so   i recently installed a new 1.3L  engine in my 88 samurai   ran great for about five hundred miles       then died ??      sometimes it tries to restart but most times it cranks but sounds like it does nt have a load (such as compression)    then it will (catch)   and try to start again     i ve never ran into a problem like this     were its not constant    any advice???

maybe a valve is sticking , have you checked your compression or done a leek down test. I'd start there

no i have nt    yet    but i have recently heard of a similar problem with spun bearings ?   

It would start if it had spun bearings, just make awful sounds..

Timing belt slipped a tooth?? 

Start with a compression test and leakdown test.

after hearing about the possible spin bearing    i removed the oil filter and cut it open      im not sure whats acceptable for a new engine but i found quit a bit of material in the filter  including brass  (bearings ??)   and some metal    probably alluminum  but not sure       i also spoke with the the guy that built the engine  and he thinks it maybe a timing issue      but i have tried to time it and the timing seems right for my location    how likely is it that a timing belt would slip a tooth ??            i would appreciate any feed back   and thank  you to those who have replied