Sorry for the cross post between 'manufactures' but my Spit just went through
this.
...like your description... a very light knock sound in the lower end.
...anyway.... I replaced the rod big end bearings. The sound disappeared.
My oil pressure only rose about 2-5 psi after the swap.
when inspecting the bearings I had removed, .... you could hardly tell
they had been run at all. On just one bearing, if you looked at it in bright
sunlight
you could just make out the brass coloring of the bearing base metal through
the gray/silver outer layer. I am still inclined to believe the bearings I
removed
plating might have been mis-manufactured or something.
Considering your crank is already 10 under (it's been ground at least once)
I'd be inclined to believe (from my own experience) it's possible that
any clearance deviations might be audible. (concentricity, clearance etc)
Paul Tegler wizardz@toad.net http://www.teglerizer.com
----- Original Message -----
From "Ulix Goettsch" <ulix at u.washington.edu>
To: "spridgets" <spridgets@autox.team.net>
Sent: Wednesday, August 23, 2000 1:52 PM
Subject: Brand new engine started knocking - need suggestions
Fellow listers,
I finally (after 2 years) got my new engine in the car and fired up for the
first time. It ran nicely and I drove it 2 or 3 times when I started
hearing a noise. It sounds almost like the engine is a diesel.
The sound doesn't seem to change with load, only with engine rpm. It isn't
very loud, no impending doom sort of noise, just a bad note to the engine
sound. The knock is not a deep rumble, it's a lighter pitched knock, like a
diesel.
Listening around the engine I can tell that the sound comes from inside the
engine, but opening the oil filler doesn't let it get louder. Using a steel
rod as a stethoscope against the head or block doesn't help. Disconnecting
the fan belt doesn't make the sound go away, nor does pushing in the clutch
make any difference.
I pulled the pan and looked around, tried to wiggle the crank and rods,
retorqued the rod bolts, made sure the mains are tight. Found that one of
the legs of the oil pickup was rubbing against a crank counter weight and
thought I had found the problem, but alas, the sound is still there.
There was nothing exciting floating in the oil pan.
When I built the engine, I had the crank measured, it only needed polishing,
it was already 10 under. The big ends were resized, new pistons fitted by
the shop, block bored to match, mains line honed.
New parts were: pistons, bearings, cam, timing sprockets and chain, lifters,
valve springs, complete rocker shaft with rockers.
I fitted all the bearings, plastigauged the mains and rod bearings, checked
crank end float.
In troubleshooting, what I haven't done is pull the rod or main caps. Since
I haven't driven or run it much since it started sounding like this, I don't
know if there would be visible bearing wear yet.
I would be grateful for any suggestions of what to check, even crazy ideas.
I'm in the process of moving and can only devote so much time to this at the
moment. I want to drive this car so bad I can taste it.
Thanks!
Ulix __/__,__ ___/__|\__
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http://www.mirafiori.com/~ulix/ '67 Sprite '74 X1/9
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