[urq] Rebuild engine seizes after 15sec's

[Frank de Kat]

Well..  There's a good clue:

" Using a wrench at the crankshaft pulley , **with the plugs removed**  
, and it barely turns."

With plugs removed, it can't be a blockage downstream preventing it  
from turning.
And you say it 'barley turns', so it's not something actually hitting  
something, but something that's really tight.  That would point to  
crank/cam bearings going tight, or pistons getting tight.

So...  What can cause that?  Maybe check oil pressure.  Could be  
something expanding in the short run time from heat, and taking that  
long to cool down again..?  (piston/rings have tight tolerances?

And of course:  Once you DO figure it out, it'll make total sense..  :-)
(But you'll go crazy until you figure it out!)

Good luck solving the puzzle!

=Frank de Kat=




> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 30 Oct 2014 23:46:48 +0100
> From: "Patrick Carlier" <p.carlier at pandora.be>
> To: "'audifans urq'" <urq at audifans.com>
> Subject: [urq] Rebuild engine seizes after 15sec's . ( non audi )
> Message-ID: <A2229E85AB6A4DFD8418D0B6A86E38FB at desktopbureau>
> Content-Type: text/plain;	charset="iso-8859-1"
>
> So guy's , i'm a bit at wits end here .
>
> Car is a 1987 nissan coupe , 8 valve carb , 1600cc . ( E16s engine )
> Bought it as a fisrt car for my 17 year old son who's very  
> enthousiastic about it :) .
>
> It came with a known broken engine , head froze to pieces .
> Found me a 1500 Turbo ( E15ET)  engine with severe big end damage
> The blocks  are identical as are the heads , only the 1500 crank  
> throw is smaller , and the compression is lower .
>
> With a bit of this and a bit of that I put together a complete engine
> Had the 1500  honed , and the head shaved .
> Used the 1600 pistons and conrods with new pistons rings .
> The 1600 crankshaft was also used with its main bearings shells  in  
> the 1500 caps .
> Bit of a puzzle , i know :) .
> And i've put in new conrod beraings .
> Meaning all moving parts are either new or matched as they were .
>
> Assembled it all , put it in the car , and fired it up .
> It won't  really idle , most likely a carburettor problem , so I  
> have to rev it a bit , and use the accelerator pump
> to keep it going .I can keep it running at abt 1500 rpm
>
> It runs for about 15 seconds and then it stalls .
> Dead stop all of a sudden .
> Tried to start again , and the starter engages but fails to  crank  
> the engine .
> Using a wrench at the crankshaft pulley , with the plugs removed ,  
> and it barely turns .
> Looking inside shows no sign of hydrolock
> Wait 10 minutes , and all's back to normal .
> Engine fires right up , and seizes again after thesame 15 to 20  
> sec's  time period .
> Plugs are oily when pulled , fresh oil , not burned or carbonized . .
> With a cold engine and the plugs removed I can turn the crank with  
> my bare hands by grabbing the crankshaft pulley .
> Also tried two grades of oil , 10w40 and 20w50 , no avail .
>
> Now I've done my share of engine rebuilds and I've never seen this before .
> And quite frankly , I don't quite know where to go from here .
> Sure , I need to pull it apart , buit then what ?
>
> Any thouhts , comments btdt's .....
>
>
> Pat
> VERY unhappy for now .