Dave Connitt wrote:
>
> Jim and List,
> Jim's comment regarding having to clear out some of the holes in his rocker
> arms makes me wonder if this is somehow connected to some of the valve
> tappet failures other list members have had after their rebuilds. The one
> that particularly comes to mind was the gentleman with the beautiful green
> TR250 that ran for 2000 miles before the tappets reduced themselves to mush
> and trashing his new motor! I haven't started on my engine rebuild yet but
> this is a concern of mine.
Don't think rocker oiling holes relate to a problem with tappets. Something
else going on there. There's so much oil splash
in the tappet area that other factors are at work--mismatched hardnesses,
failure to break in a new cam properly, etc.
> Carl and another list member have also had bad experienced with oil pump
> rebuild kits. I have purchased a oil pump rebuilding kit for my oil pump as
> part of my engine rebuild. I wonder if it would be worth it to have somebody
> test the relative hardness of my replacement parts? I am also considering a
> mild cam and new tappets for my rebuild. Part of this addition is that I
> assume the new cam and tappets will be hardened and not worn as I am sure my
> original part are.
> Just to want this thing to hold together!
I can't speak to oil pump rebuilding parts. Haven't dug into that. But, given
the relatively small difference in a rebuild
kit and a new pump, I'd put my money into a new pump from a reputable
manufacturer.
As for tappets, there have been ongoing complaints from many people about the
quality of aftermarket tappets in the last few
years, and it seems that bad batches do sneak onto the market from time to
time. Buying from a reputable supplier and heeding
the advice of those who have BTDT seems to be the best insurance.
After that, there are a lot of people who simply do not know how to properly
break in a new cam and tappets. They start the
engine, and first thing, they want to blip the throttle to hear that engine
sing. Kas Kastner, in virtually every competition
guide says, "don't do it, period." It puts a load on the valve train before
there's been time for adequate lubrication, and
something gets scored. After that, bye-bye cam lobe faces and lifters. And, cam
and lifters need some _serious_ lubrication
upon installation to protect those parts during initial start-up.
Finally, the cam faces, if they've been flame-hardened, need to be run at low
speed and load (~2500 rpm) for a minimum of
twenty minutes after start-up so that the cam lobes are burnished properly and
they have time without load to wear in a bit
to the new lifters. Keeping the speed around that point insures that there's
adequate lubrication without high loads imposed
on the cam lobe/lifter contact surfaces.
Cheers.
--
Michael D. Porter
Roswell, NM (yes, _that_ Roswell)
[mailto:mporter@zianet.com]
Don't let people drive you crazy when you know it's within walking distance.
/// triumphs@autox.team.net mailing list
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|