My 383's toast

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1968 Valiant

1968 Valiant

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Opened up my 383 this weekend and this is what I found (see attached pics).

I was hoping to check the clearances on this motor and run it as is for the summer. Guess I'm back to the drawing board or off to the machine shop.

It does have a steel crank and 906 heads though.

Has anyone seen damage like this? The motor look like it sucked up a bunch of ash.?

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looks like normal carbon build up. .. .mine only had a light film of carbon on the pistons and a little on the heads just get it cleaned up and go from there
 
I remember back in the day, my dad told me about a carbon removal technique he had used. I've done it on occasion as well.

With the engine running at about 4000 - 5000 rpm, take a small (about 1/2 to 1 cup) amount of water and SLOWLY pour it into the carb - using several small pours. The engine rpm's will drop each time (for obvious reasons) so don't pour so much in that the engine drops below 1500 rpm. The water going into the combustion chamber will knock the carbon buildup loose and blow it out the exhaust.

This method may not feel kosher to some, but I have seen it done and have done it with great success. It would correct this type of buildup without an engine teardown.
 
that's carbon build from running cheap gas , but I can't tell what that thing you are holding is in the first picture .
 
It's a mix of lead deposits, rust, and carbon. That engine hasnt run in years. I would be cautious of scraping or wire brushing that off. Wear a mask and preferably use carb clean or marvel mystery oil to keep the dust down. Also might want to wear gloves. If it turns with a wrench, it might be abel to be made to run. Clean the pistons, pull the valve springs and make sure the guides aren't seized.. Oil it all up well, and it might run. I'd call it a usable core right now.
 
Not knocking this technique, but I'd be more inclined to buy a can of Seafoam and use it before introducing water into an engine internally.
Just MHO.


PacificScamp said:
I remember back in the day, my dad told me about a carbon removal technique he had used. I've done it on occasion as well.

With the engine running at about 4000 - 5000 rpm, take a small (about 1/2 to 1 cup) amount of water and SLOWLY pour it into the carb - using several small pours. The engine rpm's will drop each time (for obvious reasons) so don't pour so much in that the engine drops below 1500 rpm. The water going into the combustion chamber will knock the carbon buildup loose and blow it out the exhaust.

This method may not feel kosher to some, but I have seen it done and have done it with great success. It would correct this type of buildup without an engine teardown.
Click to expand...
 
340_dart_power said:
Not knocking this technique, but I'd be more inclined to buy a can of Seafoam and use it before introducing water into an engine internally.
Just MHO.
Click to expand...

That trick has been around for many years (probably goes all the way back to the 20s). You just dribble a little down the carb with it running. It's free and doesn't hurt anything.
 
Thanks for the tips guys.
I did not explain well. The piece I am holding is the flange from the #1 piston. I am not sure how it broke off because the engine acually turns over freely and looks very clean inside the block. No other signs of damage.

I will be honest. I am atempting to put together a "junkyard build" of sorts. My goal is to get my valiant converted to a running driving big block. Once I have acomplished that I wil start "fine tuning" the performance upgrades (cam, heads, lower end rebuild).
Is this a bad goal?
I am finding most of the big block mopars out there pulled already meaning I will be taking a chance on weather it runs or not. Maybe I should just have this 383 rebuilt.
Is anyone running just a stock well used big block out there???
 
Water really is the best and easiest way to remove carbon. Just ask anyone (like me) that has removed a head off a car that has blow a head gasket. It is clean as a whistle.

If you really want to do a junkyard build I think I may have some stock standard piston/rod assys. I cleaned out some dudes garage and in all of the "stuff" was two 383's disassembled

Chuck
 
If you are going to give the motor a drink might not want to do it on concrete, it can make a bit of a mess...
 
for a second i was wondering if it was a product of the CASH for clunkers program. pull it apart give a good inspection. im sure you can find a piston. i have a set of pistons and rods in my garage if you cant find anything local. youd be better off raising the compression with a set of pistons, but sometimes you gotta use what you have. im doing a budget 400 with 383 steel crank, stock rods and pistons. if all checks out its just getting honed and a new balance job, small cam, timing chain, ported 452s and some used springs i have. if i put any cash into it, it will be a set of stealth heads. im not going for big power, just an efficient combo.
 
1968 valiant said:
opened up my 383 this weekend and this is what i found (see attached pics).

I was hoping to check the clearances on this motor and run it as is for the summer. Guess i'm back to the drawing board or off to the machine shop.

It does have a steel crank and 906 heads though.

Has anyone seen damage like this? The motor look like it sucked up a bunch of ash.?
Click to expand...
omg
 
that piece really looks like part of the rear main seal housing to me.
 
It looks like an engine that has sat for quite a while. Moisture has caused the carbon to come loose, and corrosion to form. I started a 53 Chevy truck once that must have looked about the same inside. Long story short, I'm glad we aired up the tires before we cranked it, as all the carbon came shooting out the exhaust as sparks and set the field the truck was sitting in on fire. Almost spilt my beer on that one.

Is that a piece of the piston crown or skirt? It may turn freely now, but I bet at one time it didn't.

You could probably have it running again pretty cheaply (same size cast pistons, hone bores, new rings, bearing inserts and polish the crank). Such would be a "freshen up" type overhaul, and not a rebuild. Otherwise you have a nice core to rebuild.
 
I have actually seen a lot worse. Moper is right you could take the time to clean the pistons and reuse them if there is not to much of a lip in the cylinder and you budget is tight. The combustion chambers in the heads could be cleaned up also. I would also take the time and make sure all of the small coolant passages in the heads are not rusted up and full of trash.
 
Would that acually work for any amount of time?? Putting in a good used piston and running it that way?
I thought rings and bearings only seat once and have to be changed and if you change those you have to get the engine honed and and crank ground or polished..?
This was why I was looking for a runner. To avoid the machine shop until I was ready to build a properly machined performer..
 
Naw, you can replace rings all you want, they're disposable. You need to at least break the glaze on the bores so the new ones seat. A simple hone and electric drill will suffice. Same with bearings, the inserts are disposable. Polish the journals with some 600 grit and a shoelace. CLEAN is what you need to do with this engine! Same with the heads, clean them up, replace the stem seals, hand lap the valves and put them back on. Since I'm starting to really doubt that little piece is from a piston (figure out where it came from) I bet you can have that engine running for about $500.
 
I looked at all the pistons and the piece is part of the piston skirt. the whole assembly rotates fine and I cant see any scoring.
I checked all the clearances with plastigage and they are all withing spec. Also there is no noticable lip where the piston stops at TDC.
If I tried to Hone this myself would I have to gauge it and use oversize pistons or would it not take off enough to matter?

Thanks for helping the new guy
 
you want to make sure you make the same amount of passes at the same speed and angle in each cylinder with the hone.
 
PacificScamp said:
I remember back in the day, my dad told me about a carbon removal technique he had used. I've done it on occasion as well.

With the engine running at about 4000 - 5000 rpm, take a small (about 1/2 to 1 cup) amount of water and SLOWLY pour it into the carb - using several small pours. The engine rpm's will drop each time (for obvious reasons) so don't pour so much in that the engine drops below 1500 rpm. The water going into the combustion chamber will knock the carbon buildup loose and blow it out the exhaust.

This method may not feel kosher to some, but I have seen it done and have done it with great success. It would correct this type of buildup without an engine teardown.
Click to expand...

I've used this several times as well. I used it on my late Mom's Valiant 6 that was REALLY carboned up(imagine how slow an 80 year old lady drives!). Trickled water down the carb while revving the engine...you should have seen the crap that came out the tailpipe!...and boy did it run better afterwards!
 
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