Scions,
Beautiful day today in Baltimore; great day to take a LBC out for a
spin. However the TR is off the road but with the leaves raked and
grass cut, I had some time to return to rebuilding the TR6 engine.
I've got a problem with the cam timing procedure as it's not going
according to the book. Upon disassembly about 18 months ago, the crank
punch mark was in the proper position, the camshaft sprocket was not
punched but the cam punch was at about the 11 o'clock position as shown
on page 136 of Bentley. I therefore marked the cam sprocket to assist
with reassembly. Today after following the manual's procedures, I'm off
by 1 cam sprocket tooth. That is, looking at the front of the engine
it's 1 tooth more clockwise according to the punch mark I made on the
camshaft sprocket. That's about 8.57 degrees advanced.
Here's what's changed in this area since disassembly: original cam (no
alterations) and cam sprocket; original crank, new crank sprocket and
new timing chain. Engine was completely disassembled and everything up
to today has gone together just fine.
Today, I think I followed Bentley's directions correctly. I temporarily
installed the cam sprocket to assist with turning the cam during valve
adjustment and I reset all the valves to .010 except for #'s 11 & 12
which in the process were set to .120. The #1 piston is at TDC as
verified by a dial gauge and so marked on the flywheel and block, prior
to installation of the head. I rocked the camshaft in both directions
in order to get an equal gap on #11 and #12, something under the
original .120 setting. Upon installation of the sprockets and timing
chain, the cam and cam sprocket are rotated clockwise by 1 tooth
according to my original punch mark on the sprocket..
I disassembled the sprockets and chain, rechecked and reset #11 & 12
valves and followed this procedure again but nothing changed from the
first time.
So, here are my questions:
1. Did I follow the correct alignment procedure today?
2 If the answer to #1 is yes, would the engine have run with the cam
timing being off by 1 tooth?
3. Where do I go from here?
4. The cam chain is a bit snug. Is this typical for a new chain?
I appreciate all help and will share answers with the list.
Gary
'75 TR6
Digest Subscriber
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