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3B (20V turbo) Engine dissection.
Last week I finished disassembly of the 3B engine which will ultimately
reside in my Not So Ur q's engine bay and I made a few observations which may
be helpful to others looking to increase the performance of their '91 200qs.
First, the exhaust manifold is fairly rough inside, with lots of casting
flash and sharp edges. I'll be polishing this up and perhaps ceramic coated.
The intake manifold could also be polished as it is fairly rough inside.
There was also ALOT of build up around the injectors, and there is only 35k
on this engine. The injectors are the pintel type (as opposed to disk type,
which I am told are better due to less mass moving in the injector). I would
like to send the IM out to Extrude Hone, but the runners are easily
accessible, so I may do it by hand and save some $. No fuel in the IM, so
this can also be polished.
The cylinder head doesn't have much of a combustion chamber in it and the
piston tops are almost flat (9.3/1 CR) compared to the MC engine (8/1?). It
lots like there would be some benefit from unshrouding the valves and
polishing things up. My machinist wants to put in Ti valves and keepers...,
he can't wait to get his hands on this head. The ports will be matched and
perhaps extrude honed ($ dependent). BTW, Bosch Platin plugs are pretty
cool looking little guys, they'll stay.
The 3B block has one difference from the MC block which I have noticed; there
is a check valve behind the oil pressure sender, which I assume keeps the oil
from draining out of the head to keep those 20 hydraulic lifters from
draining. I need to find a replacement block as mine has a very nice crack
and no A/C compressor bosses any more. The crank spins nicely in the caps,
but the nose of it is bent, so that'll be replaced too. Ouch. If anyone just
happens to have a short block laying around, let me know. I think a
naturally aspirated 20V would work as well, and they are (more) readily
available. The aluminum oil pan is a pretty nice piece, I just hope it fits
in the Ur q.
All recommendations, comments, etc. are welcome.
'82 Not So Ur q 3B2B