Hi,
Been there, done that.
Twice.
But I also have to stress the importance of initial cam break-in. Like I
keep saying this week, the first 20 min. of a cam's life will determine
whether it'll last or not.
As an aside, it is possible to "see" internal engine damage by looking
closely at the oil or even going to the extreme of cutting open the oil
filter (if you have a spin-on adapter) and looking for metal particles.
One solution to the "soft lifter problem" is to go to a completely
different source for lifters. Dave didn't mention this, but BFE can sell
you some lifters from some sort of Ford application (this mod requires
drilling out the lifter bores in the block) to a fatter lifter. Note: this
solution is not cheap - but it will last. And this is particularly true if
you go to radical cam profiles and a lot of valve spring seat pressure.
Also, several of the UK suppliers sell hardened lifter sets that will meet
the min. lifter hardness specs.
But you have to decide - do you want to spend $150 on the good lifters or
$75 for the ones that might be good.
And as a parting thought, recall that much of a TR6 cam's lubrication is
from "splash" off the crank. Some modern oils don't cling like the older
oils did, so it is quite possible to get metal to metal contact inside
your motor, especially during startup. Related to this is the fact that
TR6 owners seem to be neurotic about making thier cars idle at
rediculously low RPM's (less than 800, for example). IMHO, if you you do
this, you might as well just dump some "black magic" blasting media in
your sump and be done with it. The "splash" at low RPMs is not very much
lube to the cam.
I think the ideal solution for the TR6 cam/lifter failure is to
re-engineer the oiling to the cam (as in make a "spray bar" like some of
the Datsun racers did in the '70's. If you get better oiling on the cam,
it'll def. last longer. The "problem" with the cam/lifter thing is that
while a lot of people are familiar with it (mostly through first hand
experience), nobody wants to spearhead a campaign to stamp out the crappy
parts in the stream (because _all of us_ buy on price-points).
I know one TR6 who did two or three cam installs before he broke down and
did all the "right things", install cam bearings, bore the block for the
Ford lifters, install the Ford lifters and new cam and then run the motor
in right. Skip any step and it's likely that your new cam will last 5000
miles.
Last point - if you think I'm full of it, call any cam grinder and ask for
a cam. If they don't have new blanks, they'll want a grindable core. One
grinder that I worked with last year had "a pile" of ruined cams that were
not regrindable. I've resorted to picking up any "core" engines I can find
just for the cam cores. I have 5 or 6 engines in the garage (aside from
the two running engines in the cars and the new one on the engine stand).
Really!
'nuff said (for now).
rml
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