Hi listers
I'm rebuilding an 1147 cc engine. In fact I use to have a 1500 cc in my
MK2 and I'm replacing it with an 1147 that I've bought and rebuilt. I
was not sure that the timing marks was set correctly I suspected a
180-degree offset. The center mark (center holes) of the camshaft
sprocket was not align with the mark on the camshaft). So I followed the
procedure "valve timing (unmarked sprockets)". I've started the engine
but in order to make it run the timing has to be set at around 15 degree
ATDC. At BTDC (as per spec) it barely runs. What's wrong? Why ATDC and
not BTDC. When I turn the vernier (on the vacuum unit) in the ADV
direction it goes in the ADTC direction not BDTC. Could it be that I'm
one teeth offset on the sprocket? Should I leave it like that?
Also I've found some contradictions between the original workshop
manual and the reprint issue by Brooklands Books ltd (the green book) at
the section valve timing.
In the original workshop at page 1-138 Valve timing with unmark
sprockets they say:
Turn the camshaft until the 8 push rod has reached its highest point In
this position adjust number 1 rocker clearance to 0.040". Repeat the
procedure with number 7 push rod and adjust number 2 rocker until its
clearance is identical to that of number 1 rocker. Again turn the
camshaft until number 1 and 2 valves have reached the point of balance....
In the Brooklands workshop manual at page 1-135 Valve timing (unmark
sprockets)
Rotate the camshaft until number 1 push rod reaches the highest point of
its travel (cam follower on peak of cam. Adjust clearance of number 8
valve to 0.040" Rotate the camshaft until number 2 push rod reaches the
highest point of its travel. Adjust clearance of number 7 valve to
0.040" Turn camshaft in direction of rotation until the valves of number
4 cylinder are on the rock, i.e. the inlet valve about to open and the
exhaust valve almost close.
Which version is the good one? I went with the Broolands version
because at TDC it is suppose to be the compression stroke for cylinder
1 and both valves have to stay close. Is my timing problem related with
the difference between the two books.
Thanks for any help
Jean-Marc Dion
Spitfire Mk2, 1967
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