dimmer

I just installed new timing belt, w/p, and PK tensioner system on my 1988 S4.
I used the Contitech belt.
Everything went well with the install except the tensioner has no extension ... pulling the ping on the tensioner was effortless.
I rotated the engine manually 2 revolutions and measured the belt tension @ 0 BTDC, it is correct.
I suspect that the belt will soon stretch and give me proper extension, but I'm concerned what happens when the engine is hot.
Ken's instructions do include this contingency and recommend drilling & chamfering the holes in the tensioner to 8mm (closest I have is 5/16)
Any opinions on this? Should I be concerned and drill out the holes as suggested?
Would I be better with the Gates belt?
Do you drill all 3 holes or perhaps just the 2 leftmost (when facing the engine) to allow tensioner to rotate ccw a bit?
What's the purpose of chamferring?

PorKen

Spinning the engine with the starter may settle the belt and show a bit of extension. The Continental belt is thicker (2.56mm) than the Gates (regular 2.49 and Racing 2.39) and installs tight but quickly stretches to create a few MMs of extension. The Conti is more elastic so overall tension should not be affected much. (Until it stretches, it can be compared to having been installed with the stock tensioner.)

Drill all three holes. (Chamferring not required.) This will allow the T/D to be rotated even farther.


Another option available now (faster if you have a US mail-drop box) is to exchange for a S2 bracket, which has two lever positions, the upper allowing more extension (like the pre-S brackets). Email for more info.

SeanR

I had this worry after installing a few of them and after running the engine and then rechecking the piston extension was 2-4mm which I was good with. Checked one last week that had run for a few months and the extension was 4mm. My worries after that were zero. On installing them I'd like to have had a mm or two of it but my fears were unfounded after having been run. Much better than earlier brackets that showed 6-8mm.

Why would anyone use a Conti belt after so much reporting of stretching. I won't install one, not when Gates belts are cheaper from Roger.

dimmer

Thank you both for taking the time to share your expertise .,,, truly valued.

I'm going to try cranking the engine a few revs with the starter tomorrow and measure the extension again.
Right now it's about 1/2mm.
If it doesn't improve, I'll drill out the tensioner holes a minimal amount.
I will make note of the recommendation to use the Gates belt for next time ... After thinking about it, one of the main reasons for going with the PK tensioning system is to automatically adjust for belt stretch .