Help on setting timing on 86 NA
01-26-02, 08:45 PM
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Help on setting timing on 86 NA
I need help setting the timing on a used 86 NA motor I installed into my car. Its running a bit on the lean side and want to make sure the timing is set right before I go any further.
I have an adjustable timing light and have heard that you can't just set the dial the degrees to what you want on a rotary that you have to double it or something?
Also it seems to have LOW oil pressure, 25psi on the high side. both on the stock gauge and an aftermarket one with the Racing Beat gauge block adapter under the oil filter, and was wondering if there is anything off hand that I could check for this condition?
As for the lean conditions, I have checked for leaks and have found none so far, capped off all vac holes that are not used.
Thanks for any help
I have an adjustable timing light and have heard that you can't just set the dial the degrees to what you want on a rotary that you have to double it or something?
Also it seems to have LOW oil pressure, 25psi on the high side. both on the stock gauge and an aftermarket one with the Racing Beat gauge block adapter under the oil filter, and was wondering if there is anything off hand that I could check for this condition?
As for the lean conditions, I have checked for leaks and have found none so far, capped off all vac holes that are not used.
Thanks for any help
01-27-02, 01:37 AM
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A Mazda Rotary looks exactly like a GM DIS-fired 4-cylinder automobile. Adjust your light to work properly on this engine, and it will be correct on the Rotary. That said, an adjustable timing light is not needed anyway. With the light on the leading plug wire, you are looking for a yellow mark aligned with the pin. Loosen the CAS and rotate to acheive this.
Does the car smoke heavily? If it does, the oil seals are shot in the engine (rebuild time, or get another used egine). If the car doesn't smoke, one of 2 things can cause it. The front eccentric thermostat may be stuck closed, not allowing oil pressure to build. It is supposed to bypass the eccentric shaft when the engine is cold, but if it doesn't expand, closing off the bypass, oil pressure will be low. Also, someone may have done work on the front side housing, and not used the correct parts to re-assemble it. Mazdatrix has an excellent write up on this, see
http://www.mazdatrix.com/faq/oring.htm
As for the lean problem, replace the O2 sensor first, if it is old this is one of the symptoms. If the sensor is good, you have either a vacuum leak (or intake leak), low fuel pressure (replace fuel filter - always worth a shot), or a bad AFM and/or sensor (water thermosensor, intake air thermosensors). Good luck!
Irv, Keith's dad
Does the car smoke heavily? If it does, the oil seals are shot in the engine (rebuild time, or get another used egine). If the car doesn't smoke, one of 2 things can cause it. The front eccentric thermostat may be stuck closed, not allowing oil pressure to build. It is supposed to bypass the eccentric shaft when the engine is cold, but if it doesn't expand, closing off the bypass, oil pressure will be low. Also, someone may have done work on the front side housing, and not used the correct parts to re-assemble it. Mazdatrix has an excellent write up on this, see
http://www.mazdatrix.com/faq/oring.htm
As for the lean problem, replace the O2 sensor first, if it is old this is one of the symptoms. If the sensor is good, you have either a vacuum leak (or intake leak), low fuel pressure (replace fuel filter - always worth a shot), or a bad AFM and/or sensor (water thermosensor, intake air thermosensors). Good luck!
Irv, Keith's dad
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