Belt tentioner

[porschedavid]

doing rebuild on 1986 porsche 928 4.7
Just want to know when doing my timing belt do i want to rebuild the belt tentioner or get a after market one like the one from 928 r us which is (PKT-B - advanced 928 timing belt tentioner) What do you guys have in your engines

[stepson]

Some folks like to rebuild the stock tensioner. Some folks like the aftermarket variety. Your choice.

I chose aftermarket myself. It just made more sense to me. YMMV

[JK McDonald]

Hey Dave - Just a comment - There are a couple of the more modern tensioners available and these are preferred by many owners during the Timing Belt/Water Pump replacement. It is considered a little messy and labor intensive but I've rebuilt about half a dozen of the factory 928 TB tensioners with no performance issues or leaks. Just disassemble, thoroughly clean up the internal discs, carefully reinstall everything back together (correct orientation) like they came out of the tensioner, new oil and seals. Set the TB adjustment using a Kemp Tool - They are reasonably priced and easy to use ......The factory TB adjustment designed tensioner tools are pretty pricey.

http://www.928intl.com/repair/T-belt1.pdf

Your 86 should have come with a 5 liter engine ?

Good Luck, Michael

[5l32v4c]

I rebuilt mine, not realizing that there was any alternative. What improvment do the after-market ones offer?

[beran earms]

I'm getting ready for another T/B, and I use the PKT, do your research to compare pros and cons The PKT just made sense to me.

[Danglerb]

If you know what you are doing setting tension the factory works fine, if you don't then the PKT might work better for you. I have no plan to use other than factory on any of mine.

[harborman]

Originally Posted by Danglerb

If you know what you are doing setting tension the factory works fine, if you don't then the PKT might work better for you. I have no plan to use other than factory on any of mine.

When I did mine the car only had 37K miles, but it sat for 19 years! I just changed the fluid in the tensioner and set it with the tool (gauge), rechecked at 15K miles. I now have about 40K since I did it. All seems fine with stock set up. Someone did mention to put STP in the tensioner, but I used the spec fluid. I used the Gates Belt.

[xwcgt]

just put the old one back in. the stock stuff works great if its adjusted properly.

[Sapientoni]

The factory tension has an oil passage to the block when bolted on. That's why a gasket is used. I think this keeps some oil pressure to dampen the stacked bellevilles. For certain a 944 belt looks like it will be able to flop off the sprockets when properly tensioned, after looking at a 928 S engine.

[stepson]

Originally Posted by Sapientoni

The factory tension has an oil passage to the block when bolted on. That's why a gasket is used. I think this keeps some oil pressure to dampen the stacked bellevilles. For certain a 944 belt looks like it will be able to flop off the sprockets when properly tensioned, after looking at a 928 S engine.

No oil pressure at all. Self-contained fluid used to heat the Belleville washers only. The gasket is supposed to keep the fluid from leaking out

[Sapientoni]

I think a more critical thing to do at the tensioner is to replace the brass stamped warning connector with a piece of wire with eyelets soldered onto it. Then if it breaks (as the brass ones can fatigue at the bent areas), when it contacts the belt, it'll just bend and be knocked out of the way of the belt. The brass will rotate and machine the belt down until it's narrow enough to break........end of valves.