Timing advance (1 Viewer)

[White Stripe]

I used to have a tbi setup . I ran it for over a decade . It had a knock sensor , I insulated it from the block with a piece of rubber as per an article I read at some point . Over the years it ran really well , never left me stranded on the trail but it never really ran perfectly all of the time . I did have a speed sensor hooked up for a while and it didn't help . I never really got into tuning the prom or ecm . It seemed to run well enough for me not to bother trying to get every little wild hair that happened occasionally . Most of the issues I had were from running an HEI distributor . It used to chew up the magnetic pickup inside occasionally . I tried different distributors (toyota electronic) over the years and they never ran as well as it did with the DUI unit . From my understanding , the ecm controls the amount of advance by using the knock sensor in relation to retard the timing . 15 degrees is its capability iirc. If you don't have a knock sensor , you will have a trouble code and it won't run closed loop (all sensors responding as they should) FWIW I used to run my timing anywhere from 12 to 18 degrees via timing gun with the spout wore unplugged . Most of the time closer to 12 . I have since moved on and now run a 3fe . It is all toyota and runs better than it ever did with a TBI .

I guess one of my issues is trying to squeeze every bit of juice out of it. Eventually you reach the point where thats all their is, I think I am approaching that point, but from what I know of the stock timing curve, I was curious how much people were setting their initial advance with a stock setup and their experiences with such. That would give me insight in how much advance the 2f can handle. The timing curve is a huge part of getting the most power out of it. I think my peak timing is just about right, I have a feeling the timing curve though needs to be steeper initially from 1000 to 2000 rpm than I have it and I may be able to get a little more juice out if it.

 

[65swb45]

Couldn't resist:

 

[EBBB]

what is your base timing set at with that dui dist? just picked one up. at 700 above sea level, 86 completely desmogged 2f eng.

 

[googledave]

Ok so in response to Mark: so after a maddening bout with this, I found a small vacuum leak At a plug that was added by the PO on the intake. It didn’t show up Ike’s you sprayed half a can of carb cleaner on it…some Gasoila did the trick and back to timing carb and valves… again. So, I took it for a ride and it drives really well at 13*..

this madness started because my fj40 doesn’t like Mr Toyota’s timing…. I’m trying to figure out why… so my numbers are as follows: 7* BTDC -16hg, 10*-17hg and 13*- 18. Compression: cylinders 2-6: 150psi. Cylinder 1: 145psi.
1977 distributor with points.
My other issue is the two vacuum gauges I own show vibration in the needle as if valve guides were loose, but the head went to the machine shop where it was serviced. Either I got jipped by the machinist (I hope not) or I’m getting way to anal at my age.. wanted to get some in put.. also, isn’t 16-18hg low on a motor with 150psi?

 

[65swb45]

Ok so in response to Mark: so after a maddening bout with this, I found a small vacuum leak At a plug that was added by the PO on the intake. It didn’t show up Ike’s you sprayed half a can of carb cleaner on it…some Gasoila did the trick and back to timing carb and valves… again. So, I took it for a ride and it drives really well at 13*..

this madness started because my fj40 doesn’t like Mr Toyota’s timing…. I’m trying to figure out why… so my numbers are as follows: 7* BTDC -16hg, 10*-17hg and 13*- 18. Compression: cylinders 2-6: 150psi. Cylinder 1: 145psi.
1977 distributor with points.
My other issue is the two vacuum gauges I own show vibration in the needle as if valve guides were loose, but the head went to the machine shop where it was serviced. Either I got jipped by the machinist (I hope not) or I’m getting way to anal at my age.. wanted to get some in put.. also, isn’t 16-18hg low on a motor with 150psi?

Reset the valve lash per FSM and the needle should stop vibrating. FSM method is conservative.

 

[googledave]

Reset the valve lash per FSM and the needle should stop vibrating. FSM method is conservative.

So those numbers are good? Ahh…. So valve lash on the tight side?

 

[65swb45]

So those numbers are good? Ahh…. So valve lash on the tight side?

I didn’t say that. First step is try and stop the vibration. That could cause a valve to burn.

 

[googledave]

I didn’t say that. First step is try and stop the vibration. That could cause a valve to burn.

Thanks, I’ll try that again…