1986 timing chain tensioners rebuild kit?

[reclino]

Is there a rebuild kit for the pressure fed "chain adjuster" 930 105 058 03 ? I am looking in the PET but don't see a seal kit for this?
David

[Walter_Middie]

reclino,

I could not find a rebuild kit for my tensions which are similar to yours. The rebuild kits that are available are for a different type of tensioner. Here's what I did with mine:



First, I’d like to thank everyone that contributed to these threads in the past – you saved me a lot of money. I’m going to summarize what I learned so that the next person can benefit from what my experience.

My engine was making a metallic rattling sound around 2500 to 3000 RPM. It was quiet when cold, and after warmed up, it was quiet above 3000 RPM. It appears that one of my tensioners had a stuck check ball valve at the bottom of the “working chamber”. This allowed the piston to move with only the spring holding the chain taught. The “working chamber” was slowly emptying itself of oil, unable to pull oil from the “supply chamber”.

The chain tensioner works by filling the “supply chamber” with oil from the “oil supply”. There are 3 check ball valves. There is a relief valve at the top of the “supply chamber” that is constantly letting oil out. Don’t worry that the relief valve opens at a fairly low pressure, the “supply chamber” only has to be full of oil, not pressurized.

Once the “supply chamber” is full of oil, it can supply oil to the “working chamber”. While the engine is running, the chain tensioner piston vibrates and pulses a lot. As the piston extends, oil from the “supply chamber” refills the oil in the “working chamber” by passing through the “check ball valve” at the bottom of the “working chamber”. If the piston tries to retract, its movement is resisted by the piston spring and the oil in the “working chamber” - the piston movement is also damped by the oil.

Prior to installation of the tensioner in the engine, I filled the “working chamber” and “supply chamber” with oil. The “working chamber” was filled with oil by removing the piston and submerging the tensioner in oil. The piston was put back in, and if the “check valve” on the bottom of the “working chamber” is operating correctly, the piston should have a lot of resistance because oil can only escape from the small orifice at the top of the piston. The “supply chamber” can be filled on the work bench or on the car using a pump style oil can and forcing oil into the inlet until it flows out of the check valve at the top of the “supply chamber”.

With the tensioner filled with oil in both chambers and mounted back on the car, cranking the engine with the ignition off doesn’t seem necessary. Not a bad idea, but the tensioner should be ready to go. The check ball valves will keep oil where it needs to be until the normal engine oil pressure can begin flowing into the “supply chamber” and out the top check valve.

I bench tested my tensioner with the following tests:
1.) Remove the piston.
2.) Using a pump style oil can, fill the “supply chamber” with oil through the oil supply hole. Oil flowing out through the top of the “supply chamber” check valve shows that the chamber is full and the check valve is working correctly.
3.) Continue pumping oil into the oil supply hole while pushing down on the check valve ball at the top of the “supply chamber”. This should force oil past the check valve at the bottom of the “working chamber”, and you should see the “working chamber” now fill with oil.
4.) After filling the “working chamber” with oil, the piston (with the spring) should be very hard to insert and retract. This shows that the check valve at the bottom of the “working chamber” is sealing.
5.) If all these are OK, you are ready to install the tensioner full of oil, and start the engine.

[Walter_Middie]