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> From: Scott W. Paisley <scotty@csn.net>
> To: sugar@holly.colostate.edu; KC3565L@sprintmail.com;
tgman@ix.netcom.com; southern@ucar.edu; chris@zing.ncsl.nist.gov
> Cc: triumphs@autox.team.net
> Subject: TR6 Progress
> Date: Friday, May 16, 1997 9:55 PM
>
> To bring the list uptodate, I've milled my head down to 3.4 inches,
> giving me a CR of 9.5:1. I've ported the head, did some intake
> manifold grinding, and put a mild cam in the car. Fired it up,
> just a few nights ago, and it started right off, but there's a
> slight miss at idle. The other bizarre thing is oil pressure,
> but I'll save that for last.
>
> I think I've located the slight miss at idle problem. Actually,
> it may be more than one problem, but this is a problem for sure.
> My push rods are too long.
<snip>
> I'm sure the pushrods are hitting the inside of the rocker,
> (away from the ball) because of the nice smiley faces the
> pushrods left on the underside of my rockers.
>
> I've got pushrods on the way from TRF, they should have left
> Pennsyltucky monday, but didn't get here (Colorado) yet.
> Guess I won't have the car at the TR meet on Sunday. *sigh*
> There's no sense in taking a chance on smashing metal parts
> together that aren't meant to meet though, so I guess I'm done
> debugging until my pushrods show up. (Probably monday)
<snip>
Scott-
Sounds like you have done the "right" kind-o-stuff to you ride so
far...BUT, ya gotta watch those pushrods that "grow" on you. <g>
Whenever you mill the head very much, you'll have to "roll" your own
pushrods to keep the geometry correct. You have already experienced one
extreme, now just don't fall into the trap at the other end. If the p-rods
are too short the geometry will be such that the rocker will put more
"sideways" force on the valve stem and the guides won't hold up for long.
Now for the Good news/bad news game... Its good that you have ordered the
shorter p-rods, but bad in that you may still have to modify them to suit
your exact engine. (The p-rods were available in a total of three lengths).
The shorter p-rods have the ends pressed into them, but not welded in
place. This is a good thing as you can determine the exact length you will
need and cut the rod part down to the correct length. The easy way to do
this is to chuck the p-rod up in a lathe and use a thin bit to cut into the
p-rod just below the upper end of the rod. You do not have to remove the
end, as you can tell when you have gone through rod, which will be shiney
bright as you cut thru it, and the pressed in part of the end will still be
dark blue/black, so you can tell when to stop. Then all you need to do is
to drive the end further down into the p-rod. A piece of hard wood works
well, don't use a metal hammer.
To get a rough estimate of how to figure how much to cut off of the length,
measure your cam lift and turn the motor over till you reach I/2 of the
lift. At this point the rocker should be about parallel with the head. If
the rocker is beyond parallel so that the valve side is lower, you will
have to remove more material from the p-rod. Whatever measurement you get
between a parallel rocker and the rocker at half lift will be the amount to
remove. Yes, this is time consuming and a pain-in-the-butt, but it is the
only viable way to keep things from wearing out (or breaking). Don't use
shims under the rocker stands as this will also throw out the rocker
geometry and accelerate wear.
I've been off my "rocker" for years, but my "geometry" is perfect...
Nick in Nor Cal
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