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TIMING MARKS for Crankshaft Pulleys -- CS-206

At 05:46 PM 7/31/2009 -0600, Jim Werner in Oakmont, PA, wrote:
"I do not have the correct timing cover on my engine. I do not have 3 marks at 6 o'clock, I have 5 marks at 10 o'clock".

All MGA and early MGB (G thru GF engines 1963-1968) have (or had) timing marks at 6 o'clock. MGB 18GG and later engine had timing marks at 10 o'clock. You should also pay attention to the type of oil thrower ring being mated to the proper covers. All MGA with felt or rubber seals and very early MGB with external rubber seal use the early cup shape oil thrower. Later covers with internal rubber seal MUST use the flat oil thrower. The flat oil thrower will fit inside the earlier covers but will be less effective.

"Also, I cannot seem to find a notch in the pulley".

Remove valve cover and #1 spark plug (or all spark plugs). Rotate engine until #1 piston is at Top Dead Center. Look for the timing mark at 6 o'clock. There should be a thin notch (catch your thumb nail in it) in the edge of the rear flange of the pulley. If you have a slightly wider than normal v-belt it may shield your view of this mark.

To find exact crankshaft position for TDC you can use a dial indicator on top of piston with cylinder head removed, It may be difficult or impossible to do this with cylinder head in place. Rotate crankshaft slightly off center to about 10 or 20 degrees from TDC, measure downward travel of piston and make a mark in the pulley at the "0" pointer. Rotate crankshaft the opposite direction off center, set the piston height to exactly the same downward travel position, and mark the pulley again at the "0" pointer. Then measure carefully and split the difference between these two marks to locate the proper TDC mark position on the crankshaft pulley. File or grind a permanent notch at that position. You can do this to make a timing mark on the pulley at 10 o'clock to match the late MGB timing cover.

Without removing the cylinder head you can use a piston stop to do the same thing. Piston stop needs a male thread to screw into the spark plug port, and it needs to be adjustable (long thread) to reach far enough inside to touch the piston. You can use a long threaded rod with the metric thread to match the port threads. Or you can knock the ceramic center out of an old spark plug, tap a thread inside and install a threaded rod to match.

Rotate #1 to TDC. Turn clockwise slightly (10 to 20 degrees) from TDC. Screw in the piston stop to touch the piston. Rock crankshaft gently, back it up gently against the piston stop, and make a mark on the crankshaft pulley at the "0" pointer. Then rotate crankshaft almost one turn clockwise until the piston comes up on the next stroke and will gently touch the piston stop. Make another mark on the crankshaft at the "0" pointer. Then measure carefully and split the difference between these two marks to locate the proper TDC mark position on the crankshaft pulley. File or grind a permanent notch at that position.

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