piston stamped .070

[rollingsculpture]

bud wrote that my stamped pistons indicate that they are over size , what are the original dimensions and what are all of the steps up in oversize dimensions ive seen references to 060 and 070 what is the last size up you can bore to /.what should i expect performance wise . i only plan on replacing gaskets as i removed the head for inspection of the cyl and valves since i dont know the history of the engine and some rodent had put seeds up in the open manifold. it also had some stuck valves and i managed to get them to unstuck , they seem to operate ok as far as opening and closing now , i have the spring removal tool and can inspect and clean the carbon and reddish residue from them with out removing them from the guides.also there is the slightest hint of rust on one cylinder that had a valve open ,i know some of you must be saying well get on with it and rebuild the motor the right way and im sure i will at some point but for now if i can get things to be in working condition i would be happy to get it operational .so for now visual inspection of parts and replacement of whats missing is my goal. of coarse if this is a really bad way to go about it let me know , im always open for good advice.

[spectria]

I've restored a few vehicles in my time (this is my first Model AA).

I can tell you as a shop owner I was a perfectionist...

I would not let anything pass, especially if I had to back it.

On my own vehicle, it's now a different story. I can always go back in and redo something on a vehicle as simple as the AA.

But if you intend to use it, drive it any distance, that rust, and that red residue will kill your engine. You can't rinse it out. If you want this engine to last, pull it out, pull it down, do it right the first time.

If you have a spare motor, throw that it in to get it running, I know how much you need to hear it run... It's almost like getting a fix (although I don't know what that is like, other than the hundreds of new engines I have built, and that first start... AHhhhhhhh!)

IMHO

[rollingsculpture]

hmmmm so i need to re-bore the engine to get rid of the discolored rust? it is very fine haze... the surface feels very smooth like the others, the rings wont wear it away ehhh, alright, so whats the next size up and if im at .070 how many sizes or rebuilds do you think has happened so far ??.I will have to find a shop to machine it i would like to do the engine work so what book/ manual do you recommend for this part of the journey? im 30 miles from Brattons in md and i met their mechanic i'm sure he may be helpful but the piont of this for me is to learn as much as i can from doing it much in the spirit of Henry Ford himself . i don't have a spare engine so maybe i can locate one next, .i knew i would be hearing from the right people about this if i asked , i was just hoping to do just whats necessary considering the rest of the truck is in need of so much more , i mean ...i hear ya but the thought of doing a tear down along with the rest of the body work, welding prime, paint, wiring... etc i guess since i have to do all that i may as well really get it all solid. i was thinking there would be stages to it and i guess everyone does except those who do it for a living and know better ,but its true the engine will be easier to deal with when the cab and platform are off any way . Thanks for keeping me on track. yep im chompin at the bit. thats the reason i signed aboard with you all i knew you wont let me do what some may do but regret later. i know some of you have the heart that says leave it alone if you cant do it right or give it up to someone who can!!! i guess im on that fine line that wants both the original truck and the restored truck i think i need 2 like Rem but thats not happening yet ... this has been a terrific adventure so far but it is really a scarce find here on the east coast i had to find one in the mid west and ship it . i will be posting pics on flickr same as my name here ,Rolling sculpture and of course tagged for AA truck .i found out Photobuckets site is oriented for new mac os system not for the older one that i have, so theres one thing as far as site differences .

[spectria]

Let me make sure I understand you correctly. You think you need to bore out the engine to clean up the surface rust.

If I just wanted to get it running, I would check the depth of the ridge at the top of each cylinder. If there is no perceptable ridge, I would pull the pistons and clean them including the ring grooves, Hone the cylinders lightly with very fine stones and I might even put the old rings back on. (you got to be real careful here and use a ring tool to handle the rings without breaking them).

But that's when you start to get into Pandora's Box.

When you pull the pan you find it full of thick gunk, then you notice a crack on some engine part, then you notice the journals on the crank are scored...

I once was given an old Dodge truck with a 318 in it. It had quit in the street in front of my shop.

The owner ask for an estimate, she had run the engine dry of oil, after repalcing nearly everything on the truck, Automatic Trans, Battery, Alt, Water pump, you name it.

I pulled the plug wire on the knocking cylinder and it quieted right down.

I pulled the pan and there was no Rod bearing Number 7 & 8.

After I told her, she just brought me the pink slip.

I cleaned the pan, new oil pump, pulled all the rods with the Heads still on, polished the crank with 600 hundred cloth after peeling off the waisted rod bearing material, put in .002 over bearing on #7 & 8 and standard on the rest, put it back together and drove it for years back and forth to the dump.

I would never have done that for a show vehicle or a customer, but I didn't hesitate for a Trash Truck.

So there you go. Pick one route and go with it.

And post pics of your progress so I can learn how to do an A engine

[Brian T]

Rollingsculptor,
Just a suggestion , if I were you at this point in time I would clean everything up , studs , nuts , rust from the cylinder , pour in some Marvel Mystery oil to soak the rings , refit the head with new gasket, clean out the carburetor , change oil , make a small temporary fuel tank , and see if it runs .
You will not be spending much money to do this and it will probably make you feel good listening to it running even if knocks a little, you can then put the truck on stands and see if the transmission works and the drive line turns , if OK then when you find the wheels you can at least drive it providing it stops.
This way you can evaluate what to do next , BTW one of our members Knuck I believe , was going to make some plywood wheels to make the truck mobile so he could push it in and out of the shop until he found some good wheels.
Brian T,

[steve s.]

Rollingsculptor,

If you want a 100% restored truck, then there is no question . But if you want to enjoy seeing your truck run and move rather than being spread about the garage for years, I would say don't tear it down now.

That rust is nothing to worry about. Think about it, that same amount of rust probably exists in many " restored" trucks that have been sitting for a few years, but these truck often get a battery installed and they are off and running. No one pulled the head and no one saw the rust. No problem.

I would suggest that since you have the head off, you remove the rust with fine sand paper
vacuum out the cylinders, oil them up, and get the engine running.

If you want to tear into the bottom of the engine, go ahead, it is a good chance to see what you have , and clean the carbon behind the rings as mentioned earlier...but it really is not necessary. Remember, someone was driving this truck up until the time it was parked, and unless you have strong reason to believe there is a problem with your engine, there is no reason to create one.

As for .070" over sized cylinders, you can buy pistons in .080, .100, and .125, so parts are available and you have plenty of block left if you do need to bore it out again in the future, You could even bore and sleeve one cylinder if the rest are still ok.

So consider following Brian T's advice, and let the engine tell you if it needs to be rebuilt.

Good luck, Steve

[rollingsculpture]

Steve thanks for that useful info on the over sizes, it tells me where i started and where it may go also thanks to Brian and Dave ! I had decided at first to just do a visual tear-down to see what i have and than replace what was needed since i could always go back later to do full restoration . i think what i really lean towards is to pick up a second motor preferably with the proper year month day stamp and rebuild that since it would be more in line with "restoring" the truck . there is a stamp on the motor which is incomplete of the ""AA"" and ""stars"" the number thats there if just re-stamped by the mechanic of the times seem to indicate a 1928 ,you can see in my post about that . anywho i dont want to strand the truck by having the motor out so my method so far is everything at once . meaning engine work , cab and platform off so i can get to the frame and do some of the work that needs to be done there as well as making access to the front and back wheel assys easier, i can put the cab, fenders,hood and other small work on a cart and take it upstairs to my shop (Freight elevator with doors right into the shop, yes i am very lucky on that one!) for welding and dent removal, the garage is not heated and we've had 20- 30 degree days here with no let up in sight ,not that my shop is so warm as it has minimal heat, high ceilings and all brick walls and cement floor but im not complaining somehow just being able to work on the truck keeps me warm enough, strange but true.