Calibrating An Old Peterbilt Speedometer | Setting The Dip Switches And Checking The Wiring

My speedometer was way off so I needed to calibrate it in my 1987 Peterbilt 362. The speedometer is not the original as the manufacturing date says 2001. So I have no idea how many miles are on this thing! But I need to get the speedometer working. In this video I'll show you how I did it. How I figured out what series of Ametek it was, whether it is a 500, 700, or 900 series - this video can help. I'm not a professional, but its not too bad of a fix. My sensor is the magnetic pickup, so you just need to be sure to check out what system you have first and then follow the calibrations.
Here are some important links.
Information on Ametek speedometers: www.ametekvis.com/-/media/ame...
Technical information on calibration of the 900 series as done in the video: www.ametekvis.com/-/media/ame...
Technical information on calibration of the 700 series if you got one: www.ametekvis.com/-/media/ame...

[@mudcatadams4235]

You the man bro. My speedo been off for about 2 years. Algorithm listed your video and while I was getting loaded I done the math and I got it dead on now. Hats off to you!!! 👍👍👍

[@nedstephens]

Fantastic. Glad it worked for you!!!

[@therealchrisgaillard]

Thanks, this helped a LOT!

[@nedstephens]

Glad to hear it! 👍👍👍

[@RexMeier]

Do you know the settings for a 700 with 355

[@MrOlegalis69]

Dammit boi 😂.. I've been searching for this for years! And I'm still lost! I own a 91 379 13spd 355.
I've got a duxon speedometer..I've never seen or heard of your technique...my problem is, the needle won't move until 7/9 mph..

[@nedstephens]

Can be frustrating for sure. Hope you get it figured out bud. I’m sure there’s a publication on it somewhere and very similar steps that I did.

[@brappplife9879]

Really wish in you video you showed all the final numbers and dip pin positions this ended up just being a video to your specs haha. I paused and found what I needed but come on man. This info is actually pretty difficult to find

[@nedstephens]

Hey bud you’re probably right should have turned the speedo around and showed that. The calibration is very specific to however your setup is and just wanted to help understand the process to do it. I’ll take your tip to heart be a little better in the future. Thanks a bunch.

[@gilbertomoreno2051]

hey bro how are you getting the number 20,178 ? is that the rotation on your tire per mile?

[@nedstephens]

20,178 is the constant number used to get the rotations per mile. You take 20,178 and divide it by the diameter of your tire and you'll get rotations per mile. Anyways, you can find the equation for your specific speedometer by clicking on the links in the description. Hope that helps.

[@alan-dy9bq]

Do you know which sensor runs the rpm?

[@nedstephens]

Sure. Many times it’s located on the bottom or side of the bell housing. Similar looking to the speed sensor but picks up the signal from the gears on the flywheel.

[@federicozapata725]

Hello good evening, I watched your video on setting the speedometer & I really liked it, would you oso kind & send me a picture of the dip switch chart please so I can set my.
Your set is the 232 & my is 221 & I really can’t make up the numbers on your video.
Thank you.

[@nedstephens]

Hey bud. I think you’ll find what you need in the description. Should be a link that will pull up the pdf you need. Good luck.

[@federicozapata725]

Thank yo I got it.

[@richardhughes6757]

Did you confuse diameter and circumference?

[@nedstephens]

No, you want to find the diameter of the rear tire from top of tread straight to the ground in inches. Then you use this to find the revolutions this tire will make every mile by taking 20,178 and dividing it by the diameter. The 20,178 is a constant number valid in all applications to find the revolutions per mile. Hope that helps.