Timing belts dont like oil so either a duplex cam chain
inside or a timing belt outside the engine. The problem
with the U20 head is the limited space for any larger
diameter timing gear on the camshaft.
Thomas
Jim Cawrse wrote:
> For all:This dosnt concern me (pushrod 2L guy), but from anarmchair
> engineering standpoint a toothed gear, belt, andspring loaded
> tensioner might be the way to go. Its a basic engineering fact that
> the speed relationship betweenthe crank and the cam (and the funky
> jackshaft on U20s) isthe same on any 4 stroke engine. Therefore, all
> someone has to do is find the right toothed pullysfrom the right donor
> car that will fit inside the U20 front coverand then arrange a spring
> loaded tensioner mounted to maintaintension on the back (smooth) side
> of the toothed belt. Issues with bore diameters of the pulleys could
> be fixed cheaplyby a machine shop boreing out or sleeveing the
> pulleys, in factthey could make up a bunch of them, all at a price
> far, far,less than re-creating the whole original system. If done
> properly, this would allow for a much quieter engine, andwould perhaps
> allow greater peak RPM. All you U20 guys need is a dedicated junkyard
> smart handson engineering type guy to get this thing rolling, he
> couldactually make a fair piece of money from it if he did it right,at
> the same time doing the U20 guys a big service. Just my two cents here
> at 0647 before even one cup of coffee....Best Regards,JimChesapeake
> Virginia67 pushrod 2L/5spd72 510 wagon
>
> ----- Original Message -----
> From: datsunmike
> Sent: Thursday, May 09, 2002 6:27 AM
> To: Thomas - Sweden; datsun-roadsters@autox.team.net
> Subject: Re: U20 timing stuff
> Or an engine swap.
>
> Mike
>
> ----- Original Message -----
> From: "Thomas - Sweden" <csp311@telia.com>
> To: <datsun-roadsters@autox.team.net>
> Sent: Thursday, May 09, 2002 4:48 AM
> Subject: Re: U20 timing stuff
>
>
> > Nissan will trash all the tools and molds because they
> > want you to buy a new Altima and not drive around
> > in an old Datsun. ;-)
> >
> > There are most likely sources in Japan for new old parts
> > but unless you have the right contacts it's a closed world
>
> > for the rest of us.
> >
> > In the end you will be making this investment choise,
> > a new cam chain set or a secondhand Ferrari.
> >
> > Thomas
> >
> > Andrew Murphy wrote:
> >
> > > I seem to remember a vendor telling me that Nissan would
> not do this
> because
> > > they originally outsourced the manufacture of the timing
> components and
> will
> > > honor the contracts even after the demise of the company
> or products.
> > >
> > > So unless you can contact the outsource company and
> convince them to
> fork
> > > them over (not gonna happen) you are out of luck.
> > >
> > > Andrew Murphy
> > > SoCalROC
> > >
> > > From: Mitch Planck <mitch.planck@mail.ias.net>
> > > To: 'Andrew Murphy' <solex67@hotmail.com>,
> "'orangedawg@hotmail.com'"
> > > <orangedawg@hotmail.com>,
> "'datsun-roadsters@autox.team.net'"
> > > <datsun-roadsters@autox.team.net>
> > > Subject: RE: U20 timing stuff
> > > Date: Wed, 8 May 2002 16:47:15 -0400
> > >
> > > In reading this email, I had the idea about this that
> has a small chance
> of
> > > solving this. Basically the problem is getting the molds
> and machining
> to
> > > produce the timing components. Has anyone ever tried
> contacting the
> > > manufacturing plant where these cars were made in Japan
> to see if the
> master
> > > molds are avaliable? I don't know if auto companies hold
> onto stuff like
> > > this or just trash it after awhile, but it would be
> worth a shot.
> > > http://www.nissan-global.com is the company website and
> indicates that
> the
> > > plant in Oppama was built in 1920 or so and seems to be
> the oldest
> plant. If
> > > someone on the list with some Japanese speaking skills
> called them up
> (Tel:
> > > 0468-67-5000) maybe we could find out... Unless someone
> has further
> > > knowledge on this, it's probably at least worth a shot.
> > >
> > > Mitch Planck
> > > '69 1600
> > > '70 1600, sans body
> > > Chelsea, MI
> > >
> > > -----Original Message-----
> > > From: owner-datsun-roadsters@autox.team.net
> > > [mailto:owner-datsun-roadsters@autox.team.net]On Behalf
> Of Andrew Murphy
> > > Sent: Wednesday, May 08, 2002 3:44 PM
> > > To: orangedawg@hotmail.com;
> datsun-roadsters@autox.team.net
> > > Subject: Re: U20 timing stuff
> > >
> > > Allen,
> > >
> > > It's virtually impossible to find individual U20 timing
> components for
> sale.
> > >
> > > Once in a great while you will see some timing stuff on
> ebay but the
> vendors
> > >
> > > generally don't sell the individual components any more
> as they are so
> rare.
> > >
> > > I recently forked over a sizeable chunk of money for a
> complete set.
> When I
> > > rebuild my engine, I am keeping all of my timing stuff
> for spares.
> > >
> > > As for finding gears and tensioners, well those are the
> really hard to
> find
> > > items. The chains and guides are more available but it's
> the tensioners
> and
> > > gears that are so rare and difficult to reproduce. I
> have talked with
> all
> > > the vendors and they pretty much say the same thing-
> "It's not going to
> be
> > > cost effective to build the reproduction timing
> components because
> someone
> > > will need to foot the bill for the molds and machining.
> As soon as that
> is
> > > done, it would be a simple matter to undercut the price
> and steal the
> > > business. Sad but true."
> > >
> > > My advice would be to look for a U20 engine that is
> complete and for
> sale.
> > > Check the timing components and see if they are in
> decent shape. It
> would
> > > also be good to have the rest of the U20 engine there
> for spare parts. I
> am
> > > doing this with my U20 engine. Any part replaced will be
> kept for
> spares.
> > >
> > > FWIW
> > >
> > > Andrew Murphy
> > > SoCalROC
> > >
> > > From: "Allen Blackmon" <orangedawg@hotmail.com>
> > > Reply-To: "Allen Blackmon" <orangedawg@hotmail.com>
> > > To: datsun-roadsters@autox.team.net
> > > Subject: U20 timing stuff
> > > Date: Wed, 08 May 2002 18:03:45 +0000
> > >
> > > To List,
> > >
> > > Horror upon horrors, but a very knowledgable lister took
> a look at my
> timing
> > > gears and upper tensioner and announced that they need
> to be replaced.
> > > Curses!! Anyone got any info for me? Particularly
> jackshaft and am
> gears
> > > as well as upper tensioner? Perhaps a real good used
> set. I've found a
> > > crank gear and I've got chains, just need the above.
> Anyone switched
> over
> > > to toothed gears and belts? Anyone interested in that?
> > >
> > > Allen
> > > 1970 2000
> > >
> > >
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