Anybody got one of these and know how to use it? I just bought one off fleabay for $99, and it looks like it hasn't been used more than a couple of times. Nearly brand new condition. There isn't even any grease in the threads of the GP adapter, and it even came with the "manual" - with NO greasy fingerprints on it!

Unfortunately, though the manual shows how to hook up the meter, and talks about setting the offset before starting the engne and checking the timing, there are a couple of key bits of info missing.

Namely, on a 6.9, how many degrees of offset do you need to dial in? Once that setting is correct and you start the truck, what is the correct timing setting, and at what RPMs should it be measured?

Anybody got those specs?

 

I'm not familiar with that one, so I can't help you there. I have the Snap On diesel pulse adaptor.

As I recall, the dynamic timing is set about 5* at 650-700 RPM to use as a starting point.

Jason

 

I assume that would be 5* BTDC? For pulse meters I've always read more like 8* BTDC is better for these old IDIs...

A "lumy" meter is a whole different animal though. Seems like I've read that you should shoot for some thing more like 5*-10* ATDC because they are triggered by the actual combustion event rather than the pump's fuel pulse.

The Rotunda also has an adjustable offset, so I need 4 bits of info to use it right. Offset, RPMs, and degrees, BTDC or ATDC.

I'm hoping someone around here has experience with one...

 

Yes, that would be BTDC. I was told to use 5* as a starting point and tweak it from there. I think I have mine set at 7*. Anythiing more than that and I was getting excessive rattle and it wasn't improving my butt dyno feel at all.

Jason

 

You want right at TDC to 1.5 ATDC with the luminosity probe.
Closer to TDC is better.

1.5 ATDC was rated at 175 HP.
2.5 ATDC was rated at 157 HP.

There was a different IP used in those ratings, one is regular and the second was high altitude.

1 degree ATDC luminosity is about equal to 7 degrees BTDC pulse method.

 

O-K! Now we're getting somewhere!

So Dave, the manual says to adjust the offset on the meter before starting the truck. Got any idea what the offset should be set at in order to properly read/set it at that 1.5* ATDC spec?

Anybody got a copy of the FSM they could scan and email me the pages that give the step by step and specs?

 

If I remember right the offset is 20 degrees.

Remember the pulse method senses the fuel on the way to the injector.
The luminosity probe is sensing the start of the combustion event in the cylinder.

So that is where the different timing values come from.

 

Yeah, that makes perfect sense - pulse happens milliseconds BTDC and actual ignition of the fuel happens at or milliseconds ATDC...

OK, so 20* offset, 1.5* ATDC... @ what RPM?

Dude, this just isn't like you - having to pull one parameter at a time out of you! I'm used to seeing you spill it all at once and very thoroughly share all you know on a given question...

You feeling OK man?

 

Right now I am about wiped out from plowing last night and this morning.

And right now....RPM.....duh...blank spot.

For some reason 1500 is the only number I keep thinking.

 

Its cool man - figured it had to be something like that.

Do you have it in a book or something somewhere? If so, when you get time and get rested up, if you could look it up for me I'd sure appreciate it.

I'm in no hurry. Its running fine right now. I'd just like to see where the timing is at and tweek it if it needs it.

 

Ok I need to check one of the books I have for specs, I think I still have it.

When you use a luminosity probe, you have to get the cetane value of the fuel as one of the specs used to set the timing.
I think that was one of the reasons IH went to the pulse method, so much simpler than the luminosity method was.

 

Yeah, thankfully the meter came with a hygrometer for checking cetane. Looks like it has never even been put together - the inner glass float still has new foam around it and is inside the outer glass tube.

 

How did you make out with your timing meter? Did you go with the pulse method? I need to get a timing meter for my 1993 7.3 and I don't have a clue what to get or what is a reasonable price. Can you and the other guys help me out with this problem?
Thanks
Tom D

 

i use the luminosity timing meter.
but for most,id suggest searching this idi section for:
ferret timing adapter

that will get ya going on the right track.

 

I am probably not searching correctly. I checked the search bar and then entered "ferret timing adapter" but no luck. Did I do it correctly? Is this adapter all I need or is this just part of what I need to time the engine?
Tom