Installing chain tensioners - questions
 

I'm installing chain tensioners this week and while eveything is "out in the open", I thought I'd also do a valve adjustment, replace spark plugs and wires, and replace all of the heater hoses. I have a few questions:

1. I know I need to drain the oil to do the tensioners and valve adjustment. Since I just changed the oil about 500 miles ago, I would not like to waste all 12 quarts. Can I just drain the engine without draining the oil tank?

2. I was reading the Pelican technical article on doing the chain tensioners, and it says to submerge the tensioners in oil, pull the pin, and pump them a few times to "bleed" them. How necessary is this step? I'm worried that once I pull the pins, I'll never be able to get them back in again to install in the car. Can you just use an oil can to drip oil into the tensioner?

3. I noticed on the old chain cover that there is some sort of switch or sensor attached to the left chain cover. What is this? How difficult is it to install in the new chain cover?

Thanks for the help. I already have all of the engine tin and muffler off, so once these questions are answered, it's GO time!

Steve,
1. Not sure about this one but try it as you described.
2. No need to prime your tensioners. When you start your car the first time the air will bleed out.
Lots of people think that hydraulic pressure provides the tension. The spring provides the tension. The oil acts as oil in a shock absorber would, damping the spring motion.
3. That's the thermo-time switch. On the new cover provided with your tensioners there will be a threaded hole for it. Remove it from the old cover and install it intothe new one.
PB

Steve,

The sensor on the left chain case cover is the Thermo-Time switch, and there is a plug at that location on the replacement cover that can be removed to install the switch.

The bleeding procedure was provided by Pelican's supplier for the pressure-fed tensioners. Porsche's official position is that there is no difference between 'non' and pressurized tensioners' installation procedures, but it can't hurt. A bench vise can be used to collapse the piston, so the pin can be reinserted.

I don't know about #1. Can probably just drain the engine sump and you'll be fine.

I did #2 and it took awhile of diddling around with the tensioners to get them to build pressure. I used a pair of large channel locks with some rubber covers on the jaws to avoid marring the surface of the tensioner pushrod. You grab the tensioner with the pliers, and squeeze the pushrod down to remove the pin. Submerge the unit in the oil bath (an oil drain pain would work well) and slowly release the pushrod. Repeat the compress/release procedure until you feel the tensioner build pressure and it becomes noticeably more firm when compressing it. This may take a little while and you might have to play around with the bleeding process. One of mine just didn't want to build pressure. Then I just placed my finger over the pressure relief nipple thing (red arrow in picture) and it let out a gurgle. I put it back in the oil and it decided to build pressure. Go figure.

http://forums.pelicanparts.com/uploads/pic3.jpg

After I got the tensioner to build pressure, I reinstalled the pin and put the tensioner in place in the chain case.

I'm not familiar with the temperature switch reinstallation for #3. As long as the chain cover is threaded for the switch and you have a new seal ring for it, the switch should go right in place?

Steve, I have re-used new oil. I'm not sure of all the implications but here's what I did. Obviously, make sure the container you are using is spotless. When I removed the drain plug I caught the first few ounces of oil in tank in a small cup in case there was any crud around the area and then let the rest fall into the container. Clean the drain plug area first with something like brake clean to minimize contamination there.

I do think "bench bleeding" is a good idea and the one described by KTL should work fine. That's basically what I've done in the past and had good success.

I did not prime my tensioners and had no problems. They have been in since May of this year.

When I did my tensioner upgrade I ddn't need to drain the oil. By the process of jacking the back end up high enough the oil moves forward and never drains out the opening when removing the tensioner covers.

That's what I did.

Gunter

Agreed - no need to drain the oil. Prime the tensioners with your hand, then put back into a vise and compress...

-Wayne