replace the timing chains?

[DEAN911]

Going through an early 911 low mileage motor to do a complete reseal. Split the case and all. Only 40,000 miles in 10 years. Obviously not driven enough. any reason to replace the timing chains while I am in here? They were new 10 years ago.

Thanks,

[Mo_Gearhead]

Probably not.

Unless the chains are 'stretched' or the gear sprockets are worn/damaged you should be fine. Can't imagine either of these two being the case in 40K miles unless you had major internal (other engine) damage.

Just put them back together as they were, moving parts DO develop wear patterns.

[ChrisBennet]

Originally Posted by DEAN911

Going through an early 911 low mileage motor to do a complete reseal. Split the case and all. Only 40,000 miles in 10 years. Obviously not driven enough. any reason to replace the timing chains while I am in here? They were new 10 years ago.

Thanks,

Sprockets and chains are probably fine.
What years is the motor? I ask because the '74-77 2.7's are rarely a "split the case, replace the bearings" situation. As soon as you unbolt the case halves on those motors they more or less go "boing" (hands making motions of case halves warping in different directions).

-Chris

[DEAN911]

It is a 7R mag case from a '73 2.4. It has been a habitual leaker since Stoddard converted it to 2.7 RS 10 years ago. Getting it done right this time. Just figured that while I am in there sort of thing.

Thanks,

[dtw]

Are you checking the engine case/barrels/heads to find out why it is leaking? Take a 2nd look at what Chris is saying. On a mag-case 911 engine, especially larger/more powerful ones, it is critical that you get your parts measured out by a machine shop experienced with 911 engines. The engine case likes to 'walk' or 'relieve' over time, resulting in a leaky engine.

I bought a 'zero-mile rebuild' 2.7 last year with documentation. Threw it in the car and fired it up. Drove it all summer but it leaked like a sieve. Tore it down in the fall and found all kinds of problems. Head sealing deck was uneven, case deck uneven, pulled studs, you name it. Including head work (guides were shot), ended up spending $1,700 on machine work.

[ChrisBennet]

I paid $1000 just for the case work on a 2.7 last year (resized and case savers installed, no fancy "race" mods").
-Chris

[vntgspd]

My opinion may be biased because I am just finishing a complete overhaul of my engine...

If you are going to split the case, you MUST get it checked out by a competent Porsche machine shop. Also, regardless of wear, I would have the crank serviced and replace all of the main and rod bearings. The rods should be checked and resized if necessary. Also check the intermediate shaft and sprockets as I think these items rarely get replaced and thus may have more miles that you think.

There is just so much labor involved in tearing the engine down and splitting the case that not addressing these relatively inexpensive items my come back to haunt you later.

Along the same logic, I would replace the chains, however I would agree with teh posters above that they are probably fine. If they later stretch and must be replaced, you can do this easily without pulling the heads or anything.

Good Luck!

[DEAN911]

I hear everything you are saying. That is why I said this time it is being done right. 10 years ago I thought I paid for all of that but it wasn't done as well as it could have been. This time I hope to get a good number of leak free years. I have a friend at work who drives a 78 that only started leaking at the case a few years ago. Motor is original. Now that is how Porsche meant them to be built. I would kill for a build like that after all the oil stained cardboard I have thrown away over the last few years. I will let you know how successful things went sometime late spring.

[dtw]

Originally Posted by DEAN911

I hear everything you are saying. That is why I said this time it is being done right. 10 years ago I thought I paid for all of that but it wasn't done as well as it could have been. This time I hope to get a good number of leak free years. I have a friend at work who drives a 78 that only started leaking at the case a few years ago. Motor is original. Now that is how Porsche meant them to be built. I would kill for a build like that after all the oil stained cardboard I have thrown away over the last few years. I will let you know how successful things went sometime late spring.

I hear ya, just wanted to raise the red flag. There are, unfortunately, many different interpretations of 'done right', that's why we're all cautioning you - but it sounds like you are on the right track. Example - my 'rebuilt' engine came with plenty of documentation. Unfortunately, the so-called valve job consisted of replacing the stem seals and re-grinding the seats.

Good luck and keep us posted!