Worn Piston Rings

[Marshall V. Daut]

"That tells me that there's very little wear in the cylinder."

Perhaps so. Wouldn't that be a blessing?!? But as I wrote, the new 0.080" rings we ordered and test-fit had a 0.026" end gap right out of the box. Unless they were mis-marked and boxed in the wrong package, the cylinders must be worn at least 0.010", or as close to that figure that clumsy feeler gauges can measure. I don't have access to the very expensive cylinder wear measuring tool. That would be a nice Christmas present, wouldn't it, dear Wifey??? (Hint, hint).
At any rate, I am comfortable using the scaled down 0.0100" rings since the gaps do not close up lower in the cylinders. I guess we'll find out when the engine is back together and running. Besides being a budget rebuild - as I also wrote - this is an experiment on my part to see if jury-rigging mis-sized piston rings will work. ANYTHING is better than leaving the old rings with 0.035" end gap in place! I'm sure I'm not the first person who has attempted to squeeze a few miles out of a very tired Model A engine by doing this. Tools that re-grind piston ring end gaps weren't invented because all new piston rings fit perfectly out of the box!
Marshall

 

[Flathead]

It is important that the piston ring grooves (lands) are not worn excessively to let the rings move up and down in the piston. I would recommend a "dingle ball" style hone to break the glaze with minimal wear to cylinder wall. I have re-ringed a lot of old motors over the years without a problem.
If you desire to drive cross country at speed you will want a full quality rebuild. If you are just driving around town not racking up tens of thousands of miles a proper re-ring can do the job.
When opening up a Model A motor today you face the unknown issue of babitt condition and crankshaft wear, when they were younger the odds were more in your favor.
Use modern rings too.

 

[katy]

Tools that re-grind piston ring end gaps weren't invented because all new piston rings fit perfectly out of the box!
Marshall

Many years ago I was preparing to assemble a V-8 engine from parts, all the parts were new or had been re-conditioned. I was getting ready to check the rings end gaps when I was told that the ring gaps didn't need checking as they were manufactured to fit "as is". I decided to check a few rings "just in case". ALL the rings except one had to be filed to get the proper end gap.

So much for "ready to go, right out if the box"

Around the same time, (late 1950s, early 1960s) give or take a couple of years, I have see a few "rebuilt" engines that refused to crank over (rotate by the starter) shortly after being shut down while at running temperature, but would start after cooling down. Looking back, I suspect that those engines had piston rings w/insufficient end gap.

 

[Dodge]

The best mechanic in a can for your situation is: Restore brand Engine Restorer. It's in a silver can and does work miracles before you rebuild the engine. It's worth a try.

 

[Omar Morales]

The best mechanic in a can for your situation is: Restore brand Engine Restorer. It's in a silver can and does work miracles before you rebuild the engine. It's worth a try.

I did add the Lucas Heavy duty oil and used the stainless-steel pad in the oil fill tube. Went on a two-hour drive over the weekend, she was extra quiet and no evidence of blow by. She ran like a dream there and back!