Tom. M

I used to think the same way...that was until Colin (Lizard) put one on his 5sp 928.... they way he thrashes his car....if it can survive a beating by Colin...it can survive anything

the flyin' scotsman

You've got Amsoil in the very old tensioner don't you MK?

gbgastowers

Don't tell anyone but I adjusted my tension by tone only with my iphone. https://rennlist.com/forums/private....m&pmid=2549692

Mrmerlin

the other issue you have is that the belt your trying to adjust is a square tooth belt this may change how the 9201 tool seats on the belt.
FWIW the kempf tool is only measuring twist the 9201 is measuring tension and this will change when the mounting of the roller of the tool fits into a valley of the teeth or is placed on a tooth of the belt particularly the square tooth belt.

FWIW IDK why your using the square tooth belt or pulleys for a racing engine,
the HTD belt is stronger

mark kibort

I think u are on to somthing

Is the tool no good for square teeth??

There is a huge valley w the square teeth belt
But even using the top of the teeth the reading is only 4.0

As far as old vs new
They say the old style is good at wear and not skipping /slipping

So
How do we set tension?
I guess I should check my s4 it has been a long time
That way we can get a better idea of tension measurement differences.

James Bailey

Ah.."They say the old style is good at wear and not skipping /slipping...." they would be wrong. The round tooth is known as the high torque design and is far superior to the square tooth in the ability to transfer load.....
Just one description......"H.T.D. High Torque Drive, Complete Drive Pulley assembly (round not square tooth profile). Reduces power loss through belts and considerably more accurate timing and reliability against tooth jump on over rev. Recommended for use with high volume BDT water pump....."

There are many more references to round vs square....the Pinto motor for example.

."The Ford engineer that made the change to the half round tooth has answered my query and I report as follows.

The change was made to address a whining noise and 150K durability objectives.The belt is a HTD 2 design and in addition to being quieter, will transmit more power. The valvetrain though has been changed (roller cam, ed) to require less, not more power so this design will last significantly longer with current valve train design. The change was made only on Ranger truck, and the year following the material was changed to NBR (Nitrile Buna Rubber) that also extends the life of the system...."
The HTD(round) is better but not needed on the 2 valve cars.....

Mrmerlin

Honestly I have not used the 9201 tool to set a square tooth belt only the HTD belts,
so I dont know what the differences will be, but there will be some difference,

As far as they said and I dont know who they are ,
I would be swapping out the old square tooth drive system if I was gonna go racing, thats what I say

mark kibort

I believe you. as I said, I "heard" that it was fine. sounds like for 2 valve cars, its ok. certainly this car has had no issues. but maybe with the big cams..... oh, i didnt even check the euro 80 cam towers to see if they are HTD. I know on my change i used my old 84 cam pulleys. on scots..... hmm, we just mounted up the cam towers but they had devek level II cams so i HOPE they were changed. I dont remember that part of the rebuild . Hope we checked it.


Just went in the garage and did some measurements, but not the usual kind
I took a belt off the car from both types. HTD and the old style and put them both in the tensioner. guess which one had the greater thickness from edge of belt back to the top of the measuring roller as placed in the between tooth valley of the belt????????????????

take a wild guess............

yes, the HTD belt is a full 1mm thicker. that accounts for about 1-2 on the tensioner porsche tool scale.

Sorry Kempf tool folks, i figure when i check my S4 motor, both systems will calibrate fine. nice to have a new new porsche tool, and have it calibrated too!

i think ill use the kempf tool and be done with it. I suppose the tone test will be invalid too considering the overall belt thickness differences.

GregBBRD

I've never had a Kemph tool in my hands, so I can't tell you much about how it compares to the 9201 tool....which is all I've ever used....for both styles of belts.

Your 9201 tool location is not proper, which might be "messing" with your results....I don't know, since I've never measured a belt where you are using the tool. The tool is designed to be placed so that the "locking lever" is directly above the cast arm for the air pump. (You need to move the tool about 4-5 "teeth" closer to the cam gear.) The tool is designed so that you can gently push down on that cast arm with the tool and it will "latch" into the "locked measuring position". (If you were to install the "center" belt cover, you would not be able to get the 9201 tool as far to the right as you currently have it.)

Try that and see what results you get.

You also need to turn the engine over a few revolutions, everytime you change the tension on the tensioner, before you use the 9201 tool, so that the tension will "spread" out over the entire belt. Without turing the engine over, the majority of the "change" in tension will be "trapped" between the cam gear and the crankshaft gear.

mark kibort

so, clearly the old timing belts should NOT be tightened with the 9201 tool. think of all the WRECKED timing belts, pulleys..........etc . !!!!!!!!!!!!!!!!! its not a stretch that I may have just accidentially figured out why. who has old and new enigines next to each other, spare old and new belts laying around and has used the kemp tool and the 9201 on a old motor with belt assembly. by tightening the old belt with the 9201 to 5.0, you are essentially tighting the belt to 7.0 that would explain the grooved out cam pulleys, now wouldnt it?????

i think the manal just says twist the belt to 45 degrees and call it a day or something on the older models, right?

mark kibort

im actually pretty good with the tool, but thanks for the heads up. yes, i spun the engine several revolutions. yes, it did change the measurement slightly. a little higher after rotation a few times.

i tried the tool from almost on the pulley itself to toward the water pump. you just got a picture of one of many of the testing spots. the results were no that different when the kempf tool said "max window setting, or near 5.0". I actualy put the center cover on for a sec, becase i always use that as a reverence point too.

I also can get it to click, see the setting and then tighten the bolt to reach the desired setting. seems like a good way to do it, and I cant see any drawbacks to that, unless you do.

anyway, I just measure the differences in belts as the little round shaft fits into the belt between the teeth. its 1mm thicker, so basically, the older belt adjustment will be WAY too tight if you use the 9201 too. if you have ever used it on older models and set it to 5.0, the tension is really more like 7.0,
I used several simple ways to verify this. one way n particular was to fit both the belt and the adjustment tool in the tool itself and see what the needle did. it was between 1.5 and 2 off on the gauge!!

mark kibort

Greg,
I just tested the 9201, as you suggested, when i suddenly had the center cover on, it all came back to me. I would actually use the body of the 9201 to press down on the air pump bracket to initiate the test.

you have to notice , by doing this, you do get an artificial .5 extra tension reading . what it settles at , is the real reading, and thats why i just tryied to tighten the belt with the 9201 on the belt, engaged. makes sense, doesnt it?? anyway, if not, not a big deal.

point is. i just did it again. rotated the engne 4 times, and then checked. 3 on the 9201, and well out of the window on the kempf tool. almost a full window futher

mark kibort

i noticed that by pushing on the tensioner body, you get an extra point on the gauge, but if you just use you fingernail to push up the adjuster, it rests at exactly the same final tension. (no over run). thats the last picture below

the tensioner calibrator does the same thing.

here are the pics. the needle goes pased the final resting position with pushing on the body. ( the way i have always done it) those are the first 2 pictures.

either way, look at the Kempf tool result. wow, way out the window, by a long shot and thats at only a final resting tension of 3.2 on the porsche tool! god knows how far it would go if i set it by the porsche tool to 5.0

I also included the mesurements of the HTD belt vs old belt in the tensioner.
obviosly, the movement of thr roller is critical. 1 more additional MM of movement or distance is HUGE for the end result being further with the HTD belt vs the thinner, deeper cut , and deeper roller position of the old style belt.

ponder this stuff for awhile and let me know what you all think.

mark kibort

update: Just thought about it for awhile. since the belt just doesnt fit the 9201 the same, you have to MAKE it the same. I did this by puttiing some tape around only ONE side of the tensioner tool 9201 roller and made it apear to the belt, in the same way that the HTD belt would . when i did this, the tension goes up by 1 full point. anyway, im full window on the kempf tool now, and with the tape on the 9201 roller, its at 4.0. but before when i had the 9201 at near 4 , the tape made the result near 5.5.

anyway, there might be subtle differences in the belt as well. im a little puzzled on how to set it, but feeling a little better after figuring out the belts being held differently, is a huge issue and needs to be addressed.

Hilton

Have you tried hitting it with a hammer yet?