allowable timing chain slack

[HISSIN50]

Hello. need some advice here.
i have been trying to figure out what shape my timing chain is in (without opening the cover up).
i did the old test of watching to dizzy rotor while turnin the crank with a breaker bar.

i rotated the crank counterclockwise a smidge (back to 0* on the dampener for a reference point). i then rotated the crank clockwise till the rotor started to move. i think doing the counterclockwise rotation first put all the slack in the chain that i could get). sound good?
the dampener had moved one degree when the rotor started moving.

i have no idea if this is good or really bad. please share your thoughts. if you have a better test to do, please let me know and i will do it and let you know what i get.

thanks so much. i hate dealing with the TC, but dont want it to go. (when they go, do they normally slip a tooth or snap altogether? if they slip a tooth, does piston/valve interference occur?). thanks again.

 

[87gtconv]

I don't know of any specs on how much slack the TC should have. I know that it should be Ok if it dont slap on the cover or cause any problems when you are timing the engine. If the timing stays constant it should be OK!

 

[SPEED FREAK]

what is the mileadge on your car? I would just replace it if it is anywhere over 75,000 miles. judging slack how you are doing it isnt the best way. Unless of course the timing chain came off all together. There are too many parts between the crank and the rotor and there for the slack is going to be exponentially more than what is going on between the crank and cam.
I vote change it to aleviate your fears. You have to take the cover off to check it anyway might as well just change it.

 

[TIMMY2734]

Use a timing light. Rev the motor and and see if stays constant. If its jumping all around, then well you know....

 

[jerry beach]

I dont think you have anything to worry about if there is only 1 degree of slop. I will go out an spin mine later and I'll get back to you. Thats something I have been meaning to check on anyway.

 

[HISSIN50]

thank you all for the advice. the array of remarks have become typical of what i have found in other venues. some say to replace the chain/gears at the regularity of a timing belt, while some say they are good for the useful life of the motor.

Jerry, i appreciate your checking (if it was something you were going to do anyhow). dont do extra work on my behalf (BTW, i have been meaning to shoot you a message. real busy of late).

Timmy, that test can be flawed with faults in the dizzy and ignition, though it is one i have recommended before.

thanks all for the advice. i read a bunch of threads in here and the corral, and it seems that many think the chain is good until the motor needs a rebuild. but there were some that said the chain was toast after 80K. seems to be luck of the draw or severe abuse possibly (living at redline, perhaps). so back to the test i go, figuring that was more objective.

Please let me know if any of you have done this test (or as i said, other tests that can be quantified - i will try them for comparison).

thanks a bunch!

 

[Michael Yount]

It should be good for the useful life of the motor. If you're not havin' any other symptoms, I'd leave that one alone and go fix one of those motorcycles - spring's comin'.

 

[HISSIN50]

Michael, thanks so much for the info.

thanks for reminding me about the bikes. the CBR is still sick. gonna work on it tomorrow. you forget, in Tucson, 'Spring' never leaves. most enjoy the riding season from October through May. Summer is too hot, unless at night. LOL. i take it you are giving the Zook a once over for it's upcoming first ride?
im just burned out on cars and bikes (and home improvement stuff).

thanks again for your input. i really appreciate it.

 

[Michael Yount]

Put the charger on it tomorrow - Sat's supposed to be 60F.

 

[Idwitheld-1`]

So, do you check the chain when it's cold or when its "hot"?

I wonder i there is a difference?

There must be a backlash spec somewhere? Common Ford Engineers...where are ya?

 

[HISSIN50]

Mike, enjoy the maiden voyage of the season. watch the rocks and road salt (if applicable) from the winter. im sure you are much better/smarter, etc than i, but i get very rusty.

Idwitheld, i check it cold. i dont think it matters too much as the chain should not appreciably stretch (or expand) when warm. that would not be good.
and if it matters, the method of checking it that you elude to is by removing the cover and checking the freeplay. but were i to do that, i would not check anything except the torque values on my NEW gears and chain. LOL. i think you can have a 1/2" deflection (faint, probably faulty, memory).

i know a really loose chain will "S" out when the motor is revved. i think this is part of what allows the timing light test to work (it makes an S, then gets slack out of it, recursively).

i was worried that they used nylon gears or nylon caps on the teeth of the gears in an effort to quiet things down. we all know that sucks. i hope someone would mention it if so (I know Michael knows if i can bother him out of another response). i dont recall anyone mentioning it. i think that was a GM trick.