ideal timing for a 3FE?

[Spook50]

You're trying way too hard. Advance to the highest idle (turn counterclockwise). Drive, and back it down (*clockwise) until there's no pinging under load. Congratulations. Buy beer with timing light money.

Well I've already got the light so I figured I'd use that method first, but given the lack of access, nixed that idea. I'll use the vacuum method instead, and since my hearing's in poor shape, timing it by ear isn't a good idea for me. That was how I originally tried to time the 225 in my Duster, but had no luck so I caved and bought a timing light and am working off actual numbers and just trial and error trying to find the best ignition curve for it.

Just to confirm: the 3FE's curve is all electronic, right? I see there's no vacuum pot on the dizzy, but having never had it apart beyond a cap and rotor change, never knew for sure if there was any kind of mechanical advance to it.

 

[Wile E Coyote]

Clack: it'll likely be okay, but you'll have to pay very close attn after you do it. Adjusting right now vs in the dead of summer could change your results. O'course, a 2f/3fe would be crawling so slowly pulling a boat on steep inclines a guy could leave the dizzy loose and adjust on the fly while walking next to the truck, hehe.

Spook: yep, zero advance in the dizzy; all computer on the 3fe. Set base timing at proper rpm's and forget it.

 

[Yspen]

This is one of my pet hates . I get the timing right ( about 12-13 degrees ) and after the next service it is back to 7 degrees .

( they do not want to leave it where I set it and they do not want to listen )

 

[euclid]

Only time mine was ever unhappy at 13 BTDC was at 13K feet on Monarch pass. Found a tank of 85 and it got happy again. I could have diled the timing back too, but was too lazy.

 

[Moby]

I'm with the others that have commented about too many factors influencing exact timing. There is tons of data on this on the web. Personnally I run a J&S Vampire Safeguard knocksensor that does individual cylinder timing retard based on knock. I have the sensor mounted to the head using one of the heater hardline bolts. The unit has an LED that indicates when and to what degree it hears knock and a sensitivity adjustment. I do see very light amounts of knock in some 3000+ rpm/high engine load scenarios. This is really nice peace of mind to know that I'm right up against my engine's knock threshold but am protected. It would be very difficult to hear this knock over the engine, Flowmaster, road noise and tires. Best and cheapest suggestion that I've read, if you really want to identify knock, is a foam cup tapped to the block connected to a mechanic's stethescope or noise cancelling earphones. I've never tried this but it is interesting.

But all this is overkill unless you're really trying to squeeze every bit out of your engine or your engine is modified. If you're concerned about detonation set your timing at 10 degrees BTDC. You can still feel an improvement with this and you'll likely be out of the range of most detonation. Pay attention (listen) during hot temperatures, elevation, and low humidity. If you're really working the truck hard in these conditions consider 91/92 octane.

 

[Mark W]

You have a knock sensor that is actually effective on this engine with solid lifters and a cam in the block?


Mark...

 

[Wile E Coyote]

You have a knock sensor that is actually effective on this engine with solid lifters and a cam in the block?


Mark...

No crap, huh?
Moby, this is a 3FE you have in the truck, right? I'm interested in how the vampire does individual retarding with a conventional dizzy? Did you go Vortec, and that's how the vampire can work?

 

[Spook50]

Well I used the vacuum method, set it to 21 on the gauge, turned the idle back down to what it should be and took it for a drive, and it pinged like crazy. I was able to turn the dizzy all the way to the end of the slot and the vacuum kept climbing, so I backed it back off and went to just below 21 on the vacuum gauge (went up to a max of 22 from the 19 it showed before changing anything). It's a pretty big gauge, so I'll back it off to 20.5 in the morning tomorrow and see where that lands me.

Oh yeah, I attached the gauge to the manifold vacuum source for the tcase, in case anyone's wondering.

 

[Clack]

For the sake of those with a non adjustable timing light, I put the 7 mark at the left bottom side of the hole and it pinged like crazy. Putting it back until I can get my hands on an adjustable timing light.

 

[Spook50]

For the sake of those with a non adjustable timing light, I put the 7 mark at the left bottom side of the hole and it pinged like crazy. Putting it back until I can get my hands on an adjustable timing light.

I'd say try putting the mark halfway between the two and seeing where that lands you. Though I still don't see how it's even possible to see the damned window with all the stuff in the way on a 3FE.

 

[Clack]

Small step stool, from the side, directly over the dizzy, through the wires. Small space indeed.

 

[Mark W]

For the sake of those with a non adjustable timing light, I put the 7 mark at the left bottom side of the hole and it pinged like crazy. Putting it back until I can get my hands on an adjustable timing light.

You may have some carbon buildup on the pistons... uncommon in the 2fs but often seen in the 3FE. (The 3FE also often cooks the oil on top of the head badly which is rare in the 2Fs)

I have adjusted many 3FEs to this setting and never had a pinging problem.


Mark...

 

[Moby]

You have a knock sensor that is actually effective on this engine with solid lifters and a cam in the block?


Mark...

Yes. The J&S is very sensitive and uses knock detection algorithms that John (owner/designer) has spent years perfecting. It is designed to filter out knock (pistons rocking in the bores due to the impact of two or more flame fronts) from false positive noise.

You also are free to position the knock sensor wherever you like. I had it low on the block at first, not ideal, but I started there due to the noise of these engines. I later moved it to the passenger side of the head, probably the worst place from a noise perspective but better for hearing the knock (factory installs usually like center of the head for inliners or in the lifter valley for Vs). Even with the sensitivity dial just above the middle mark it rarely lights the knock LED. I'm not sure if the tiny bit of LED action that I do see if false positive or real knock, I'm not sure that I could hear that level of knock over engine noise at that RPM so I've never bothered to try and confirm it.

It also does individual cylinder retard. No cutting of wires required for the install. It is not cheap and it will take forever to get one of these. And it is totally unnecessary for most landcruiser applications (boosted or high compression engines are the target audience). But they are very slick units.

 

[Moby]

You may have some carbon buildup on the pistons... uncommon in the 2fs but often seen in the 3FE. (The 3FE also often cooks the oil on top of the head badly which is rare in the 2Fs)

I have adjusted many 3FEs to this setting and never had a pinging problem.


Mark...

My 3FE pinged at low rpm/low throttle angle prior to being rebuilt. My suspicion was carbon build up. You can have someone run a bore scope through the plug holes if you are worried about this.

 

[Clack]

Well my 7 mark may have been well below the view hole if viewed from the front as I was viewing it from the top. Kicked it back a little, no ping and it does seem to have a little more pep than at stock.

I did a can of seafoam through the intake manifold 2 weeks ago to clean up potential carbon. Not that I'm convinced it does anything but make a lot of smoke.

 

[Mark W]

water applied this way does a great job for carbon (better maybe)... and nothing but steam into the air from it

cheap too


Mark...

 

[Spook50]

water applied this way does a great job for carbon (better maybe)... and nothing but steam into the air from it

cheap too


Mark...

Probably won't make crap build up on your spark plugs or O2 sensors either.

 

[PabloCruise]

You may have some carbon buildup on the pistons... uncommon in the 2fs but often seen in the 3FE. (The 3FE also often cooks the oil on top of the head badly which is rare in the 2Fs)

I have adjusted many 3FEs to this setting and never had a pinging problem.


Mark...

Mark,

Does the 3FE cook the oil on the head due to the different PCV design?

 

[PabloCruise]

For the sake of those with a non adjustable timing light, I put the 7 mark at the left bottom side of the hole and it pinged like crazy. Putting it back until I can get my hands on an adjustable timing light.

I thought when I advanced my timing (w/ non-adjustable light) my 7 degree BB was in the top of the window?

This is for a 3FE mated to a 1 or 2F bellhousing..

 

[slcfj62]

water applied this way does a great job for carbon (better maybe)... and nothing but steam into the air from it

cheap too


Mark...

How much water? And how fast do you introduce it into the intake? Engine cold or hot?