vibrations !

[Olivier PAGES]

I am french so excuse me for my bad english. I ave the same problem (vibrations of motor at 1600 and 3300 rpm) and y am sure that my balance shift are not well adjusted. The O indication and U are well aligned so I dont think there is a problem whith oulley and balance shaft.
Does the marks "O" and "U" aligned whith the notches on fixed part arround the pulley or does the notches on the external parts of the pulley aligned with the fixed marks ?
I have Haynes documentation but I have difficulties to understand the good maner to indexe timing and balance belts.

[singpilot]

Check out the website 'Clarks Garage'.

There is a very clear explanantion.

www.clarks-garage.com

Good luck, your english is perfect.

[SoCal Driver]

The pulleys on the balance belts have two key ways. If your car has had a re seal recently it is a possibility that these pulleys may have been put back on 170 degrees out.

Here is a graphic of where the keyways and pulley marks should line up.



You can use a stiff piece of wire to probe for the key in the pulley slot without having to remove the pully. Just the bolt.

[Olivier PAGES]

Thank you very much for your help.
Really américan technical forum are better than french one !
Happy new year.

[SoCal Driver]

I think that everyone has something to add/offer even if they are just asking a question then chasing the answer.

[Manute]

Bienvenue Olivier!

Please add your car type at your signature,to know better what are we talking about.

Why don´t you download the factory workshop manuals?they are quite useful!

[Zero10]

Download them?? Where? I have been looking for them.

[SoCal Driver]

They are --- everywhere!

PM me and I will explain all!

[Olivier PAGES]

Vibration of 1985 944
With the indications of SoCal Driver and his graphic, I can verify that all alignements are good !
I verify the position of the key (up in front of O mark on pulley, down at the oposite of O mark) and the position of crankshaft and camshaft at TDC whith camschaft pulley and mark on flywhell, all is ok.

So I didn't know the raison why I have a vibration near 1600 and 3400 rpm...

I have an old 1976 924 without balance shaft and I never have vibration, and the same whit an very old (1962) MGB.

Really, a "normal" 944 does not have any vibration when you increase the rpm ?

In france we say "I give my tongue to a cat "

I don't know american term !

[Olivier PAGES]

I forgot ask you how is it possible to download factory workshop manual. I have Haynes manual but in some cases a good graphic is better than a picture.
Thanks

[944boyfutureman]

Yes, vibrations are common for me too. My 944 still has the factory muffler however, so the backpressure drowns out the other vibrations.

[SoCal Driver]

Oliveir you have something wrong with the balance shafts or belt. This is the only thing the will incur vibrations at a give frequency.

The chart shows where the pulleys and shafts line up when the engine is at the top of the stroke on cylinder number one.

This means that the mark on the cam pulley and the mark on the fly wheel have to line up as well as the pulley set up on the balance shaft pulleys have to line up.

It is possible that the balance shaft pulleys are lining up but the engine is half a cycle out of sync.

[Manute]

Olivier,and everyone interested,manuals are available from various sources,personally I use a share program called emule,it´s free and simple to use.

You need to download it from www.emule-project.net , then install it and search for porsche 944 stuff.Manual then will appear,there are about 450 mb long. Long download,but worths it.

[Olivier PAGES]

SoCal Driver I am accord whith you, and last nigth I verifie a new time that all marks are in exactly in line at the same time. I change camschaft belt on great number of my cars (maserati, jaguard, aston martin, porsche, BMW) so I am sure that I do not make mistake. But I am accord whith you. Perhaps one of my balance schaft is broken ? When time was fine I use my MGB and I dismantle motor to find the origin of my problem. Thank you for help.