The lifter / cam discussion is always troublesome.
There are two ways you can do it:
1 - you can install (as Greg said) taper cams with crowned lifters
2 - you can install flat cams (Newman or Kent for instance) and put a dead
flat lifter on
Both will work.
I think in USA it is easier to find tapered cams than in Europe.
Cheers
Chris
-----Urspr|ngliche Nachricht-----
Von: fot-bounces@autox.team.net [mailto:fot-bounces@autox.team.net] Im
Auftrag von Greg Solow
Gesendet: Samstag, 6. November 2010 21:50
An: Mark Eginton; Friends of Triumph
Betreff: Re: [Fot] Odd wear
If the main bearing picture is the center main, then either the crank
journal is ground tapered or there is just insufficient clearance. You will
notice the rod bearing wear is on the side of the big end where there is no
alignment dowel. So it could be that the cap was on slightly twisted so that
it did not align on that side or else the rod is not straight & round.
You are right about the lack of rotation of the lifters. The lifter
bores are offset from the cam lobes to promote rotation of the lifters. It
is not enough, we have found. All of our cams are ground with tapered lobes,
to give an additional impetus to the rotation. The tappets must also be
ground with a crown to them that matches that taper. I would have the cam
reground and the lifters all hardness tested and then reground to match.
I think you should assemble your new block with main bearings with the
caps torqued in place, measure the id of the main bearings, then measure the
journal diameter so you can compute the actual clearance. It should be over
.002" and less than .003". Have the crank checked for straightness and make
sure that none of the journals are tapered. Have the rods checked for
straightness and bolt the caps on, make sure the side of the cap is
perfectly aligned with the rod, torque them to 60 psi using "Auto" bolts or
80 psi using "Bees" bolts. The id of the big end must be within specs and
round within .001" It is very hard to get them more perfect than this. Once
you have determined this is true, then put bearings in the rods & measure
the id of the bearings to compare it to the diameter of the crank journals.
you want .003" to .0035" rod bearing clearance. You may have to have the
crank ground & polished to get there. Good Luck.
Greg Solow
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