Yes, you have the direction right. I think the picture on page 24 is probably
the best to show that.
There isn't a torque spec anywhere that I can find, but the tensioner bolts are
M6 x 1.0 and the "standard" torque for a grade 8.8 in that size is about 7
ft/lb. The book lists the U20 cam tower nuts (the small ones) as M6 and gives a
torque spec of 5.1 ft/lb, so I'd say right in that range is correct.
Fred Katz wrote:
> 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
> >
> >
--
Gordon Glasgow
Renton, WA
http://www.gordon-glasgow.org
|