Getting Ready to do a Timing Belt

jonvo · jonvo's Garage

1987 porsche 944 NA

I just ordered the flywheel lock tool, timing belt, balance shaft belt and water pump. Is there anything else I should replace while I'm in there?

Also, is there anything I should know before starting? Any useful tips from personal experience? I have read the procedure on clark's garage, and it doesn't seem too difficult.

I have probably done about 100 timing belt replacements on hondas/acuras, but never done a porsche. I left the honda world for porsche. haha

HondaDustR · 08-26-2009, 04:51 PM

You don't need the flywheel lock unless you plan to do front seals and/or waterpump. If you plan to do front seals and/or the waterpump, it will be alot easier with the balance shaft sprocket pin spanner tool to hold the sprockets while loosening or tightening the mounting bolt.

There are several posts out there outlining checking the tension by trying to turn the water pump pulley. Do a search. It's the best "by hand" method in my opinion.

John_AZ · 08-26-2009, 04:54 PM

The Porsche 944 engine has interference valves, meaning the valves will hit the piston if the cam belt breaks or is not tensioned properly. ( I should have put this on your other post- http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/493221-random-944-facts.html#post4848620)

Too tight and the belt will either snap or ruin the water pump bearing and this may cause the belt to go slack and ruin the valves when they hit the piston. Too loose and the belt may jump the cam gear or the crank pully gear or just grind off teeth of the belt and again ruin the valves when they hit the head.

You need a tension tool. www.arnnworx.com has tools and his "projects" show you how to use them. In time you will know the correct tension by feel, like the 100 belts you have changed in the past.

GL
John_AZ
1988 924S + 1987 924S

Icey1174 · 08-26-2009, 04:59 PM

New rollers are usually advised. If you have any front end oil leaks then now is the time to fix them. The front seals are easy to get at while you have her opened up.

Maybe a new cap and rotor while you will have it apart anyway.

Do you have any oil leaks at all from the cam tower gasket or the rear cam tower gasket? Now is a great time to replace them too while you have the belts off. If you have a couple extra hours and another $30 for the gaskets I would do them now to save you the pain of doing them six months from now as that ALWAYS seems to be the case.

There is a lot of info here about proper tension of the belts. Some people swear by the tool while many others of us fly by the seat of our pants and tension them by hand. I tension by hand and I have no problems. Maybe I am just lucky.

Make sure both the crank AND the cam are TDC when you lock it. If they are not both there then crank it another 180 degrees and then they should both match.

jonvo · jonvo's Garage

Quote:

Originally Posted by HondaDustR

You don't need the flywheel lock unless you plan to do front seals and/or waterpump. If you plan to do front seals and/or the waterpump, it will be alot easier with the balance shaft sprocket pin spanner tool to hold the sprockets while loosening or tightening the mounting bolt.

There are several posts out there outlining checking the tension by trying to turn the water pump pulley. Do a search. It's the best "by hand" method in my opinion.

You don't need the flywheel lock to loosen the crank pulley bolt?

jonvo · jonvo's Garage

previous records show that the water pump was replaced 34k miles ago. Should i still replace it?

Techno Duck · Techno Duck's Garage

You do need the flywheel lock to get the crank bolt off. But you only need to take that off if your changing the pump. With 36k miles on I would leave it, but do check the pulley for excess play just incase. Typically most follow the 2 belts for every pump schedual, or roughly every 60-70k miles.

HondaDustR · 08-26-2009, 10:09 PM

Yeah, you can fanagle the cam belt on and off without removing the crank sprockets. Installing the flywheel lock is a minor pain, but definitely necessary if you need to remove the carnk pulley bolt. You know the sole reason you even need to remove all that crap just to do the water pump is all because of that stupid plastic rear timing belt cover. Nothing can happen beyond the cam belt without removing that stupid thing, which is required for all the other stuff needed at the front of the engine.

Techno Duck · Techno Duck's Garage

Well if doing the water pump I would do te front main and the oil pump drive sleeve also. Basically you get one relativley painless belt job, then one slightly more PITA one

.

jonvo · jonvo's Garage

Is it necessary to do the oil pump while I'm in there also? At 183k, I haven't seen anything in its history of being replaced.

HondaDustR · 08-27-2009, 07:07 PM

Oil pumps pretty much last as long as the engine, unless they get messed up sucking debris in the oil. I guess they wear out eventially, but not until they have a bazilion miles on them.

jonvo · jonvo's Garage

Quote:

Originally Posted by HondaDustR

Oil pumps pretty much last as long as the engine, unless they get messed up sucking debris in the oil. I guess they wear out eventially, but not until they have a bazilion miles on them.

That's the answer I was hoping for! Those things are expensive. I just bought the car and want to do all of the preventative maintenance before auto crossing it.