Opel GT Forum banner

1 - 20 of 22 Posts

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #1 · (Edited)
!!! VERY IMPORTANT !!!

The "Sectional View - Timing System" illustration used in ALL 1971 - 1974 Factory Service Manuals AND many aftermarket Opel Repair Manuals is WRONG!! :(

With the cam drive gear shown at ignition timing for the #4, THAT'S RIGHT, the #4 cylinder at TDC, the crank keyway is shown at 6 o'clock, cylinders #1 and #4 BDC position, and SHOULD BE AT 12 O'CLOCK instead. :mad:
 

·
Old Opeler
Joined
·
5,564 Posts
Disasters in the Making

The drawing is a sectional view showing the timing chain/oil pump general layout whereas the picture is showing the valve timing marks.

One of the great peculiarities of the CIH engine is that the timing chain and sprockets are put on with the engine at TDC on the compression stroke at cylinder #4 then the whole kit and caboodle is rotated till cylinder #1 is on the compression stroke before the distributor is installed and set.

The drawing shows the motor with cylinders #2 & #3 at TDC with the woodruff key down - half a rev away from where it should be - either back or forward - depending on whether the cam or the distributor is being timed.

I can only think it is something to do with getting the notches in the camshaft lined up so the head bolts can be put in and that he drawing is just happenstance - the draughtsman just got it wrong when comparing it to the actual position.
 

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #4 · (Edited)
Re: Disasters in the Making

GTJIM said:
1 The drawing is a sectional view showing the timing chain/oil pump general layout whereas the picture is showing the valve timing marks.

2 One of the great peculiarities of the CIH engine is that the timing chain and sprockets are put on with the engine at TDC on the compression stroke at cylinder #4 then the whole kit and caboodle is rotated till cylinder #1 is on the compression stroke before the distributor is installed and set.

3 The drawing shows the motor with cylinders #2 & #3 at TDC with the woodruff key down - half a rev away from where it should be - either back or forward - depending on whether the cam or the distributor is being timed.

4 I can only think it is something to do with getting the notches in the camshaft lined up so the head bolts can be put in and that he drawing is just happenstance - the draughtsman just got it wrong when comparing it to the actual position.
TAKEN IN ORDER:

1 This sectional view drawing is titled "Sectional View - Timing System", so why would any FSM depict an engine that not only will not run as depicted, but is certain to damage its valves if even a single rotation of the crank is attempted!!?

2 The reason that the engine is assembled with both the crank key and cam dowel at 12 o'clock (#1 and #4 pistons at TDC) is that this aligns the camshaft notches vertically to allow installation of the ignition-side head bolts. The ignition timing at this alignment is for the #4 cylinder, an Opel CIH anomaly, as you stated.

3 Cam and crank are a 1:2 rotational relationship while cam and ignition are in 1:1 rotational relationship. What I'm saying is that the cam and ignition can ONLY be timed correctly ONE way . . . it's a four stroke (cycle) engine and requires TWO revolutions (two piston TDCs, two piston BDCs) of the crank for ONE complete combustion cycle of any cylinder.

4 Already explained in 2 above.
 

·
Old Opeler
Joined
·
5,564 Posts
JUst a Little Challenge

Perhaps someone thought the peculiar Opel cam/ignition setup was not difficult enough and added a little extra challenge in the shape of the timing drawing!

I knew it was something to do with the notches in the cam for head bolt clearance too. The cam HAS to be in one position and one only for them to line up correctly and when cam/crank and cam/cranl/distributor timing are all so interrelated I see it all becomes very complicated.

At least we can write "WRONG" under the drawing in out workshop manuals, thanks to you! ;)

Probably saved a few horror stories.
 

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #6 · (Edited)
Re: JUst a Little Challenge

GTJIM said:
. . .

. . .

At least we can write "WRONG" under the drawing in our workshop manuals, thanks to you! ;)

Probably saved a few horror stories.
Instead, why don't you simply put a dot at the top of the crank nose with a red felt tip pen to indicate where the crank key should be. Everything else is correct in the illustration. :)
 

·
Old Opeler
Joined
·
5,564 Posts
Twink!

I twinked out the key at the bottom and carefully drew in a new one at the top.

BTW the Haynes Opel B series Owners manual that I have has a correct drawing in it .....
 

·
OPEL-LESS!!!
Joined
·
2,116 Posts
i dont remember the name of my book but it had the correct drawing in it. the exact drawing Baz posted. its old and has a white manta with a black stripe on it for the cover.
 

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #10 · (Edited)
Aftermarket Opel service manuals . . .

Clymer evidently just copied the Opel FSMs for their "Timing System" illustration and have it wrong.

Autobooks Owners Workshop Manual for the GT has it correct, but their Opel Ascona/Manta has it wrong, go figure.

Chilton uses a photograph with the head off to show the timing relationship.

I don't have any Haynes manuals.

:cool:
 

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #11 ·
Re: Hayes Manual

GTJIM said:
Here is a correct drawing from a Pommie Hayes Manual
Haynes?
 

·
Old Opeler
Joined
·
5,564 Posts
Yep!

Correct, Teke aar - seems the " " was missi g from my keyboard!

Moderators Note: Sorry, I couldn't resist. Otto is the only guy I know with a "spellcheck" on-board. In his head. :)
 

·
U-2 Driver
Joined
·
126 Posts
Baz/ anyone,

I can't tell the difference between the one Baz posted, and the correct one. The crank key appears to be at the 12 O'clock position on both, right? Are they both right? I am looking in my 1973 FSM, and it looks like the first/second? I think my motor was put together this way, how do I tell?
 

·
boomerang opeler
Joined
·
5,636 Posts
the photo i posted is from the same haynes manual that jim posted the drawing from so should be the same , the other manuals listed (north american ones ) are wrong is what otto is saying and show the key at the 6 o'clock position
 

·
U-2 Driver
Joined
·
126 Posts
Thank goodness!
I have an FSM 73, and my photo is right! I was worried sick becasue i just got my motor together and was ready to fire it up before I saw this thread. Thanks for the info!
 

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #16 · (Edited)
'71-'74 FSM engine 'timing' illustrations

T-6 driver said:
Thank goodness!
I have an FSM 73, and my photo is right! I was worried sick becasue i just got my motor together and was ready to fire it up before I saw this thread. Thanks for the info!
If you indeed have the '73 FSM (maroon cover, right?), both the "Figure 6A-2 Sectional View - Timing System" and "Figure 6A-5 Engine Lubrication System" illustrations are wrong!!! That was the whole purpose of my original post!

Figure 6A-2 showing crank key at 6 O'clock and pistons #2 and #3 at TDC is correct, but cam dowel shown at 12 O'clock is incorrect . . . cam dowel can only be at 3 or 9 O'clock when #2 and #3 pistons are at TDC.

Figure 6A-5 showing cam dowel at 12 O'clock and pistons #2 and #3 at TDC is wrong, pistons #1 and #4 should be at TDC instead!
 

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #18 ·
'68 - '70 FSM 'timing' in illustrations

nbrcrnchr said:
I have the black cover 70 FSM, is that one wrong also?
To answer your question, a quick review of the illustrations used to show 'timing' in the '68 through '70 FSMs might be in order here:

'68 FSM - Red/Black:

Figure 60-30 Side Cross Section
- crank key at 6 O'clock with #2 and #3 pistons at TDC is correct, but cam dowel at 12 O'clock is incorrect . . . cam dowel can only be at 3 or 9 O'clock when #2 and #3 pistons are at TDC.

Figure 60-54 Valve Timing Marks - crank key and cam dowel are both correctly shown at 12 O'clock, but it must be remembered that this is VALVE timing . . . the ignition timing would be for the #4 cylinder as shown!

Figure 60-57 Engine Lubrication System - cam dowel at 12 O'clock with #2 and #3 pistons at TDC is wrong . . . cam dowel can only be at 3 or 9 O'clock when #2 and #3 pistons are at TDC.

'69 FSM - Maroon:

Figure 60-50 Side Cross Section
- crank key at 6 O'clock with #2 and #3 pistons at TDC is correct, but cam dowel at 12 O'clock is incorrect . . . cam dowel can only be at 3 or 9 O'clock when #2 and #3 pistons are at TDC.

Figure 60-76 Valve Timing Marks - crank key and cam dowel are both correctly shown at 12 O'clock, but it must be remembered that this is VALVE timing . . . the ignition timing would be for the #4 cylinder as shown!

Figure 60-80 Engine Lubrication System - cam dowel at 12 O'clock with #2 and #3 pistons at TDC is wrong . . . cam dowel can only be at 3 or 9 O'clock when #2 and #3 pistons are at TDC.

'70 FSM - Black:

Figure 60-50 Side Cross Section
- crank key at 6 O'clock with #2 and #3 pistons at TDC is correct, but cam dowel at 12 O'clock is incorrect . . . cam dowel can only be at 3 or 9 O'clock when #2 and #3 pistons are at TDC.

Figure 60-82 Valve Timing Marks - crank key and cam dowel are both correctly shown at 12 O'clock, but it must be remembered that this is VALVE timing . . . the ignition timing would be for the #4 cylinder as shown!

Figure 60-85 Engine Lubrication System - cam dowel at 12 O'clock with #2 and #3 pistons at TDC is wrong . . . cam dowel can only be at 3 or 9 O'clock when #2 and #3 pistons are at TDC.
 

·
Old Opeler
Joined
·
5,564 Posts
Adding to the Confussion ...

The CAM timing must be done with the cam dowel and the crankshaft key both at 12 o'clock
In this postition the motor is at TDC for cylinders #1 and #4 with #4 at the ignition point. To install the distributor in this position the motor MUST have the Ignition timing done on cylinder #4

To do the Ignition timing on #1 cylinder the motor must be rotated one complete revolution to where the crank key is at 12 o'clock and the cam dowel at 6 o,clock ...... after the cam chain has been installed - or the valves will be bent if the cam does not rotate with the crankshaft!!
 

·
Super Moderator
Joined
·
5,298 Posts
Discussion Starter · #20 ·
GTJIM said:
The CAM timing must be done with the cam dowel and the crankshaft key both at 12 o'clock
In this postition the motor is at TDC for cylinders #1 and #4 with #4 at the ignition point. To install the distributor in this position the motor MUST have the Ignition timing done on cylinder #4

To do the Ignition timing on #1 cylinder the motor must be rotated one complete revolution to where the crank key is at 12 o'clock and the cam dowel at 6 o,clock ...... after the cam chain has been installed - or the valves will be bent if the cam does not rotate with the crankshaft!!
. . . "does not rotate in time with", perhaps? . . . once cam chain has been installed, cam's going to rotate with the crank regardless! :lmao:
 
1 - 20 of 22 Posts
Top