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Blown engine

To: datsun-roadsters@autox.team.net
Subject: Blown engine
From: "Sochoux, Stephan" <SSochoux@dbc.com>
Date: Tue, 12 Oct 1999 07:51:01 -0700
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.

>
> Howdy,
> 
> I think i' ve paid my dues to the roadster God. In the last 
> 6000 miles, my roadster has seen two 5th gear neutrals, new 
> chains, new 1/2 rear main seal and a rebuilt head (due to a 
> dropped valve seat). Also, falling in the minor category, new 
> recored radiator, complete brake job, wheel bearings, starter 
> and master/slave cylinder. I'm sure i'm forgetting something 
> here.  Why mention all this ?  Well, while driving home last 
> night, i heard a horrible metallic rumble coming from under 
> the hood while on the 92W 101S connector. The roadster stalls 
> immediately  and i'm stuck on the connector while cars fly by 
> me. Luckily, the connector is sloping down so i manage to 
> coast to an open spot, safe from all the crazed commuters. No 
> visible damage under the hood but since i don't have my tool 
> box i can't wrench anything. After waiting 2 hours for a tow, 
> i'm back home ready to start investigating.  I pull the cam 
> cover and don't see anything wrong. The engine turns manually 
> but not a complete cycle. I pull the spark plugs one by one 
> and #3 is soaked wet. With a flash light, i peek in there and 
> Oh NO, i see little chunks ! Looks like another dropped valve 
> seat ? broken rings ? More to come when i take it apart.
> Is this just bad luck or what ? Why causes the valve seats to 
> drop ? Anyone else with this problem ? Maybe i'll get them 
> all welded if it turns out to be the problem.
> Who has put 50K or 100K trouble free miles on a roadster ?
> 
> Stephan
> '69 2000 BADROC
> 

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