I need to know how to set the timing on a rebuild on the first start up. From what I read, the rpm should be idling at 750. But I doubt that the rebuild will be able to idle that low on a first start up. What am I missing here? thanks

~Dave

 

set the idle at 1500 for just rebuilt motor. after 800-2k miles drop it to 750. Do this gradually if you like, I don't think it matters but it will be a good indicator of how well the apex seals are accommodating the housings.

If you don't know how to set the idle please see the FSM which you can download free of charge via links from the faq. The FSM also explains how to set timing. I don't think I could explain it any better than Mazda has.

I tried setting timing right off the bat on a rebuilt motor and after finally breaking it in i realized that you must be idling the engine at 750 to set timing because of the progressive timing system. I'd recommend just centering the CAS and then twisting it by hand with the motor running till it sounds the best.

 

basically if you look at the CAS you will see a witness mark where the bolt was clamped down to hold it in place, use this mark to initially time the engine and use it as a rough starting point for base timing and if it was timed correctly before it shouldn't be more than a few degrees off time if the CAS is not a tooth or several teeth off.

i set timing after 30 minutes of run time, the engine will be hard pressed to idle lower than 1000RPMs with less run time than that on a rebuild with used housings.