Installing a 1948 346 & Hydra-Matic in 1939 LaSalle 5027

[las39]

Brief history

Part 1

My 39 LaSalle has already gone through a complete engine overhaul with the original 322 matching number engine. This car was purchased from Sweden and was imported from Mexico. Build sheet shows it was purchased by General Motors De Mexico, Mexico City.
Options was radio, flex wheel, LC ratio, Chrome Trim Rings, export clock and kilometer speedo.
All these are still on the car. It had no heater and thermostat hole was covered and had a Delco vacuum fan behind steering wheel. Also, a pair of Trippe Speedlight spot lamps.
Car was running ok but used oil, smoked and heated up but I could live with that, only using the car in summer and planned overhaul in winter.
Winter came and engine was removed and dismantled and sent to rebuilder. To our shock we noticed most of the cylinders has the infamous cracks between valve and cylinder. But the engine builders in Mexico had re-sleeved all cylinders and reused original 4 ring pistons. It seems to work but piston slap was incredible. Lower end bearings also loose.
To keep engine original 322, a complete set of 30 oversize pistons and bearings was ordered and engine was refurbished and put back in car. All is good I thought but alas the smoke began again and increased. Heating problem disappeared and engine ran very well except oil smoke. Rebuilder was disappointed for he made all to specification and even balanced the crankshaft, machined the head and cylinder etc.
After another year smoke increased especially when letting off gas and coasting, oil smoke filled in cabin and was unbearable. Driving behind me was also embarrassing. Removing the exhaust crossover, I noticed smoke was coming from right bank so head came off for inspection. One piston and valves where black form oil residue. It took me several days to figure out how the oil was getting into the chamber. In the end I noticed the sleeve has gone loose and oil seeped between sleeve and cylinder during vacuum. I guess new tighter piston and rings, sleeve workmanship didn’t go together.
Now I had the choice of re-sleeving it and keep the 322, re-sleeve it to 346 or get another engine.
The cracks where putting me off so the 322 was taken out and I looked for another, but in this country, chances are slim so post war 346 was only option. Finding a 346 manual will be even harder.
There where a couple of 346 with Hydra-Matic for sale and all promised they were newly restored etc, but I wasn’t tempted after seeing how they have been worked on. Modern rounded bolts on engine was a no go for me. But finding and untouched original was also far fetched until I saw an ad for a 48 that has been for sale for many years. He said it was stuck and rusted. It came in a container from US form some junk yard filled with 50-60 cars.

[las39]

Engine was terrible to look at, it came with Hydra-Matic and was for sale cheap. Looked like something pulled up from the Titanic. I studied every fastener and noticed the where all sharp edged untouched. It had an optional oil filter with a bracket mounted to heads with two special bolts normally used for hose necks and return feed through long bolt on chain cover. Head bolts where the original 11/16”. Dip stick and hole had a thick black tar-like gunk. Took the engine home and hoped for a low mileage uncracked.
Removing heads bolts was troublesome. Welded nuts on them, heating them, cooling off, reheated did the work. I was curious if it had cracks. To my surprise, no cracks.
Two pistons had water and wrist pins where rusted so much that slicing pistons was the only way. Pitons said Cadillac 058302 inside skirt and no oversize marking on crown. Crankshaft, camshaft and lower parts was covered in two-inch black tar gunk. After cleaning parts, it all looked new and bearings and cylinders where all std size. What a find. Engine builder couldn’t believe his eyes. This 70 plus years old engine as in better shape that the usual 20year old Chevy 350s he works on.
Due to some pitting from one wrist pin on rear cylinder wall, we decided to get 30 oversize pistons. But where will I find STD con rod and lower end bearings? Egge didn’t have them neither the other usual vendors. After searching the net, found a NORS set on eBay. He was happy to lower the price as demand was low. Engine got the same big work, ultra-sonic cleaning. resurfacing, balancing, boring, honing. Bearings etc. New valves seats and valves where grinded to 3 “to camshaft.
Installed the rounded LaSalle heads, fuel pump and carburetor. All in all, it was a success and engine fired up first turn and has since run fantastic with no issues. This happened late spring and I needed to get car ready but haven’t figured what to do with the 3-speed gearbox. Thinking the engine was untouched, I hoped the Hydra-Matic must be in same condition and took measurements to see what it took to make it fit in the car. I didn’t want to cut or destroy anything so the three speed can go back at some other time.
I was surprised to find out the overall length of the Hydra-Matic with tail shaft is exactly the same length as the three speed. Mounting holes are also the same. With no drive shaft or mounting hassle, I opted to try the automatic and see what all the fuss is about 😊
Unfortunately, side case cover was rusted, levers where broken and yoke was missing. These parts where purchased from a fellow CLC member living in England. Thank you, Mr. Steve Passmore.
I blocked the inner shift lever on steering column from moving with a bolt and used the outer lever for shifting. Using the original hand lever for shifting. Getting the shift pattern correct with carb and tv lever was tricky. The only modification was made to the floor under the huge inspection lid.
A small cutout of floor to the left for the protruding pressure regulator hex.  External band adjustment was also made easy without the lid.
All in all, I’m very pleased with the Hydra-Matic but it leaks from torus and this winter, transmission is coming out and will get an overhaul.
It’s been a long and painful (expensive) relationship but I guess we are all a bit mad owning these cars. 

[las39]

Engine before

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piston skirt

[las39]

Same engine from rebuilder

[harry s]

Very Nice! A very worthwhile project with a great outcome. Did you change the rear end ratio? If not how is your cruising speed/rpm?     Harry

[savemy67]

Hello Mo,

That is quite a project you undertook, but it looks like a job well done.  The '48 Hydra-Matic is relatively easy to rebuild.  If you need any parts, you might try Dave Edwards at autotran.us.

Christopher Winter

[las39]

Very Nice! A very worthwhile project with a great outcome. Did you change the rear end ratio? If not how is your cruising speed/rpm?     Harry

Thank you. Yes a bit high and wanted to change the ratio but was discouraged after reading here several topics about post war axles not fitting the later differential. Even thought overdrive along driveshaft but then again are rpm really that high or are we just accustomed to low noise highway crusting? Listening to revolutions of tanks and landing crafts rpm, they are run much higher and could do it all day.

[las39]

Hello Mo,

That is quite a project you undertook, but it looks like a job well done.  The '48 Hydra-Matic is relatively easy to rebuild.  If you need any parts, you might try Dave Edwards at autotran.us.

Christopher Winter

Thank you Christopher. I hope it all will be downhill from now. I also don't think they are that hard to rebuild. Have already made special adjustments tools and jig thanks to YouTube.

Funny you should mention his site. During "in-car" band adjustments, I couldn't get the 3-4 shifting correct even following the Cadillac and Pontiac Hydramatic documents. It just kept on slipping. I found the correct adjustment procedure on his site. That helped a lot.
Thanks I will contact him for parts.

[Terry Wenger]

Hi:

For your leakage at the torus cover, be sure there is a gasket between the crankshaft and the flywheel and that the flywheel bolt threads are covered with sealer. I found out about that on my '49.

Terry Wenger
CLC 1800

[las39]

Hi:

For your leakage at the torus cover, be sure there is a gasket between the crankshaft and the flywheel and that the flywheel bolt threads are covered with sealer. I found out about that on my '49.

Terry Wenger
CLC 1800

Do you mean the 32 bolts ?

[Steve Passmore]

Looking good Mo.
Had I known I have stocks of STD main and big-end bearings. Oh well.

[las39]

Looking good Mo.
Had I known I have stocks of STD main and big-end bearings. Oh well.

Thanks Steve. Yeah isn't that typical, but good to know next time I fall over a STD flathead 

[Steve Passmore]

Thanks Steve. Yeah isn't that typical, but good to know next time I fall over a STD flathead 

I have one of those as well!!!