Timing belt happiness

SolReaver · 09:53 PM

Hey Guys!

Just did the timing belts on "Blinky" and wanted to share a few things.

First, I did not remove the crankshaft pulley. Clarks does suggest that you do. I found it a snap to snake the new belt in. Soak the new belt in warm soapy water for a few minutes and work it around the pulley counterclockwise. If you are careful, there is no danger to the belt.

Second, The gods must have been smiling down upon me for I had no leaking seals and all the tensioners and rollers were perfect. Honestly, they spun as smooth as glass. The Water pump had no leakage or seepage. IOW, I replaced nothing but the belts! What a concept! All of the equipment in there has been deemed to be good to go for another 3 years or 30K, whichever comes first. At the next change out, I will get everything, but some generous PO or mechanic with the initials VH seems to have replaced everything in December 2000 as per the engraving on the inside of the timing cover.

The belts themselves were loosey goosey and the lower balance shaft was off a tooth. I don't know if this was due to a skip or an alignment on "VH"'s part, but, since he was kind enough to buy a new WP 8 years ago, I am going to give him the benefit of the doubt and say it skipped. Just for giggles, I tensioned up the old belts and gave em a feel. They were not bad for over 8 years old but a little stiff. I suspect this car hasn't actually put on a lot of miles in those years. Anyhow, 8 years as we all know is wayyy tooo long, So off like a prom dress!

Clarks suggested that the tensioner be removed. I have a spring tensioner setup. However, My spring tensioner isn't like the one described in Clarks, with 3 bolts and a spring that mounts to an integral bracket. No, mine is held in with 2 bolts (tension and set) and the spring is held to the tensioner with a banjo bolt looking plunger at the tensioner end and a donut shaped metal bracket on the case. If you have one of these DO NOT REMOVE IT! Aside from taking a bit of skin off my knuckle, It was a major pain in the ass to get back in. Fishing the belt around the installed tensioner was again, a snap. (same method) (rinse with water to remove soap)

Anyhow, If you folks come across such a cam belt tensioner while doing a belt job, don't take it out to do the job, I wasted almost an entire day futzing with that POS and snaking the belt is not really a hassle. Also, don't remove the crank pulley unless you need to get in there for the seal or something. Clarks is a wonderful resource, but, in this instance I must respectfully dissent with the methods advocated.

The marks lined up beauty! I cleaned it all before hand and painted the front of the cam and balance shafts with festive bright paint lines to make it all easier. Tensioner you ask? No, none. The spring tensioner did it's job nicely after it was cleaned and rebuilt and I used the twist method and feel on the balance belt. Remove the lock, turn the engine around a few times and check it all again, Perfect! and the tension and timing are still right on.

OK, now I am sure there are some in the audience who advocate that everything be replaced and that I am doing this all wrong. Fine, this IS America and we are all entitled to our own opinions. However...IF you really feel that way...Is anyone willing to bet a beer on it? Ha ha, No, Seriously, I am betting Thousands of dollars of critical Porsche components against a catastrophic failure, What are YOU willing to put up? Mind you it is a 3 year or 30K bet, but if you see me posting "WTB rebuilt head", then you can probably guess what happened. In any event, the car is MUCH better off with the new belts.

dangerous · dangerous's Garage

Although this thread doesn't seem to be asking for any comments, I'll just add one for the benefit of those who read it and have not done many of these. New tensioners and rollers do not "spin like glass"....worn ones do though.

I'd be a liar if I said I don't re-use worn rollers at times. When you ge the chance, spin a new roller and see how it feels. It will give you an idea of what the "ideal"condition is and better enable you to judge the condition of used rollers.

Gordon Rankin · 09-09-2008, 09:57 PM

Sol
I am going to replace my belts in a couple of months when its cooler. Can we get together then?
I will need some coaching and I can provide some adult beverage and food.

Arizona_928 · 09-09-2008, 10:06 PM

wow how long did it take for you to write your post?

SolReaver · 09-10-2008, 06:48 AM

Kid: About Ten minutes. I am a very good typist and it was a "stream of thought" kind of thing.

Gordon: I may be temporarily re-locating to Houston again because of a job situation, but I bounce back and forth between here (LB) and Houston, yea, we can have a party. Just understand that sometimes I work a little slow and deliberate. It took me an hour to be Absolutely sure that the crank was right there. I label all parts with tape and clean everything. My mechanic style has been described as "where ADD and OCD meet"

Dangerous: My main aim was to guide fellow travelers down a better path. Again, although I value Clarks opinion and guidance, In this case It was in error and I am hoping that sometime in the future a person searching : Tensioner : Spring : removal , or whatever will see my post and not go down the same bad path of removing that nasty little grubber. Or in the alternative, get the special tool to deal with the situation Before doing the job. Lastly, I was advocating freedom of choice in the method used and the parts to be replaced. IF it ani't broke, Don't fix it! Scrap that tool, use your thumb!

dangerous · dangerous's Garage

Quote:

Originally Posted by SolReaver

Kid: About Ten minutes. I am a very good typist and it was a "stream of thought" kind of thing.

Gordon: I may be temporarily re-locating to Houston again because of a job situation, but I bounce back and forth between here (LB) and Houston, yea, we can have a party. Just understand that sometimes I work a little slow and deliberate. It took me an hour to be Absolutely sure that the crank was right there. I label all parts with tape and clean everything. My mechanic style has been described as "where ADD and OCD meet"

Dangerous: My main aim was to guide fellow travelers down a better path. Again, although I value Clarks opinion and guidance, In this case It was in error and I am hoping that sometime in the future a person searching : Tensioner : Spring : removal , or whatever will see my post and not go down the same bad path of removing that nasty little grubber. Or in the alternative, get the special tool to deal with the situation Before doing the job. Lastly, I was advocating freedom of choice in the method used and the parts to be replaced. IF it ani't broke, Don't fix it! Scrap that tool, use your thumb!

Hey I Hear ya
I share your philosophy
(although there's validity in preventive maintenance at times as well)

not a critique of your thread
just adding some info
your thread is informative and very helpful....very thorough too

Sometimes we just have to keep in mind that some of the readers here might misinterpret a "judgement call." If you or I (or the reader) has a pretty good idea of what a servicable roller feels like, they can make that call with confidance. If they have no idea, and are looking for some info about what to look for when determining whether or not to replace their roller, it can be helpful when additional input is provided.

That's why this forum is so successful. In the end, everyone is free to use the info as they desire.

SolReaver · 08:46 AM

Dangerous: I concur wholeheartedly. To someone not experienced with doing the job the decision to re use rollers can be a tough one and not to be taken lightly. These looked and felt good even with a little load. Also, I am fully expecting to go back in there or at least remove the upper cover to re check everything fairly soon. (remember the OCD thing) as belts stretch. I am thinking a few months or a few thousand miles. With the components cleaned I will be able to detect even the slightest weeping or seeping of the precious seals behind the pulleys and shafts.

A Professional mechanic will, correctly, advocate the replacement of everything as the vehicle then leaves his shop and he has no control over what happens. In order to protect against come backs he (or she) will replace everything to ensure that a component doesn't fail. My situation differs in that, I will be keeping a close eye on things because I am paranoid about a catastrophic fail and also I am plainly too cheap to pay for a new head.

If, someone wanted a "fix and forget" solution...well, off comes all the pulleys, in go all new seals, and of course a brand new WP should get installed.

Funny thing, the balance shaft Idler pulley (again in good shape) doesn't seem to do all that much in my configuration. The belt seems to skate or just lightly graze it even in the highest adjustment position. I think this is just to keep the belt from slapping inward and possibly deflecting under the upper balance shaft or other components. This is a question where I really don't know why it is there but figure since some german engineer put it there I better just go along.

Upon the subject of belt tension feel I wanted to add that playing the bass seems to help develop the feel and a good belt feels a bit like the solid "plung" of an open E, or maybe an A. In any event, it feels a bit like tuning a bass by ear IMHO and the twist you use is just enough force that it is easy to get the first 1/4 turn, gets harder to do about 3/8, and pretty much refuses to get all the way to 1/2 unless you really tweak it. It is hard to describe in words. Oh, and old belts like old strings still sound, but sound less "bright" due to a loss of elasticity. the old belts did not "sound good" the new belts sounded strong and bright.

Rasta Monsta · Rasta Monsta's Garage

Quote:

Originally Posted by SolReaver

Oh, and old belts like old strings still sound, but sound less "bright" due to a loss of elasticity. the old belts did not "sound good" the new belts sounded strong and bright.

OK, you are hilarious. Great job!

SolReaver · 09-10-2008, 10:42 PM

Ok, I started the car and it had just the smallest whine from the balance belt. So, to be perfectly honest, It was a little tight. I backed it off just a hair (blondie) and drove it around for about 50 miles today. Happy, Happy, Joy, Joy.

nynor · 09-11-2008, 09:47 AM

worn out rollers will spin like a metal roller skate wheel. just my .02 per threads above.

congrats on doing your own belts. its not that bad and you feel good about it afterwards.

kosh · 09-11-2008, 10:19 AM

all im gonna say is that i would never enjoy driving the car again..id be listening for rollers goin and always wondering if something might happen if ya pushed the car or drove her hard.

If ya replace the lot i think the extra money means u payed for all new gear and more importantly.....peace of mind.

Kosh

IM getting the whole lot done by mechanic next tuesday which is why i commented on this post.

SolReaver · 11:59 PM

Kosh: I understand the reasoning and logic behind your words and acknowledge that for you that is a good course.

I on the other hand will never let a monkey touch my car (aside from Trans rebuild and A/C service) Most of my problems have come from botched and bumbled jobs that work just long enough for the car to roll out of the shop.

I AM a mechanic, or , well... I was one for many years, just not on Poorsches and I can tell you hours of horror stories of picking up after bad mechanics. If you have a good one you can trust treat him well and be thankful.

Anyhow, My point is that FOR ME, the stress would be in NOT knowing, not actually seeing and checking the parts myself and installing them with care and precision. Besides, I have seen my share of factory pooched parts that are bad right out of the box so although you may think freshies all around will keep the gremlins at bay, It is really the skill of the mechanic. If he says it's got to go, then it's got to go. However, this endemic and superstitious belief that money will actually buy you security is just ludicrious. Security comes from Checking the components on a regular basis and making the call.

Besides, the wear on components other than the belts is mainly due to use, not time. This Car had EVERYTHING done in December of 2000 and very low mileage since then. The Belts on the other hand, are TIME dependant. They get weaker or "wear" just sitting there. When you get all freshies installed, Won't you want all of your mileage out of them? 3 years from now will you do it all over again and blow hundreds of dollars to replace parts that are designed to last 80 to 90K? How about if you only drove the car 5K in those 3 years?

Just for giggles, can I have the old Idlers and tensioners? I will be fabricating wrenches soon and I want something I can test fit them on. I would use my own, but, well.. they are in the car right now.

As for pushing the car....ha ha...Done and done again. I didn't want to push her Until I had the belts done, fresh oil, and a strong clutch. All testing was done in a responsible fashion, on a closed course. The real test is that of time.

Oh, I take back what I said about the balance shaft Idler pulley. It does something. When retensioning the belt to get rid of the whine I noticed that it can have a very fine effect on the tension. The belt was just skating on the surface when I retensioned and that change in angle put pressure on the idler so that the belt was riding upon it. This gave the belt just a hair more tension than I wanted, hence the whine, I backed the idler off to skating mode again and perfect! So, when you tension the balance belts set the tensioner and then check the idler.

As I am not an expert at doing this, could someone chime in as to whether or not the idler needs to "load" the belt or whether the belt should just "skate" or skim along the idler. Hey Kosh, ask your mechanic when you drop the car off, he will know.

rickharrison · 09-12-2008, 06:01 AM

IIRC the idler lets the belt skate along it, thus avoid it slapping around when it stretches.

I agree with you too...no tensioning tools here either...twist method works fine.

When you said "they spin like glass" I think some read it as not so smoothly...I know what you meant.

If you want something done right...do it yourself I always say.

SolReaver · 09-12-2008, 07:19 AM

Just a clarification here, "smooth as glass" was meant to mean that they spun freely. There was, of course a little roller noise and feel as they are roller bearings (duh). Evaluation came after I removed and thoroughly cleaned them. Previously the surface grit on the Bal idler made it sound bad. After a clean up It was good to go. To test the bearing I have a strip of rubber that I lay on a strong flat bench. with a dowel in the center I press down on the strip and run along it with the bearing. Any crunchyness or looseness is grounds for rejection. The selection process is ruthless and unforgiving.

Anyone with a better method for testing these critters pipe up.

Has anyone else wondered why a standard bearing in a thin shell with a wacky center hub costs $40.00??? What is the mark up on these beauties?

Gordon Rankin · 07:42 AM

Sol,
Is there anything different in my '83 as opposed to your '87 in terms of tensioner, belts, rollers?

And is there a way of modifying an '83 engine so that it has the more "automatic" tensioners of the later models?

( I understand that the 2.7 and 3.0 engines have self tensioning components and dont need the tensioning tool that our cars should use?)

SolReaver · 09:11 AM

Per Clarks, you have an eccentric tensioner. yes it is different, you tension your cam belt with a 27 mm special wrench and I tensioned mine by releasing the lock bolt on the tensioner. (OK, I had to prep the tensioner by cleaning it and working it around a bit) I actuall prefer your setup as it is more straight forward and kinda "Old School". the design is cleaner and the belt is easy to get around it. The only downside is that if that stud goes, you are totally F'ed up, So be nice to the stud and clean and inspect it well. Also, THAT little tensioner pulley is soooo crucial that I would replace it even if it was in perfect shape. Some people advocate replacing the stud as well. I find that brings about as many problems as it solves.

As to a different setup on an 83? Hmmm. That IS a tough one. First of all I don't know what to call my kind of tensioner as it is not depicted in Clarks and secondly I am pretty sure the block details are different for an 83. I am fairly certain you don't have the circular flange that the spring rests against. I am clueless as to whether or not there are even bolt holes in your block to mount the thing.

Offhand, I would say, probably not without more difficulty than it is worth. Although a spring tensioner delivers approximately the right tension when it is released. It is locked down after the tensioning process and does nothing until the next time it comes to tensioning the belts. Also, the spring tensioner is not a panacea for tensioning woes as the tensioners can be innacurate in themselves and I have yet to see a reliable method to calibrate them.

The eccentric tensioner doesn't give you any idea at all as to how far to set the belt, however, It is a pretty elegant "no frills" solution and to be honest with you, the belt does not know the difference between tensionings.

The best solution would be an auto tensioning setup like hydraulic. IF you were to go through that sort of aggrivation, I would humbly suggest researching the latest technology and determining just what tension you want to apply with a force diagram or something along those lines.

Caveat: If you don't have to go in there, chances are you won't. If you have the perfect auto tensioning setup, you will still need to go in there to replace the belts at regular intervals. Therefore, all that work will essentially be to make sure your belts are at all times tensioned correctly. The same result can be achieved by going in there at regular intervals and you have the benefit of being able to inspect what is going on under there.

Like thousands of owners before you, you figure there has to be a beter way. The truth is these cars take a lot of maintinace and going under the timing covers on a regular basis is just part of it. I would love it if my 924 has a timing setup as beefy as my honda's 80 to 100K belt setup, or the Timing chain on my Saturn that has 160K on it and is going strong.

The problem is (IMHO) you have the space for 1 belt, and you have 2 belts in there. Hence they are thin and less durable. Any re-engineered solution is going to have to deal with the space limitation and that is not an easy thing.

I have thought about 1 big serpentine monster that touches all of the sweet spots, but that would increase the size of the front cover to obscene proportions and require a relocaton of the waterpump (to where?) Any chain solution would require even more lubrication and more seals to leak oil (just what these cars need right?)

Nah, we are stuck with the cards that the Porsche engineers gave us over 20 years ago. Get used to going under the covers, get yourself some good special tools, and just do what needs to be done.

And Just in case you thought that you've heard and seen it all on this subject....In a few months I may reveal a new way to tension belts.

moorepower · 09-12-2008, 10:59 AM

Sol, great write-up, and I agree with you that the rollers are good for two belt change cycles. I think alot of people alternate between changing rollers at one belt change, then water pump at the next, and then rollers, and so on. I've only done mine once, and since the previous owner did everything at the last change, all I did was the belts as well.

The only issue I have is with your tensioner. I think you do have the same spring tensioner as Clark's describes. The two bolts on the face of the tensioner are only used to release and lock the spring. There are three mounting bolts hidden deeper behind it. You have to feel around back there. Once you find the bolts, it only takes a minute to remove it, and it makes routing the belt alot easier. But I also agree with you that removing the crank pulley is not necessary. It's easy to feed the belt behind it, and it is a royal PITA to get the bolt out of the crank.

moorepower · 09-12-2008, 11:03 AM

Oh, I forgot to mention, the factory manual says to adjust the balance belt idler to within .005" of the belt once the belt has been tensioned. There's some fancy factory tool you can use for this, but a feeler gauge works just as well.

nynor · 09-12-2008, 11:15 AM

when you say they spun freely, are you saying that they would spin? as in you could flick them over and they would continue spinning? also, you said you could feel the bearings when you were rotating them. could you elaborate?

aj951 · 09-12-2008, 11:39 AM

Quote:

Originally Posted by moorepower

Oh, I forgot to mention, the factory manual says to adjust the balance belt idler to within .005" of the belt once the belt has been tensioned. There's some fancy factory tool you can use for this, but a feeler gauge works just as well.

The manual states 0.5mm which is approx. .020".

A.J.