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-   -   Installing timing belt (http://forums.pelicanparts.com/porsche-928-technical-forum/527375-installing-timing-belt.html)

harborman 02-20-2010 07:06 AM

Installing timing belt
 
I am now at the point of installing the new belt. I have it on the crank and oil pump and trying to get it to fit as tight as possible around the cam gear on drivers side. It seems to be about a half tooth off to get it real tight, otherwise a little slack between gear and oil pump/crank .

The cams did not moved when I removed the old belt, still on marks. I was able to slide the old belt off each cam gear and they stayed in position as they are now.

How tight do I have to get it on that first cam gear?

Mrmerlin 02-20-2010 09:22 AM

try turning the cam CW when looking at it just enough to fit the belt then turn it back without moving the crank
Turn the cam with the 30MM looking washernut under the cam securing nut.

harborman 02-20-2010 09:50 AM

Quote:

Originally Posted by Mrmerlin (Post 5195777)
try turning the cam CW when looking at it just enough to fit the belt then turn it back without moving the crank
Turn the cam with the 30MM looking washernut under the cam securing nut.

Ok, will do. I just came in from the garage to check here. I know those have to be tight between gears. Otherwise everything seems to be going well. Got the pump on. I still have the flywheel lock in place and at 45 degrees on damper. This is the 32 valve engine.

Mrmerlin 02-20-2010 10:02 AM

OK no changes
BUT on the oil pump if your replacing the gear with a new steel version, then you also remove the 1MM spacer that was on the aluminum gear, the steel gear is an upgrade part.
make sure you also have all curved pulley teeth as well as a curved tooth belt otherwise know as a HTD hi torque drive

harborman 02-20-2010 11:18 AM

Quote:

Originally Posted by Mrmerlin (Post 5195833)
OK no changes
BUT on the oil pump if your replacing the gear with a new steel version, then you also remove the 1MM spacer that was on the aluminum gear, the steel gear is an upgrade part.
make sure you also have all cur ved pulley teeth as well as a curved tooth belt otherwise know as a HTD hi torque drive

All gears are original and have the curved teeth and also on my new Gates belt. I believe the belt was changed once back in 1992 before it was put in storage. It had a Uniroyal belt, not Porsche. Now when I marked the gear for 45 degree one pointer fell on the top of a gear the other in a valley or close to it. When I put the new belt on, should I align it to original hole marks in gears or to the way it came off? We are talking about maybe a one tooth slight difference. I am at 45 degree on crank now, locked in place. It looks like the hole marks are about 3 groves to the Left or close to it on the 45 degrees from my marks.

Could the last mechanic been off one grove distance between the two gears?

Hope I have not confused you.

Mrmerlin 02-20-2010 03:32 PM

well to start i hope that you marked the cams at 45 deg if you have them marked then fitting the belt is easy, once you have the belt on and the tensioner is snugged turn the crank to TDC it wont be much then recheck the timing of the cams and crank, once the timing marks are set then tension the belt and turn the crank 2 revolutions till it comes back to TDC and recheck the tension.
You want the pointer of the kemp tool to be at the top or furthest edge of the window, in other words with the highest tension

harborman 02-20-2010 04:00 PM

Quote:

Originally Posted by Mrmerlin (Post 5196255)
well to start i hope that you marked the cams at 45 deg if you have them marked then fitting the belt is easy, once you have the belt on and the tensioner is snugged turn the crank to TDC it wont be much then recheck the timing of the cams and crank, once the timing marks are set then tension the belt and turn the crank 2 revolutions till it comes back to TDC and recheck the tension.
You want the pointer of the kemp tool to be at the top or furthest edge of the window, in other words with the highest tension

Thanks so much.
I think I have it. The belt is on, when on TDC the little holes line up right under the "V" marks on the back. I rotated crank several times, all lines up. Never having done a belt timing, I think I got it. It seems to be by the "book" as all lines up after rotating the crank several revolutions by hand. There is no "slack" between gears which was my concern thanks to your advise on turning the cams slightly to install the belt. So far so good, will do a few more rechecks. It appears the 45 degree position on both gears is exactly 3 groves to the right of the zero TDC holes marked on the back of the gears. After several rotations of the crank, the holes all lined up right under those "V" indicators at TDC. Better to be safe than sorry! I will reset tension and check.

Mrmerlin 02-21-2010 04:11 AM

make sure to fill the tensioner with oil I suggest STP use a visene bottle with the tip drilled out remove both nipples and then fill from the hole closest to the right fender put a rag under the other hole and keep filling till you see the STP oil come out.
Using the visene bottle will prevent you from over pressurizing the tensioner and possibly blowing out the inner sealing clamp

harborman 02-21-2010 06:51 AM

Quote:

Originally Posted by Mrmerlin (Post 5196808)
make sure to fill the tensioner with oil I suggest STP use a visene bottle with the tip drilled out remove both nipples and then fill from the hole closest to the right fender put a rag under the other hole and keep filling till you see the STP oil come out.
Using the visene bottle will prevent you from over pressurizing the tensioner and possibly blowing out the inner sealing clamp

Yes, I just did that this morning. The tensioner boot all looks new, no cracks. Thought I had an oil leak but it was just from me doing the tensioner fill. I will double check this later.The radiator hoses are original but now that the system is drained, I think I will change the big hoses at least. They are still soft, not hard but date on them is 1985!! Easier to work on with fan removed. All small belts had been replaced recently so those are Ok. Big snow storm heading here so good time to be in the garage!


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