how common are busted rings due to hitting the wear ridge?

Status
Not open for further replies.
Joined
Nov 29, 2009
Messages
7,216
I've heard that sometimes engines that were driven lightly most their life then driven hard can sometimes end up with busted piston rings when the connecting rod and bearings stretch a tad when coming back down. Or is this not really an issue?

I'm thinking like a teenager who ends up with grandma's car that only went down to the grocery store once a week, so now the teenager opens her up to see what she can do. lol.
 
Originally Posted by motor_oil_madman
I've heard that sometimes engines that were driven lightly most their life then driven hard can sometimes end up with busted piston rings when the connecting rod and bearings stretch a tad when coming back down. Or is this not really an issue?

I'm thinking like a teenager who ends up with grandma's car that only went down to the grocery store once a week, so now the teenager opens her up to see what she can do. lol.



i've never heard that bs before
 
I have never heard of this. Also, if an engine "stretches" I don't think it was good to begin with haha.
 
With improved machining methods and modern high quality oil this is a non issue. As far as a conrod "stretching" you would only see that in a highly stressed race engine and even that it would be maybe .5mm stretch at the most and maybe if that on a Top Fuel engine where I would default to the resident expert 02SE. When taking engines apart with 150-200,000 miles you don't see a ring ridge and still see cylinder machining cross-hatch.
 
Cylinders in engines getting rebuilt in the 70's and early 80's commonly had ridges and required a ridge reamer to remove enough material to get the pistons out. Fuel injection (resulting in less gasoline contamination) and better motor oils where responsible for mostly getting rid of the issue in my opinion.
 
Originally Posted by dogememe
Originally Posted by motor_oil_madman
I've heard that sometimes engines that were driven lightly most their life then driven hard can sometimes end up with busted piston rings when the connecting rod and bearings stretch a tad when coming back down. Or is this not really an issue?

I'm thinking like a teenager who ends up with grandma's car that only went down to the grocery store once a week, so now the teenager opens her up to see what she can do. lol.



i've never heard that bs before


Ah well, if you've never heard it, must be bs.

Plus it seems reasonable to me, though I dunno how common it is/was, and I'd think it would happen at TDC, not "when coming back down"

I've heard of stepped "ridge dodger" rings for re-ringing engines (presumably without a hone) but when I was doing that couldn't find any.

I think I put a chamfer on the new top ring with an oilstone, but I dunno if this was necessary. Engine seemed to run OK afterwards, until corrosion got a rear spring hangar.
 
Last edited:
Originally Posted by bdcardinal
With improved machining methods and modern high quality oil this is a non issue. As far as a conrod "stretching" you would only see that in a highly stressed race engine and even that it would be maybe .5mm stretch at the most and maybe if that on a Top Fuel engine where I would default to the resident expert 02SE. When taking engines apart with 150-200,000 miles you don't see a ring ridge and still see cylinder machining cross-hatch.

Originally Posted by Snagglefoot
Cylinders in engines getting rebuilt in the 70's and early 80's commonly had ridges and required a ridge reamer to remove enough material to get the pistons out. Fuel injection (resulting in less gasoline contamination) and better motor oils where responsible for mostly getting rid of the issue in my opinion.



The last engine i found a ridge in was an 81 302 out of a truck. Just don't see that anymore. It sure seems that cylinder ridges went away with the carburatores, now, will we start seeing them again with DI fuel dilution and 20wt oils?

Fortunately the heads and valves seem to last longer too. Even if it happens it won't matter. Most people won't be opening up an engine before 200k like the 70's.
 
Last edited:
Originally Posted by spasm3
The last engine i found a ridge in was an 81 302 out of a truck. Just don't see that anymore. It sure seems that cylinder ridges went away with the carburatores, now, will we start seeing them again with DI fuel dilution and 20wt oils?

Fortunately the heads and valves seem to last longer too. Even if it happens it won't matter. Most people won't be opening up an engine before 200k like the 70's.


I dare say most people don't open up engines period. We rarely take a head off a block anymore. We will do it on a 6.0 diesel to put on headstuds. But most of the time we just put in a new or reman longblock.
 
On a rering we would use a ridge remover, but it didn't clean it up perfectly. I still have a couple, never to be used again. A ring set sometimes contained a spacer to fit on the top of the top ring, making it sit lower....I have used a rail from an oil control ring for the same job. This is stuff we were doing in 3rd world NZ 30 years ago, we wouldn't think of doing it now. Not a modern world problem. In my experience rings shatter from detonation.
 
Originally Posted by Silk
This is stuff we were doing in 3rd world NZ 30 years ago, we wouldn't think of doing it now. Not a modern world problem.


No doubt true for a pro.

As an amateur, I'm to some extent free to pick my own problems.

They don't have to be "modern world" and on the whole I prefer them when they're not.

Good tip about the oil control rail. I'll bear that in mind if I have to do this again, though I'd guess it isn't very likely.

Last time was an 1800 B series in a Marina, which, IIRC, was relatively easy because you can get the pistons out with the engine in the car,

Sump removal was trivial. I rather miss that.
 
Last edited:
OK, here goes. It used to be common. Flathead Fords were somewhat notorious for this. Family car that never got run hard in 100,000 miles and then some kid would buy it for cheap and start busting things. It was in the days of poorer oil and carburetors ... Carb'd engines have much faster cylinder wear.

All modern FI engines should not have this issue unless the ECU was really buggered ... They very seldom show much wall wear at all. Last engine I ridge reamed was the 283 on the engine stand in the shop. It was a core from a 1966 Chevelle.

The thing about rod stretch needs to be understood. Rods do not separate or stretch under load. So the compression and power stroke are safe enough. But high winding an engine leaves them vulnerable to no-load on each exhaust stroke and inertia will do the dirty work. Piston speed is very high at say 6,000 RPM and that sudden stop at the top of the exhaust stroke will pull the piston and rod as far as the worn rod bearings will let it go plus a smidge of actual stretch. Bingo, the top ring can contact a wear ridge that it has never seen before ...

283's and 327's were vulnerable to this as both had forged steel cranks and kids could cam one, change the valve springs on the heads and go street racing. They never looked into the combustion chamber, so when they tried that stop-light drag and either missed a gear, or over wound the old block and rotating assembly, things would break. Smart back-yard boys would do new rod bearings and that would often keep the piston from going as high ...

If it does contact, it may break the ring, may crack the ring land, or a combination of the two. Then it's all over but the time it takes to actually fail. Sometimes you could catch this as puffs of blue smoke out one exhaust ... Often it was just buzzed one more time and the motor hand grenaded
frown.gif


Been to enough of these parties as a young person, back in the day. Street racing is tough on old cars ...
 
Originally Posted by BrocLuno
OK, here goes. It used to be common..... Smart back-yard boys would do new rod bearings and that would often keep the piston from going as high ...Street racing is tough on old cars ...



Thanks for the solid confirmation.

(Incidentally I don't seem to be able to reply to a poster without quoting. Nothing happens when I click on the button.

I don't often want to do that so it may have been like that since the "upgrade", dunno.)
 
Last edited:
Engines are not feasible to fix anymore. That may be a big part of why you don't see any ridge. I worked in a shop for years and they just don't take engines apart anymore.

More vehicles reminding people to change their oil, check their oil, and better oils probably all help as well.
 
I've re-ringed a few saturns by yanking the head, and popping the pistons up and out, leaving the block in the car.

Never any ridge. I never did anything inside the cylinders, except wipe with an oily rag.

Put it all back together with my fingers crossed and everything worked.
 
Originally Posted by eljefino
I've re-ringed a few saturns by yanking the head, and popping the pistons up and out, leaving the block in the car.

Never any ridge. I never did anything inside the cylinders, except wipe with an oily rag.

Put it all back together with my fingers crossed and everything worked.


Never seen a ridge in a saturn s.
 
All rods and rod bolts will stretch to some extent during high rpm use that is a non debatable fact. The questions are how much stretch, is there anything for the piston to hit at the top of the bore and is the stretch enough to be catastrophic allowing the bearing to spin in the rod big end bore.

A light rod and heavy piston do not like high rpm's it is for this reason high rpm engines like those found in motorcycles use a light piston with heavy rods with large very high strength bolts.
As far as bore ridge goes, it is not as common today are it was on older cars because of fuel injection but the reprieve may not be permanent. Studies are showing an increase in bore wear with DI engines due to fuel wetting of the cylinder walls.

The question being asked by the OP has too many variables to be answered with anything more than a guess. I would not be surprised if my MIL 12 yr old car with 23K on the clock had a bore ridge, it spends a lot of time never getting warmed up and I would have to guess sees a lot of cylinder wash down.
The other thing to consider is the piston ring material and its effects on bore wear but that a whole different story.

A few articles, the pdf for GDI is interesting and a worthwhile read.

GDI PDF

https://www.dragzine.com/tech-stories/engine/debunking-aluminum-rod-myths-with-grp/
 
Originally Posted by Trav

As far as bore ridge goes, it is not as common today are it was on older cars because of fuel injection but the reprieve may not be permanent. Studies are showing an increase in bore wear with DI engines due to fuel wetting of the cylinder walls.



Thats what i think also, its one reason i don't run 20wt in my DI mazda. Even with 30wt it may not matter due to the injection pressure. Time will tell. The tech is too new to have a lot of data yet.
 
Last edited:
I may also consider a 0w40 A3/B4 in a DI engine. I am interested in bore wear and DI, at what point in the OCI does bore wear spike? Can it be prevented by changing the oil before say fuel dilution increases at a certain point and does dilution cause a loss of lubricity?
I don't know but would be interested in some hard data (not opinions)
 
Status
Not open for further replies.
Back
Top