New to me 78 NYB on its way but please Don't tell my wife

[73 T&C]

Just for the record, here is a description of the issue.

engine fires off perfectly from dead cold. Normal.

with choke in, and enrichment circuit on carb is engaged…. Up to the FSM spec. engine temp of 150 degrees cuts it out.

up to that point engine runs fairly well with only a hint of the later “issue” in the form of a low level vibration. Cold power is actually better, crisper and more responsive.

So far… exactly the same as before when it had a bad and failing head gasket. Only a little better performing.

Once warm, the problems begin. Engine runs and pulls but not to the expected level it should even with the lean burn system still on it. If anything it’s exactly the same.

As it reaches normal operating temp of about 180, it runs like it’s missing. Same as before. Yet: everything is up to spec and working correctly.

I checked the the harmonic balancer for alignment to make sure it didn’t slip. It’s fine. Dead on fine in fact.

Because I’ve repaired the cooling system to where it works correctly, a previous “feature” of this engine has gone away. Before it would run hot. And once it got up to just about 7/8 of the guage… the engine would run smooth. I may just try that for shits any giggles.

My latest and last work on this engine was that I leak tested the cylinders and all were the same with only slight pressure loss on leakdown dead cold. That’s all I had left to check and….. nothing. All cylinders lost about 12 pounds across the gauges or about 10%.

The same famed Gremlin is just laughing at me. (Sorry… my ADD makes me personify things and issues…. It’s taken me 58 years to learn not to take it personally)

I’ve been chasing this particular gremlin almost since I got it after my initial recommissioning and tuning.

My conclusion is that there is something wrong with this engine that I just can’t fix. And it would be shear stupidity and hubris on my part to continue to try given all that has been done.

It’s just a bad engine.

as you can see from my handle, I have a 73 440. That old fucker runs like silk. And I have no problem after a typical tune getting it running so smooth that it is almost imperceptible when your sitting in the car. It’s how it should be here… and there are no more excuses.

I also believe that I’m not the only one whose been chasing this particular ghost in the machine either.

Readers of this post will remember that, when I got it, the heads had been done and the radiator and block had been fouled with stop leak and other “cures” to what had been ailing this engine by the previous owner. Probably chasing the same issue.

Well gentlemen, I’m done chasing, I now have a truly beautiful car whose other systems and features are all working as they should. Time to just kill the outlier and enjoy it.

I am looking for a similar spec short block to replace this one and starting today. Same 9 to one or slightly better compression and same lift cam. Heads are fine so I will reuse those. All block accessories are also either new or recently replaced so I will reuse those. But the block has got to go.

Issues that I think might be wrong with it are: internal crack in the block, bad bad casting with metal in one of the jackets causing variations in block temp big enough to make cold cylinders run “lean” long after temp is reached on the rest, bad mix of metal in the original casting or some other temp related issue with the block that is causing it to allow the crank to go off kelter. Cast crank is just bad, wrong or out of balance. (Not even going to go there).

wish me luck.

by force of habit…. I will probably continue to throw rocks at the gremlin for entertainment value till the new engine arrives. But.. like all of you… I have worked hard, have the desire and can say **** IT!
When I need to.

 

[LeBaron1973]

Just for the record, here is a description of the issue.

engine fires off perfectly from dead cold. Normal.

with choke in, and enrichment circuit on carb is engaged…. Up to the FSM spec. engine temp of 150 degrees cuts it out.

up to that point engine runs fairly well with only a hint of the later “issue” in the form of a low level vibration. Cold power is actually better, crisper and more responsive.

So far… exactly the same as before when it had a bad and failing head gasket. Only a little better performing.

Once warm, the problems begin. Engine runs and pulls but not to the expected level it should even with the lean burn system still on it. If anything it’s exactly the same.

As it reaches normal operating temp of about 180, it runs like it’s missing. Same as before. Yet: everything is up to spec and working correctly.

I checked the the harmonic balancer for alignment to make sure it didn’t slip. It’s fine. Dead on fine in fact.

Because I’ve repaired the cooling system to where it works correctly, a previous “feature” of this engine has gone away. Before it would run hot. And once it got up to just about 7/8 of the guage… the engine would run smooth. I may just try that for shits any giggles.

My latest and last work on this engine was that I leak tested the cylinders and all were the same with only slight pressure loss on leakdown dead cold. That’s all I had left to check and….. nothing. All cylinders lost about 12 pounds across the gauges or about 10%.

The same famed Gremlin is just laughing at me. (Sorry… my ADD makes me personify things and issues…. It’s taken me 58 years to learn not to take it personally)

I’ve been chasing this particular gremlin almost since I got it after my initial recommissioning and tuning.

My conclusion is that there is something wrong with this engine that I just can’t fix. And it would be shear stupidity and hubris on my part to continue to try given all that has been done.

It’s just a bad engine.

as you can see from my handle, I have a 73 440. That old fucker runs like silk. And I have no problem after a typical tune getting it running so smooth that it is almost imperceptible when your sitting in the car. It’s how it should be here… and there are no more excuses.

I also believe that I’m not the only one whose been chasing this particular ghost in the machine either.

Readers of this post will remember that, when I got it, the heads had been done and the radiator and block had been fouled with stop leak and other “cures” to what had been ailing this engine by the previous owner. Probably chasing the same issue.

Well gentlemen, I’m done chasing, I now have a truly beautiful car whose other systems and features are all working as they should. Time to just kill the outlier and enjoy it.

I am looking for a similar spec short block to replace this one and starting today. Same 9 to one or slightly better compression and same lift cam. Heads are fine so I will reuse those. All block accessories are also either new or recently replaced so I will reuse those. But the block has got to go.

Issues that I think might be wrong with it are: internal crack in the block, bad bad casting with metal in one of the jackets causing variations in block temp big enough to make cold cylinders run “lean” long after temp is reached on the rest, bad mix of metal in the original casting or some other temp related issue with the block that is causing it to allow the crank to go off kelter. Cast crank is just bad, wrong or out of balance. (Not even going to go there).

wish me luck.

by force of habit…. I will probably continue to throw rocks at the gremlin for entertainment value till the new engine arrives. But.. like all of you… I have worked hard, have the desire and can say **** IT!
When I need to.

Nobody has put more effort into their car than you, especially since most laughed when you said you'd straighten the bumpers, but then you actually did so. Considering your comments re: stop leak etc, there's obviously been a longstanding problem so replacing the block is a no brainer.

All the best once a suitable block is located and installed.

My condolences to all in Florida on that building collapse, probably being repaired but years too late.

 

[73 T&C]

Nobody has put more effort into their car than you, especially since most laughed when you said you'd straighten the bumpers, but then you actually did so. Considering your comments re: stop leak etc, there's obviously been a longstanding problem so replacing the block is a no brainer.

All the best once a suitable block is located and installed.

My condolences to all in Florida on that building collapse, probably being repaired but years too late.

Thanks for the kind words. This damned engine has me a bit miffed to say the least.

That building collapse has us all in the building profession a bit frazzled. Totally unexpected. When I hear something I can put my finger on as to the cause I’ll be sure to post it here. Right now we’re all just praying that some may have survived but the local count is about 100 “missing”.

 

[Ripinator]

Just for the record, here is a description of the issue.

engine fires off perfectly from dead cold. Normal.

with choke in, and enrichment circuit on carb is engaged…. Up to the FSM spec. engine temp of 150 degrees cuts it out.

up to that point engine runs fairly well with only a hint of the later “issue” in the form of a low level vibration. Cold power is actually better, crisper and more responsive.

So far… exactly the same as before when it had a bad and failing head gasket. Only a little better performing.

Once warm, the problems begin. Engine runs and pulls but not to the expected level it should even with the lean burn system still on it. If anything it’s exactly the same.

As it reaches normal operating temp of about 180, it runs like it’s missing. Same as before. Yet: everything is up to spec and working correctly.

I checked the the harmonic balancer for alignment to make sure it didn’t slip. It’s fine. Dead on fine in fact.

Because I’ve repaired the cooling system to where it works correctly, a previous “feature” of this engine has gone away. Before it would run hot. And once it got up to just about 7/8 of the guage… the engine would run smooth. I may just try that for shits any giggles.

My latest and last work on this engine was that I leak tested the cylinders and all were the same with only slight pressure loss on leakdown dead cold. That’s all I had left to check and….. nothing. All cylinders lost about 12 pounds across the gauges or about 10%.

The same famed Gremlin is just laughing at me. (Sorry… my ADD makes me personify things and issues…. It’s taken me 58 years to learn not to take it personally)

I’ve been chasing this particular gremlin almost since I got it after my initial recommissioning and tuning.

My conclusion is that there is something wrong with this engine that I just can’t fix. And it would be shear stupidity and hubris on my part to continue to try given all that has been done.

It’s just a bad engine.

as you can see from my handle, I have a 73 440. That old fucker runs like silk. And I have no problem after a typical tune getting it running so smooth that it is almost imperceptible when your sitting in the car. It’s how it should be here… and there are no more excuses.

I also believe that I’m not the only one whose been chasing this particular ghost in the machine either.

Readers of this post will remember that, when I got it, the heads had been done and the radiator and block had been fouled with stop leak and other “cures” to what had been ailing this engine by the previous owner. Probably chasing the same issue.

Well gentlemen, I’m done chasing, I now have a truly beautiful car whose other systems and features are all working as they should. Time to just kill the outlier and enjoy it.

I am looking for a similar spec short block to replace this one and starting today. Same 9 to one or slightly better compression and same lift cam. Heads are fine so I will reuse those. All block accessories are also either new or recently replaced so I will reuse those. But the block has got to go.

Issues that I think might be wrong with it are: internal crack in the block, bad bad casting with metal in one of the jackets causing variations in block temp big enough to make cold cylinders run “lean” long after temp is reached on the rest, bad mix of metal in the original casting or some other temp related issue with the block that is causing it to allow the crank to go off kelter. Cast crank is just bad, wrong or out of balance. (Not even going to go there).

wish me luck.

by force of habit…. I will probably continue to throw rocks at the gremlin for entertainment value till the new engine arrives. But.. like all of you… I have worked hard, have the desire and can say **** IT!
When I need to.

Javier: I've followed this thread and your adventures for quite a while, and listening to your description of the problem, I can't help thinking that it almost sounds like a burnt valve issue. I know you did a leak-down test and all, but I can't help thinking the problem may be related to the heads and not the block. I think you said someone else did the heads?

 

[70bigblockdodge]

As much as I hate to admit it, Chrysler had problems with quality control. Your car is near the end of the road for big blocks, so porosity and thin spots/core shift could be a problem.

 

[73 T&C]

Javier: I've followed this thread and your adventures for quite a while, and listening to your description of the problem, I can't help thinking that it almost sounds like a burnt valve issue. I know you did a leak-down test and all, but I can't help thinking the problem may be related to the heads and not the block. I think you said someone else did the heads?

While it is true I did not personally do the heads for this build, they were just redone as part of this build and had new hardened seats installed with a three angle valve job. I agree it is a similar set of symptoms. But it became obvious, when we did the leak down test, that a bad valve was not the problem.

I’ve had a burned valve in my other 440 and was similarly scratching my head with a bad idle. But it ran fine under load and was only just slightly smoking. I tried everything until I finally did a compression and leak down test and it was obvious that I had a bad valve on number 3. Air escaping out the tailpipe told us it was an exhaust valve. My first. We pulled the head and bingo.

the proof of my bad block casting suspicion will be if I change out the thermostats to a high temp one and the problem “clears” when engine reaches the upper end of the temp gauge. That was a curious phenomenon of the engine when I got it. This engine would have a miss and uneven idle until it had reached the upper limits of the temp gauge. Once reached, the engine smoothed out and the miss seemed to go mostly away. It made me scratch my head at the time as well each time I observed it. But, even if it does positively affect the running characteristics, I’m not about to drive a car on the edge of overheating in South Florida. Besides, the transition to that temp is horrible to drive. Missing, vibrating and occasionally stalling. There was no way to set the mixture either lean or rich enough to get a happy transition from cold to high temp smooth.

the more I think about it, the more I think that may be the issue….. Bad friggin block casting or blocked cooling jacket(s?) filled with sealer that has turned to concrete.

I’ve never adjusted a carb so much in my life chasing this issue. Hell! In the almost three years I’ve owned this carb, all I’ve had to do to my other Thermoquads is the occasional spritz with a little gumout, check the dash pots weren’t leaking and make sure the linkages were not binding. It ain’t the carb!!!!!

Thinking it was the lean burn, I got it working perfectly and even just switched it out for testing…. Just to be sure.

 

[70bigblockdodge]

Did you ever put a air fuel ratio gauge on it? Still seems like a lean miss.

 

[commando1]

Go up two heat ranges on your spark plugs.

 

[73 T&C]

All interesting ideas. Will be among the rocks I will be throwing over the next few weeks…. Until Jeff gets back to me about some 440’s he’s got.

BTW… so far everyone needs my core back that I’ve talked to about a new short block.

lol….. don’t worry. I won’t add to the entropy of the system.

 

[73 T&C]

I’ll be posting what I know and hear about the collapse on a separate post as some have been PMing me with questions.

 

[73 T&C]

TAAA-DAAA!!!!!

Before…….

polished them myself…. What a job…

 

[commando1]

polished them myself….

Where's the reflective stripe?

 

[75LandYacht]

TAAA-DAAA!!!!!

View attachment 473082




Before…….
View attachment 473091

polished them myself…. What a job…

View attachment 473137

Now that’s what I’m talking about, that’s damn sexy right there.

 

[73 T&C]

Miss went away today. Not sure what I did or what it was. I suspect it was the intake gasket.

I brought her home to get her out of the way at the shop. I hadn’t driven her since I went in with the miss over a month ago. On the way home she was horrible. Missing stalling, bucking.

So…. Started throwing rocks at the gremlin starting with new set of plugs. I thought to myself…. ”Let’s check everything before we get too tits deep in the rabbit hole”…..and that seemed like a good easy place to start.

I used Champion RJ12YC’s. Same plug used on the 69 440 which was the intended model for this build.

Found that the Idle stop sensor was unplugged… probably left over from the ignition system swap. Better….

Found one weak wire and changed it as I replaced the plugs. (I did this already a couple of times).

started her up cold to check the Freon in the A/C and at least get the car comfortable while I chase the gremlin. She sputtered a bit as I had forgotten to prime her but as she came on she started to clear and bingo…. No miss and idle settled.

transition to temp came up and she got a little iffy. Quickly turned idles up 1/2 turn and better. (I had leaned her out as the miss was blowing too much raw fuel out of the exhaust).

Now she has a minor vibration…. All through the rpm range with definite harmonic points.

I’m working on my house at the same time so I partnered cleaning the stoves and ovens in between working on the car. I need to put a tach on it to see what RPM is max vibration point.

All cylinders firing fine. Idle is almost acceptable. Drove her around the block and the Power is better. Exhaust is now a much more laminar affair with only the occasional puff. No rich smell even with the adjustment I made.

Need to reset the kickdown…but I think I want to put 500 easy miles on it before I see what she can do.

Meantime…. Still throwing rocks at the gremlin. I’ll keep you all posted.

If I can lick this last issue….. I may be ok.

of course I had to wash the shop dust off….hose is for scale.

 

[73 T&C]

In case you were wondering….

….. and yes; some power tools were used.

 

[commando1]

That digital keypad.... I give it 6-7 years.

 

[commando1]

8 tops...

 

[73 T&C]

Drove in to work in “The Beautiful New Yorker” and was the talk of the town (or at least the office).

Started up first turn but ran a little rough under choke…. Like too much choke. Cleared as soon as it started releasing. Did not stall.
Transition to temp better than yesterday but still unacceptable.

Vibration diminishes a bit with temp. I could swear it’s a bad valve. More checking before I get there to do a leak down.

One thing for sure, engine throttle tip in is smarter and it takes very little throttle to get up to city speeds. I need to take it up to highway speeds next.

Engine temp is stable at between 1/2 and 2/3 of guage. Fluctuates with fan clutch. Of Course…. A\C is on at 65 and blowing nice and cold.

Vibration is a fucker. It diminishes under part throttle. But definitely directly tied to rpm. Just barely perceptible under engine idle/coasting with mild engine braking.

At times it thrums a bit….. which is really weird…. Under very light throttle.

Could my converter be out of balance with engine?

I wonder…. Need to read up on that.

 

[73 T&C]

8 tops...

It’s 10 years old. Other than the crud, it works fine.

 

[commando1]

It’s 10 years old. Other than the crud, it works fine.

Any day now, then...