TheBirdman
Registered User
So a while ago I bought a Fox Valley luminosity timing probe secondhand from a forum member, and I finally got around to using it, and in my research, I found that it seems like nobody either on here or on fordtrucks.com knows the proper way to use it, or at least they havent shared their wisdom. Ive seen plenty of posts of people doing it half to three quarters wrong, and many more just giving up on it, so since I just got done timing my truck with it, and Ive got a few minutes to kill and a glass of whiskey to finish, I figured Id write up my findings. Since these adapters are way cheaper than ferret adapters, Im pretty pleased that it worked out so well.
First off, and I believe this to be the origin of most of the confusion, the manual is mostly useless. It was designed for an old style timing meter with a magnetic pickup, and we're not going to use that. Such old meters needed a 20 degree offset in order to operate, so when the manual says to use a 20 degree offset, it confuses people. The only useful piece of information the manual has is the timing spec, which is 4-8 degrees ATDC (AFTER top dead center) at 1400 rpm. The second point that I believe causes a large amount of confusion is that if youre using an inductive timing light, you cant dial in the setting to before tdc, just after. Ive found this to be completely a non-issue with one simple trick. The trick? Basic math.
Tools needed
___________________
luminosity probe timing adapter
gas engine style timing light with advance (knob or digital is both fine)
piece of tin foil (trust me)
paint marker
First, clean the timing mark on the harmonic dampener and the bracket with the timing holes. Then mark the timing mark so that its easier to see, and mark one line on the timing bracket along the centerline of the top timing hole. Yes, I know, the top timing hole is 20* atdc, bear with me here. If you want, you can put a mark on the bottom hole too, but that simple trick I mentioned earlier involves the top hole. Here is a picture:
Next, warm up the engine to full operating temp. Hop in and drive down to the grocery store and get a case of beer for yourself and some flowers for your significant other, or a card for your mom. Tell them you were just thinking of them.
Once youre back and the engine is nice and warm, remove the glow plug from the #1 cylinder, install the luminosity probe, plug the timing adapter into the probe, and clamp your timing light onto the pickup coming out of the adapter. There is a right and wrong direction, so point the spark plug end of the timing light toward the spark plug symbol. If youve never used the adapter before, you might want to unscrew the case and check if the 9v battery is still any good. You know how. Heres where the tinfoil comes in handy, loosely wrap it around the pickup wire and the clamp on the timing light. If you read the other threads about people using these, youll see that they often complain about erratic readings. Ive found that the readings cleared up nicely with the tinfoil. This is because the signal coming out of the timing adapter acts like an antenna and blasts the immediate area with electromagnetic interference, and that screws with the electronical guts of the timing light. The tinfoil shields the timing light from the interference, much like it shields your brain from the effects of the governments mind control rays.
Now youre ready to start reading timing, and heres where I explain the trick. Timing lights cant be set to before top dead center, but weve got a nice timing mark at 20* atdc now, so if you set your timing light to 20* btdc, you can use the timing light with the mark at the top hole, and the timing mark on the crank will line up perfectly as if you were reading top dead center. Now, to retard the timing light, just hit the down button a few times to subtract however many degrees you want atdc from the 20 degrees we just set in. For example, I wanted to set my engine to 5* atdc, so I subtracted 5 from 20, and set my timing light to 15* btdc.
Now make triple sure your truck is in neutral, and start up the engine. Youll need to find a way to hold the throttle at 1400 rpm, I used a ziptie. hold the rpm at 1400, then point your timing light down at the crank, and bobs your uncle, you can time your diesel just like a gas engine now. Just make sure you dont try to adjust the pump with the engine running, that would be most unwise.
In my case, I found that my timing was set at 2* btdc, which is 7 entire degrees more advanced than I wanted. That would probably explain why this truck has always struggled to make boost and sounds like a pile of hammer heads in a steel barrel. I retarded it to 5* atdc, and on my test drive the motor was way quieter, and under a wot run it pulled more boost empty than it ever has while towing. I hope someone finds this helpful, and I hope people with stop badmouthing these adapters now.
First off, and I believe this to be the origin of most of the confusion, the manual is mostly useless. It was designed for an old style timing meter with a magnetic pickup, and we're not going to use that. Such old meters needed a 20 degree offset in order to operate, so when the manual says to use a 20 degree offset, it confuses people. The only useful piece of information the manual has is the timing spec, which is 4-8 degrees ATDC (AFTER top dead center) at 1400 rpm. The second point that I believe causes a large amount of confusion is that if youre using an inductive timing light, you cant dial in the setting to before tdc, just after. Ive found this to be completely a non-issue with one simple trick. The trick? Basic math.
Tools needed
___________________
luminosity probe timing adapter
gas engine style timing light with advance (knob or digital is both fine)
piece of tin foil (trust me)
paint marker
First, clean the timing mark on the harmonic dampener and the bracket with the timing holes. Then mark the timing mark so that its easier to see, and mark one line on the timing bracket along the centerline of the top timing hole. Yes, I know, the top timing hole is 20* atdc, bear with me here. If you want, you can put a mark on the bottom hole too, but that simple trick I mentioned earlier involves the top hole. Here is a picture:
You must be registered for see images attach
Next, warm up the engine to full operating temp. Hop in and drive down to the grocery store and get a case of beer for yourself and some flowers for your significant other, or a card for your mom. Tell them you were just thinking of them.
Once youre back and the engine is nice and warm, remove the glow plug from the #1 cylinder, install the luminosity probe, plug the timing adapter into the probe, and clamp your timing light onto the pickup coming out of the adapter. There is a right and wrong direction, so point the spark plug end of the timing light toward the spark plug symbol. If youve never used the adapter before, you might want to unscrew the case and check if the 9v battery is still any good. You know how. Heres where the tinfoil comes in handy, loosely wrap it around the pickup wire and the clamp on the timing light. If you read the other threads about people using these, youll see that they often complain about erratic readings. Ive found that the readings cleared up nicely with the tinfoil. This is because the signal coming out of the timing adapter acts like an antenna and blasts the immediate area with electromagnetic interference, and that screws with the electronical guts of the timing light. The tinfoil shields the timing light from the interference, much like it shields your brain from the effects of the governments mind control rays.
You must be registered for see images attach
Now youre ready to start reading timing, and heres where I explain the trick. Timing lights cant be set to before top dead center, but weve got a nice timing mark at 20* atdc now, so if you set your timing light to 20* btdc, you can use the timing light with the mark at the top hole, and the timing mark on the crank will line up perfectly as if you were reading top dead center. Now, to retard the timing light, just hit the down button a few times to subtract however many degrees you want atdc from the 20 degrees we just set in. For example, I wanted to set my engine to 5* atdc, so I subtracted 5 from 20, and set my timing light to 15* btdc.
Now make triple sure your truck is in neutral, and start up the engine. Youll need to find a way to hold the throttle at 1400 rpm, I used a ziptie. hold the rpm at 1400, then point your timing light down at the crank, and bobs your uncle, you can time your diesel just like a gas engine now. Just make sure you dont try to adjust the pump with the engine running, that would be most unwise.
In my case, I found that my timing was set at 2* btdc, which is 7 entire degrees more advanced than I wanted. That would probably explain why this truck has always struggled to make boost and sounds like a pile of hammer heads in a steel barrel. I retarded it to 5* atdc, and on my test drive the motor was way quieter, and under a wot run it pulled more boost empty than it ever has while towing. I hope someone finds this helpful, and I hope people with stop badmouthing these adapters now.
