23 replies to this topic

[daniel_johno]

i started rebuilding my block today and when trying to putin the first piston a bit of the top ring snapped, about 5mm of it.

I dont know if its because the piston ring compressor is a cheap rubbish oval shaped one or because i tried compressing the rings whilst one was outwith a groove.

this engine i was needing built back up by next weekend, is there anything i can do? the pistons are standard 1275 hepolite pistons, cant use the piston with a 5mm gap in the top ring can i?

Daniel

[Jimmyarm]

There is one you can do, get new rings !

[Bill USN-1]

There is one you can do, get new rings !

Or if the top and middle rings are the same size, grab one of the old ones that you removed and stick it in the second groove with a new one on top.

Then hope for the best!!
Did you do a light hone on the cylinders to help the rings seat?

[daniel_johno]

Or if the top and middle rings are the same size, grab one of the old ones that you removed and stick it in the second groove with a new one on top.

Then hope for the best!!
Did you do a light hone on the cylinders to help the rings seat?

I just stripped the engine to check everything was ok. I am on a super budget rebuild and wanted it rebuilt by the weekend so was reusing pistons, big end and main bearings etc.... the engine looks in good nick and seems reusable plus im only going to be using it a few months whilst i finish my turbo engine so dont want to spent loads on it.

I work as a production machinist for a big oil company so have access to almost unlimited tooling. Could i have a piston ring manufactured for me at my work? if so what material is it make from?
It just seems a waste of money spending out £60 for a new set of rings when i only need 1 replacing.

Daniel

[Dan]

They're made of unbelievably-super-uber-hardenified-tungsten-steel or something like that!

You can't use it with a big old gap, it'll smoke like anything under load and the snapped end will just score the bore deeply. You really need new ones, which means you need a hone and running in too.

[daniel_johno]

They're made of unbelievably-super-uber-hardenified-tungsten-steel or something like that!

You can't use it with a big old gap, it'll smoke like anything under load and the snapped end will just score the bore deeply. You really need new ones, which means you need a hone and running in too.

i work with Inconel alot which is a nickel alloy and very strong but ive porbably no chance off getting one to work right,

How bout a second hand ring? I really dont want to pay out for the engine to be honed.

Dan

[Bill USN-1]

They're made of unbelievably-super-uber-hardenified-tungsten-steel or something like that!

You can't use it with a big old gap, it'll smoke like anything under load and the snapped end will just score the bore deeply. You really need new ones, which means you need a hone and running in too.

i work with Inconel alot which is a nickel alloy and very strong but ive porbably no chance off getting one to work right,

How bout a second hand ring? I really dont want to pay out for the engine to be honed.

Dan

You won't be able to make a ring to work properly.

Honing is breaking the glaze (shiny) on the cylinders and putting the cross hatch back in them.
This should be done when just installing new rings. (re-ring)

Boring is when the hole is enlarged to put new pistons and rings in.

You disassemble your motor and from what I can tell you bought new rings.
So you should have honed or deglazed the cylinder to install the new ones.

Now this means you still have the old rings correct?

If so then see my first post!!

Or just spend the money on a new set.

Either way you should not reassemble an engine with the old rings still on the pistons.
They get wore in to the cylinder and when you remove them you turn them.
without the cross hatch from honing they will probably not seat back in and will smoke like crazy.

Just my $.02

[Guess-Works.com]

The ring is useless as said above, the only option is new rings

When rebuilding the engine did you check the ring gap, and personally I would hone/deglaze the bores without question is the pistons have been removed.

Finding new piston rings for std AE pistons..... try our sponsors

or try these guys.. http://www.ultrapart...e/Web_Index.htm

[TimS]

I had exactly the same problem while building up my 1330. There was nothing I could do except to get new rings.

[daniel_johno]

i just called minispares for rings but they say that they dont have my piston listed and i need to measure the ring height then they can supply me with a set. My pistons are hepolite pistons with the number 21962 stamped on them. does anyone know what set i need or what the ring heights are? i really wanted to order the rings today but cant get hold of a mic to measure the ring height till i goto work tonight.

nothings every easy......

Daniel

[Guess-Works.com]

Ring hights are

1st 1.5mm
2nd 1.5mm
3rd (oil control) 3.0mm

These are std on last of the A+ 1275 units (mini and metro included) Heapolite ring set ref R41570

These are the ones you want... http://www.minispare....aspx?pid=37903

One thing to add, if you do get new rings, you will need to deglaze/hone your bores and then check the ring gap and clearance before fitting the rings to the pistons....

The clearance is the space left in the ring land of the piston, this should be 0.0015" to 0.0035" on the compression rings (1 and 2)

The Ring gap ( the space left between the ends of the ring when situated square in the bore)

- top compression ring 0.010" to 0.017" ( but I believe 0.015" is about the limit for a new ring )
- 2nd compression ring 0.008" to 0.013"
- Oil scraper rails ( the thin ones ) 0.015" to 0.041"

If the rings are over the threshold then the bore needs machining up to the next rebore which will be +0.020 and new pistons aquired.

If you explain this to minispares they may accept the ring set back against a new set of pistons

Edited by GuessWorks, 09 January 2007 - 12:51 PM.

[Jammy]

Strange that MiniSpares didn't have those on their system!

[daniel_johno]

Strange that MiniSpares didn't have those on their system!

just ordered the above mentioned ones but they had no idea they would fit my pistons and had no listing at all for the 21962 piston.

ive also just ordered a draper honing tool off ebay.

do i measure the ring gaps using my old rings or new ones?

Thanks for all the help.

Daniel

[Guess-Works.com]

New ones...

Those rings are actually for the 21253 HC pistons but also fit the profile for the std piston used in the late carbed mini cooper and injection models ( and those used on the Metro Turbo / VDP)

I double checked a 21962 piston which I have to make sure before posting...

Out of interest do you know the source of the engine and engine number ( just to put my mind at rest now )

[daniel_johno]

New ones...

Those rings are actually for the 21253 HC pistons but also fit the profile for the std piston used in the late carbed mini cooper and injection models ( and those used on the Metro Turbo / VDP)

I double checked a 21962 piston which I have to make sure before posting...

Out of interest do you know the source of the engine and engine number ( just to put my mind at rest now )

i wasnt doubting you i was just suprised minispares have never heard of my piston.

engine number 12HE25143916
piston number 21962 G8 S24

Thanks

Daniel