Author Topic: Broken Rings  (Read 223 times)

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410bruce

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Broken Rings
« on: May 20, 2019, 10:40:40 AM »
Hello guys. New to the forum but not to Ford engines.
Picked up a 410 and was tearing it down. When removing the pistons and rods, there were several broken rings--maybe 5-6 pistons worth--all the top and second ring. Lot of miles on it I'm sure but it more than likely had been refreshed at some point as the head gaskets didn't appear to be factory and it has brass freeze plugs.
The gentleman I bought it from said it made a knocking or tapping sound on his way home from work one day pulling a hill but was quiet the rest of the way. He parked the truck after that and pulled the 410 and replaced it with a 390. Said the 410 always ran great with a lot of power. All the rod bearings look good with only one showing some copper.
Any Ideas why there would be so many broken rings?
There was a bit of a ring ridge I pushed the pistons through removing them but have done that before with other engines and not had any rings come out in several pieces like these did.

Thanks for any input.

gt350hr

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Re: Broken Rings
« Reply #1 on: May 20, 2019, 10:49:28 AM »
     Cast iron ring breakage was pretty common and one of the reasons ring manufacturers went to "ductile iron" and most recently steel for top rings as they see the high cylinder pressures. Second ring breakage is a bit less common but will happen with detonation over time. Ring ridge is a tell tale indicator of a cast iron top ring . Barrel faced, moly rings are MUCH easier on cylinder walls and ring ridge is not as common.
   The pistons usually suffer in the ring grooves when a ring breaks. They tend to "wallow" out , getting too wide to properly seal if reused. They also crack or break off if the detonation is severe enough.
    Randy

410bruce

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Re: Broken Rings
« Reply #2 on: May 20, 2019, 08:13:34 PM »
Thanks Randy, I appreciate it.   8)

Barry_R

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Re: Broken Rings
« Reply #3 on: May 20, 2019, 09:45:14 PM »
Randy has this covered.
Detonation. 
The guy heard it knocking and continued to drive it that way. 
Probably got a load of bad gas or something.

Plain cast rings are sensitive to breakage. 
Once the top ring fails, the 2nd ring takes the beating.

410bruce

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Re: Broken Rings
« Reply #4 on: May 20, 2019, 09:54:05 PM »
Awesome, thank you Barry.  8)