Just did timing belt for first time

[Brozoar]

I'm gonna open up a can of worms here. Ready?

[*click*] [*HISSSS*]

What about the studs for the tensioner rollers? Doesn't Clark have a great story about how his sheered off and threw his timing? I've never replaced those, but that's pretty scary stuff.

I like how we're all just looking to John for answers on everything.

[John_AZ]

Rainy, lazy day in AZ...

should I replace teh tensioner stud? - Rennlist Discussion Forums

[Slam]

I thought that's what John was here for...

Ah, timstar. He's famous in the 924 world, and I'll spare you the details.

You know, I think there's a cult of timing belt fear with the 944, and I used to be a member. But after living with these cars for so long now I take a much more relaxed approach. I'll give the belts a twist, give the water pump a yank, and if I'm not happy then tweak things a little. I do use the krikit and discovered a couple of weeks ago it measured bang on 40lbs when I checked my wife's 87 TB after install - neat test, as she's got the spring tensioner. I sleep fine.

[nightheart]

Since I started this thread, I'll chime in about the tensioner stub. I didn't replace it this go round, probably try at the next belt change when I'm planning on doing the WP and rollers. I emailed Ian a few months ago about the different size studs and here was his reply:

Good morning
Thanks for the e mail

The studs are ALL the same length for the years that they were used
And on the really early ones a spacer was used

You can see the spacer in this link to the oil pump[

944online.com - Find Parts For Your Porsche 944 And Get Your Car Back On The Road.

Let me know

Ian


I haven't verified this info, and from what I've read online, I think he's mistaken.

[dangerous]

+1
The whole subject can be a bit intimidating but in reality it causes more sleepless nights than it should. I've only used twist and kricket, and I know a few pro p-car mechs back in the fatherland who only twist. never had a belt slip or break on my car but I've repaired cars that have. Worst case, Bent valves is not the end of the world and I've seen cars get back on the road for less $ than you'd think (8v that is).

I thought that's what John was here for...



Ah, timstar. He's famous in the 924 world, and I'll spare you the details.



You know, I think there's a cult of timing belt fear with the 944, and I used to be a member. But after living with these cars for so long now I take a much more relaxed approach. I'll give the belts a twist, give the water pump a yank, and if I'm not happy then tweak things a little. I do use the krikit and discovered a couple of weeks ago it measured bang on 40lbs when I checked my wife's 87 TB after install - neat test, as she's got the spring tensioner. I sleep fine.

[mytrplseven]

The first time around is a bit daunting. Three tools will make it a snap: Flywheel lock, 27mm open-ended wrench tool to hold the tensioners while they're being tightened and either a tool with two little points on it to hold the balance shaft sprockets or (like I do) long needle-nose pliers with a 90 degree bend at the ends. After you've done it and get familiar where your hands go, it's easy. Also, don't 100% trust the spring-loaded tensioner. After you let it fall into place, check the water pump for slight slippage when trying to turn it by hand. Also, both belts will settle in and tension should be rechecked around 1500 miles. Good luck.

[lake_harley]

Originally Posted by John_AZ

First tension per Porsche approved method or any method or tool you have and feel comfortable with.

Porsche updated the procedure for the "machanical spring tensioner" on the late cars:



Then use the Water Pump Pully Test




I retension the cam belt after 500 miles. This gives the belt time to "fit" in the pulley cogs and initial stretch.

I change the $12 cam belt every 2 or 3 years or sooner if any coolant or oil fluid gets on the belt.

John

I'm a noob here, and a noob to my 1985 944. It was my son's car and I ended up with it when it developed it's latest problem, a leaking cam assembly gasket. He's a typical broke college student and I always wanted a 944 since 1985 when I almost bought a new one. He decided he maybe needed something different so we got him lined up with another car. So much for background....on to my first question......

I read and re-read the Haynes manual on R/R-ing the cam assembly to replace the leaking gasket. On returning the cam belt tension to where it was/is, they suggested a method of finding a drill bit that fits between the water pump pulley and the cam belt tensioner pulley to return it to it's previous tension. Seems reasonable so I found a good fitting dril bit as a "feeler" (21/64") In searching for additional info on this forum, to make sure I wasn't about to make a grave mistake, I came across the suggestion to check for proper tension using the above "water pump pulley turning by hand" method. I guess this is for a 944 of the vintage I have? Giving the belt the "twist" method also seems reasonable, but where along the belt's length (between which pulleys?) is this done and how many degrees of twist is proper? (I think Ducati motorcycle mechanics use a twist method on Ducati timing belts at times). The belts (timing and balancer) as well as water pumps and assorted parts were replaced in the last 1,000-2,000 miles, so the belts should be good to go, and have probably had enough use to "seat in" a bit.

I'm not a stranger to working on cars, but this is my first experience with this car and would rather not make any noobie (read that expensive) mistakes. Hanes made no mention of setting belt tension at TDC, but is that the proper way to do it?

Thanks, in advance for any help.

Lynn

[John_AZ]

Thanks for not making the "grave mistake"

The early 944s up to 1985/1 do not have the mechanical spring tensioner.
The late 944s from 1985/2 have the mechanical spring tensioner.
Do you have the early or late 1985 944?

Clark's Garage Home Page is the site you want to visit.

Here is the section on the cam belt tensioning.

Timing Belt and Balance Shaft Belt Tensioning

If you do not have the tension correct you will bend valves--the 944 is an "interference engine"--the valves will hit the piston if cam belt tension is not correct.

Gl
John

[lake_harley]

WOW! That was a fast response! Thanks.

If I read the tensioning link info correctly the P9201 Porsche tension checking tool MUST be used? I hope that's not the case since the nearest Porsche dealer is 1.5 Hr. away. Or, is there another acceptable method? (ie; the "water pump pulley" method)

Oh, almost forgot to mention that my car has the "eccentric" adjuster. I'm not sure if it's a early or late '85. I'll have to refresh myself on the differences. My son know, but was unable to reach him this evening (his 22nd birthday today)

Lynn

[Volhv]

The eccentric tensioner was used until 86.
87 and later got the spring loaded one..... same time they got the different offset.
I like to to think of the 85.5 and 86 as a transition between late and early, since they share traits from both.

[lake_harley]

I did a little searching on Google and through that I believe my car is a early '85

The 10th through 13th characters in the VIN are FN47. The site I saw suggested that FN47 was early '85, and FN45 was late '85.

Also, the site had info that suggested my car is a early '85 since; my car's fuse panel is under the dash (, where I can hardly get to it), the antenna is on the left front fender rather than imbedded in the windshield, and the steering wheel is so low I can hardly get my right leg under it getting in. Are these legitimate differences...particularly the last three?

Lynn

[Gawernator]

Yep, you have an early model. Biggest giveaway is simply the dash and A/C controls. The later model has a completely redesigned interior. Also, if your tachometer starts at 0 RPMs facing the wrong way, you have an early model

[944sracer]

I have done my own TB and BB replacements on both my DD n/a and the 951S race car. We have the "special" Porsche tool that the FSM refers to. It has been the best $500 ever spent - Average cost to do the belts is about $300 in labor so payback is within 2 changes. Our replacement method is as follows:

For any car that is new to us gets the belts and rollers replaced ASAP.

For DD cars they get both belts and rollers removed and spin tested every 30k. WP gets replaced every 60k. No need for flywheel lock. we did modify a 1-1/16" Combo wrench to hold the eccentric tensioners in place.

Race cars get them every 3 years no matter how many track days. lately it has been a few a year .
Same story with water pump replace.

The cars are late model with the auto-tensioner and we follow the earlier posted FSM method.

No offense to the others on this forum but the WP pulley method sund like a backyard special. It has been awhile since I have looked into early cars but I believe you can update the water pump housing to hold the auto-tensioner. Well worth the research and updating brain pain IMO. The "special" Porsche tool is used for the BB only.

While you have the belts off look for coolant leaking out of the WP weep hole, leaky front seals, the distributor cap and rotors are known to fail so look for carbon build-up.

Overall, if you are going to be working on your car alot I would invest in a set of FSM. My experience has been that if you follow the FSM guidelines you will have very little problems with these cars. I HATE the "tighten until *snug*" method. Think of the anal retentive german engineer who designed these cars. Using the terms "feel", "snug", and "tight" is Verbotten!

Just another garage junkies mindless rantings

[ckelly78z]

The easiest way to tell an early car from a late car is the dashboard. The late car is more ergonomic with an oval gauge pod that is about 3 ft wide with a cubby hole under the stereo, while the early cars have 3 large (yellow) gauges in a squared off pod about 1.5 ft wide and no cubby hole storage area.

I will probably pick up another 83 944 this weekend and plan on towing it the 3 hours home on my car dolly to prevent and timing belt surprises as the seller admits that it is time for replacement.

[lake_harley]

944sracer....I'm guessing that FSM=Factory Service Manual?

On the water pump, seals, etc. you suggest checking, these were replaced recently, at the same time as the belts were done. The water pump had gone out and I had the shop check and replace as needed while it was all apart. I just wish now, that the oil leak had been enough to notice at the same time.

On the oil leak subject, the leak is/was at the rear of the cam assembly, just above the rear cylinder exhaust port. It's been a few months since I got the car with this problem and did some research, but if I recall correctly there's a pressurized oil passage that feeds the cam assembly in that area, correct?

Thanks for the feedback and advice.

Lynn

[Gawernator]

On the WSM/FSM (workshop manuals) a quick google search for the PDF's will save you a nice chunk of change

[John_AZ]

Originally Posted by 944sracer

I have done my own TB and BB replacements on both my DD n/a and the 951S race car. We have the "special" Porsche tool that the FSM refers to. It has been the best $500 ever spent - Average cost to do the belts is about $300 in labor so payback is within 2 changes. Our replacement method is as follows:

For any car that is new to us gets the belts and rollers replaced ASAP.

For DD cars they get both belts and rollers removed and spin tested every 30k. WP gets replaced every 60k. No need for flywheel lock. we did modify a 1-1/16" Combo wrench to hold the eccentric tensioners in place.

Race cars get them every 3 years no matter how many track days. lately it has been a few a year .
Same story with water pump replace.

The cars are late model with the auto-tensioner and we follow the earlier posted FSM method.

No offense to the others on this forum but the WP pulley method sund like a backyard special. It has been awhile since I have looked into early cars but I believe you can update the water pump housing to hold the auto-tensioner. Well worth the research and updating brain pain IMO. The "special" Porsche tool is used for the BB only.

While you have the belts off look for coolant leaking out of the WP weep hole, leaky front seals, the distributor cap and rotors are known to fail so look for carbon build-up.

Overall, if you are going to be working on your car alot I would invest in a set of FSM. My experience has been that if you follow the FSM guidelines you will have very little problems with these cars. I HATE the "tighten until *snug*" method. Think of the anal retentive german engineer who designed these cars. Using the terms "feel", "snug", and "tight" is Verbotten!

Just another garage junkies mindless rantings

Hi Blake,

Good info.

A little confusing but it may be due to sucking exhaust on the track with your spec car.

(quote) "The "special" Porsche tool is used for the BB only"
If you buy a $500 Porsche P9201 belt tension tool, the cam belt is the most important.

Also the "mechanical auto (spring) tensioner" cannot be added to the early cars or an updated water pump.

John

[944sracer]

John,

You are correct about the P9201 tool being most important for the cam belt. I only have late cars so we only use it for the balance shaft belt.

Sorry about the confusing ranting lol it always sounds better in my head

Lake,

There is a known oil leak issue on the back of the cam tower. The OEM seal is a cork gasket that tends to leak from expansion and contraction over time. Lindsey Racing sells a different seal that claims to fix this issue. I have not tried it yet but it is on my list. Those dang cork gaskets are a constant pain so I think it would be worth the extra $$ to try the lindsey one.

Link - REAR COVER PLATE GASKET 944 / 951 / 928 16v (#3 / 12) at LINDSEY RACING - Your Porsche Performance Parts Center

[lake_harley]

944sracer....Just yesterday evening I became aware of the fragile cork rear cover gasket. I hadn't picked up on it's presence from the Haynes manual. Dumb noob mistake! I had looked for the source of the oil leak using a mirror and was sure it was coming from the rear of the cam assembly, but now I wonder if it wasn't maybe just the rear cover, since it's so nearby to where I was seeing oil. It's just spilled milk at this point though, since the cam assembly is already removed for a gasket replacement. I'll be sure to replace the rear gasket though at the same time, and will look into the "improved" non-cork gasket.

Thanks!

Lynn

[John_AZ]

Rear cam cork gasket DIY.

A plug for member massive aka 944foot 2 the floor.
944 Foot To The Floor: Porsche 944 Camshaft Gasket Replacement Procedure

(and he used my cam housing picture with the cactus )

His entire DIY site:
944 Foot To The Floor: Tutorials

GL
John