4AGE: Setting timing

[Raptor13x]

The BGB for the BT states that the timing should be set at 10 degrees, but if I go anything less than around 15-20, the engine stumbles and runs like ****.

Also, it idles at around 1500rpm. Shouldn't it be closer to 900 or 1000?

[mr2magic]

Is your dizzy maybe set way out of spec?

[Raptor13x]

"out of spec"?

[mr2magic]

Sorry With out of spec I mean rotated to far left or right, so your static timing may be right but the ignition is out of sync. You get my drift?

[Raptor13x]

Maybe.

For now, I just set it the best I could by ear. It runs great. I really wish there were some flywheels out there for the 4age that are lighter than 9lbs, with lightweight clutches to match. Even with the fidanza flywheel and lightweight crank pulley, with the lightweight rotating assembly of the blacktop, it still doesn't rev quite as fast as I'd like. It's way better than any family sedan, but still, I miss how my YZF-R6 revved.




On a side note, while checking for top dead center earlier I noticed something disturbing- the spark plugs were not even finger tight, so I went through and made sure they were all torqued down properly.

[mr2magic]

How about lathing of even more?? Isn't that soemthing others have done?

You'd be surprised how little torque is required for spark plugs! Just a tad more than finger tight is good (I think about 19Nm is right).

[Raptor13x]

Yeah, I've seen people try to tighten them to 100ft-lbs, but I was always told to go finger tight, then 1/4 turn. They don't require much force, which is surprising considering they hold back extremely high pressure gas.

[mr2magic]

100 ft-lbs!! WTF!

[Raptor13x]

I was exaggerating. It's not like they held up a torque wrench and did it, but I've seen people really go overboard tightening them.

[boycelaforest]

Originally Posted by Raptor13x

The BGB for the BT states that the timing should be set at 10 degrees, but if I go anything less than around 15-20, the engine stumbles and runs like ****.

Also, it idles at around 1500rpm. Shouldn't it be closer to 900 or 1000?

Cam timing/distributor off..... Idle is high because it is advanced.

[Raptor13x]

How would the cam timing or distributor be off? I never touched the cams, and the distributor only fits in one way.

[toyotaspeed90]

dizzy only fits in one way on a 20V..... sounds like you may be a tooth off on the timing belt

[Raptor13x]

Which is interesting considering I didn't touch the timing belt.

[tjmr2]

Are you 1 tooth off when reinserting the distributor into the head? I think is the question.
This would not allow you to move the distributor far enough to bring your timing down to the ~ 10 deg BTDC. (the 16 valve can be inserted 1 tooth off fairly easily, not sure about the 20v, I never took mine out.)

Are you jumpering the connectors when checking the timing?

At the 15 to 20 deg advanced are you hearing any pinging?

High advance will cause a higher idle, possible pinging and overheating under load.

[Raptor13x]

The BT distributor can only be inserted one way.

Yes, I'm jumpering it.

I'm not hearing any pinging. If I go less than 15 degrees, the engine stumbles progressively more severely. Advancing it causes it to run more smoothly, with better throttle response.

[328FTW]

Just play it by ear then, my 3sge is farting and popping like a mofo at the moment so I'm going to rev its nuts off in the pits tomorrow before racing and just listen for it. You can get the timing pretty damn good by ear if you know what to listen for.

[boycelaforest]

Originally Posted by Raptor13x

The BT distributor can only be inserted one way.

Yes, I'm jumpering it.

I'm not hearing any pinging. If I go less than 15 degrees, the engine stumbles progressively more severely. Advancing it causes it to run more smoothly, with better throttle response.

Sorry I am too lazy to look it up. Yes the distributor goes in one way, but the rotor can mesh via gear into different positions right? If there is a flat key space at the bottom then it can go in 2 different ways (one with rotor pointing at TDC on cyl 1 and pointing the opposite way)

Also I would not assume your cam timing is right just because you have never changed it. I got a sr20 for a swap awhile back and the distributor was off 15 Degrees due to the rotor being 1 tooth off.

I would pull cover, put engine @ tdc, check cam gears, verify the rotor is @ cyl1 on the distributor... if that is all good then start looking at ECU control issues. (computer advancing timing, etc or other sensor problems, or vacuum leak)

[tjmr2]

If I remember correctly when I reset - checked the timing on my BT it was a real bear to see the marks. I think I got it close and decided to see how it ran.

Just wondering if the marks you are looking at might not actually be 15 degrees but 10.

Without it pinging or overheating you could be where you need to be.

[fevil]

Originally Posted by Raptor13x

The BGB for the BT states that the timing should be set at 10 degrees, but if I go anything less than around 15-20, the engine stumbles and runs like ****.

Also, it idles at around 1500rpm. Shouldn't it be closer to 900 or 1000?

I also have the same problem of the engine running better with 15-20 advance.
Idle is around 900-1100.
Had found when I first ran up the engine the idle was all over the place.
Cleaned out the ISC valve with carb cleaner, sorted that.
Idle 2000rpm cold 1000rpm hot, about 850rpm with aircon on.

Like you, I did not like how the engine ran at 10deg.
Still waiting for an answer to the problem.

[jimmer411]

Originally Posted by Raptor13x

How would the cam timing or distributor be off? I never touched the cams, and the distributor only fits in one way.

It could be possible the cam timing is off from the previous owner of the engine. If you need 15-20* advance to run decently then its safe to say that your cam timing is off a tooth.