Timing a 3F and 1FZ-F Carbureted Model Enigine (1 Viewer)

Joined
Oct 21, 2020
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Me and a friend both have 70Series LCs ( 92 and a 95) but they are carbureted. His has the 3F engine and mine has the 1FZ-F. I’ll start with mine.

Following the Service Manual.....

YbQbYbQ.jpg


1. Warmed up engine to operating temp.
2. idling at 650ish....no Tachometer available.
3. no EFI so I don’t have to jump the TE1-E1
3. AIM timing gun at marks
4. 7 Degrees BTDC is where I’m set.

Now my dizzy has a vacuum advance hooked to it.....line from dizzy to carb. No where in the manual does it say to disconnect it prior to getting timing. Correct? Also are all readings done from idle?

Eiy2gN2.jpg



Now on to the 3F .....which was interesting!!!

Following the service manual

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1. Warmed up engine to operating temp.
2. idling at 650ish......no tachometer available
3. no EFI so I don’t have to jump the TE1-E1
3. AIM timing gun at marks on fly wheel ( round circle and pointer)
4. His was set dead on the circle ( 7 BTDC) I advanced it so the circle was near the bottom of the window to advance it some. runs great with no detection of detonation.

His also has a vacum advance on his dizzy but again, no where does it say disconnect it while setting timing so it was left in place.

looking at the service manual it goes onto another step discussing setting it at 12 Degrees BTDC. The 3Fs marks sure make it hard to get an accurate timing. Now my gun has the advance adjusting so I could just set it to + 5 ( 7+5=12) and get there correctly.

any guidance or advice will be greatly appreciated.
thanks!!!
 

OSS

Joined
Jun 30, 2017
Messages
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Oblivion
While I'm unfamiliar with both of those engines, the carbureted 3F is very similar to the 2F. If you follow the steps exactly in the factory manual, you'll be fine. I've never seen a Toyota manual that has incorrect information.
Setting timing isn't an exact science. Depending on the fuel used and altitude driven (and driving style) the engine may run best a few degrees off (either way) than the factory specification.

The best way to set the timing is to set it according to the manual instructions - then drive the vehicle under varying conditions and note the performance.

Then set the timing about 3° advanced from the spec and take it for another test run. If even the slightest bit of pinging/detonation can be heard, the specified advance recommended in the manual is ideal.

Low level detonation can't be heard - but the engine is still pinging, so you can't base ideal timing soley on listening for the rattle
 

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