Timing chain + gears

[Guest Jim Piro]

I have an 89 that I bought new and have restored to mint condition (Senior preserevation awards the last two years-Barney has seen the car). It has 115k.

1.Do I consider changing out the timing chain? Car runs perfect as is.

2. Are the gears in this engine plastic or steel?

3. What is the projected life of a timing chain?

Any input would be greatly appreciated.

Thanks,

Jim <img src="http://www.aaca.org/ubbthreads/images/graemlins/smirk.gif" alt="" />

[harry yarnell]

The gears are all steel. Your mileage isn't high, and WHEN to change the chain has been debated on this list for awhile.What DOES wear, is the chain tensioner. I've seen 200k on these 3.8's with the origional chain, and they're ticking right along. Bear in mind these 3.8's turn at alot slower than engines of the past, so things last longer. One bright spot; the chain isn't difficult to change.

[Guest Orono]

I agree with Harry that the tensioner is the first thing to go. If you hear <span style="font-style: italic">any</span> chain rattle, I would suggest changing the whole assembly including the tensioner and cam magnet, maybe even the water pump. It is easier & cheaper to do the repair once.

[Guest]

Harry,

I have a question. My '91 is ideling rough once it gets off automatic choke rpm level. Is that any indication that my timming is off or is it normally a case that the idle level needs to be adjusted to a higher rpm? The motor has 118,000 on it. When I bought it it had about 117,000 and ran smooth. Now once the auto choke cuts out it idles rough and at a lower rpm level. Any ideas?

Steve

[harry yarnell]

Ho boy, this problem could be a ton of things; including the timing chain. But not likely. First off, there is no automatic choke. There is no choke. Vacuum leak, dirty throttle body, engine (ignition) miss, come to mind as possible first things to check. How's the engine vacuum?

[padgett]

"Lower RPM Level" meaning what ? Factory idle on my 88 is 625 rpm warm. I raised it to 700.

Rough/low sounds like a stuck Idle Air Control Valve which is supposed to adjust to ECM command. Working properly it can make an engine with a dead cyl seem OK.

BTW there is no choke, the ECM just commands a higher idle and richer mixture.

[Guest]

Harry & Padgett,

Thanks for your posts. Since I thought there was a choke that raised the rpm level, and there is not choke. You can see how much I know. I will check the rpm level at cranking vs when it warms up and idles. Will get back to you to let you know. Harry, you mentioned to check the vaccum. All I know to tell you is that all the functions that are vaccum driven, heat, defrost,etc. seem to function fine. How do you check the vaccum level that motor is creating? If you let me know, I will check that too and advise.

Thanks again for your posts and please have patience with me until I have a clue.

Steve

[harry yarnell]

By checking vacuum, I mean what are the numbers? is it stable, or is it all over the dial? Or flutter? Padgett mentioned a sticking IAC valve. This would be the first place I'd look, plus a dirty throttle body.

[Guest]

Harry,

Thanks for the "start point". Will check this out and see if that gets it done.

Take care.

Steve