Engine about timing and timing chains

about timing and timing chains

I was wondering with my 98 corolla if I were to replace the timing chain would I regain power. I noticed that my power has been lacking. I have 117k miles on my car presently. I also noticed that after removing the valve cover and checking the timing chain that it has some slack in some areas of the chain. I was going to try and replace it myself if I need to looks like according to the haynes manual that its not too hard to replace. Also... this may be a stupid question but what is the different between timing advancing and retarding.

Toyota says to replace the chain at 100k, so it's not a bad idea to do it since you say it's showing some slack. I looked at factory service manual, and it looks like a hell of a job IMO.

100k where does it say that ?? It should last the life of the engine. The timing belts (some) are rated at 90K. I heard that there is a timing chain tension adjustment for these. CW

Whoever told you that just wanted to sell you parts and labor. The 1zz-fe has a timing chain that does not need replacement unless it becomes damaged. Cars with timing belts need replacing anywhere between sixty thousand and one hundred thousand miles. In most cases, a timing chain should last the life of the motor no problem.


If you have slack in the chain then the chain tensioner may not be doing it's job. The chain is placed under tension by a tensioner located half way down the chain on the side of the block. If the chain is indeed loose then replacing this should cure your problem. If the chain has in fact become stretched beyond tolerance then you reallly need to look at what you're putting your poor little motor through...

its only certain sections of the chain that have slack..... when I pulled the valve cover and looked at the chain segment between the two camshaft gears the chain had a little slack.... then when i turned the engine a little i looked at another segment of chain between the two gears and there wasnt any slack

im going to buy a compression guage and do a quick check and see how healthy my engine is..... also where can I hookup a vacuum guage to check the engine vacuum pressure? I cannot find any unused ports to do a vacuum check.

Make a gauge out of three pieces of vacuum line and a T fitting and a gauge if you can't find a port. Just run a piece of hose of the three fittings on the T-fitting the install the gauge on one and run the other two in place of one of the vacuum lines. It’s a good idea to check all lines for cracking and replace them every other year or so. It's a pain in the ass locating and fixing a leak once you have one. Depending on the type of gas you use, you may want to do a decarb to get rid of any carbon buildup. Also using a good quality injector cleaner every 3000 miles will help out a lot in keeping your engine running smooth.

don't worry about replacing the chain, it lasts the life of the engine, unless it rusts or breaks or something, but then you'd have bigger problems. i don't think replacing it would do that much of a difference, unless it had somehow become so loose that your timing is off just enough to cause crappy performance and not detonation / backfires...

i would spend your money on a nice fuel injector cleaning job or maybe even an intake manifold port and polish.

I have over 152,000 miles on my timing chain..

I was told that it's a ~$1200 job (if you pay someone to do it)..so if I ever have to replace it, hopefully I'll manage without paying someone.

Over what time span has your power decreased? Have you added anything since then (ie 200lb of stereo equipment, etc)?

nah nothing on it right now...... I did notice that sometimes when I start it up the tach will go up to 2500 like normally then go down really low even lower than the normal 750 rpms that it idles and it was really idling roughly...... im just going to do a compression check and go from there.... i know it would probably be a better idea to trade my car in but the rest of the car is in great shape... its just the performance of the engine im concerned about.

If you can swap the engine yourself (or have friends that can help), you should be able to get a new/rebuilt/used/something engine in for under 500 bucks..that might be better than trading. =)

I looked in the 00 Corolla manual and it shows a tensioner that must be pushed in and then released it appears to be a self adjuster that would move out as the chain stretches and keep the tension on the chain.

Unless this is an addition for 99 or 00 you should have the same tensioner on your motor.

CW

i got some help and found out its not the timing chain like i though... in fact everything is in tip top shape it turns out i have too high of compression... its that i have too much carbon buildup so Im going to use some high strength fuel injector cleaner/combustion chamber cleaner and if that doesnt do the job ill just take the head off and clean it. I might do a valve adjustment too. who knows. :-B im such a dork lol... jk