Projects Found a nasty ugly piston today

... While trying to go over everything to get my car back on the road I decided to pull the head just to check things out. I have only driven the car once and that was from the semi transport to the house. It seemed like it ran fine and strong with only a slight misfire heard at the exhaust. I'll put ho the video of it it running..

But, once I pulled off the head everything seemed nice and pretty till I used some cleaner and a soft brush to clean off the carbon.
This is the furthest front piston....










Here's how the others look

 

so it got corroded at some time....and it's already 60 over...

I would just run it and see how it does. If it uses more oil than you like, you could get the #1 hole sleeved and a new piston for it, and spend lots of money doing that...but in the end it's still just an old Desoto six that probably isn't going to ever get a whole bunch of miles on it.

 

Pour some gas on top and see if it leaks down faster than the others.

 

looks like the top of the piston might have been damaged somehow and someone tried to "clean it up" with a file or wood rasp. check the distance from the deck to the top of the piston at TDC and see how much lower in the bore it sits. should tell how much they removed.

 

Run a compression test on it. First dry and then squirt some oil in each cylinder and see what kind of readings you get. If they are within range drive it.

 

Looks to me like somewhere in it's history someone s****ed the carbon off and used too rough a tool. I say clean up the block and head and ****on it up. Old engines like your 6-226 MOPAR were tough and you won't have a problem.

 

I don't tear things apart till I have done a leak down test. If it's sealed up and don't have a bunch of piston noise (and it wouldn't if it's tight) who cares what it looks like inside. Looks aren't everything.
The Wizzard

 

Looks like it might have had some moisture in that cylinder at one time, some pitting in the deck between the cylinder and exhaust valve.

 

Thank you for all the replies.

Aaggie, I just found out it's not the original engine. It's in a 48 Windsor so I thought up till now it was the 6-251

I poured some MMO on it and it didn't stay full very long at all

 

how does it compare to another cylinder? If they are all about the same, then you probably shouldn't worry about it. But it would be good to get the head back on and do a compression test, too.

I guess the main thing you need to consider, is how nice you want this engine to be, how much use it will get, and how much money you want to spend.

 

Would it be too much to say I would like it to be very nice and able to drive all day every day with little cash out of pocket? [emoji16]

I tend to over worry too, things that may be small or no big deal will eat at me.

 

Here's the videos as well...

 

sounds like a rather fast idle for an old engine like that....

First things first, I like to start with a compression test, and if it looks ok (all cylinders within about 15%) then I'll put some miles on it and see how it does.

If you seek perfection, you won't ever drive the darn thing.

 

Thank you, very true words. I also thought the idle sounded fast... I read it supposed to be around 450. And if the idle is too fast I was told the transmission wouldn't work properly

Easiest way to check idle rpm?

 

A tachometer is what you use to check RPM. In the old days, we'd use a Dwell-Tach meter, which was a combination test set you'd use when doing a tune up.

If it's a fluid drive, then yeah, the idle speed needs to be set properly.

 

Using MMO I'm not surprised it didn't hang long. That motor most likely has one piece Oil rings. Ring end gap is like an open p***age. Seems strange to me to pull the head to find a slight mis fire. Did you check points and plug wires first? To set idel R.P.M. you need a tach. Most remote dwell meaters have a tach in the unit. Using one of them might have shown you an ign. issue.
The Wizzard

 

Thank you, I'll look up that dwell tach.

I didn't necessarily pull it to find the misfire, that video was made a couple weeks ago.

I pulled it to really just sand blast the head and repaint it. I already had the water pump off since I was replacing the water distribution tube. So it was easy and tempting. Once back together I'll check the compression.

Only time I actually drove it was from the transport home which was about 2 miles. Only gave it a little throttle in that time and it seemed like it had good pickup

 

You can pick up a really nice gently used dwell-tach off feebay for really cheap. They are really easy to learn how to use. They take out a lot of the guess work. Look for one with a booklet (how I figured out how to use mine).

 

Now I understand. From the sound on the video it's running pretty good. I wouldn't worry to much about the looks of that one piston. What ever caused that is in it's past.
The Wizzard

 

Like this one?

 

Cool, thank you. If I didn't take the MMO and soft bristle brush to the piston I would of never noticed it. It wasn't until I wiped everything up that I saw the surface. It seems like the carbon filled in all the groves before making a uniform surface.

 

That is indeed the kind of tune up meter we're talking about.

 

I can't find one thats actually says it works for 6 volt, they all say 12 volt. Now if I'm only using it to set the idle RPM's will the voltage matter?

My car is a 1948 Chrysler Windsor with a 6 volt positive

 

I don't think it matters. Your reading dwell and R.P.M. at the coil. Near all old 12 volt and point systems ran a resister that dropped coil voltage to between 6 and 8 volts. I've never had a dwell meeter with a voltage switch on it.
The Wizzard

 

If it ain't broke don't fix it.

That's the economy-minded rodder's mantra.

If it was running okay before you yanked the head then stop worrying. At the very least you will now have a fresh head gasket on it to go with the new paint on the head.

 

Home attempt at Signh grooves?

Sorry, couldn't help myself.

Put it back together, drive it & don't fret. Most of the old flatties were low compression, very lightly stressed designs. Think IHC Farmall, or 2 clyinder John Deere tractor. As such, they will forgive much. Much different if high compression, high rpm trying to squeeze out every last bit of Hp & torque.

Worken2much

 

S18 = 1953 DeSoto 251 cu in 116HP engine. Same displacement as your original engine but 2 more HP, a tad more compression, and the best full flow oil filter.

This is actually the best of the Chrysler flathead sixes, except for the 265 used in 53 54 Chrysler Windsor.

 

I have an old dwell-tach that I bought at a garage sales for $2.00. It works (all functions) on both my 6 volt '51 Ford and my newer 12 voltbcars.

 

Thank you guys, I'm feeling much better about bolting it all back up and enjoying the miles ahead.

And Rusty, thank you, 2 HP might not seems like more but that means I can enjoy that extra doughnut and still scoot myself around.