Pistons...

S

Smudge

Guest

• May 15, 2006

• #1

Hi all,
So my frothy coolant/head gasket change has revealed a cracked piston,
so I've decided whilst all the top and sump are off, to replace all
four, the bores all look in pretty good condition so it shouldn't be to
much of a drama, thing is the pistons all have 020 stamped on them.
Does this mean I need to buy the 020/20thou pistons to replace them
with?

Thanks in advance

Smudge

 

S

Steve

Guest

• May 15, 2006

• #2

"Smudge" <[email protected]> wrote in message
news:[email protected]...
> Hi all,
> So my frothy coolant/head gasket change has revealed a cracked piston,
> so I've decided whilst all the top and sump are off, to replace all
> four, the bores all look in pretty good condition so it shouldn't be to
> much of a drama, thing is the pistons all have 020 stamped on them.
> Does this mean I need to buy the 020/20thou pistons to replace them
> with?

It means they're 20-thou oversize pistons, in other words it's been bored
out once already. You can get new +20-thou ones to put in there, but
personally I'd consider getting it bored to +40-thou and fit new +040
pistons to match. Looking in pretty good condition and being in pretty good
condition are not necessarily the same thing. Besides, if you fit another
set of +20's you're starting with brand new pistons in half-worn bores. If
you're intending to keep it for any decent length of time after the work's
done then bite the bullet.

Steve

 

S

Smudge

Guest

• May 15, 2006

• #3

I'd like to bore it out, but its an '86 110 with 140k on the clock, and
I have no facilities to get the block out at home, and therfore I'm
looking at a lot of cash to get it towed to a workshop and have the
engine removed before I even get into reboring. Realistically the
baulkhead and chassis have only got a couple of years left in them, so
its dificult to justify the cost...

 

R

rads

Guest

• May 15, 2006

• #4

On 15 May 2006 08:04:19 -0700, "Smudge"
<[email protected]> wrote:

>I'd like to bore it out, but its an '86 110 with 140k on the clock, and
>I have no facilities to get the block out at home, and therfore I'm
>looking at a lot of cash to get it towed to a workshop and have the
>engine removed before I even get into reboring. Realistically the
>baulkhead and chassis have only got a couple of years left in them, so
>its dificult to justify the cost...

From memory, you have to be careful about fitting new rings into "old"
bores. There will be a ridge at the top of the bore which could smash
your new rings the first time it is turned over. For a BMC A series
you used to be able to get a set of stepped rings to prevent this. No
idea if they are available for your engine.

May be talking b*ll*cks, but hey, it's usenet!

David

 

D

David G. Bell

Guest

• May 15, 2006

• #5

On 15 May, in article
<[email protected]>
[email protected] "Smudge" wrote:

> I'd like to bore it out, but its an '86 110 with 140k on the clock, and
> I have no facilities to get the block out at home, and therfore I'm
> looking at a lot of cash to get it towed to a workshop and have the
> engine removed before I even get into reboring. Realistically the
> baulkhead and chassis have only got a couple of years left in them, so
> its dificult to justify the cost...

I remember my father fussing around with feeler gauges between piston
and cylinder wall, and there's the possible wear-step as an indicator as
well. We ended up replacing a couple of pistons on a 2.25 diesel without
doing a rebore, and the engine outlasted the chassis (Exposure to salt
water launching a lifeboat, back in the Seventies, and we retired it a
qyarter-century later).

--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."

 

A

Austin Shackles

Guest

• May 15, 2006

• #6

On or around 15 May 2006 08:04:19 -0700, "Smudge"
<[email protected]> enlightened us thusly:

>I'd like to bore it out, but its an '86 110 with 140k on the clock, and
>I have no facilities to get the block out at home, and therfore I'm
>looking at a lot of cash to get it towed to a workshop and have the
>engine removed before I even get into reboring. Realistically the
>baulkhead and chassis have only got a couple of years left in them, so
>its dificult to justify the cost...

which engine? if it's a TDi, it'd be worth the expense in that you could
either sell it later or transplant it into a better chassis later.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"Nessun maggior dolore che ricordarsi del tempo felice nella miseria"
- Dante Alighieri (1265 - 1321) from Divina Commedia 'Inferno'

 

L

Lee_D

Guest

• May 15, 2006

• #7

Austin Shackles <[email protected]> uttered summat worrerz
funny about:
> On or around 15 May 2006 08:04:19 -0700, "Smudge"
> <[email protected]> enlightened us thusly:
>
>> I'd like to bore it out, but its an '86 110 with 140k on the clock,
>> and I have no facilities to get the block out at home, and therfore
>> I'm looking at a lot of cash to get it towed to a workshop and have
>> the engine removed before I even get into reboring. Realistically the
>> baulkhead and chassis have only got a couple of years left in them,
>> so its dificult to justify the cost...
>
> which engine? if it's a TDi, it'd be worth the expense in that you
> could either sell it later or transplant it into a better chassis
> later.

I did a VM piston replacment with no issues.

I say go for the Pistons, It's a Landrover at the end of the day not a F1
racer. If she blows up in 20 thousand miles hey ho! Chances are if cared for
you'll need to replace summat else before the bores get that bad again,
especially as it's been done once.

Lee D

 

J

jOn

Guest

• May 15, 2006

• #8

"Smudge" <[email protected]> wrote in message
news:[email protected]...
> I'd like to bore it out, but its an '86 110 with 140k on the clock, and
> I have no facilities to get the block out at home, and therfore I'm
> looking at a lot of cash to get it towed to a workshop and have the
> engine removed before I even get into reboring. Realistically the
> baulkhead and chassis have only got a couple of years left in them, so
> its dificult to justify the cost...
>
I've heard of people getting their engines rebored on site without removing
the block from the car.
--
Jon

 

P

Phil Gardiner

Guest

• May 15, 2006

• #9

"Smudge" <[email protected]> wrote in message
news:[email protected]...
> I'd like to bore it out, but its an '86 110 with 140k on the clock, and
> I have no facilities to get the block out at home, and therfore I'm
> looking at a lot of cash to get it towed to a workshop and have the
> engine removed before I even get into reboring. Realistically the
> baulkhead and chassis have only got a couple of years left in them, so
> its dificult to justify the cost...
>

From memory when I partially rebuilt a mini engine there are large piston
rings available which allow for worn bores. You will need to hone the bores
though (using one of these http://makeashorterlink.com/?V1F124D1D )
otherwise the step at the top will knacker the top ring in double quick
time.

Regards

Phil Gardiner

 

E

EMB

Guest

• May 15, 2006

• #10

rads wrote:

> From memory, you have to be careful about fitting new rings into "old"
> bores. There will be a ridge at the top of the bore which could smash
> your new rings the first time it is turned over. For a BMC A series
> you used to be able to get a set of stepped rings to prevent this. No
> idea if they are available for your engine.

You've got 3 options:

- use a ridge removing tool to take the wear ridge out of the bore (IMO
the worst option)

- use 'normal' rings but chamfer the top edge of the top ring slightly
with a file (sounds drastic, works very well)

- use 'ridge-dodger' stepped rings as suggxted above (the best option,
but quite possibly bloody expensive or unavailable)

--
EMB

 

E

EMB

Guest

• May 15, 2006

• #11

Phil Gardiner wrote:

> From memory when I partially rebuilt a mini engine there are large piston
> rings available which allow for worn bores. You will need to hone the bores
> though (using one of these http://makeashorterlink.com/?V1F124D1D )
> otherwise the step at the top will knacker the top ring in double quick
> time.

Honing a cylinder does NOT remove the wear ridge - it merely de-glazes
the bore to allow the new rings to bed in and seal.


--
EMB