1. Home
  2. General Toyota Forum
  3. 1993 Corolla LE valve timing

1993 Corolla LE valve timing

1993 Corolla LE, 1.8 L, 7A-FE engine, 300,000 km (186,000 mi).

Jack confesses,

What have I done to this poor car? I did something I shouldn't have when I was changing the timing belt. Usually I put soft rope in #1 cylinder to hold the crank so that I can undo the harmonic balancer bolt.

I don't know what got into me but... this time I 'experimented' by putting a rag between the camshaft gears. I gave up on this right away, after a tentative pull on the crank pulley bolt with the 20" Johnson bar. The gears didn't move much, and it was obvious right away that the old belt was too springy to hold enough to loosen the crank bolt.

Although I checked the cam timing marks carefully on installing the new belt, the distributor timing was way off, as a timing light showed. (When setting the distributor timing, I jumped the specified terminals to eliminate computer moderation.)

Now I am getting around 31.5 m.p.g. instead of 40.4 m.p.g. on average. When fully accelerated suddenly, the car seems to hesitate for a split second. Otherwise, the car appears to run normally overall, with perhaps a bit less power.

Is the valve timing off? Have I twisted the timing belt gear on the end of the camshaft? How would I go about diagnosing the damage?

Your expert comments would be much appreciated, A very repentant - Jack

Reply to
Ralph
Loading thread data ...

I thought I knew a lot of tricks, I'll admit that that is the first time I heard of putting rope in the cylinder or a rag in the gears

In the future, you may want to invest in a spanner-type tool to hold the pulley while you remove and install the bolt. OTC supplies Toyota dealers, and the tool can be used on most Toyotas, or you may be able to find a generic tool to do the job or invest in a compressor and impact gun.

I doubt if you can exert enough torque on the crankshaft bolt to twist the timing belt gear on the end of the camshaft. If camshaft timing is off, the engine would run pretty poorly all the time.

Check for a vacuum leak and check distributor timing advance.

Reply to
Ray O

Thanks Ray O.

Whatever I did put the distributor off somehow, I gather, and it is driven (I think) by that camshaft which is in line with the belt gear (as opposed to its twin shaft).

Does the fact that the distributor was pushed off mean the camshaft is off too? (It was retarded, thus out by 10 degrees or more.)

Thanks again for your comments.

Reply to
Ralph

If distributor timing was off by 10 degrees AND the distributor hold-down bolt was tight, I would double-check the camshaft timing. I imagine that the engine would barely run if one of the camshafts was off by a tooth, but it might run well enough for the symptoms you're describing.

Reply to
Ray O

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.