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removing pistons on a 1935 LaSalle with engine on

Started by 47bigcadillac, June 25, 2012, 08:31:17 AM

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47bigcadillac

Is it possible to remove the pistons from a 1935 LaSalle straight eight, without removing the crankshaft and with engine on car ? How easy is this process ?

I have both the Oldsmobile and Cadillac manuals for 1935 but there is not much written on this procedure besides mentioning that pistons must be removed from the bottom.

There is a lot of blue smoke whenever I accelerate, this does not bother me that much because the smoke is greatly reduced if I don't accelerate much, but this may be bad in the long run for the engine.

I drive only about 1000 miles a year given that I have other classics to drive as well.
I use a 20W-60 oil, the thickest I could find where I live.

Engine runs smooth with no issues other wise.

I removed the plugs and #7 has a noticeable amount of oil.

There also is heavy/intermittent blow-by coming from the crankcase tube outlet, the explosions are clearly pushing the pressure & exhaust into the crankcase.
Needless to say, the oil gets dark very quickly after a change.

All this leads to either a stuck or broken oil ring, or more. I would like to dig under the car and start pulling those pistons out to have a look at those rings.

Thanks
Rob
R. Brandys

1932 355B  5 pass Coupe,  Fleetwood          
1935 LaSalle Coupe  5077
1947 Club Coupe      6207

1937 LaSalle coupe

Hi Rob. Since you only drive about 1000 miles a year, I don't think you could justify a engine rebuild, especially if car runs OK and only smokes a little. I could live with that. Oil changes are cheap vs a rebuild. I would maybe go to a hotter spark plug. I had a engine that smoked alot and I put 50w Castrol in it. Almost completely done away with the smoking problem. Maybe even consider taking oil pan off and cleaning up the inside of it. Drive and enjoy... John Lehman CLC# 26365...

47bigcadillac

Yes but that may just push the inevitable ring job and perhaps make it worse if carbon builds up around the valves, requiring additional work down the road

I already use a 60w oil, the thickest available

Cleaning the pan will have no effect

Costs are going to be low because I will do the work myself if it's possible, which I am trying to evaluate here.

Once I get those pistons out, I will replace the rings and hopefully that will do it
R. Brandys

1932 355B  5 pass Coupe,  Fleetwood          
1935 LaSalle Coupe  5077
1947 Club Coupe      6207

47bigcadillac

#3
Hi everyone
I just wanted to update this thread because it may be useful to others with the same straight 8  1934-36 LaSalle engine.

Removing and putting back pistons with engine on is really easy and takes only 10 minutes once you have the oil pan and flywheel cover out.

This is done by removing the cotter pin and 2 bolts holding the connecting rod, then simply puling the piston down by the connecting rod, and sliding it by the side of the crankcase and in-between the counterweights of the crankshaft.

This requires slightly turning the crankshaft to get the piston to pass through, therefore removing the flywheel cover and all 8 spark plugs is required in order to easily rotate the crankshaft holding the flywheel by hand, and also to get the oil pan out as its edge may be blocked by the counter weight of the piston no1 (like in a 346 engine)

Most of the time was spent working on the 30 oil pan bolts, and the changing the oil pan gasket because someone had the great idea to use cement on both sides of the pan.

Removing the ring compressor was a bit troublesome, but that's because I did not use the best tool, which is one of those special Cadillac ones. The one I used could be rolled out and somehow forced down without too much damage.
R. Brandys

1932 355B  5 pass Coupe,  Fleetwood          
1935 LaSalle Coupe  5077
1947 Club Coupe      6207

Steve Passmore

What you could have done Rob is what we do on the straight eight Buick's when the big end journal will not pass through the bore, push the piston right out through the bore, fit the rings on the top and push it back done to journal, saves all that messing trying to get the ring compressor in and out from up inside the crankcase.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

47bigcadillac

#5
I wanted to do it without removing the head, which is a lot more work and involves extra risks (bolts breaking, head gasket damage etc..) and those bolts seem very tightly torqued.

There is really no need to remove the head, everything can be done from under the engine with minimal work involved.

This is must be the best engine design when it comes to ease of piston access.

The big issue I had was finding over sized piston rings for my bore (3")...but that's another story.

Next time I do another piston I will also build my own ring compressor which will be shorter and have clamps that can be easily disassembled.
R. Brandys

1932 355B  5 pass Coupe,  Fleetwood          
1935 LaSalle Coupe  5077
1947 Club Coupe      6207