Timing Question---Procedure

This is actually a question on prepping the engine for timing. The magnetic pickup goes into one of the two holes on the front of the engine. If my memory is right, it goes into the upper hole, the smaller one. Am I right?

My memory also tells me that the hole usually needs to be cleaned out. I also recall that the recommended method to clean it is using a drill bit, hand twisting. I think that some one posted about that recently. What size drill bit? Just visually comparing the pickup head to my bits, it looks like 11/32 or 23/64.

I don't, of course, want to make that hole too large. I don't want the magnetic pickup to wobble around in the hole. Hence the question, what size drill bit?

Yes, it’s the smaller hole. 5/16”

Okay, thanks. I got the hole cleaned out, the probe goes in/through. I think I have another problem, though. The clamp-on transducer is 6mm. I'm almost positive the fuel line it clamps onto is 1/4 inch. It will clamp on, but it's not quite fully closed, and therefore does not have contact all the way around. I'm not getting a credible reading. I get a reading, yes, but I find it hard to believe my timing is 14+ degrees BTDC at 2000rpm. I don't think the truck would run as well as it does at 14. The rpm reading on the meter differs from the truck tachometer by 200+rpm.

I've got to get a 1/4 inch transducer.

What type of equipment are you using.

I think you may be okay with a 6mm sensor on a 1/4” line. At least it will be tight. I tried using a 1/4” sensor on a 6mm line, and it was loose, and wouldn’t give me a consistent rpm. I think it’s very possible that you’re tach is not reading accurately.

14 degrees is not that far off from where it should be. My truck was running decently when I got it, and it was set at 0 degrees.


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Did you clean your line off before attaching the transducer clamp? I don't know if that will affect the readings or not, but it's worth a try.

The connector for 1/4” line is 6.35mm. I had a ferret and that’s the size it came with. If yours is 6mm it is slightly smaller. 1377/100000 not much. Clean the line real well, put adapter as close to injector as possible and on a straight portion. If there is a ground clamp make sure it is clean and within a couple inches of clamp. If your engine hasn’t been timed in a while 14 degrees does not surprise me. It’s not that far off.

6.35!! I hate to say it, but it never occurred to me that they marked the transducer in decimals. I read 6 and disregarded the rest. Yes, it is labeled 6.35. So, I do have a 1/4 inch transducer. We'll chalk that up to a prolonged senior moment.

I think I cleaned the injector line well enough. I went at it with a fine grain sandpaper. It's hard to see, though. There may be bits of paint left. I'll do it again. I think the ground may be a problem also. About everything in there has been painted. I guess I'll hunt more for a bare surface, or sand some paint off for a good contact.

I'll try some more, maybe tomorrow.

What equipment are you using? Some have an offset input that you have to set or the meter won't be reading accurately.

I've found when the line isn't clean enough, or a bad ground, I'll get a low and varying rpm reading and the timing indicated will jump around a lot. If it's okay, the rpm and timing reading will be steady.

That's using both the mt257/snap on light and my j33300 tach-n-time unit.

14 might not be way off if the ring on the damper has slipped....

I'm using a DTI (Design Technology Inc) timer, model 3300-s. I'm running with an offset of 20 degrees.

You've named the two problems I'm having. The RPM on the meter is not steady, the reading is jumping more than the actual rpm. I have it set so I can read the meter from inside the cab, compare it with the truck's tach. The timing indicated on the meter is also not steady. There are instances when it reads as a negative number. I take that as a sure sign of a bad connection.

I've sanded the injection line so I think it's good. I can't see the entire sanded area, so I'll sand some more to be sure. My bet is on a poor ground. Believe it or not I'm having trouble finding a bare metal place within reach of the ground cable. Ford seems to actually have been pretty good at slathering on the paint in there. If need be I'll sand a place bare. Can I ground it to the injection line right next to the inducer? On the face if things that would seem like a bad idea, though easy to do.

The ring on the damper might have slipped? Can that really happen? That never entered my mind. I'll look to see whether there is any indication.

I used the fuel line for ground with my ferret. On conestoga diesel he has a timing video and uses the fuel line for ground. The worst you can do is try it.

A dimes width at your ip is about 3-4 degrees of timing. It doesn’t take much for 6 degrees of timing.

Scribe a line so you can return to where you started if things go south. Then adjust.

Ground it to the same fuel line you're clamped to. Sand a whole inch of paint off if you have to. It doesn't need grounded to the truck per say, the "ground" clip needs to have a good connection to the inner ring of the transducer, so that the voltage spike produced can be read by the machine. We're dealing with a tiny amount of voltage being made, so any corrosion or issues will be noticeable, which is why I ground it next to the transducer.

Some insist on it being necessary to have the clamp being between the bend and the injector, I've found that isn't the case. It can be clamped before the bend if it's easier to get at, and it will be close enough. You're timing allowance is 1 degree anyways. The timing difference between the 2 locations is way way less then that.

Yes, the ring can slip, the rubber can degrade after a few decades. Now, it isn't common, but something to keep in mind if you're timing # isn't making sense. I've seen it before on gas engines when they're wanting 50+ degrees of timing. Check the balancer/marks and they're 20 degrees off. New balancer solved the problem.

Mine was 13 degrees BTDC when I first put the meter on it, if yours has never been timed it can certainly be off by that amount.

I finally got a steady reading, so I'm going to call it good. It ranges from 10.4 to 10.7, depending on whether I read RPM from the tach or from the meter. The RPM is ~150 difference. But the engine sounds so good, to my untrained ear. I'm going to leave it as it is.

I tried grounding to the injection line, and couldn't get contact. I found a bolt below there which did work.

I thank you all for your help and suggestions.