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Timing question

To: Spitfire <spitfires@autox.team.net>
Subject: Timing question
From: Jean-Marc Dion <dion.longpre@sympatico.ca>
Date: Sun, 04 May 2003 21:03:17 -0400
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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