60K miles is the recommended changeover of chain stuff. Although you can
probably get a lot more miles out of it by babying it, as with any
engine. I'm no expert, but my high school autoshop teacher had the best
advice. Change the oil often, and avoid dry starts. He was driving an
old jalopy with about 400,000 miles on it and it ran great. When I
rebuilt my U20, I made sure the oil galleys and ports were clean and
wide-open in the cam and head. Changed oil several times the 1st 1000
miles, and then switched to synthetic. Keep the oil clean, and you'll
reduce wear on the metal parts from contaminants and acid (the acid
forms as the oil gets old).
Don't know about blipping the throttle, I don't need to. You might want
to take apart the carbs and make sure everything slides freely without
hangup. I used crocus cloth (emery paper) to take down high spots so the
pistons slid without friction in the SU domes. Also, check often that
the SU pistons have oil in them (I keep a small bottle of automatic
tranny fluid for that).
Fred - So.SF
-----Original Message-----
From: owner-datsun-roadsters@autox.team.net
[mailto:owner-datsun-roadsters@autox.team.net] On Behalf Of James
Hoffman
Sent: Friday, May 27, 2005 5:01 AM
To: datsun-roadsters@autox.team.net
Subject: a few questions
Hi-
How many miles do you guys think one should get from the U20 timing
chain/tensioner/guides? How do I check for wear besides waiting for the
big loud racket when it's beat? Why do these wear relatively quickly?
I had a 280ZX with 225K miles & never replaced anything in the engine.
Of course it had updated technology but just wondering.
Is there any significate difference in the U20 between 67.5 and 70?
When driving my car (2000 with SU's) I often have to "blip" the throttle
to get the RPM's to settle back down below 2000. Is this the throttle
return spring? Any other likely causes?
Someone told me that when parking on a hill to put the stress on the
emergency brake instead of putting it in gear, letting the trasmission
take the tension then setting the brake. Any validity to this?
Eric Hoffman
Atlanta, GA
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