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MG MGA - timing gear question

I'm tearing my engine down for a rebuild, and removed the timing chain cover. With the crankshaft keyway at TDC per the workshop manual, the timing marks on the chain gears do not line up. The crankshaft mark is as shown in the manual, but the camshaft mark is about two gear teeth counter-clockwise from being opposite the crankshaft gear timing mark. I looked at a spare engine I have and see the same thing. I don't understand, can any one explain why this is?
Thanks, George
G Goeppner

George

The camshaft key way should be at one-o-clock with the crankshaft key at TDC.

Steve

Steve Gyles

Steve, yes, the camshaft keyway was at about one o'clock, and the car had run fine before starting the restoration. When I line up the timing marks on my original engine per the manual, and compare the camshaft keyway location with the spare engine also having the offset timing marks, the camshaft keyways are about 10 degrees different from each other.
G Goeppner

George,
Here's a response from my friend Ed K. (AKA Buddy Palumbo)...

All timing gears from this generation have chain play ..... take up the slack in the right direction and the marks will line up .........

Whatdaya think...Is your chain tight?

Gerry
G T Foster

When installing the timing chain, lay a straight edge across the sprockets in line with the rotation centers, align the punch marks with the straight edge, install the chain in that position, then install the sprockets on the shafts. The crankshaft key will be at TDC while the cam key will be around 1:00 o'clock position (+/-) as shown in the Workshop Manual, Figure A.6.

As a side note, this positions the cam with #4 cylinder at TDC on the compression stroke. You need to rotate the crankshaft one turn to put #1 piston at TDC on the compression stroke before installing the distributor drive gear.
Barney Gaylord

I don't know guys, the only way I can get the timing dimples to line up is by rotating the camshaft about 10 degrees from the position it was in originally. I can't believe I would have this condition on 2 engines, and both be wrong. BTW, both engines are early 1500's with the BP15GP prefix to the engine no. I also see two camshafts listed in the Service Parts book. I think I'll call John Twist and see if he can add anything.

G Goeppner

When I installed a Fast Street Camshaft it called for non-original cam timing, needing to be advanced 6 degrees. I did this by skipping the timing chain over one tooth to advance it 9 degrees, then installing an offset cam key to retard it 3 degrees. This might fool the next mechanic by having the can sprocket intentionally out of place. See if you can find a part number stamped on the camshaft.
Barney Gaylord

George,
Did you ever decide what was going on?
Gerry
G T Foster

This thread was discussed between 28/07/2008 and 01/08/2008

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