Bulova Caliber 8136

The Bulova caliber 8136 is a quartz chronograph watch movement that was introduced in 2014. Bulova refers to it as a 3 eye chronograph movement. It is made in Japan and has 0 jewels.

In Bulova’s own words:

“Six-hand chronograph movement features proprietary high-performance quartz technology with 262 kHz vibrational frequency for precise accuracy.”

Miyota Base?

There is virtually no information about this caliber provided by Bulova, but we think we have narrowed it down to being based on a Miyota 6S20 movement.

The major difference is that the Miyota 6S20 runs with a frequency of 32,768Hz, and the Bulova is cranked up to an Ultra High Frequency (UHF) of 262 kHz as it is advertised on the dial of watches with the 8136 (similar to the P102). This would mean that it is using Bulova’s 3 prong quartz crystal that vibrates 8 times more than a standard quartz crystal (32.76 * 8 = 262).

Bulova and Miyota are both owned by Citizen.

Ultra High Frequency Technology:

Accuracy:

Bulova claims their Ultra High Frequency movements are accurate to about +/-5 seconds per month. Please share your experience in the comments below.

Battery Life:

According to Miyota, the correct SR927W battery cell should last about 4 years in the caliber 6S20, but the Ultra High Frequency movements seem to have shorter battery life than standard quartz watches. That is not to say 8 times shorter, but we need more information to confirm the expected battery life from the 8136. Please share your experience in the comments below…

What we do know is that running the chronograph means the watch is working harder and this reduces the battery life. For example, Miyota’s battery life claims are based on using the chronograph function for 60 minutes or less per day. For that reason, it is advised to only use the chronograph when you need it. If you are not going to wear your watch for a while and want to save the battery, pulling out the stem (aka hacking the movement) will reduce the battery consumption.

Resetting the chronograph to zero

If your chronograph hand is not resetting to 12:00 or “zero” position, then you can try the following steps:

1. Pull the crown to position 2 (time setting position).
2. Press button A to advance the chronograph hand forward until it is lined up with 12:00. If you long-press A, the hand will move forward faster.
3. Press button B to advance the 1/20 second subdial.
4. Push the crown back to position 0

Note: if you push the crown back in to position 0 while the chronograph hand is still advancing forward, then it will stop the chronograph hand and recognize it as zero position. In this case, you will have to start over again.

Examples of Bulova watches with similar movement:

Additional Resources:

• Bulova Precisionist official manual here
• Also see: Bulova caliber NP20

Caliber image submitted by @kafer_18