4AFE Timing Belt

[cherbini]

Hello All,

I have a 1990 4AFE that threw a timing belt last Friday.

I changed the belt out, and was very careful with aligning the rotor, camshaft mark and crankshaft mark (red dot on inner toothed gear with machined bump on case)

Started right up, but ran like crap. I immediately went for the timing.

I jumped the two wires in the diagnostic port, but even with the maximum clockwise adjustment of the distributor, I can't get the timing past 5 degrees or so.

The distributor isn't geared, but a T slot type of fitting, so it's *almost* completely idiot proof. I would imagine the thing wouldn't even start if I turned the distributor around.

I'm thinking one of two things.

1) Vacuum tubes - could this affect my timing this much? Is there a diagram of ALL of the factory connections?

2) I'm off a tooth either on the crank or cam. If so, knowing that my distributor is rotated fully clockwise (and can't get past 5 degrees) which way am I off? Would it be best to move a tooth on the cam or crank?

I appreciate any thoughts. The car runs OK, just not like it did before the new timing belt/cap/wires/rotor.

Thanks!

JC

[SuperRA]

Its best to just open it up again and re-install it. Chances are you'll get it right the next time.

[SCT]

I agree with SuperRA, re-align the gears and reinstall the belt. You may have skipped a tooth without knowing. Which was why I was unsure of myself when I had to change my timing belt over a month ago. Unlike accessory belts, can't pull the timing belt to tension it between gears without holding whatever gear its' on in place. Otherwise you end up turning it off mark.

But make sure, if you want, that all other parts you installed are not faulty. I remember buying wires from autozone and one of them was brand screwed.

[cherbini]

Originally Posted by SCT

I agree with SuperRA, re-align the gears and reinstall the belt. You may have skipped a tooth without knowing. Which was why I was unsure of myself when I had to change my timing belt over a month ago. Unlike accessory belts, can't pull the timing belt to tension it between gears without holding whatever gear its' on in place. Otherwise you end up turning it off mark.

But make sure, if you want, that all other parts you installed are not faulty. I remember buying wires from autozone and one of them was brand screwed.

Good idea...I'll make sure I have good spark, and then just re-do the belt. Once you've been in there once, it's not too bad.

Thanks for tips, just wanted to make sure I wasn't missing something stupid.

JC

[toyotaspeed90]

you don't actually have to pull the crank pulley or the lower cover... if you have a flashlight you should be able to see the crank gear mark and the mark on the oil pump to align it to... just pull the water pump pulley and the upper 2 covers (might just be 1 cover on a 4afe).

sounds like you're off a tooth up top.

[cherbini]

Originally Posted by toyotaspeed90

you don't actually have to pull the crank pulley or the lower cover... if you have a flashlight you should be able to see the crank gear mark and the mark on the oil pump to align it to... just pull the water pump pulley and the upper 2 covers (might just be 1 cover on a 4afe).

sounds like you're off a tooth up top.

You were right on point. I took the top two covers off, and could then get to the tensioner.

With the lower cover and pulley in place, it was easy to see that I was off a tooth up on the cam.

Runs like a beast!

Thanks!

JC