42 DeSoto runs VERY rough, help needed

I can't imagine that it's much fun to lean over those huge fenders to work on the front of the motor!

Yikes, it's been 6 days without an update!

Don't leave us hanging! Have you learned anything yet about what's going on with the timing on the '42?

Sorry, this has been the first day in a week that I've had time to get back to this. Update coming soon!

Lol, you mean you have a life besides filling us in on your De Soto activities?

Ok, I just put a few hours in and got to the point where I need to post a question. I got everything off as pictured but was stumped by the threaded wheel pictured. How does this come off? Do I simply unscrew the large nut in the middle? If so, which way, left or right? I'm afraid to unscrew this without advice!

from my interpretation of the '49 shop manual, your crank nut is holding on a keyed flange that your harmonic balancer was bolted to.

Instinctively I believe that the nut is left hand threaded, and should turn off in the normal righty-tighty/lefty-loosey direction.

After you remove the nut, you'll probably need to pry (gently) the flange from the snout of the crankshaft so that you can then remove the timing chain cover.

Depending on your toolbox, there is no doubt a puller that will remove the flange. If you don't own one, you may have a parts store such as AutoZone or O'Reilly's in your area that has a tool loaner program. My local rental store where I can rent a roto-tiller, or sewer snake etc. has a remarkable array of automotive pullers that I can rent on an hourly or daily rate.

Thanks Tim. I have a gear puller so I'll see how it goes. I'm just not sure why the engine wouldn't turn with that nut, but we'll see. Stay tuned!

It might turn the engine, depending on how beefy the guy was that installed it.

When I'm trying to loosen a nut on something that rotates, I can sometimes get away with striking the wrench to "shock" the bolt/nut/whatever loose before the part starts to rotate. Of course, an impact wrench would do it as well if you have the room.

Or, you could wedge a block of wood or something into the teeth of the flywheel against the bell housing or similar to prevent the crankshaft from turning.

Your advice worked Tim. I turned the crankshaft bolt but the engine easily turned with it. I opened the bottom vent cover on the bell housing and banged a metal drift into the geared outer part of the fluid drive. This was enough force that I was able to loosen the front bolt and remove it.

Getting the hub off was another story... There is no room for a gear puller so I looked through my tools and found a flaring tool. I'm really trying to do this without removing the engine! The flaring tool had two openings just the correct distance apart from two opposite threaded holes in the hub. I went to Home Depot, got the longer 5/16-24 bolts and connected it all to the hub. I used a deep socket in the shaft for the tool to press against. It worked! Hub is off. My next post will be when I get the timing cover off...not sure when it will be.

All connected ready for tightening (loosening).

Hub is off.

Ok, here's the timing marks on the cam and crank sprocket. They appear to align perfectly at ever other turn. The chain and sprockets appear in excellent condition and there is no more than 1/8" of travel when I press down on the center of the chain between the sprockets. I'm glad and I'm not. Correct me if I'm wrong, but the problem here is something else other than the timing chain? Suggestions? By the way, coolant poured out of the top-most timing cover bolt hole... Didn't know it would do that.

I've been kinda worried about this outcome, but at least you can cross off any anxiety about the condition of your timing sprockets and chain.

One thing nagging me in the background is that the #1 piston hasn't been at TDC when the timing mark has been at 0 degrees like we would expect. Can you now set your harmonic balancer back on the snout of the crankshaft and determine that the timing mark orients where we would expect it to be? Maybe without the flange on the crank it's not easy to do. Is the harmonic balancer keyed? If so it would be easy to orient it correctly while you have the dots lined up.

Is there any chance you were misinterpreting watching a valve through the spark plug hole instead of the piston? It seems like it would be tough to see the piston travel by looking through the spark plug hole.

What doesn't kill us makes us smarter. I can tell you that by judging from the pictures you posted it's VERY likely that I was judging TDC thru the spark plug hole from the valves INSTEAD of the top of the piston. Both the spark plug hole and valves appear to be on the left side of the engine. I thought the piston would be right under the spark plugs, it appears they're over the valves??

The harmonic balancer is not keyed. I can orient it in one of six positions. I should be able to temporarily check it however. I'll check it tonight.

This must be why there's that plug over piston #6.

Tell me this please:
When the timing dots line up on the sprockets, the #1 AND #6 cylinders are both at TDC, correct? I can check that.

When the dots are lined up, #1 & #6 are at TDC, and the valves for #1 are both closed. The exhaust valve for #6 would be open.

The cam turns at half the revolution of the crank. That's why you could bring the mark on your harmonic balancer up to the "0" on the timing cover and not necessarily be at #1 TDC. Without checking for certain, you could possibly be on the compression stroke for #6 or "180 degrees out"