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piston rings

Melissa

Enthusiast
Messages
131
Location
France The Lot
#1
Hi all, as no one is making pistons & chemises kits for my car anymore (782cm2 839 engine) so I'm going to replace the rings, saw these on Lebon, my engine is a 1126 but these Goetze ones look v different to the original ones, they have a spring thingy on the middle & oil rings...anyone have any experience of them? cheers
 

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JdeW

Enthusiast
Messages
488
Location
Laarbeek The Netherlands
#2
Parts for the 839 engine still widely available.
At Melun Retro passion (France) https://www.melun-retro-passion.com...-8mm-thickness-1-75-x-2-x-3-5-id-301000N.html
At R-Quatre (Netherlands) 4x https://www.renault4onderdelen.nl/W...eren-voor-één-cilinder-motor-839-(782cc).html
There a 3 piston rings per piston, from top to bottom 1,75 mm, 2 mm and 3,5 mm for the 839 engine with 55,8 mm pistons.
The top 2 rings are compression rings, the bottom ring is an oil lubricating and scraper ring and may consist out of 3 parts
New rings can slightly differ from the old original ones, especialy the scraper ring may differ, the 2 top rings are straight forward but differ in thickness..


Remove the old rings, clean any carbon residu and place carefully the new rings starting from bottom to top, so first the bottom scraper ring, then the middle (2 mm) and finally the top ring (1,75 mm).
The pistonring opening shouldn't be in one line but positioned at a 120 degrees interval.

End result may look like this:
155.jpg
 

Melissa

Enthusiast
Messages
131
Location
France The Lot
#3
yes, lots of places sell the rings but not the pistons or sleeves, so I plan on using mine, they've cleaned up well. The Goetz ones have an inner spring on 2nd & lower rings, just wondered if anyone had used them.
 

JdeW

Enthusiast
Messages
488
Location
Laarbeek The Netherlands
#6
yes, lots of places sell the rings but not the pistons or sleeves, so I plan on using mine, they've cleaned up well. The Goetz ones have an inner spring on 2nd & lower rings, just wondered if anyone had used them.
Normally only the rings wear out causing loss of compression, the pistons and sleeves will last several lifetimes when nothing strange happens, so why would you change pistons and sleeves?
It's easier to find a second hand 839-06 engine for spares then looking for NOS or aftermarket pistons and sleeves
Engines:
https://www.leboncoin.fr/equipement_auto/1700956928.htm/
https://www.leboncoin.fr/equipement_auto/1388646724.htm/

Pistons:
https://www.leboncoin.fr/equipement_auto/1694932328.htm/

Pistons, sleeves aftermarket:
https://boutique.techni-tacot.com/k...mbase-60-renault-68001-et-02-747-cm3-4cv.html
 

Melissa

Enthusiast
Messages
131
Location
France The Lot
#7
Normally only the rings wear out causing loss of compression, the pistons and sleeves will last several lifetimes when nothing strange happens, so why would you change pistons and sleeves?
It's easier to find a second hand 839-06 engine for spares then looking for NOS or aftermarket pistons and sleeves
Engines:
https://www.leboncoin.fr/equipement_auto/1700956928.htm/
https://www.leboncoin.fr/equipement_auto/1388646724.htm/

Pistons:
https://www.leboncoin.fr/equipement_auto/1694932328.htm/

Pistons, sleeves aftermarket:
https://boutique.techni-tacot.com/k...mbase-60-renault-68001-et-02-747-cm3-4cv.html
That's exactly what I did, 100 euros for a 2nd hand engine & it gave me confidence taking it apart before I did mine, also came with carb starter, alternator & a few other spares he chucked in. I thought I might need to replace the sleeves & pistons as that's what Paul thought I'd have to do, but when I took my engine apart they all look like they're in really good condition, just needed lots of thick black cleaning out of the grooves, which I've done. But that's really reassuring advice thanks. & cheers for all the links too. I'm going to rebuild the spare engine & have it as back up!
 

angel

Enthusiast
Messages
1,900
Location
Athens, Greece
#8
Especially regarding the oil control rings, each manufacturer has its own way of building it, and there are one-piece rings, three-piece rings, one piece with expander etc. As long as the fitted width and diameter are OK, don't worry about the rest.
Goetze, in particular, is top-notch when it comes to piston rings and far better choice than the no-name stuff sold by "well-known" R4 parts suppliers.
 

Melissa

Enthusiast
Messages
131
Location
France The Lot
#9
Especially regarding the oil control rings, each manufacturer has its own way of building it, and there are one-piece rings, three-piece rings, one piece with expander etc. As long as the fitted width and diameter are OK, don't worry about the rest.
Goetze, in particular, is top-notch when it comes to piston rings and far better choice than the no-name stuff sold by "well-known" R4 parts suppliers.
cheers Angel, it says on the instructions to use a special tool when fitting the oil ring pieces, I might just take them to my local classic car guy & ask him to fit them I don't want to mess em up, also take my sleeves to get him to make sure they're 100% although they feel very smooth, no grooves or scratches inside them at all, he's v helpful & friendly too!
 
Messages
128
Location
English but live in France 87250
#10
cheers Angel, it says on the instructions to use a special tool when fitting the oil ring pieces, I might just take them to my local classic car guy & ask him to fit them I don't want to mess em up, also take my sleeves to get him to make sure they're 100% although they feel very smooth, no grooves or scratches inside them at all, he's v helpful & friendly too!
I would also hone the bores to break the glaze on them and help the rings to bed in quicker
 

angel

Enthusiast
Messages
1,900
Location
Athens, Greece
#11
If you are careful you can fit the pistons in the liners from below, compressing the rings one by one by hand, before fitting the assemblies in the block. The liners have an adequate chamfer that allows this.
 

Melissa

Enthusiast
Messages
131
Location
France The Lot
#12
If you are careful you can fit the pistons in the liners from below, compressing the rings one by one by hand, before fitting the assemblies in the block. The liners have an adequate chamfer that allows this.
great advice, many thanks all
 
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