Speaking of Austin Area Roadster's
Mark Kalmus moved to Round Rock about a month ago. His email
address bounced, and I have lost his address. Mark are you
still out there?
Spent yesterday helping out a fellow Datsun owner. In this
case the timing chain on a KA24 in a Nissan Truck. I thought
it would take about 5 hours. Wrong, ended up being over 10
hours. First time in my life I thought a roadster timing
chain is easier to replace! [Note, the KA24 uses a single
roller chain, and should be replaced by 100,000 miles].
Since Andrew did most of the work, and I just pointed out
tips, it was pretty enjoyable letting someone else do most
of the work and learn from my esperience.
He followed my advice and steamcleaned everything on the
engine the previous week. Makes life easier to work on
a clean engine.
Andrew wasn't sure how to keep all the front cover bolts
in correct order when they go back in. Trick was to use a
piece of cardboard, sketch the front cover, and poke holes
with a ball point pen (or screwdriver) into the cardboard
where bolts go. Then as the bolts are removed, stuff them
into the cardboard. Ditto for any brackets or spacers that
came off.
Also it is nice to place a large sheet of cardboard under
the vehicle. Drop a nut, and can not reach it... pull the
cardboard out to help retrieve it. Typically I wait until
I am done removing everything, as I drop more than one
nut.
Andrew got the chain back on, and everything looked good.
After I got the front cover back in place, I tried the
good ol' method of rotating the engine a full 2 full turns
at the crank BY HAND. Uh oh... valve to piston interference.
Thankfully Jason Gray had stopped by, and helped out with
the "what did we do wrong?". Took a little bit, but the cam
was off by 1/8 turn. Not sure how we did that, but did.
Since the cover was on, we rotated the crank 90 from the
"TDC" position. Then rotated the camshaft for "TDC" alignment.
Slowly rotated the crank back up to position (keep in mind
the engine at TDC#1 means #4 is 180 degrees out with both
valves open. Simple matter of repeating this process of
crank and cam until we could get both aligned close enough
without intereference, then reseting the last link so both
match up to "top dead center". Mu usually trick of measuring
#4 valve spring depression does work on this engine, as it
has hydraulic adjusters making an exact measurement harder.
Thankfully the cam down and alignment mark are easy to
align.
I should have cranked the engine to TDC #1 before starting.
I had set it to #3 TDC, and noted the distributor was off
by 180 degrees... but with three of us, and moving things
back and forth... well, the moral is check the chain timing
BEFORE you put the front cover back on!
Other comments, you never can have enough lighting in a garage.
My "clip on" lamp (100W), 300W floor lamp (reflects off a white
ceiling), and 500W floor light... it helped! More lighting,
the better.
Next time I "complain" about the U20 timing chains... well, it
is much quicker than a older KA24 truck engine. Ironically my
'96 has much less "plumbing" than Andrews '90 version did.
Cheers,
Tom Walter
Austin, TX (actually Round Rock, TX)
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