[Vwdiesel] RE re-ringing a rabbit--

[greg rich]

>Can a hydraulic head be used on a NON hydraulic block ?

YES, it can be done, I had a car that came that way...long story short it 
didn't run well and I removed the head to change the gasket and have a look, 
(92 Jetta td canadian car) and it had a hyd lifter head on a C? code block 
(rabbit block CR or CY or ??). I am not sure what gasket they used, I cannot 
remember. I still have the head, it was finished...full of pits around the 
cooling passages, no way it would ever seal a headgasket again. I sold the 
block for rebuilding and put in a regular diesel. It had run three years 
with the hyd head on it, I had looked at the car previously when the engine 
was assembled the first time (but didn't buy it until the second time, at 5% 
of the price!). I think it would work fine if you used good parts to start 
off with, this person had used junk yard cores and it didn't last.
All they had done was plug one passage where the hyd head has an extra 
"bump" out with a brass plug.

>
>   Don't think so.  The oil returns are different.  I'd almost suspect the
>supply hole is bigger too.  Don't know for positive.  I've only seen one
>hydraulic head gasket and there was NO way that it would work on a
>solid head 1.6 block
>
> >
> > >>Bart Winelands  1.6 NA   ----- I would suspect that just installing a
> > different
> > >>cam may affect oil pressure.
>
>
>   Shouldn't unless the cam journals were worn, which isn't too likely 
>since
>the mating surface is aluminum and the flow to the heads is comparatively
>low.  Cams are interchangeable at least in the 1.6 solids, turbo, and 1.5.
>I wonder if the hydraulic has different ramping than the solids like on
>domestic engines?  Although I don't think you could make those ramps
>much steeper!
>   I'm a bit concerned with that new head I got.  The cam bearing surfaces
>look to be .002+ larger than the cam journals.  Feels sloppy.
>
> >
> > >>Cam bearings are linebored  IMHO.   So  attention would be needed in 
>that
> > area.
>
>
>   For what?  All the heads I've had surfaced and resurfaced, including one
>that
>a shop claimed was warped .024 but I measured (on a digital height gauge
>and surface plate) at .017 were NOT straightened or align bored.  Cam
>journals were better than +.001 in relation to alignment to eachother.  
>Never
>
>broke a cam from it and only had them surfaced.  Only had to replace the
>cam from my Jetta from wear.  Journals were fine but the lobes were
>all a bit short.

I have just heard that cams should not be swapped because they would each 
wear differently which could cause problems overtime. The way it was 
explained made full sense, that each head would "warp" differently and since 
there are no replacable bearings for the cam they shouldn't be 
interchanged...along the same lines the injectors shouldn't be 
interchangeable between solid and hydraulic or 1.5 to 1.6 but we all know 
they can be now...what is written doesn't always apply but when someone has 
a problem you do have to look at the big picture and find out where it went 
wrong...


Greg
>
> >
> > >>IMHO   VW Rabbit diesels  rely on lots of oil flow for COOLING   that
> > translates >>in to LOW oil pressure.
>
>
>   Most 1.5's had 100psi +.  Early 1.6's were a bit below 100psi.  Turbo 
>and
>hydraulic lifters drop pressure down to more of what you normally see
>on other engines.  40 to 100 psi, even a little lower.  Squirters and
>turbo are each worth about 25 to 30 psi loss so in came the 36mm pump.
>
> >
> > >>Bart does your block have oil squirters on piston skirts like the 
>Turbo ?.
> >
> >
>
>   I wouldn't expect an '86 NA to have them.  If they did, it would've been
>easy for one or more to get damaged while honing and lose pressure.
>That didn't happen to me on the 5000 though  but then it has a bigger,
>circular gear oil pump.
>      Loren
>
>
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