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How to set timing


Sent to Car Experts April 26, 2005 5:41 p.m.
I really need step by step instructions on how to set the timing for a '79 Mazda Rx7, I already know the firing order and any help would be so appreciated.
Customer (name blocked for privacy)
Status: Closed   Value: $5   
Answer
April 26, 2005 5:45 p.m. (4 minutes and 2 seconds later) 		ACCEPTED Check Mark
 

Rotary Engines

1979 RX-7

See Figures 12 and 13

This timing procedure applies to all 1979 RX-7s EXCEPT those after chassis No. 522504 that are equipped with an automatic transmission. For 1979 RX-7s after chassis No. 522504 with an automatic transmission, see the procedure which immediately follows.

  1. Warm the engine up until it reaches operating temperature, then shut the engine OFF and connect a tachometer.

  2. On automatic transmission equipped vehicles, securely apply the handbrake, block the wheels, and put the car in Drive.

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Fig. 12: Timing marks on 1979-85 RX-7s-the arrow points to the LEADING mark, while the TRAILING mark is beside it


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Fig. 13: On early model 1979 RX-7s (and late models with MT), adjust the leading timing by rotating the distributor, then adjust the trailing timing by moving the vacuum unit (MT) or adjusting lever (AT) in or out


  1. Read the tachometer as for a conventional four cylinder engine to verify that the engine is running at its normal idle speed. If not, adjust idle speed to specification.

  2. Stop the engine and connect a timing light to the leading (lower) spark plug of the front rotor. Then, restart the engine. Aim the timing light at the pin on the front housing cover and observe the timing.

  3. If the timing pointer does not line up with the first (yellow) notch on the pulley, loosen the distributor locknut and rotate the distributor either way until timing is correct. Tighten the locknut and check that timing is still correct.

  4. Stop the engine and connect the timing light to the trailing (upper) spark plug of the front rotor. Start the engine (put automatic transmission equipped cars in Drive), and check the trailing timing. The timing pointer should line up with the second (red) notch in the pulley.

  5. If the trailing timing is not correct, loosen the vacuum unit attaching screws (manual transmission) or the adjusting lever attaching screws (automatic transmission), and move the vacuum unit (manual transmission) or adjusting lever (automatic transmission) in or out until the timing pointer lines up with the second mark on the pulley. Then, tighten the screws and recheck the timing.

1979 RX-7 WITH AUTOMATIC TRANSMISSION AFTER CHASSIS NO. 522504

See Figures 12 and 14

  1. Warm the engine up until it reaches operating temperature, then shut the engine OFF and connect a tachometer.

  2. On automatic transmission equipped vehicles, securely apply the handbrake, block the wheels, and put the car in Drive.

  3. Read the tachometer as for a conventional four cylinder engine to verify that the engine is running at its normal idle speed. If not, adjust idle speed to specification.

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Fig. 14: On late model 1979 RX-7s (with AT), adjust the trailing timing by loosening the breaker base attaching screws, then loosen the external lever attaching screws and move the lever in or out


  1. Stop the engine and connect a timing light to the leading (lower) spark plug of the front rotor. Then, restart the engine. Aim the timing light at the pin on the front housing cover and observe the timing.

  2. If the timing pointer does not line up with the first (yellow) notch on the pulley, loosen the distributor locknut and rotate the distributor either way until timing is correct. Tighten the locknut and check that timing is still correct.

  3. Stop the engine and connect the timing light to the trailing (upper) spark plug of the front rotor. Start the engine (put automatic transmission equipped cars in Drive), and check the trailing timing. The timing pointer should line up with the second (red) notch in the pulley.

  4. To adjust the trailing timing, stop the engine and remove the distributor cap and rotor.

  5. Slightly loosen the breaker base attaching screws, then reinstall the rotor and distributor cap.

  6. Start the engine. Set the transmission selector lever in Drive and run the engine at idle speed. Move the external adjusting lever in or out until the timing pointer lines up with the second (red) mark on the pulley, then tighten the adjusting lever attaching screws.

  7. Stop the engine, remove the distributor cap and rotor, and tighten the two breaker base attaching screws.

  8. Install the rotor and cap, then recheck the trailing timing.

PictureTech501  -- Auto Service Technician -- 96% Positive Feedback on 739 Car Accepts
38 years exp, ASE Mastertech with L1 Advanced Engine performance
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April 26, 2005 8:14 p.m. (2 hours and 28 minutes later)
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Edited by Tech501 on April 26 2005 at 8:15pm
PictureTech501  -- Auto Service Technician -- 96% Positive Feedback on 739 Car Accepts
38 years exp, ASE Mastertech with L1 Advanced Engine performance
Reply
Sent April 26, 2005 8:28 p.m. (13 minutes and 55 seconds later)
How can I accomplish this if I can't get it to start and the distributer has been taken out?
Customer (name blocked for privacy)
Answer
April 26, 2005 8:38 p.m. (10 minutes and 17 seconds later)
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PictureTech501  -- Auto Service Technician -- 96% Positive Feedback on 739 Car Accepts
38 years exp, ASE Mastertech with L1 Advanced Engine performance
Reply
Sent May 01, 2005 1:33 p.m. (4 days and 16 hours later)
what could go wrong if I welded on the exhaust without disconnecting the battery and it would crank but would not start?
Customer (name blocked for privacy)
Answer
May 01, 2005 1:37 p.m. (3 minutes and 17 seconds later)
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PictureTech501  -- Auto Service Technician -- 96% Positive Feedback on 739 Car Accepts
38 years exp, ASE Mastertech with L1 Advanced Engine performance

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