timing adjustment

[1991toyrolla]

Hello Forum,

On my '91 Corolla sedan DX with only 34,000 original miles I plan to do a basic tune-up. I also plan to buy a timing gun. How do I adjust the timing? I am sure it is at 10 degrees but I want to know if there is a performance benefit to adjusting it higher & if so how high is too high? I don't want to affect its reliability because I plan to drive it out of state a few times. Reliability is my 1st priority which is why I am not going to swap out the engine just for more performance. I just want to get the most out of the 4AFE as is possible.

The only major mod I plan to do is to replace my 3 speed tranny with an overdrive one. Our transmissions are not computer controlled so all I have to do is wire a toggle switch for the OD to engage.

I also will replace the stock muffler with a DYNOMAX - 17731 series which supposedly breathes a lot better than OEM with no "fart can" sound.

I know that on the old carburated V8's adjusting the timing improved performance but I don't know much about the 4AFE.

P.S. I installed an instrument cluster with a tach off an LE corolla so I can monitor RPM's as I adjust the timing.

Let me know please, Thanks

[patcal]

If it is at 10BTDC, leave it there. That is the base timing and the ECU will make any further changes. If you advance it you may get pinging. Also, make sure you check it with the diagnostic connector jumped. If you have a service manual it will tell you where that is and how to jump it.

[Createdtoburn]

Yeah you're probably better off leaving it the way it is. I just did my timing belt and accidentally got the crank off by 1 notch but both cams were alligned right, and the car started up and ran "ok" but the car was slow as shit hah.

But foreal, it's an easy job if you know what to do. All you need to do is line up all the marks. There's little tiny marks on the crank pulley, and the cam gear(s) 4AFE has 1 Cam gear obviously. Just lign them up with the little tiny marks on the engine.

Easiest way is just get them lined up right before you take off the belt, then carefully take it off and put the new one on making sure everything is good. You'll be fine!

[wondermelon]

get a Haynes manual and do what it tells you to do.