440 piston ring question

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69B-Cuda

69B-Cuda

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I have a question on piston rings. I have a 73 440 out of a motorhome, stock bore, I honed the cylinders and the ring gap is a bit bigger than specs. I"d like to get the file-to-fit rings. A lot of them I see are 1/16 thick instead of the 5/64. Was there 2 different ring thicknesses from the factory, or can you put the 1/16 rings on pistons that have 5/64? (assuming not ...)
 
all Im going to say is if you build them lose that's how they stay...........:burnout::burnout::burnout::newb::newb: Im sure you will here a lot of :bs:about engen biuding unless your hering it from (Rob)or rustyratrod as you know him.............I will be :lurk::lurk::lurk: Artie
 
you need to buy the thickness of the rings that your pistons take....

you can not put 1/16 rings on a 5/64 ring land....or 5/64 rings in a 1/16 ring land on the piston...

if you are using an OEM or OEM replacement pistons..they are going to be 5/64....
 
70aarcuda said:
you need to buy the thickness of the rings that your pistons take....

you can not put 1/16 rings on a 5/64 ring land....or 5/64 rings in a 1/16 ring land on the piston...
Click to expand...

What he said. And you should measure the ring groove clearance too, at the bottom of the ring. Not sure about today, but usually if you were not going to bore the cylinders you would just want to break the glazing or touch them up with a very fine hone quickly. If you take off too much metal you ring gap will suffer. They don't make oversize rings.
 
thanks, I understand about measuring ring gap as well as clearance in the groove, was just double checking to see if I was missing something specific to a RB Mopar... but, mechanical principles really don't change! ... no go on swapping rings, that is what I thought. This engine sat and got some water in one of the cylinders before I got it, and it is pretty ugly (the one cylinder). I did not really want to go through the expense of punching it, new pistons, balancing, etc.... that will turn my "great deal" into a not so great deal... although it has a forged crank that has never been turned, bore is std, and the engine did not cost me anything except to go pick it up.
 
So it had water/rust damage in one hole? How much did you hand hone it?
 
It is about 4.322 right now. Ring end gap (one of the used rings from another hole) was .035... loose specs in the book are .025. I have 2 440s, the one with water damage is a 73 with forged crank and 215 heads. It is std bore and crank is std on rods and mains.

the other is a 76 or 78 (don't remember which). It is .030 over and crank has been turned .010/.010. It has the 452 heads on it.

I am trying to figure out which one I want to run. the newer one is probably in better condition (at least the bores are) but the older one has the forged crank....
 
Here are some pics... first 3 are cyl #2 (worst one) last pic is cyl #3.... the others do not have any water damage and would not bother me to run.
 

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That should be bored, IMHO. I am anal when it comes to bore finish. Bore wear.....you can kinda fudge on......as long as the cylinder is round and has no water damage. But those should be bored. JMO.
 
Bore .030 and buy a set of pistons with a higher Compression height to get the pistons as close to zero deck as possible.
 
Yeah, I was thinking it needed to be bored. Then re-balanced, rods reconditioned, so much for an engine I was told was rebuilt 10K ago!

am I correct in thinking that I can run the tranny (727) and converter from the engine with the forged crank behind the cast crank as long as I use a weighted flexplate from B&M? If so, which one do I need? the 10238?
 
Yeah, you can do that. I ain't familiar with all them fancy part numbers. Just as long as the flex plate and balancer are for a cast crank, you'll be fine. I like the flex plate that's round and looks like it has a bite took out of it. They are pretty strong.
 
so by running that flexplate, you don't need the weights on the converter, correct?
 
I agree with RRR. You could run it - but it will suffer from oil use, lowered power levels, and short life.
 
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