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I just bought I 390 that I am going thru. Is there a way I can check the timing chain to see if it is a timing set that is pre 1972? Am I making any sence?
Yes, and that's the first thing I checked on this engine, was to make sure it was replaced. I heard somewheres before that you wanted to get a pre 72 timing set, because they advanced/retarded the timing a bit on the post 72 timing sets.
I was trying to think of how two gears and a double roller chain could effect this, and thought I would throw the questions in here for any info.
Yes, and that's the first thing I checked on this engine, was to make sure it was replaced. I heard somewheres before that you wanted to get a pre 72 timing set, because they advanced/retarded the timing a bit on the post 72 timing sets.
I was trying to think of how two gears and a double roller chain could effect this, and thought I would throw the questions in here for any info.
Yes, the cam timing was changed for '72. It really killed the engine, apparently. I believe it was advanced (on edit: retarded) 12 degrees (not sure about that #) killing the mid-to-high RPM range.
Take a known pre-72 timing set, and put the two gears next to each other with the dots aligned. Now, take YOUR timing set and put the two gears the same way, and compare the key-ways on the inside diameter of the gears.
If you have a pre-72 timing set, the key-ways will be in the same spot. Come to think of it, the cam gear might have a hole where a pin goes to align it, not a key-way - can't remember
Last edited by krewat; May 30, 2006 at 04:35 PM.
Reason: Dumb mistakes