86 hatch ea81 timing question

[alexinvancouver]

due to the sluggish performance (22sec 0-60)

did some timing checking on my '86 hatchback

initial was 7 (corrected it to 8 which is not a big deal)

it climbs steadily with rpm increasing 9,10...20

but then all of a sudden when it passes aprox 2500 it jumps to what it would be 40 degrees (aprox. since there're no marks)

once again from 20 to 40 big jump once it goes over 2500

vacuum hose connected

any thoughts?

thanks in advance!

EDITED

finally bought timing light today =o)

it only does the timing advance jump from 20 to 40 degrees

only when i connect vacuum line

so, how do i bypass vacuum advance valve?

thanks

Edited February 6, 2012 by alexinvancouver

[l75eya]

Vtec kicking in.

[naru]

Hmmmm...

That`s unusual.

Centrifigual advance should be all in by 2000 rpm and should add about 12 degrees max.

Try it again w/the vacuum line disconnected.

Make sure the rotor is tight on the shaft.I`ve seen some flop around.

Check the shaft for play while you are there.

Edited January 15, 2012 by naru
+ shaft play

[alexinvancouver]

yeh, it could be around 2000 or just a bit over

i was watching the mark more than rpm's =o)

but it definitively jumps up

i had a timing light borrowed for one day only.

(don't want to buy one since i'm planning swapping the engine later anyways)

i'm gonna look closely into it when get back in a week.

going to monte-carlo next week to spectate first round of world rally championship!!! =o)

Centrifigual advance should be all in by 2000 rpm and should add about 12 degrees max.

Try it again w/the vacuum line disconnected.

Make sure the rotor is tight on the shaft.I`ve seen some flop around.

[bheinen74]

checking timing with vac advance hose off?

[naru]

checking timing with vac advance hose off?

 

sure that eliminates any effect of the vac advance mechanism.

did you want to be told to plug it?

Edited January 15, 2012 by naru

[bheinen74]

unplug vac advance hose, plug hose with something while checking timing.

that is how it is done.

 

probably know that, but just in case, here it is.

[naru]

yeh, it could be around 2000 or just a bit over

i was watching the mark more than rpm's =o)

but it definitively jumps up

i had a timing light borrowed for one day only.

(don't want to buy one since i'm planning swapping the engine later anyways)

i'm gonna look closely into it when get back in a week.

going to monte-carlo next week to spectate first round of world rally championship!!! =o)

 

Turn the distributor shaft against the spring tension.If it turns much more than about 6 degrees, the centrifigual advance has problems.

 

Be sure to send us some rally pictures.

Edited January 15, 2012 by naru
change 12 degrees to 6, duh

[naru]

unplug vac advance hose, plug hose with something while checking timing.

that is how it is done.

 

probably know that, but just in case, here it is.

 

for base timing sure

in the real world,removing the vac hose only makes a base timing difference if the idle throttle position is maladjusted or some comedian has it hooked up to manifold vacuum.

it doesn`t need plugging for as long as it takes to figure that out.

it doesn`t need plugging for the few seconds it takes to figure out wheteher the excess advance at rpm is related to the vacuum signal either.

Edited January 15, 2012 by naru
+ manifold vac.

[alexinvancouver]

 

Be sure to send us some rally pictures.

i shoot lots of vids and a few pix

here're couple of them

recognize those guys?

oh, and of course i was the only one wearing SUBARU cap=o)

Edited January 29, 2012 by alexinvancouver

[alexinvancouver]

it only does that with the vacuum advance line connected

so, how do i bypass the valve?

thanks