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From: steve robinson on 13 Jan 2010 15:09
asahartz wrote:

> On Wed, 13 Jan 2010 15:16:38 +0000, martin <usenet(a)etiqa.co.uk>
> wrote:
>
> > On 13/01/2010 14:55, steve robinson wrote:
> >
> >> Most 'mechanics' now are fitters not mechanical engineers and
> wouldnt >> be able to perform small engineering tasks .
> > >
> >> How many garages actually rebuild/ re engineer engines now , i
> dont >> know of any , the just parcel them off to a specialist
> >
> > Yes I agree with you there. I've rebuilt two engines totally
> > (both top and bottom ends) and had the blocks into a machine shop
> > for rebore prior to fitting oversized pistons/rings. The first
> > took me a month because I went very slowly, the second a week
> > because I knew what I was doing. Similarly for gearboxes, strip
> > down, remove the broken parts, refurbish and replace what's
> > needed and rebuild.
> >
> > Talking to modern car mechanics it's something they just don't do
> > anymore, whereas the old timers of my age it's more bread and
> > butter. Now it's drop the gearbox out, put in a refurb and ship
> > old back to refurb.
>
> Isn't that the case with most things these days? My father was a
> TV/video engineer before he retired, and even 10 years ago was one
> of the few left who could repair most faults, while other engineers
> just changed a whole panel.
>
> Years before that, my grandfather, who was a skilled toolmaker,
> would look at what broke in his car, think it through, redesign it
> and machine up an improved part!

I remember going to the garage with my father over 45 years ago and
they had lathes and what looked like large drilling machines to a
young lad , the engineers thier used to let me watch as they machined
and milled parts up for some of the older cars

Went into citroen before Christmas just rows of toolboxes , ramps and
a computer system , no pits or beam lifts
From: Ian Jackson on 13 Jan 2010 15:19
In message
<7677da5c-121b-4d86-b268-e333b58f38c0(a)34g2000yqp.googlegroups.com>,
Jethro <jethro_uk(a)hotmail.com> writes
>On 13 Jan, 19:30, Cynic <cynic_...(a)yahoo.co.uk> wrote:
>> On Wed, 13 Jan 2010 15:16:38 +0000, martin <use...(a)etiqa.co.uk> wrote:
>> >On 13/01/2010 14:55, steve robinson wrote:
>>
>> >> Most 'mechanics' now are fitters not mechanical engineers and wouldnt
>> >> be able to perform small engineering tasks .
>>
>> >> How many garages �actually rebuild/ re engineer engines now �, i dont
>> >> know of any , the just parcel them off to a specialist
>>
>> >Yes I agree with you there. I've rebuilt two engines totally (both top
>> >and bottom ends) and had the blocks into a machine shop for rebore prior
>> >to fitting oversized pistons/rings. The first took me a month because I
>> >went very slowly, the second a week because I knew what I was doing.
>> >Similarly for gearboxes, strip down, remove the broken parts, refurbish
>> >and replace what's needed and rebuild.
>>
>> >Talking to modern car mechanics it's something they just don't do
>> >anymore, whereas the old timers of my age it's more bread and butter.
>> >Now it's drop the gearbox out, put in a refurb and ship old back to refurb.
>>
>> Purely as an idle question from a rank amateur - when drilling out a
>> glowplug or spark plug without removing the head, how much risk is
>> there of getting metal bits into the cylinder that causes damage as
>> soon as the engine is started after the repair?
>>
>> I well recall my father dropping a single small washer into the open
>> throat of a carburetter while the engine was running, and the mess it
>> made of a cylinder lining, piston and cylinder head.
>>
>> I would have thought that a small bit of swarf that fell into the
>> cylinder may well be practically impossible to spot and even less easy
>> to remove.
>>
>> --
>> Cynic
>
>Very high ...
>
>even a speck, milligrams, could get stuck on the valve seat and lead
>to it burning ... as another poster suggested, when carrying out this
>procedure, it's a good idea to put the cylinder in question to TDC to
>close the valves and shield the cylinder wall ... but the risk still
>remains. Another trick is to smother the area in grease in the hope it
>will catch any swarf, but you now what sods law is like ....

Was that airline (used several times) a blower or a sucker? It didn't
seem like a sucker to me.

It would be wise to use a miniature inspection camera to check inside
the cylinder, to see if any swarf and other crud was lying inside.

Finally, I would flood the top of the cylinder with thin oil, disable
ignition (how, on a diesel?), put a rag over the open glowplug hole, and
crank the engine for a few seconds. That should get rid of any remaining
crud (via the valves or through the hole).
--
Ian
From: Cynic on 13 Jan 2010 16:07
On Wed, 13 Jan 2010 20:19:09 +0000, Ian Jackson
<ianREMOVETHISjackson(a)g3ohx.demon.co.uk> wrote:

>>Very high ...

>>even a speck, milligrams, could get stuck on the valve seat and lead
>>to it burning ... as another poster suggested, when carrying out this
>>procedure, it's a good idea to put the cylinder in question to TDC to
>>close the valves and shield the cylinder wall ... but the risk still
>>remains. Another trick is to smother the area in grease in the hope it
>>will catch any swarf, but you now what sods law is like ....

>Was that airline (used several times) a blower or a sucker? It didn't
>seem like a sucker to me.

>It would be wise to use a miniature inspection camera to check inside
>the cylinder, to see if any swarf and other crud was lying inside.

>Finally, I would flood the top of the cylinder with thin oil, disable
>ignition (how, on a diesel?), put a rag over the open glowplug hole, and
>crank the engine for a few seconds. That should get rid of any remaining
>crud (via the valves or through the hole).

How much gap is there between a piston and the cylinder wall? ISTM
that if a small metal filing were to get into that gap and sit on the
top piston ring, it may well escape all the above methods, and become
dislodged only with the detonation of the first power stroke.

The question really I suppose is whether the risk is low enough to be
worth the saving (and risk) of removing the head. Head removal in the
only cars I have ever worked on was a quick and easy job, but a look
under the bonnet of a modern car suggests that it was designed by
someone who was a master at both jigsaw puzzles and tetris ...

--
Cynic

From: Ste on 13 Jan 2010 17:32
On 13 Jan, 21:07, Cynic <cynic_...(a)yahoo.co.uk> wrote:
> On Wed, 13 Jan 2010 20:19:09 +0000, Ian Jackson
>
>
>
>
>
> <ianREMOVETHISjack...(a)g3ohx.demon.co.uk> wrote:
> >>Very high ...
> >>even a speck, milligrams, could get stuck on the valve seat and lead
> >>to it burning ... as another poster suggested, when carrying out this
> >>procedure, it's a good idea to put the cylinder in question to TDC to
> >>close the valves and shield the cylinder wall ... but the risk still
> >>remains. Another trick is to smother the area in grease in the hope it
> >>will catch any swarf, but you now what sods law is like ....
> >Was that airline (used several times) a blower or a sucker? It didn't
> >seem like a sucker to me.
> >It would be wise to use a miniature inspection camera to check inside
> >the cylinder, to see if any swarf and other crud was lying inside.
> >Finally, I would flood the top of the cylinder with thin oil, disable
> >ignition (how, on a diesel?), put a rag over the open glowplug hole, and
> >crank the engine for a few seconds. That should get rid of any remaining
> >crud (via the valves or through the hole).
>
> How much gap is there between a piston and the cylinder wall?

Depends how old the engine is!



> ISTM
> that if a small metal filing were to get into that gap and sit on the
> top piston ring, it may well escape all the above methods, and become
> dislodged only with the detonation of the first power stroke.

It depends what sort of filing it is. Filings that are basically
"dust" will not, in small doses, lead to any problems - certainly not
in the short term, anyway - and are likely to be blown away in the
normal operation of the engine. Larger filings (i.e. of the order of
millimeter size or bigger) would be far more of a problem, but
realistically there is no excuse for leaving these behind.



> The question really I suppose is whether the risk is low enough to be
> worth the saving (and risk) of removing the head.  Head removal in the
> only cars I have ever worked on was a quick and easy job, but a look
> under the bonnet of a modern car suggests that it was designed by
> someone who was a master at both jigsaw puzzles and tetris ...

Lol. BMWs are a prime example.
From: Culex (The Infamous Culex) on 13 Jan 2010 20:03
On Jan 13, 8:19 pm, Ian Jackson
<ianREMOVETHISjack...(a)g3ohx.demon.co.uk> wrote:
> Was that airline (used several times) a blower or a sucker? It didn't
> seem like a sucker to me.

The last operation seemed to use a vacuum hose as it was inserted in
the hole formerly occupied by an injector; the tubing was also rather
thicker than that of the airlines I use..

> It would be wise to use a miniature inspection camera to check inside
> the cylinder, to see if any swarf and other crud was lying inside.

Could ants be trained to remove any swarf that got into the cylinder?

> Finally, I would flood the top of the cylinder with thin oil, disable
> ignition (how, on a diesel?), put a rag over the open glowplug hole, and
> crank the engine for a few seconds. That should get rid of any remaining
> crud (via the valves or through the hole).

As I doubt that thin oil would wash out a bit of swarf stuck between
the cylinder wall and the piston, might it not be a sensible
precaution to add some thin oil via the injector hole before the
process was started?

Of course, this would mean that the ants would also have to be trained
to swim.

-- -

Culex -- the Infamous Culex
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