running seem okay. Drive for a few minutes and all the symptoms reappear. The engine has been retimed several times and checks out. 2 new sets of points also.

A friend mentioned a similar problem traced to a cracked distributor.
Comment by Tony and Ginny 429 on July 6, 2016 at 12:23pm
When ever there is a high heat issue , the thermostat ,would be the first thing to check for proper operation
High heat for a period of time will cause damage to it
Gotta love it ,when ever , it is a simple fix
Time will tell here


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