So far, folks think it's detonation. I don't know the history of this car
prior to me, but I do know I've never had a problem with spark plugs looking
like detonation, nor any running problems I always ran 92-93 octane in this
car. . I was comparing the pictures I took prior to the rebuild and looks
like it was #2 and #3 were the broken pistons. Oddly enough, #3 was my best
cylinder. Well that helps out some! At least now I KNOW what's in this
car instead of wondering!
Now to figure out what I need to get this head back on this decked block!
ARGHH!! I told the guy... call me if you have to cut the head, it's VERY
important for proper timing. Wouldn't you figure that if the head cutting
was so vital that it may not be a good idea to deck the block? I can't
seem to find any documentation on where/how to measure the block for
acceptable specs. Will keep on looking. time for work! Thanks for all
the help so far!
Eric
----- Original Message -----
From: "Eric Frisbee" <efrisbee@charter.net>
To: "roadster list" <datsun-roadsters@autox.team.net>
Sent: Saturday, January 22, 2005 10:51 AM
Subject: U20 block height and piston question
>I think I may have a problem... my machine shop smoothed off the top of my
>block, where the head goes. I used to be able to see the block numbers
>clearly , but now can barely make out the "U20" and only "13" of the block
>number. Where would I measure to and from on the block to make sure
>they I don't have a problem with the timing. So much for having this
>engine back in the car fairly quickly...
>
> The other question I had was about the lands and grooves on the pistons.
> Two of my pistons have broken lands about 1.5 to 2 inches on the right
> side (distibutor side, not the carb side) of the piston. These have been
> broken for a while as there are no sharp edges and they have been
> rattling, found it smooth inside the break areas. Does anyone know what
> may have caused this to break like that? Best I can tell, the affected
> pistons are from 1 and 2. All the pistons show damage from intake valves
> hitting them as well. I just want to avoid that happening again with this
> newly rebuilt engine!
>
> Thanks in advance!!
>
> Eric
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