[urq] Rebuild engine seizes after 15sec's

[Stephen Kraus]

Check the cylinder walls to make sure they are not rounded out
On Oct 31, 2014 11:58 AM, "Frank de Kat" <fdekat at sentex.net> wrote:

> 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 .
>>
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