henreezy

Hey all, I bought my new to me 944 a couple months back and based on the PO's response, the belts hadnt been done during the time he owned it (2020- June 2024), and had no info on the PO before him. Based on the advice of some forum legends, Peanut and Chalt, I tried tackling the erratic idle issue I had before addressing the belts. I fixed the idle issue for the most part and had no timetable to do the belts, but it appears maybe the Porsche gods are giving me a sign.
Belt Concern
When i inspected my belt through the little peephole it was off of the camshaft sprocket .5-1 cm. Off towards the engine (Kicking myself for not taking a picture)
Feeling Lucky, I started it and it ran alright, idled high (1400RPM, but i know i have a bad TPS installed.) the start really shook the car around.
I drove it home from work (around a mile) and inspected it again and it was flush with the sprocket but is it? Is it at all normal for the belts to walk like that? (First Image) In that pic it almost looks like the belt is propped on something or torsioned/stretched in the back? Hopefully the image quality transfers, but I got the cover off and peeked at the belt and it looked fine (curious to know what others think) In the Second Pic i have the cover off and tried getting a picture of the top of the Timing Belt. The Third picture is the balance belt and there is a slightly worn groove that i dont know how to feel about. Let me know any opinions! thanks!

Forum On Erratic Idle Issue with List of Installs at end:
https://rennlist.com/forums/924-931-...​​

VilleJKL

To my eyes that belt doesn't look ok. The backside looks streched or just worn out. Maybe the timing belt is overtensioned or maybe waterpump or idler is on its way out.

mazdaverx7

I don't like the line in the balance shaft belt to start. I'd have to look at my timing belt to compare with the cog spacing on the last picture. However, my rule of thumb is that if I suspect an issue with the belts, I'm going to replace them. They're cheap enough and not terribly difficult to replace. They can lead you down a rabbit hole of maintenance if you do the balance shaft seals, keys, front oil pump seal, water pump, etc. If those components are good or recently replaced, when in doubt, just replace the timing belt and balance shaft belt. Replacing them is honestly cheap insurance.

henreezy

Thanks VilleJKL and mazdave, yeah i was tempted to put it all back together, but this may be the only warning sign i get. Got a Belt and Roller kit off of pelican. I know theres a lot of resources and ill try to utilize them to the best of my ability. I hear some say its an easy job they could do in a day, and some say its multiple week ordeal. I'm a little nervous as this is my first car and have never worked on an interference engine like this before. My Porsche dealer in Nowhere Indiana most likely is not capable of this but i will call them to see if they can tension it later on.

I have a URO waterpump with the turbo outlet valve so i'll need to get a block off plate. I'd be curious to know if anyones had that pump (heard conflicting things about URO).
Thanks for all feedback

Mark Bogle

walfreyydo

If you firmly understand the basics of how engines operate, and understand how to correctly set the engine to TDC, you shouldnt have any problems. Secondly, when you do get the job finished, turn the engine over by hand a few revolutions to be absolutely sure everything is lined up correctly and turns without any obstruction. Rotate the engine a few times and recheck the cam and crank TDC marks - if they still line up you are good. This will go a long way for peace of mind when you do go to start it up and also serves as a safety double check on your work.

There are a ton of existing resources on how to do this job, from Clarks to Pelican to the FSM and youtube videos and forum posts. 90% of the work is studying and preparation, understanding the process from start to finish fully (including the underlying principals of how engine timing works and how to find and verify TDC) and having the right tools (such as a flywheel lock).

I cant emphasize enough how important it is to do your research before picking up a wrench. Seek the authority sources of information yourself and cross check various sources for consistency so you can ensure you have the correct information (as we should do with all information not just car related by the way).

henreezy

Thanks for the reply walfreyydo. I am studying for this belt job like its surgery. thats good advice about TDC and turning it first before starting. Noted.
Man, I completely forgot about the flywheel lock. good looks

Ill be using a cheap amazon spanner as a cheap alternative to the balance shaft locking bar. If thats a bad idea please let me know
Also bought a cricket tension tester to get a ballpark on the belts before finding a pro

I will definitely have rennlist and Clark's favorited on my hotbar, and found some good vids by edredas and nc944er on it
Haynes recommends not doing it, but also gives me all the steps to do it. So that will be an asset as well.
Aiming for this weekend

walfreyydo

Do not rely on the Haynes manual. It doesnt have the correct info for all the different years/models of 944 which can cause confusion. The FSM (factory service manual) for your year/model is the only hard copy document I recommend anyone uses. Haynes manuals were ok back in the late 90s (when I started wrenching) before the internet when that was all we had, but now there just isnt any reason that I can see to continue using them. Especially given the free availability of the Porsche FSM's in PDF format which is year/model specific and much more detailed information...

In terms of the balance shaft locking bar, I didnt need one, I instead used a 90 degrees needle nose pliers inserted into the holes of the gear to hold it, but any homemade tool or alternative that holds the gear should work. Flywheel lock I would 100% recommend spending the $50 on. Kricket tool isnt bad (I used one too) and the twist method is also workable. After starting the car you may need to re-adjust balance shaft belt tension if it whines too much (very common). I am lucky and have an auto tensioner so I didnt need to worry about timing belt tension but again, I think the twist method outlined on Clarks is pretty good for both belts.

FSM download
http://p914-6info.net/944%20Manuals.html

You got this.

henreezy

Thanks for the vote of confidence and FSM docs
hope to update soon

Zirconocene

The other thing to be aware of on the balance shaft belt tensioning (I screwed it up and had to go fix it, but not a big deal) is which way to turn the tensioner pulley. There's a right direction, and a wrong direction, and they'll both tension the belt, but only one way will give you the right clearances to the other things it runs near.

You got this

henreezy

I've spent the week slowly disassembling everything and am now at the point where I'm setting TDC and installing the flywheel lock.

I was turning the engine and lined up the camshaft lines, looked over the bell housing and the OT line is off from the guide by about a tooth or two. I read some forums on the topic but havent been able to find my exact scenario. If the flywheel OT is visible while the camshaft is lined perfectly, how can I realign this system? Ill try to get lighting good enough to take a picture shortly

Side Question: I also discovered my power steering belt tensioner is bent exactly where it needs to pivot. Is it ok to just uninstall the linkage and let it fold intowards the alternator while i wait on one from Only944?

Jfrahm

You line up the crank, the cam position changes due to belt tension and wear. Ultimately the cam might be off a half of a cam sprocket tooth when the belt tension is set but hopefully somewhat closer.

The v-belt tension turnbuckles bend like that because people do not adjust them properly, often breaking the strut and/or breaking accessories or engine mounting ears. The end "eye" bolts need to be loose and the accessory pivots need to be loose before adjusting. With one hand and a short wrench you can easily bend or break stuff with the leverage provided by the tensioning struts. Breaking an AC compressor mounting ear is popular, as is having a strut fall off and the belt likewise while on the highway.
It's OK to unbolt the tensioner strut, loosen the accessory first. Often the strut needs to go on after the belt due to clearance.