[Vwdiesel] Rebuilt IP / Engine Won't Start

[brian gochnauer]

I've rebuilt hundreds of Caterpillar diesels and have often had to ream the
ridge to get the piston out, but would never use a cylinder (liner) that had
a ridge in it. I've never rebuilt a VW diesel, but have heard this reaming
honing and puting new pistons and rings in the bore on forums many times.
I find it hard to believe that this can be a good practice, I'd say that a
ridge would be at least .020 to bore size and is VERY hard to accurately
measure because of the slope of the ridge.

William,
If you measured the bore after completely removing the ridge, what was the
bore size.?

I'd say leaving any ridge in the bore is going to be a problem because the
new piston and ring could constantly 'slapping' that ridge and break the
piston ring. Honing is only going to make the bore bigger. Fitting the ring
(gap) in the bore is going to be far from good considering the taper.
Although a crank speeds the rings may expand fast enough to keep a seal
against the cylinder wall at higher speeds that is going to more difficult.
Of course that explains why I hear about people re-ringing the engine every
50k miles, to keep it running.


On Sat, Sep 20, 2008 at 10:09 PM, William Longyard
<longyard at ix.netcom.com>wrote:

> I've got a rebuilt IP pump that I just put on my rebuilt engine.  I'm
> having
> trouble starting it.
>
> I used new turbo piston in my 1600NA engine, and I ridge-reamed and honed
> before installing them.  Ring gaps are to specs.
>
> My compression from 1-4 is: 380, 385, 380, 375psi.
>
> I believe this compression is low, but know that the rings haven't seated
> yet, and those are figures for a stone cold engine.
>
> When I crank over the engine for a long time it ALMOST wants to run, and a
> couple of times I have been able to get it to run for a few seconds.  I
> found that by backing the idle screw all the way OUT, it seems to want to
> run a little bit more.
>
> However, if I step on the throttle it dies immediately.  Is the governor
> set
> wrong?  How do I set the governor?
>
> Other ideas?
>
> Thanks,
> Bill Longyard
>
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