Re: 2-4kq's stumbling when cold

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <199902021943.TAA23168@specialdevices.com> "Ken Keith" writes:

> quk@isham-research.demon.co.uk (Phil Payne) wrote:
> >
> > They oftem come off when injectors are pulled past hardened seals.  One
> > part of the 'injector pulling' task is to check that the seat and lower
> > shroud are clear.  These days, I routinely wind out the seat after I've
> > pulled the injector just to check.  The seats on the MB engine are 13mm
> > Allen - I've ground the shank of a FACOM D.107-13 so it's an _exact_ fit
> > in the upper part of the seat.  I think the 4k and WR/WX engines are
> > 12mm.
>
> Is there any benefit to replacing the seat seals?  I didn't touch the seats
> when I did my injector seals on my last Coupe.  I almost seemed like the seats
> would have broken if I tried to remove them.  Maybe new seats and seat seals
> would finish off the job pretty tidily.

There is a benefit on the MB/1B/MC-2 engine, because you get to inspect
the lower shroud.  There are _two_ injector seals - a bit fat one that
keeps the injector in place, and a little tiny thin black one around the
tip.  This little black one is meant to provide a seal between the
injector and the lower shroud, forcing the air circulating around the
injectors to exit between the injector tip and the injector body.

I find these lower shrouds are rarely intact at 100k miles or more and
the lower deal is thus ineffective.  This is supposed to affect the
injector spray pattern under heavy load.

The problem is the seat gasket, which is trapped between the
injector seat, the lower shroud and the cylinder head.  It's rare to
get these out in less than four or five pieces each.

The seat itself is brass and impervious to damage.  The upper and lower
seals, the lower shroud and the seat gasket are all 'replace with new'
items.

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
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