What did I do wrong now?!
 

Just did a waterpump/timing belt job along with AOS seals, and the hoses under the intake.

I just got everything back together and took it for a test drive.

It was vibrating a lot more than when I started the job. As well as I noticed the balance belt seemed to be nicking the front roller looking thing on the waterpump.

Could the vibrations be bad timing?
What about the belts?

My best guess is the balance shafts are not lined-up properly. Re-check marks for both top and bottom balance shafts, and also ensure the proper tension is set. If you have the Porsche factory manuals for the 944, the procedure is in there. If you do not have the Porsche factory manuals then visit Clarks Garage for the proper process on ensuring your balance shafts are properly set-up.

If your timing was off, your pistons would be running into your valves.

Good luck.

Belt: did you put the rollers back on with the shoulders on the proper side? Stumbling: Check your AFM plug for contact and recheck the vacuum line routing on the throttle body. It's easy to get those two little ones on the wrong stubs. Check your connections on the injectors. A noid light (cheap at the auto parts store) will help you check to see if an injector's not pulsing. Perhaps a spark plug insulator got bumped and broken. If in doubt, pull the plugs and see if one's not firing (look for wetness on the plug).

+1--^-- every thing mytrpl777 said.

Double check the balance belt rollers mentioned by TibetanT

Photo

http://forums.pelicanparts.com/uploa...1381968813.jpg

My input---lower the balance belt by the WP pulley by tensioning the BB tension roller CW-clockwise

J_AZ

Yes and don't drive till you check..

Ok so I pulled each plug on the injectors and they seemed fine. I also switched the vacuum lines and that didn't seem to change anything.

So this would loosen the tension?
And from what I remember it was in line just like the picture. I guess I'll have to recheck.

Dare I ask why? haha

Although everything 777 said could be a problem, My best guess is a BB problem. Pay particular attention to the O-U markings on your BB sprockets and the pic that John AZ posted. very easy to install the sprockets improperly. The BB can def cause your vibration, Timing belt will cause your engine to cease operation very quickly.

As mentioned, Clarkes has an excellent DIY instruction!

He said that the balance belt was "nicking" the water pump pulley. If the belt was doing that doesn't it sound like it's really loose? I'm thinking if it's that loose then it's probably jumped out of time as well, which would cause this vibration..Yes?

^ Yes, too loose. May skip. Remember: bal shaft keys BOTH face up, then sprockets go on with their notches at the rear, aligned with the timing marks on the inner cover.

Ok I will definitely check that out. I know I had the notches lined up perfectly but I may not have had the bottom balance shaft key facing up. I'm not sure though.

I did take it for about a 2.5 mile test drive. Do you think I really screwed something up by doing this???

It is possible to drive without the balance shaft belt connected so I don't think you "screwed something up". However, a loose balance shaft belt that breaks and binds the timing belt could be catastrophic. I don't think the balance shaft belt is specifically the issue with why they are advising you to not drive, but the chain of events that could happen as a result from balance shaft belt failure.

Your issue is lower bal shft is 180 out of time. Trust me i did it too. Sprocket on bottom BS needs to be intalled180 off of mark (turned 180 degree off of top shaft orientation).

Also, as John mentioned, BS tensioner needs to be rotated counterclockwise to provide .5mm clearance between belt and idler. The only golden rule is Keyways Up.

I'm pretty sure the BS tensioner (the eccentric roller at the very bottom left of the loop) needs to be rotated clockwise, otherwise the belt will be too high and it will hit the water pump pulley.

mike 944 you can ask the answer is I did not have this issue but we all know what could happen if things go sour:confused: I'm just trying to help some save their engine..

+1 easy mistake, common error. Will do no real harm but the vibration will annoy the hell out of you. Generally goes away above 4000rpm and not too noticeable at idle but it's there in the most used rev range.

And those vibrations, if left uncorrected, can cause cracks to show up in the oil pickup tube.

Thanks everyone! I haven't driven it since so I'm gonna take care of that ASAP!

BB tensioner roller is Tensioned Clockwise!!

This is from Pro tech Techno Duck (now installing the LS1 engine in the 951)


http://forums.pelicanparts.com/uploa...1382068778.jpg

(where is that bottle!!)

J_AZ

Pay particular attention to the "Pre-Load Idler", where it says 0-1mm.

That is the amount of deflection the idler should cause to the belt, and not the amount of clearance, so that idler should just be touching or slightly deflecting the balance shaft belt when properly adjusted, and .5mm off the belt/idler assembly below it.

I usually tuck a credit card under it to set that clearance, then I can just focus on the top one.

John, I think I've got that bottle...

I'm sure I did mine ccw so it would give me the right clearance on the idler. But as I age...

OP - Note that if the belt rides on the idler it'll whine like a hungry toddler with his pant full.

++++poop/plop http://forums.pelicanparts.com/support/smileys/wat6.gif

So when I put the balance pulleys on and align the marks the keys should be in about the 10-11 o clock position? Because that's what they're doing when I just put them back on.

Look at the picture in post 4--the pulley keys are at 12 o'clock (the little black squares on top of each shaft).

J_AZ

Yes but I believe the picture is rotated. There is no way that the key can be at 12 o'clock and the notches line up.

They will line up exactly as pictured if you follow the Clarks-Garage procedure.

Timing Belt and Balance Shaft Belt Installation

Both of my 924Ss ---BB many times removed and replaced---exactly as shown---notches at 12 o'clock.

J_AZ

Hmmm well I will try again. There just didnt seem to be any combination that would make it work.
Do the balance pulleys have different part numbers?

Note that each sprocket has 2 keyways and is stamped with an O and a U. Over and Under. You can't go wrong: keyways up, notch on sprocket aligned with timing mark. Have a look at the first pic posted in this thread.

What can happen is that rotating the tensioner can pull the bottom sprocket out of time. If so, you can gently slip it one tooth or so back I to time, or compensate by installing the lower out of time and pulling it into time as you rotate the eccentric tensioner.

My top tbalance timing notch is literally at 12 o'clock so how can the key be at 12 o'clock too?

The notch is in the 12 o'clock position
http://forums.pelicanparts.com/uploa...1382212808.jpg

Here this better explains my problem.

This is the upper balance shaft. You can see that when the key is at 12 oclock, the notch is waaaay off.
http://forums.pelicanparts.com/uploa...1382214930.jpg

Same for the lower.
http://forums.pelicanparts.com/uploa...1382214958.jpg

Should I line up the notches or the keys? There is no possible way they can both be aligned

If that last picture is right, I think you have installed the sprockets on the wrong shafts. The one marked with an O should be on the top shaft (upper - Oberen) and the U should be on the bottom shaft (bottom - Unterste). Swap them around and perhaps it will all come good.

Both sprockets are exactly the same. Neither have a U on them either.

I have just been out to my old block and had a look. The upper shaft timing mark is at 12 o'clock, therefore the keyway cannot also be at 12, it has to be slightly counterclockwise (10 or 11). You appear to be right regards the picture in the PWM - it has been rotated clockwise a few degrees. If you look at the Clarks diagram - that shows a more acute angle between the shafts and is much closer to the actual reality of a fitted engine. The rule is the keyways must always be up, but they cannot be at exactly 12. However, the notch on the upper sprocket will be.

Yes, some later sprockets did not have a U stamped on them, they used the thin metal cover with holes in to identify the sprockets. On the upper one the O appears in a nice large round notch and two pin ways are also clear. On the lower the O appears in a rectangular slot and the other two pin ways are clear.

Here is a (grainy) photo taken from the PWM. It show the upper shaft, as you can see the O (visible in its nice round notch) is at about 11.

http://forums.pelicanparts.com/uploa...1382220973.jpg

Hope this helps.

Have a read of Clarks ENG-08, they discuss the sprocket id issue and the problems that can occur due to Porsche not stamping U on them..

You're over-thinking this. Keyways up, rotate to align notches on belt install and done. In your pics you look fine. Just align the timing marks.

Mike, here's a link to Youtube video series that goes through the entire process and should clear up any questions you may have. I hope this will get you back up and running in short order. Good luck

Porsche 944 Timing Belt Replacement - YouTube

Thanks everyone.

I ended up just putting it back together with the keys up as far as possible and it works perfect so I'm not stressing it anymore!

^^^ Result - nice one Mike..:):):):)