Fred,
The front of the piston was just blown to pieces, intake port on #3 and rear
carb throat are coated with tiny little fragments. Looking down the
cylinder, the wall is scored and already completely rusted out. I don't know
how to tell if the block can be saved, but it sure looks ugly to me. I'll be
saving that piston !
I'll have some pics soon.
Stephan.
> -----Original Message-----
> From: Fred_Katz@ci.sf.ca.us [mailto:Fred_Katz@ci.sf.ca.us]
> Sent: Tuesday, October 12, 1999 9:54 AM
> To: datsun-roadsters@autox.team.net; Sochoux; Stephan
> Subject: Re: Blown engine
>
>
> Stephan,
>
> Wow, bad news! The engine isn't necessarily trashed. It just
> depends on
> how much cash you have sitting around! I think you're on the
> right track
> - get another runner or engine, as your '69 U20 will take a while to
> repair. If you tear down the engine, don't throw away the piston as
> it'll be something everyone else will want to see.
>
> When you say vaporized, do you mean "melted" or do you mean
> fragmented?
> If it's the front of the piston, that's where the intake valve is, so
> it's possible that something got pulled in. Maybe one of your rings
> broke and took the piston top out. That's the only way I
> could see the
> hex screw head causing problems, if it got squished and the
> metal jammed
> the rings. When I cleaned up my pistons, I found some metal jammed in
> one of the ring landings, so I know it happens. You should
> drop the oil
> pan, and pop out that piston so you can inspect the condition
> of the #3
> cylinder. If you didn't get any metal fragments dropping below the
> piston, and #3 cylinder isn't damaged, it may be possible to
> re-hone the
> cylinder and put in a new piston without pulling the engine. But get
> second opinions on this, as you will be better off going the whole
> distance by a complete teardown. Let me know what you need as
> I have the
> tools.
>
> Fred
>
> ________________________ Reply Separator __________________________
> >Subject: Blown engine
> >Author: "Sochoux; Stephan" <SSochoux@dbc.com>
> >Date: 10/12/99 7:51 AM
> >
> >A little update on my latest "breakdown":
> >
> >Pulled the head off last night, front 1/4 of piston #3 is
> vaporized !
> >Head looks fine though. Any clues to look for to determine
> the cause ?
> >I did notice that the head of the hex screw on the throttle shaft
> >holding the butterfly (rear carb) was sheared off. Why that would
> >happen is a mystery by itself, but would such a tiny head
> screw crumble
> >a piston if sucked in ?
> >Anyway, i'm looking to buy a U20 engine or possibly a low windshield
> >2000 project car (running) while i pull the motor out. I think it's
> >trashed.
> >
> >Thanks-
> >
> >Stephan.
>
>
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