Projects Mild custom '51 Pontiac Chieftain

In New Orleans!

On the gearbox front, the governor is worn, totally. It did a couple of gear changes properly on the way home but generally it's being awkward. Needs a new one.

Did make it home though.

Things to note:
Engine really comes on cam at 2200RPM.
Fuel economy isn't its forte, 9.3MPG
Brakes need adjusting again
Bump bang crash, it's a little low for the lovely pavement around here

Phil

 

I've decent luck semi-repairing sun-baked crazed plastic like that by using heavily-thinned clear lacquer. The paint is generally too thick to 'wick' into the cracks, thinning it at about 10% paint, 90% thinner and dipping it will help, allowing some 'soak time' for it to penetrate. Heating the part to about150 degrees before dipping also helps. If you've already painted it, soak it in straight thinner first to remove as much of the paint as possible. It's impossible to eliminate the cracking if it's really deep, but this can make it less obvious.

 

The cracks are a little deep to do that, and the okay is quite heavily discolored from the sun. Fine surface crazing absolutely I could see that working but this is beyond any real redemption. Close up, there are some chunks of plastic missing, even.

Phil

 

Reproduction hood ornament inserts are available from California Pontiac Restoration (CPR) but they do cost $86.25....even with the crazing, yours still looks pretty presentable. http://www.pontiacparts.net/Body/default.htm

 

I had seen them, and am going to budget for an insert and a new front grille badge next year.

 

Decided a trip post-mortem was in order.


That's not a bad array. 1-8 left to right.

7 is a bit oily but I knew that already; they're all firing though which is good and the mixture is pretty even, which I'm happy about considering that was mostly high speed cruise (2200-2400rpm).

Phil

 

Just shot Fatsco an email asking about the governors- they have 2 listed and I do not know the difference between them.

I was hoping that valve would last a little longer than 400 miles...


Phil

 

To describe what's happening:

Normally, the piston face meets the bottom of the bore and stops. However, this has happened so many times and the piston is much harder than the bore is hammered a recess into the bottom of the bore.
Normally dirt gets caught by the top of the piston in the void created by the machined edge.
Now that machined edge fits snugly into an indent it's made, there's nowhere for the dirt to go so it jams the piston.

Phil

 

Got the car warmed up in the garage and tried a method my father used for setting the ignition to the fuel in the tank.


Set the timing by ear at idle. Set the ignition for the fastest tickover, then adjust the idle mixture, then timing, mixture until you got the sweet spot.

Looks to be about 15 degrees advance. Book says static timing is 10 degrees, so that's not bad.

I'll see how it runs when it's back on the road.

Phil

 

Jacked the car up tonight and used the oldest tool I have to try and fix the gearbox. Occam's Razor.

I had been messing about with the carb linkage and didn't correctly adjust the gearbox modulator shaft. It was set all kinds of wrong.

So I've adjusted it back up and added a spring to the lower lever arm where it should have one and now, cold, it's changing gears very smoothly.

I'll have to get it all hot again to see if the problem resurfaces.

Phil

 

Went for a quick run to the next town.

Engine is now holding temperature very well, it's quieter and the gears are changing well.

I'll be happy if that was the fix.

Phil

 

Half of it.

The governor is still sticking when it gets hot; cold it behaves very nicely.

Edit: In fact, people had written that this gearbox is smooth- adjusted wrong it was pretty smooth. Adjusted right it's as smooth as any hydraulic gearbox I've driven. I'm genuinely impressed.

Phil

 

Governor and a new side pan gasket ordered. Should be in Wednesday or so.

Phil

 

Carburetor heat shield arrived.


Cleaned it down.


Gave it a coat of paint (silver underneath).

Phil

 

Mental note, need to purchase some crocus cloth.

 

Good news is the replacement governor I ordered arrived. It moves freely and doesn't even feel like it's going to stick, unlike the current one. This one also, looking at the wear patterns, has done significantly fewer miles than mine.

Phil

 

Liberated the side pan. Transmission oil looks pretty good but there's still a fair bit of dirt that's washed through. A change isn't a bad thing a few hundred miles after a rebuild.

Got the valve block and sleeve out. Governor valve wasn't totally free to move.
Typically mine is a hybrid of the two available types... We'll see how it runs.

Need to find all the torque settings in the book again.

Phil

 

Tonight's task, pull the main valves out, inspect operation, clean and remedy. The manual states the valves are in good working order if they fall to the top and bottom of their bores under their own weight.
The block above is the piece that pushes back against the governor speed control and makes the gear changes later the harder you push on the throttle.


That got cleaned thoroughly and some very fine grit paper to take the burrs off. The slides now fall out under their own weight.


Main valves were dirty, and the outer two were not exactly free moving. They were a little easy to get hung up before and that didn't improve with dirt.


I pulled it all out and cleaned it down, found a couple of small nicks, which I very carefully took the edge off. They all move better now.

Reassembled it all and now it's ready to go back together.

Phil

 

Fingers crossed...

 

Good luck with all of it. I very much look forward to all your updates, no matter how seemingly insignificant or otherwise. The level of detail is enthralling.

 

Thank y'all.

Tonight saw reassembly.

Amidst the biggest rain storm we've had in months, I set about putting everything back together.


Centered the fluid sleeve, torqued down and set the reverse piston spring stop to 1/2".

Torqued down the valve block evenly (6lb/ft), and the side pan (12lb/ft).


With it all back together, I took the carb off to install the heat shield.


Finally, all back together, on the floor again and awaiting being filled up with transmission fluid (on the to-go-get list still).

Phil

 

Went through after-work checklist, as my neighbor had stopped in to chat as I was finishing up and I lost track at that point.
Gear shift mechanism engages correctly at the correct points. Reverse pawl engages correctly too without the mechanism going PLINK ZING into pieces inside the gearbox.


I took the passenger door handle off because the key had stopped operating the lock. Reason? The anti-rattle O-ring had fallen apart and the button was sat too far out, and as such the key mechanism wasn't reaching.


New O-ring.


All cleaned and back together again, tested operational. That's better.

Phil

 

Add oil.


Test drive. It's occasionally very good, like in this video. Other times not so much.

One last thing to check and that's the pressure regulator. I did a forward/reverse rock of the car rather to do a good cycle of the valves and get the oil round- every couple of goes the reverse locking pawl would engage, something that's not meant to happen if there's oil pressure.

I can get a gauge and hook it up also to check.

Phil

 

Cleaned the pressure regulator and it's better but not great.

Probably got some dirt trapped somewheres. I'll see if it clears up.

Phil

 

Took the pressure regulator out but it's still occasionally getting stuck, particularly after it's been in neutral or reverse.

Time to pull it all to bits again. Again.

Phil

 

Bummer! I have no doubts though that you will solve this.

 

A photo from today that made me smile.

I'm off to the burger stand to get a cheeseburger and a chocolate malt.
Phil

 

And finally a photo from tonight.

Phil

 

Phil,
These early GM autos are a challenge! You are doing a great job with it! My 53 Pontiac (back in post 497) had a huge leak, I mean like adding a quote every other fill up. I took it to a local transmission guy and his father had worked on these back in the 60’s and was glad to work on it as long as we weren’t in a rush. It fought him bad! There were 2 leaks and it looked like in the past, the torque converter was dropped and my local guy had to send it somewhere for repair. Then getting it to shift correctly was a challenge. He had to re do it at least once. Why am I telling you this? Because after waiting a month, I finally got a nice leak free transmission and $1700 poorer. So if you are getting frustrated just think of my $1700 bill and keep going...and keep posting too!!
Greg

 

Worth waiting for. When they shift right they're not bad at all.
I'll fix it in the end, one of the main things with this that the been fighting is moving parts that are just plain worn out.
It's amazing it works at all in the first place...

Phil