Timing Chain Help!
 

This is for a friend,

he thanks you guys in advance!

"Im potentially looking at a 74 911 with what is said to have a 3.0ltr engine, which doesnt run at the momment but is claimed it needs a timing chain. Now I havent gone to ask for any additional info yet, hopefully ill go look at teh car, What im curious to know , IF ALL IT NEEDS IS A NEW TIMING CHAIN, how involved would the replacing be? Ive noticed the timing chains are fairly cheap around $50 in the performance parts catalog and I have experience with working on cars *motor swap on imports, wiring etc* so im mechanically incline. Just wondering if this could be like a weekend swap or would it involve pulling the motor and needing additional hands *a buddy* and acess of tools?,
"being that the car is a 74, im pretty sure someone did a motor swap since it has a 3.0ltr.

There are 2 timing chains, one for each side, 2 cams. These are interference engines, many timing chain issues = bent valves. You can't successfully tear the cam timing area of a 911 engine apart and reassemble it without experience or books. This is not a small block Chevy or a Honda. There aren't any timing marks to line up, you must time the cams by measuring the amount of lift at the valves with a dial indicator, a special fixture, and a long set of instructions. You should buy Wayne Dempsey's book (he owns Pelican Parts) before your friend buys the car, and probably Bruce Anderson's book too. I recently bought a 2.7 that was "rebuilt" by a mechanic that didn't know Porsches, He ruined the cams, valves, pistons and cylinders, and stripped a couple of bolt holes in the case. I think that he might have been able to pull it off if he'd bought at least one of the books for about $20.00. Instead he ruined $1500.00 worth of parts (used). If it needs timing chains it might really need tensioners or a Carrera chain tensioner upgrade if this hasn't already been done, the parts for the upgrade are around $650.00.
You need more information than you will probably get anyone to type out here. In my opinion a 911 engine has more in common with an aircraft engine that it does with most automobile engines.
I would rather drop the engine for that job. It's possible to replace the chains in the car, but not by much. These engines are too easy to remove to make it worth it to deal with the frustration of limited access and poor visibility.
BTW, a 3.0 has a part number starting with 930 on the side of the case visible from under the car, 2.7's and smaller have a 901 part number.

I concur with all the above. And I very much doubt just a timing chain would be needed. If it was worn to the point of needing replacement, look at chain sprockets and chain ramps too.
If it broke, the pistons hit the valves and it needs at least a top end rebuild. The motor will need to be dropped and inspected, heads and cam towers separated from cylinders.

Aurel

But I may add that YOU TOO CAN REBUILD A (eleben engine....I did mine no sweat...(well ok a lil sweat )) But I ONLY used Waynes book and it came out A O K!

Let's back up a bit. The key thing is the engine is not running. In that state, it should be valued as a core. Simple as that. The rest of the drivetrain, too, since you can't determine how well it functions.

The claim that all the engine needs is a timing chain is specious, and shows a lack of knowledge on the part of the seller. If I were a potential buyer, I would factor in the price of a full-on engine rebuild and other unknowns into my offering price. The seller might get upset, but if he or she expects to move the car, why don't they fix it if it's so simple?

Brian

The claim that all the engine needs is a timing chain is specious, and shows a lack of knowledge on the part of the seller. If I were a potential buyer, I would factor in the price of a full-on engine rebuild and other unknowns into my offering price. The seller might get upset, but if he or she expects to move the car, why don't they fix it if it's so simple?




+1

I think this is one of those "run Forest run"