reuse cylinder rings???

R

ruggiero06

Member +
not for my car but a buddy is replacing his bent rod. his compression is fine across the board he says. since hes only replacing the rod and not the piston.

is it ok to pull the piston/rod out, replace the bent rod with 4 fresh rods and just use the same piston with rings since we dont want to be pulling the block out and honing the cylinders and breaking in the motor?

i was hoping this would work as we are using the same rings for the same block so it should be seated good.


rep will be given...we are starting the work today on the car in a few hours so its time sensitive...thx guys
 
Last edited:
KrissyB

KrissyB

Member +
Usually a bent rod could cause scoring of the cylinder wall and also scoring of the Crank journals on that Rod . You might want to check the crank and the the bearings on that particular Rod.

Im no mehanical G-whizz but it's best to be safe and check dude a bent rod usually damages other parts of the engine aswell.
 
R

ruggiero06

Member +
if the crank is damaged in anyway it will be replaced with a good used one we have along with new bearings if thats the case.

reusing the rings is only an option if the cylinder walls are not damaged.

the question is mostly about is it possible in general to reuse the rings i was wondering if it would not hold compression or something because of a need to break in with new crosshatching and new rings.




so to review....if everything else checks out can the rings be reused.
 
KrissyB

KrissyB

Member +
ruggiero06 said:
if the crank is damaged in anyway it will be replaced with a good used one we have along with new bearings if thats the case.

reusing the rings is only an option if the cylinder walls are not damaged.

the question is mostly about is it possible in general to reuse the rings i was wondering if it would not hold compression or something because of a need to break in with new crosshatching and new rings.

Id's assume so if the wall isn't damaged as they all check out okay;)
Click to expand...
 
finx

finx

Member +
case in point, but why would you go to all the hassle of pulling the engine out, taking the head off rods/pistons out, clean all parts and then just re assemble it with the same old parts? its a total waste of time.
youll be replacing the head gasket and bolts anyway so you might as well do the rings and at least the big ends at the same time for piece of mind. at least then you know you will have a mint engine (assuming that it is all re assembled properly). no proper engine builder would ever put an engine back together with old rings and big ends.


the bores will not be damaged if the rod has bent as the rod never comes into contact with the bore at all. if it does bend that much and by some miricale doesnt snap then the damage to the bore would be to server to even think about using the block again.
tell me your thinking behind how the bore could be at all damaged by having a bent rod?

whats the big deal about running the engine in? its not difficult just time consuming. i would personally rather do it properly 1st time instead of taking half ass short cuts and end up having to have it all apart again a few months down the track.

to answer your question yes it can be done. but highly discouraged.
 
J

jabran200

Member +
I personally would do as finx says as it will give you peace of mind.

Also with the 4e there is usually a good chance atleast one of the ringlands will be cracking or showing signs or cracking if the engine has done a good amoutn of mileage. so Inspect the ringlands for cracks mate.
 
R

ruggiero06

Member +
the problem is time. he doesnt have the 2 weeks it would take to do this 100% nor does he have the funds...this is his daily driver and he uses it to get to his 3 jobs.

the bearings are all going to be fresh...my whole thing is why fix whats not broken especially since that fix is 1-2weeks. right now i take him to work or he takes me to my 2 jobs until his car is fixed. i would love to rebuild his motor from the ground up and be brand new because i love working on motors...but the situation sucks and i was trying to figure a way to save a few weeks time and get him his car asap.

from the research i been doing and the shops ive talked to reusing the rings is fine if the bores arent scored and are holding compression fine.


thx for the help guys...lots of good info here...rep given to all :]
 
finx

finx

Member +
given your situation i do know where your coming from having been in the same situation before.

it is possible for the rings to be re used. but as i said before it is highly discouraged.


jabran200: just because the engine is kigh mileage doesnt mean the piston ring lands will be cracked. i have had several 4eftes apart that have done around the 300,000km mark and the ring lands were fine. high km wear is normally due to poor servicing. as when the oil breaks down it looses its viscosity and just becomes a useless substance in the engine thus no or little lubrication and you get more metal to metal contact and more wear. its generally the bores, rings and skirts/sides of the pistons that wear.

only reason a ring land will break is due to to much pressure in the combustion chamber with insufficient fuel and or timing, which causes detonation and this kills the ring lands.


the compromise for this build would be the following.

pull engine apart in place

hone bores with hand hone
replace piston rings
replace big end bearings

wouldn't take as long as a full engine rebuild but still replaces most of the important parts which you will already have apart/ off anyway. giving you the best possible outcome.
 
You must log in or register to reply here.
Top