timing chain question

[83911sc]

I am planning on doing the pressure fed tensioner upgrade and am getting into the "while you're in there mode" so, here are the tag alongs that I'm potentially dealing with:

new chain ramps
new oil pressure sending unit
new cat bypass pipe
and possible new timing chains


my question is about replacing the timing chain - Why doesn't anyone talk about this as a logical simultaneous maintenance issue? I assume that it can only be because its such a pain in the butt job - have to re-set it. SO - is it worth it? Or, should I just plan on the upgrade and go for a nice ride?

BTW, this is my first "major" project, so if its just the tensioner upgrade, I'll probably fly solo w/ some emergency wrenching resources available. I've been reading about it ad nausem and I think oil is starting to actually leak out of my ears If its changing the timing chains, then I think that I'll need to punt and watch the pro do the job.

What do you think?

Adam

[john walker's workshop]

if the left side arm of the idler support is within 1/8" of touching the inside of the housing, the chains and sprockets should be replaced. basically, you don't want the tensioner to be anywhere near fully extended. the chain housings should be removed to replace the chains. i suppose it could be done with them in place, but it would be a pain. it's doable in the car of course.

[83911sc]

thanks John -

do you think I should replace the chains even if left side arm of the idler support is not that close to touching the inside of the housing? I don't want to get too sucked into the "while you're in there" mode, but I also don't want to waste a good opportunity to do some preventative stuff.

Adam

[yelcab1]

May be I just did not have the touch but I was never able to replace the chain of my 84 911 with the engine in the car. The replacement chain went crooked, got caught and the engine came out. My opinion is if you do not have issues with the chain, leave it alone and just do the others.

[john walker's workshop]

the left side gives you a clue that the chain may need to be replaced by how close the idler support arm gets to the housing. there's really nothing on the right side to measure. so if the left side is close, the other chain must have the same condition, and you would do them as a pair. if there's still plenty of space between the arm and housing, just do the swap and don't worry about the chains. i've seen some where the tensioner was fully extended and there was still slop in the arm.

[Superman]

Don't know how many miles are on your engine Adam, and of course JW is more than welcome to correct me if I'm mistaken, but I think chains normally last as long as the engine.

[Doug Zielke]

Thats another great tip. Thank you John!
(One of these days I'm going to bring you a copy of the 911 repair book you didn't know you wrote!!)

[kepperly]

except on a turbo, i had to do chains at 43k mi.on the 77 930 i used to own. went ahead and did pressure feed tensioners at the same time. got the motor in then found a broken stud what a nightmare that car was.
keith

[83911sc]

THanks for the info - I've got 107k on the clock - I think that unless I find the reduced clearance, then I'm not going to push it with the chain replacement-

Again thanks alot for the info, keep your fingers crossed and wish me good luck

Adam

[Wayne 962]

Don't ever let tension come off of your chain when replacing the tensioners. NEVER!

-Wayne