On Thu, 20 Oct 2005, Navarrette, Vance wrote:
> Sloane:
>
> 10W-30, Valvoline or Pennzoil.
>
> When I ported my Z28 Camaro with 20,000 miles on it, the cross
> hatching
> was still pristine in all 8 cylinders using this grade of oil. I was
> impressed.
> I would have thought it was impossible to have so little wear at 20k
> miles.
> So, after my rebuild, that is what I started using in my six.
> Time will
> tell if the benefits accrue to the same degree. I don't plan on opening
> the motor
> anytime soon =:-o
If you don't really really blueprint your TR6 motor, chances are pretty
high that suing 10w30 will result in your having to open the motor sooner
rather than later. Trust me on this. I've been in a few motors where the
owners tried 10w40 and other odd combos and they all had wierd failures -
like broken pistons. I don't profess to know why, but that is my
experience.
Remember - it's the "whole package", not just the cross-hatch on the
swilinder walls. You need something clingy for the cam (to protect against
dry startup) and something thick for the hot bearings (the "50" part of
the equation). Also recall that if you are building a motor now, there are
significant tradeoffs made that you have no control over - like the
aluminum-clad bearings. With the old tri-metal bearings you might have
been able to get away with thinner oils, but I doubt it.
Sorry to jump in like this, but IMHO this is one case where newer is not
necessarily better. Our motors were never intended to use some of the
newer oil stuff that is out there. Period.
Besides - what's the advantage of 10w30 oil? Getting 28 MPG instead of 27?
I'm serious. Also, your Camaro would have had the advantage of millions of
units on the road for dialing in the motors over the years. Put together
all the 6-cylinder Triumphs ever produced and you're talking in number far
less than 2 million (total). That's a totally different sample with regard
to engineering change data over time. And the last 6-cylinder Triumph
motors were produced nearly 30 years ago. A lot of stuff has changed in
that period in terms of the composition of the oil and the materials and
methods used in the manufacture of engines.
As a point of information, the last time I took my TR6 motor apart, it had
116,000 miles. The motor is _still_ running with the original pistons. As
regards the cross-hatch on the cylinder walls, it was still there on the
entire bore of every cylinder except at the very top. We "busted the
glaze" with a hand hone (and kerosene as the lube) in an electic drill.
Oil consumption now is less than one quart per 3000 miles. It actually
leaks more than it burns out the tailpipe. Oh, the motor now has about
130k miles.
The 20w50 thing seems to work okay for this owner.
> Vance
regards,
rml
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