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100M Timing

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MikeAH100M

MikeAH100M

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Anyone know the proper timing for the 100M with the modified advance curve? I was unable to initially find the timing mark on the drive shaft pulley so used the old "put a dowel in the first cylinder" routine. I then cleaned the pulley some more and found a small hole drilled in the pulley that had been filled with paint!!! Matching that to the TDC arrow on the timing cover was a challenge so I JB Welded a small arrow on the cover. Very crude and not concours but really helped my poor eyes. Picture enclosed.
 

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Hi, according to the publication Austin Healey Special Equipment and Tuning Instructions, the initial static timing for the 100 with the engine modifications is 9 degrees BTDC. Also, the car should be road tested and the best timing arrived at by using a stopwatch to determine the best top gear acceleration. The tappets should be adjusted to .015 inches, but remember that this is with the thin head gasket, not the stock gasket.
 
Thanks. Very helpful. Do you know if there is any way to determine if the gasket is stock or thin without pulling the head?
 
I do not know if there is a way to tell if a 100 has the high compression cylinder head gasket. Someone with more technical knowledge than I have may know. My 100m had had a valve job before I bought it, and I didn't know which gasket was used, so I set its tappets to .015 inches. I had replaced the rocker shaft and bushings. I observed no problems with the way the engine ran.
 
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