Replacing timing belt, debating about the seals
 

Just picked up a 88 944 in December (90 k miles). Haven't drove it yet because the there is no history of the timing belt or water pump being changed. I was planning on NOT replacing the seals at this point because I really dont what other repairs that will be needed to make it a reliable car, and I didn't want to break the bank so soon. I thought I would replace the water pump, belts and rollers now, and do seals the next time i replaced the belts.

So I started the job, and noticed a fair amount of oil residue on the inside of the timing belt covers. I also noticed some oil near the back of the camshaft sprocket housing and where the cam tower meets the head.

Is this amount of oil a concern? Does it seem like it is from the camshaft seals?
Would it be a bad idea NOT to replace all the seals? Do these seals ever fail and create a huge oil leak that get could all over the belts?

Thoughts?
http://forums.pelicanparts.com/uploa...1710738096.JPG
http://forums.pelicanparts.com/uploa...1710738096.JPG
http://forums.pelicanparts.com/uploa...1710738096.JPG
http://forums.pelicanparts.com/uploa...1710738096.jpg
http://forums.pelicanparts.com/uploa...1710738096.JPG

I recommend doing a full front reseal (front balance shaft seals, oil pump drive gear, front main seal, front cam seal) if you are doing the belts anyways, its a "while you are in there" sort of thing.

Otherwise you will be doing it again in a years time. Make sure you do a lot of research on the needed seals. Theres an onion skin seal on the balance shafts, as well as the sleeve which must be replaced, and a very specific order of seals on the oil pump drive gear, as well as the oil pump drive gear itself which also should be replaced. The rubber seal wears a ring into the sleeves and the drive gear which causes the leak, and is why you should replace them

Go ahead, cheap out now... you will always have time to do it right later!!! :):):)

I second Walfreyydo and 944.
Do the front end seals, Water pump, probably oil pump toothed gear/sleeve, balance sleeves, too.
If your car has 8 valves, do the camshaft housing gaskets, too (the big one on top and the funny looking one at the very end).
Might as well do the oil/coolant radiator gaskets, too.
Thermostat,
Check all sprockets (balance, cam and others) for stripped woodruff key ways.
MIght need to get a new bolt that holds cam shaft sprockets.
That huge nut (32mm?) in the center of cam shaft sprocket is not threaded!!!!! not a nut!!! it's used to just move cam left/right for timing belt installation (without much torque).
Have fun!

944,
you're so cruel.

I dont think those seals will cost a fortune.. I can relate to the financial concerns an have a similar project. I was planning to do the belts, I'd definitely do the seals if I see oil in there like that. I hadn't considered the waterpump quite yet, maybe its not smart not to ignore it, but thought i'd at least get mine driveable and maybe go back and attack the pump after.. for sure they can fail without a lot of notice so its like paying for insurance so that it i less likely to fail at an inopportune moment.

in volvos, which i have had ore experiences with they can have an issue wth the flame trap plugging up and that can cause a buildup of pressure in the crankcase, a buildup of crankcase vapor pressure puts oil pressure on those engine seals. I don't know if similar happens with the 944 , i haven't heard that it does.

I would say though that oil on the outside of the engine from leaks like that does destroy rubber parts.. and some of that is the hoses,, often there are people having issues with vacuum leaks due to rubber parts being attacked by oil..

The expensive OEM motor mount might be a concern.. Ive seen solid ones for racing etc. Perhaps there is an after-market motor mount solution that is less pricey. I think anything you can do to cleanup any stray oil is probably time well spent because oil saturation decreases the lifespan of rubber. Like with rust , oil residue sort of never sleeps but slowly attacks any rubber it reaches. that may mean things we hadn't considered like maybe the brush holders in the starter motor or wiring connectors or who knows what else. the clutches have a rubber center and they fail too evidently.. and a OEM clutch plate seems pricey..

I think when the belt is changed it is said to remove the starter and to use a tool to lock the ring gear there, well if the starter is removed I'll probably take it apart, clean inspect brushes, check it's bearings, similar with alternator.. rather than waiting for the brushes to wear out or problems because the motor and it' armature is oil soaked..

if its apart you can feel if bearings are rough, or "noisy" the bearings themselves are probably standardized parts and available off the shelf at bearing suppliers, similar with most oil seals. some may be proprietary,, if you have time whole things are apart, you can try look for look for seal numbers or bearing numbers rather than Porsche part numbers.. then google those..

, a rebuilt starter or alternator is an option but if it works , and you are on a shoestring budget, i'd just clean it up and inspect, change the brushes if they are short,, Once all checks out ok and You've cleaned and lubed any parts where needed, etc,, you are probably "more safe" for a while. sure if you have a fat wallet you can just buy a new or rebuilt alternator or starter and replace ..

wheel bearings, similar stuff, you can take it apart and clean out the bearings, examine and repack with fresh grease, if you ignore, sure it may be fine, or it may turn and surprise you.. but at 35 years I think that's a thing i will plan to check, especially since my brakes are stuck and plan on replacing caliper seals.. IF i have a caliper off , it's a good time to go a bit deeper and look at the bearings and repack them and maybe change a seal or a bearing in there if needed.. That's all more work than parts expense.

I believe if we look into the service recommendations and at some of the longer term ones, it may give a list to use as a general guide.. things like oiling your door / hood hinges or repacking bearings, or looking at the headlight lift system or lubing the cable to release the hood, or checking the battery cables and ground locations are likely on the list but not at the forefront of one's mind, as examples..

I know I can;t restore the car in a day or a week so it's a process. I was hoping to start in on mine and just then .. My dayly driver , a volvo 240 , had an issue where the signal lights stopped working.. crap I can't drive it like that.. ok it takes priority then..

darn it took all weekend just to get back where I was on friday, one step ahead , one step back.. it turned out that Volvo powers the signal lights through the DPDT hazard light switch and the hazard light switch failed.. oh but the flashers did work..

to figure that out took all weekend.. with help from some really old forum posts, I was able to feed the relay from a new wire from the fusebox directly to the relay, and that solved it for now.. I was having a very hard time understanding the schematic because it is pretty complicated.. hard to even see..

it took a whole lot of head scratching and I took half the dash apart.. at first I though ok its just a bad flasher or a fuse or loose wire,, half hour job,, no it was all weekend.. anyway I won, its driveable again now but there went the weekend..Such is life sometimes.. Bloody old cars ;-)

Howdo...is this your first 944?

Later Edit: (assuming that this is your first 944)

Gotta jump in with other folks on this...and recommend that you just go ahead with the seals.

As for the oil in your photos...yes, I'd be really concerned that this can get thrown around and end up on your timing belt, which over time can cause it to degrade, and also to slip a tooth or two on the upper cam gear, which can throw the timing off enough that valves and pistons could collide and you'd need to replace valves and possibly rebuild the head.

Given that you're doing belts, pump, and rollers anyway...you're already in it for most of the cost - so just keep pulling things off and clean as you go.

When you do pull the oil pump sleeve...do note the order of stuff that you remove to get to it (especially the O-ring), and the orientation of the lower timing belt gear as its slides off of the crank. If that geared pump sleeve does have a groove, you should replace it...but do know that you might receive one that looks a bit different as some of them (like the one I replace on my 89NA) have been re-designed but which otherwise work fine.

If you are removing the upper cam gear (to change out the O-rings) without removing the cam housing itself, be careful to very securely "counter lock" the camshaft collar with a wrench braced against something solid, like the top of the air intake manifold, so that when you turn out the cam bolt itself, which can take a bit of effort, you don’t risk turning the camshaft with enough force to damage valves…and do not leave the cam belt on expecting it (assuming you’ve locked the the engine at the starter ring gear) to hold things still as you struggle (yes, it can take a bit of effort) with getting that cam bolt to break free. And whatever you do…do not use an impact wrench to remove the cam collar! While this may be tempting, you could spin this collar and ding up its keyway (slot), the key itself, and worse still…you might damage the keyway slot on the front of the camshaft itself, meaning that you’d need a new camshaft.

When dealing with the thermostat, do note the orientation of the open end of its outer lock-ring, and think about orienting the open end of this ring in consideration of your own orientation (from above or below the engine) from which you might be removing this ring in the future.

Be very careful to correctly orient each of the two balance shaft gears to ensure that these shafts can do their job correctly. It is very easy to get the bottom gear off by 180 degrees, so do check with a resource like Clarks Garage, Mike at Lindsey Racing, or George (Ecology) here on this forum.
And by no means should you simply trust the timing belts “automatic” spring tensioner to set the timing belt tension correctly. The actual tension that this device applies to a timing belt can change over time as its spring can weaken slightly, and as things get gunked up in general (like from that oil getting thrown around)…so you should always check the tension at the belt itself. You might even consider having the belt tension checked and adjusted from an experienced professional, and then with clean hands go ahead and give that belt a twist between thumb and forefinger, to see what a properly adjusted belt actually feels like.

I’ll also recommend that you check out Van Svenson’s video covering this (timing and balance belt change) topic. Lots of great “tips and tricks” in this video!

As for the variety of belt tension checking tools available, I’ve tried a number of them and have settled on Bruce Arnn’s product - but still like to do a final check by hand.

With the t-belt properly adjusted, and given your own level of new-found confidence in being able to set this tension yourself in the future, you can go the extra mile and take that auto tensioner apart, give it a good cleaning, and re-adjust its spring (mine has an adjustment locking collar at one end of the spring) to a point to where it sets the actual, “correct” tension before you lock it down. But even so…still check the tension yourself - always! And don’t forget to check again at 1000 miles…making sure to modify the adjustment to the new spec. for a belt that’s been stretched a little bit. After this just pull the top cover off a couple times per year to check it.

Again, having not waited for your response about whether you’ve owned one of these cars in the past…I’m assuming here that you have not. But if I’m wrong about this, I hope at least that you might glean something useful from my somewhat rambling, way too long text! And keep in mind that while there is much common knowledge on this forum, we also tend to employ some different approaches to solving similar issues.

At any rate…good luck - have fun, and don’t hesitate to walk away from things once in awhile to take a break!

nice post 944 !
I appreciated the details, and the warnings about what can go wrong. - much appreciated.

only thinkId add, take photos! not just to show us but also it's a easy fast way to know what things looked like days later upon reassembly, even just stuff like ok where did the longer bolt come from?

obvious , but a bunch of sandwich bags to bag parts in some sort of logical sequence helps a lot. upon reassembly just start grabbing the bags in the reverse order.. It's harder to loose stuff that way too.. I know we've all had moments where we curse ourselves for dropping something little, or setting it aside with out mind on something else. you can write on the bag with a sharpie..

often I think "oh i'll remember"... and then there is some huge delay between sessions.. they cost about a nickle apiece..

Thanks everyone for the responses, this convinces me i should go ahead and do the seals. My hesitation was not because I was trying to cut corners just to do it later, but trying to understand the necessity of doing the seals considering a bunch of other work could be right around the corner. Also, I may only drive this car 1000 miles a year. But now I can see the logic of doing the seals at this point.

I have been watching some videos about the belt change and seals, but wasn't aware of the oil pump drivegear sleeve. Good to know.

OK-944, yes this is my first 944. And I totally appreciated the detail you provided!

Thanks!
Howdo

howdo,
another advice:
definitely get yourself a flywheel lock.
Balance shafts (BS) have different seals, one for each, because BS rotate in opposite directions, therefore the seals must be specific to each one. Each BS seal has an arrow as a direction mark.
definitely take pictures.
Here's another video to watch:
https://www.youtube.com/watch?v=psmQveG7cGc
The guy on the video above has 2 or 3 more videos dedicated to 944 (especially Timing and Balance belts).
If you have 8valve engine, note that Camshaft seal has a different internal diameter (ID), than BS seals, don't mix them up.
Check proper belts alignment 3 times or 4.
If you decide to tinker with an oil/coolant radiator (cooler), you also need to buy an alignment tool, than insets during an installation instead of the pressure check valve... There are two different types - one with smooth bore (early models), another with a thread. If you can't tell before disassembly, you'll know for sure after...
What else?
for ease of reaching the work area, remove the fans and fan shroud. put a thick cardboard on the face of the radiator facing the engine to protect the fins.
Also,,, if your expansion tank (coolant) is dirty inside, use lacquer thinner to clean it....Of course, remove it before and drain it....
If you ever be in need to remove an intake manifold, inspect the rubberized studs that hold idle control "valve" and adjacent vacuum hoses. New intake gaskets will be needed.
Note: if the oil pressure gauge wont work properly after the repairs, check the wiring. In my case the oil pressure sender went bad and I bought a new one.
Note: Balance shaft sprockets are held with thick conical washers, the conical parts must be out.

All these procedures are not that difficult than what it looks now and how we explain them to you.

I did the same repairs as you're about to perform, and I ended up doing these:
1 - Timing and BS belts (as a kit)
2 - if you replace original WP with an "updated" one, know that the roller (upper right corner) on the WP body needs to be replaced with a bigger one (original is about 33mm, new one is about 46mm)
3 - Front end seals
4 - oil pump gear (or sleeve), Original has long splines, new one - shorter splines.
5 - BS sprocket (mine was overtorqued and, as a result, has damaged (stripped) keyway
6 - new woodruff keys (half-moon and straight)
7 - oil cooler gasket KIT
8 - oil cooler installation tool
9- camshaft housing gasket (top) and its endcap gasket (looks like a cow's head)
10 - new camshaft bolt
11 - new camshaft sleeve (that looks like a huge flange nut)
12 - intake manif. gaskets
13 - oil filler tube o-rings.
14 - rubberized studs (for idle adj. valve).
15 - Throttle body gasket (because of intake manif. removal)
16 - Engine mounts (Uro)
17 - two coolant temp sensors (one is for the computer, another is for the dashboard gauge). The former was still good.

In all this excitement, the started died - new starter.

for TB installation, watch this video:
https://www.youtube.com/watch?v=jpR6dWWiILk

With all that oil, I would definitely do the seals. When I did my 44K mile refresh, everything was bone dry, so I skipped them, as I had no idea if the car would even start. This is a TIME issue, not a $$ issue, the seals were reasonably priced. If I saw any oil, I would have done it though.

If I have do do them in the next year so be it, that's the way it goes. I'm 1K into it, and next week will pull the cover off when I do a coolant change, and double check everything to see how belt adjustment looks and to look for any oil weeping at the seals.

**In addition to the flywheel lock, get the pin tool to hold the various idlers and TB rollers/gears in place while tightening.

Welcome!

Howdo,
one more thing - in 944 world, we stick to the rule: "if you there, do everything possible".
I worked on Timing and Balance belts 4 times on my car within a 4-year period. That's because I wasn't aware of potential problems and some other problems have happened. During the third time I did all seals/gaskets except the exhaust and rear mail seal. The fourth time I had to deal with the Balance belt, because the damage (my fault).
Unfortunately, some parts are expensive.

Read and prepare before you even touch a wrench (found through a simple google search):
https://www.pelicanparts.com/techarticles/Porsche_944_Turbo/67-ENGINE-Balance_Shaft_Seals_Replacment/67-ENGINE-Balance_Shaft_Seals_Replacment.htm
https://www.clarks-garage.com/shop-manual/eng-14.htm
https://www.pelicanparts.com/techarticles/Porsche_944_Turbo/73-ENGINE-Oil_Pump_Seal_Replacement/73-ENGINE-Oil_Pump_Seal_Replacement.htm
https://www.pelicanparts.com/techarticles/Porsche_944_Turbo/60-ENGINE-Timing_Belt_Replacement/60-ENGINE-Timing_Belt_Replacement.htm
https://www.clarks-garage.com/shop-manual/eng-08.htm

Dont worry, the turbo is the same as the NA cars, and for the most part, the 16V cars as well (besides the cam seal)

Make sure you carefully create an inventory of the parts needed beforehand and order them all at once, and get the correct parts for your model year

Thanks again for the insight. This is a great forum.

For the camshaft seals, is it best to remove the cam tower as shown in the NC944er video, or is there a safe wat to do it while its on the car?

https://www.youtube.com/watch?v=0rBlCGLDSLw

Also, thoughts on the URO vs Laso waterpump?

You don't have to remove camshaft housing for the seal replacement.
Uro is good for simple parts - their electronic or precision parts may not be that good.

I'm about to do all of my front seals, just got my flywheel lock. So much appreciate this forum and how much everyone shares. If you haven't found it yet, which seems impossible if you're looking up 944s on the internet, check out Edredas youtube channel. Here's a video with some specific tricks for the timing belt I haven't seen on any other video. He also has one for the balance shafts belt. I like that he shows the procedure on an engine out of the car, and then again in the car.

https://www.youtube.com/watch?v=jpR6dWWiILk

I'm so glad to see that Edredas (his name is Brent?) is giving more thorough explanations recently.

In some of his past videos (but to be fair, not all of them)...I'd find it a bit frustrating that he basically would omit most details of a particular procedure - beginning a segment by saying something like: "Just getting ready to install the belts now," and with the very next segment would come "belts are all finished and looking great!" In other words...almost no details about the actual process.

I hope and pray that he's changing his tune as it looks here - because otherwise he seems like a great person...and someone I'd trust my car with completely if I weren't already doing all of my own wrenching. Hope to meet him someday...perhaps at an upcoming 944 Fest in Ohio.

OK-944,
Do you ever go to the swap meeting in Carlisle (Pennsylvania)?

Never been to the swap meet...hope I can get there sometime!

Also a plug for another 944 fixit U-tuber...which is NC944er. I find his videos to be very comprehensive and informative - and presented very professionally and with great clarity. His video on belt changes is slightly different than that from Edredas, plus he also mentions torque settings - which I feel are pretty essential!

if replacing the balance shaft seals, also replace the races or they will leak.

https://cpa-pca.org/events/2024/4-24/swap/index.html

Welcome to the World’s Largest Porsche-Only Swap Meet!
Swap Chairman Steve Baun

The Central PA Region of the Porsche Club of America is once again bringing its world-famous Porsche-Only Swap Meet to Carlisle Fairgrounds, Carlisle Pennsylvania, on Saturday, April 27, 2024. This is without exaggeration the largest event of its kind on the planet. It typically brings nearly 650 vendors, around 1,000 Porsches, and over 6,000 visitors from all over the world together every year. If you’re seeking an obscure Porsche or an obscure part for your Porsche, this is your best chance to find it. Every dealer and Porsche packrat in a 250-mile radius will be bringing their odds and ends for sale or swap. You’ll see exotic Porsches found nowhere this side of Stuttgart, and Porsche personalities ranging from PCA muckety-mucks to (sometimes) celebrities like Jerry Seinfeld. As always, we’ll feature a People’s Choice Concours, too!

so what did you find you really need in way of special tools? is there a certain type of belt tensioner recommended?
Im pretty ok normally with just adjusting belt tension by feel, because I'm a millwright I've had quite a bit of experience changing belts but of course I dont want an issue of a valve / piston crash..
. I may be able to borrow one when I get there, this is a tool obviously not needed often so maybe people are just buying them as needed and maybe selling them or loaning them to friends after..

the other tool to lock the flywheel i could buy but it didn't seem like it would be too hard to lock the flywheel, maybe by welding up something similar, a hunk of ring gear and a flat plate.. It seems its just being locked during installation to keep the engine on its timing mark, right?

i got the belts, some various seals the cover gasket to take the timing cover off, I might need to take stock and see what else I need. If I get stalled I'm not really up against time.. just don't want it all apart so long i loose track of stuff..Im ok with just "over the summer" as a timeline.

thought I'd flush the rad and replace hoses, so I I thought I might pull the rad first and any fans..pull the starter out for inspection and lube etc.. maybe with the rad out , I figure it'll just be easier to see, then do some cleaning. If I go back later and do the waterpump would that mean a lot of wasted time? of course draining the rad again if I fill it..

maybe I can get some of the rad flush stuff , hook it to a pump , set it in a plastic bin and let it sit there recirculating a day or two? would too long rot the rad out? the one in my volvo plugged so I tried that.. I tried vinegar too.. it didnt really help a lot.. maybe loosened it up..
with that one I unsoldered the top and bottom, it did work out well.. i cut a wood stick to fit the fins and carefully pushed it through each one , That was really what it needed.. the rad worked way better after that. I think if I did that all again I'd just unsolder either the top or bottom of it and just flush out the rest after poking out the stuff..
with the volvo one I pressure tested in a sink and went back and soldered up a few pinholes then sprayed it with epoxy to look nice, not the fins too much, it worked out.. the pressure bottle was obsolete so I made one out of copper tubing and fitted an end on it for the cap, that was ok but in the porsch there may not be extra room.. the bottle is ok but i have seen them deteriorate and blow, because they do hold some pressure, are others seeing their water reservoirs crack up?

I took the one from my ford van in to a rad shop , they did have the solder bath thing to take them apart easier, i just used a torch, they immerse the whole thing in molten solder.. anyway the rad shop just sold me an aluminum one , it worked ok.. I set the copper one aside knowing it can be cleaned if it comes to that.


The only tensioner I'm familiar with using really is the brekoflex meter.. It works by sensing the vibrations and from the vibration frequency belt tension can be determined, In most cases I'd just set the tension by feel. 1/4 turn method basically, but maybe i need more accuracy..

I assume if I recheck my work its probably not going to fall off.. I assume I can do most of this work and then worry about the adjustment just before the cover is reinstalled so maybe I don't need to spend on that thing yet?

If I do shop for one is there a personal favorite or one that is cheaper and will suffice?

I think I need a thin metric wrench, thought I can probably grind one thin enough... pin wrenches and stuff like that I'll have or can just make up.. I have all the common tools..

i tension with the twist method and then fine tune with an automotive stethoscope.

However if you haven't heard of the Arnworx tool, check it out here: https://www.*****************.com/Belt-Tensioning-Tool-p/awx-920v6.htm

Regarding hershey, you could score some nice used parts and some nice accessories. There aren't as many 944 items as there are newer Porsche models. it is still fun and there are a ton of old porsche's in the car corral and parking areas.

You can weld, therefore you can easily make a flywheel lock by yourself. That a plus.

The coolant expansion tank is relatively solid. I've never heard any complaints about it from my "944" friends.

Adredas on youtube explains well about tensioning Timing and Balance belts. A thousand-dollar tool is too much. There are cheaper versions (I don't remember the price) and really simple plastic ones, which are good for a few times.

Can't wait to be able to attend this again..... 2025 I will be back on the East Coast. FOR GOOD!

When using a stethoscope to adjust belts, I listen to the water pump housing near the pulley. Too loose and the belt flops when you gun it, too tight and it whines and wears the bearing too much. For the balance belt, listen to the adjustment pulley in the same way. I suppose the tension gauge yields the same result.

Also if you want a cheap belt tension tool, look at krikit. Buyer beware. http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/682726-belt-tension-gauge-tool-krickit-cricket.html

Lastly herre are the specialty tools I have acquired over the years. I think the wrenches and flywheel lock are from Arnworx.

http://forums.pelicanparts.com/uploa...1711193807.jpg

Something that bothers me about the Arnnworx tension setting gauge (I have version 6.1)...which is that the two "sleds" that rest on top of the t-belt get somewhat squeezed between the belt and the top of the rear plastic wp/belt/roller housing - causing the t-belt to deflect.

I'd be very curious to know if others here might have a comment on this.

At any rate...it is because of the "Arnnworx squeeze" that I ultimately rely on a "three tiered" method of "pluck, twist, and spin." Pluck, as in like a guitar string (watch Van Svenson's video for a nice description). Twist, as in...90 degrees. And spin...as in, spinning the water pump pulley by hand - with a cool engine and gripping the outer diameter of the pulley (unlike Edredas which shows gripping slightly less than this full diameter).

None of those do I trust completely by themselves...but all of them together and I'm good to go!

But again...any others have the same "issue" with their Arnnworx tool?

That is how I did mine. 90 degrees on timing belt, 120 on the balance belt. The balance belt feels almost too loose. The idlers on the timing belt on the S2 do a good job keeping the timing belt in place. Takes a couple hundred miles to settle in.

When I get the car back to VA I should be at about 1500 miles, and I am taking the car into my trusted Porsche Mechanic to go over the car and check for belt tension. After that I am not going to worry for the next 30K miles or 5 years. Yeah Yeah, I know CW says 3 years.....

At some point every Spring I'll remove both (upper and lower) wp/belt/roller covers...to re-check tension - but as much to also just get a look at things in general to see that all is well...that there is no ingress of oil or dirt from anyplace, that the rollers and wp all feel tight. I'll also watch this area while open with the engine running and gun the rpms by hand to see if anything looks amiss. Just for a bit of piece of mind I guess!

I've always thought of how nice it would be to have clear plastic/acrylic front covers to at least make the visual inspection process easier!

This is from Gates website:

91107 KRIKIT
Product # 74010071

Proper tension, installation and maintenance can extend belt life and reduce costly downtime. Gates® Krikit gauges provide a simple and quick way to measure belt tension on V or V-ribbed belts to ensure long belt life and optimal belt drive performance.

Provides a quick and easy way to check belt tension.
Not recommended for timing belts.

Got the Krikit first...then the 928 tool. Never trusted either of those.

What about that device someone here invented and 3-D printed - used in combination with a torque wrench set to a certain value...which would make its "click" at a specific degree of deflection? Hmmm...I think I might trust the "moving vane indicator" type of torque wrench for this application - and not the "clicker."

Why do we need a tool? Why can't we just press on the belt midway and observe or even measure the belts deflection?

If the belt is too loose it can jump timing or even come off.

If the belt is too tight it could break or wear out the roller bearings too quickly.

If a belt is too tight and a bearing overheats and seizes it could cause the belt to come off.

If the belt comes off or breaks the valves will be bent when they hit the pistons.

DJ,
I know these possible outcomes, but the question was about the easier method of measuring belt's tightness by its deflection under "normal" (define that!) pressure.
Let's say that someone installed TB or BB with the proper tool (assuming Porsche's) and, then, measure deflection?
Assuming that the initial installation is correct, the deflection method must give measurable and correct value.

I have done this a few times so I am far from an expert. However Clarks states the initial adjustment is a 1/4 twist of the belt. I found this to not be very accurate, the belt might be too loose and slap or to tight and the WP would whine. So I developed my own stethoscope method to fine tune it. I have not tried to verify this with the 9201 tool.

Timing Belt and Balance Shaft Belt Tensioning

Initial Tensioning on Belt Installation (1983 -1986 Model Cars Without Spring Tensioner)

Pre-tension the camshaft belt by turning the tensioning roller eccentric nut (thin 24 mm or thin 27 mm open end wrench) counter-clockwise until the belt can be twisted 90° using the thumb and forefinger. This should be checked at the midpoint between the cam sprocket and the crankshaft sprocket. Tighten the tensioning roller locknut to 45 Nm (33 ft-lbs). Apply counter-torque to the tensioning roller eccentric nut while tightening locknut to prevent altering the belt tension.

Note: Originally, this was the only method of tensioning used on 928s and 924s. I know of several shops that have never purchase Special Tool 9201 and use this method on 944s as well. However, it is very risky and I strongly recommend checking the belt with the factory tensioning gage.

often what I will see in machine adjustment manuals is a reference to a fish scale deflection. You just attach a spring loaded fish scale to a predefined position, like mid-way of the longest track where there is no pulley.. or similar..

that way a value ( pounds or KG) of pull, can deflect the belt , for example, "1/2" deflection with a 30 pound pull midspan of the belt"

It may not be the ideal or most exact method but this method is often a written way to express tension to machinery technicians. The 1/4 turn or 1/2 turn method, or "thwapping" the belt with your finger, or the stethoscope method can be used additionally but these methods are more open to a particular person's individual feel and interpretation, than by way of reading a fish scale. - because the fish scale although perhaps not as accurate, is numerically quantifiable.

I have a little electronic scale used to check the weight of bags prior to arrival at an airport, that might work perfectly for this.. Likely lots here own one of those..

I was thinking one might use a proper factory gauge to obtain a fish scale deflection value, ( or have it done by a shop)

- Then upon rechecking they could at least have an actual measurement and perhaps less guesswork. maybe that method could be a way of rechecking and keeping an eye on things.

How about a WARNING INDICATOR?
I got to thinking it might be possible to create a microswitch that would activate should the belt come a bit too lose, maybe it could set off a light or buzzer to alarm the driver.

It could be set to activate a simple "holding circuit" with the warning so that in the event it gets triggered, that it needs to be reset ( and presumably examined) to get the light out.

My idea here is that it would only come on in the even the belt was loose enough to whip against and trigger the microswitch.
Not sure if there is room in there but a microswitch isn't too large.. I'm just thinking out loud basically.. but maybe it makes sense as a bit of added insurance.

Do others here think a fish scale can be used to quantify tension? Or would this be impractical due to obstacles such as the cover?

I'm not making the argument that proper tools are not necessary or that the fish scale is accurate, but maybe it's an additional reference that can be used for the purpose of monitoring belt tension at intervals. Pulling the cover periodically makes sense .

thanks to others for all this great info. I hadn't heard of the stethoscope method but do own one, so that helps.. I was not aware that the seals for the balancer were directional and that sounds like an easy detail for the unwary to miss.

tension indicator with a warning lamp is possible if your car has a tensioner - less tension, more tensioner "arm" deflection, switch is triggered. but..
there's always a "but".... upon deceleration, TB's tension would drop, right? Switch may only work with stable rpm's, like an idle.
switch detecting a wobble won't work well. My TB was replaced, and idle roller was incorrect (the one between camshaft sprocket and upper balance shaft). The stretch of TB between camshaft and crank pulley was wobbling.
After installing a correct idler (46mm or so), the wobble disappeared, and "moved" to the area below camshaft and WP.
You can't fit fish scale in the belts' area and the scales may not be precise.

Folks you are a wealth of knowledge, I would like to tap into. My car is an 1986NA. My car is in need of belts and the front seals replaced. I have quite a bit of oil leaking. Also, is it possible to have the balance shaft 180 degree off? Without taking everything apart. How do I know which water pump roller I have. Pelican parts list different 2 kits, defined by 32mm or 46mm. My goal is to do the belts, water pump, and all the necessary seals.

old water pumps are "equipped" with smaller, 32mm roller (situated between cam sprocket and upper balance sprocket), the newer (updated?) water pumps are designed for a larger roller (46mm).
I also didn't know about this, and installed new WP with old roller. Later, I noticed that this roller "doesn't do nothing" and TB (timing belt) wobbles.
When I installed a proper 46mm roller, the wobble "transferred" to the other span of TB - below cam sprocket (left side, if you look at the engine from the front).
you can measure the diameter of that roller. Either way, the correct roller should touch the TB.
Yes, you could have balance shafts installed 180 opposite.
watch this video - THE BEST VIDEO FOR BALANCE BELT REPLACEMENT on YT.
I had to touch TB and BB 4 times because I didn't think about front end seals at all and some other mistakes on my end.
After vigorous cleaning, the front was still oily and only then I decided to replace all seals/gaskets (front end, oil/cooland radiator, intake, oil tube, camshaft housing, fuel injectors). I also installed wrong seal on camshaft and it leaked, which drove me mad.