while your in there sugestions

[germanfan]

my valve guides are starting to go bad @ 170k....on my 3.2
i know this is a can of worms, but what MUST i do with the heads off?
and good bang for the buck to do tips are appriecated

[Ken911]

With 170k you should pull the whole thing apart. as a minimum you need to pull the jugs and measure the pisons and cylinders then re ring it. But it's not that hard to split the case check the crank replace the bearings and new timing chains. 100k is ok for a top end rebuild but close to 200k you should do the whole thing even if just for the self assurance of knowing it's ok.

[CaptainCalf]

Originally Posted by Ken911

With 170k you should pull the whole thing apart. as a minimum you need to pull the jugs and measure the pisons and cylinders then re ring it. But it's not that hard to split the case check the crank replace the bearings and new timing chains. 100k is ok for a top end rebuild but close to 200k you should do the whole thing even if just for the self assurance of knowing it's ok.

+1, it would be a shame to do a top end rebuild and then have to go back and rering it after another 30K. Besides it would make a great winter project if you live in an area that has to dig out of the snow come spring

[germanfan]

yup, rings, chains and bearings sound prudent.
could do that while the heads are off getting massaged.

[JJ 911SC]

Get a good line of credit

[VitoV]

I have to disagree. If oil pressure's good and there's no serious bore wear, why pay money you don't need to pay? Just check for chain stretch, cylinder scuffing, etc while you have the heads off. If the bottom end's not perfect, big deal. It'll let you know when it needs attention. Knock knock!

If you feel you absolutely must open the bottom end, have a look at what flat6pack did in the "marks its spot" thread. As a wise man once said, if it ain't broke...

Just my opinion!

[Jesse16]

I just had the same thing this past fall/winter. If its a DIY job, then the extra cost to do the bottom end may not be so bad. Paying someone else, the cost is roughly double for basic job. Its most likely that your engine is in fine shape other than dirty and lots of gunk inside from 170K of burning dirty gas. Mine had normal wear for 180K miles and just got bearings, rings, chains/ramps, and re-sealing as part of the bottom end.

[500_19B]

I agree that the decision to split the case may be influenced by whether you are doing the work yourself or not. In my case, I am doing the work, so the incremental cost to split the case is really not that bad. In my case, the main bearings look great, but the intermediate shaft bearings are showing copper, so it is nice to change them (although I imagine they would still be fine for quite some time). Engine is at 107K FYI.

Splitting the case also makes it easier to change the connecting rod bolts to ARP (or Raceware) which, for a 3.2, is a definite stuctural upgrade.

However, there is a lot of labor in the bottom end and if you are paying someone to do it, it will not be cheap...

[Jesse16]

I actually chickened out and was a bit unsure/not confident on my ability to evaluate the bottom end. Also felt like having an "expert" evaluate and measure the bearings and cylinders/pistons, oil pump, etc.. I took my stripped engine with the cylinders attached to one of my areas well known Porsche shops and they did that part for me. (this part isn't so heavy so easy to move) Can't remember what it cost exactly but I think around $2500 for all. Came back clean and hopefully well assembled. I visited when it was apart (waiting for parts) and they showed me the normal wear on the bearing. Did all the rest myself and I'll be cleaning my teeth in a glass before it needs that kinda tear down again.

[KTL]

This one is a tough call if you're on a tight budget. I say that because you may think you're arresting your problem of oil consumption (if that is indeed an issue) with valve guides. Then you button it all back up and your engine still consumes some noticeable oil. Darn, should have re-ringed it/reconditioned pistons and cylinders.

So while you're at it, you look at the P's & C's and some are out of spec. Now you have to get some replacement P's & C's. Best to take a look at them now while you have it all apart that far. However if you're an avid/frequent DIY'er, you could leave well enough alone and tear it down again some other time. All depends on how much you're willing to tackle.

Regarding intermediate shaft bearing wear, they start to show copper quite soon after new replacement. They just do, due to the load placed on the sprockets by the chains. However it's not a terminal failure issue waiting to happen because they all seem to do it w/out causing a bad failure if left unattended to.

[germanfan]

thanks everybody! i will go in and check the tolerences. so two ?'s
is there a specific valave guide to get that is better/more durable? and what would be some suggestions to get more power?