22R Distributor Vacuum Advance Qs

[CivicFerio]

Hello Everyone!

I'm getting my 84 4X4 XtraCab with 22R ready for smog. So far the engine has been running good with 230K miles on the original motor (according to the previous owner).

Here is the question. Underhood Label says Ignition Timing must be at 5° BTDC with (2) both vacuum lines off the distributor. But when I plug back in the vacuum lines it remains at 5°. I check the vacuum and one is at 5in. Hg and no vacuum on the other hose during idle. The other hose however gets very good vacuum at around 20in. Hg when the throttle is slightly open (is this ported vacuum??).

Vacuum from the other vac. hoses at idle is 18in. Hg while the one going to the distributor only gets 5in. Hg. Is this normal or do I have a vacuum leak? Also both ports of the Distributor Vacuum Advancer diaphragm doesn't hold vacuum, is it busted or normal? Thank you!!

 

[WristPin]

seems normal to me.
the In Hg increases when you rev it, cus it wants to advance the timing.
the diaphram wont hold vacuume cuz its tendioned by springs.
and you wouldnt want it to hold vacuum, cuz then it would be advanced when it should be retarded.

 

[KliersLC]

Yep, sounds right to me, but then again, its been awhile since I set the timing on a 22r. You shouldn't have any problems whether it is working just right or not-those trucks run pretty clean. Also, to determine if your vac adv is working, rev the motor while watching the timing mark, if it moves, she's working.
Dan

 

[Bob_Garrett]

Sounds like you have a bad vacuum advance diaphram. The timing should advance to 12 deg or so (at idle) when you connect the vacuum hoses. Remove it and apply vacuum to either port and see if the advance lever moves. It should stay in the advanced position as long as you have vacuum applied.

 

[KliersLC]

Sounds like you have a bad vacuum advance diaphram. The timing should advance to 12 deg or so (at idle) when you connect the vacuum hoses. Remove it and apply vacuum to either port and see if the advance lever moves. It should stay in the advanced position as long as you have vacuum applied.

you could be right, the springs should overcome any residual pressure after letting off the throttle.......

Hmmm.......

let us know what you find out, I am curious to know as I have never taken apart a 22r vac adv....


Dan