Hi Gordon,
The other clue for replacement, is wear between the gear teeth, forming
circular notches. That's what my old gears looked like. Another clue is
finding the lower chain guide broken, with pieces in the oil pan (I also
found that!)
I've got a couple of questions for you. Tonight I installed the new timing
chains on my rebuild. The lower chain tensioner assembly doesn't bolt onto
the block in one fixed position. There's a little bit of play before
getting torqued down. Does it make any difference where it gets torqued
down? I more or less held it against the bolts away from the timing chain,
before torqueing it down. Also couldn't find the torque value, so I guessed
it's 5 ft-lbs. One more question - what direction does the rubber head of
the tensioner point to? The picture in the manual is hard to make out, but
it looks like the rounded end points to the left towards the jackshaft,
while the almost straight narrow end points towards the crankshaft. Did I
get it right?
Thanks, Fred - So.SF
BADROC
----------
> From: Gordon Glasgow <glasgow@serv.net>
> To: datsun-roadsters@autox.team.net
> Subject: Re: timing
> Date: Wednesday, August 18, 1999 9:03 PM
>
> There are a few clues to look for, but there are no guarantees that I
know
> of.
>
> First, if the upper bracket is still on the timing chain guide, inspect
the
> driver's side of the bracket for wear marks that would indicate that the
> timing chain has been coming into contact with it. If the marks are
there,
> everything needs replacing.
>
> Second, put the car in a forward gear and roll it BACKWARDS by hand
enough
> to put tension on the passenger side of the timing chain. That will leave
> all the slack on the driver's side. Push against the chain and see if it
> will touch the bracket. If it does, it's time to replace things.
>
> But keep in mind that this condition can also be caused by having a head
> that has been milled too much (over .030") withou having had the cam
towers
> shimmed up to compensate. The timing chains might not be worn, but the
> condition will need to be corrected anyway.
>
> Gary Griffin wrote:
>
> > Can you tell by inspection whether the timing chains and or other parts
> > of the timing mechanism need or should be replaced on a U20 motor?
> >
> > --
> > Gary W. Griffin, ARM
> > Warren McVeigh & Griffin, Inc
> > 1420 Bristol Street North
> > Suite 220
> > Newport Beach, CA 92660
>
> --
> Gordon Glasgow
> Renton, WA
> http://www.gordon-glasgow.org
>
>
|