Another belt / cam post - I thought I'd CYA - please comment
06-26-2011 | 12:44 AM
#1
Thread Starter
6th Gear
Joined: Sep 2010
Posts: 6
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From: Chicago
Another belt / cam post - I thought I'd CYA - please comment
OK, after reviewing the forums and the factory service manual, I performed what I considered major service on my 968 myself, as follows:
- new variocam plastic tensioner pads and chain. I bought the 9226 tool to help remove the cams. I marked the old chain with the cam gears and the tops of the cams so that I didn't change the timing or spacing. The old plastic tensioner pads were only slight worn, maybe 1mm on both top and bottom. Last record of service was approx 50k miles ago. I also installed a new cam cover gasket kit, with spark plug holes and cover bolt rubber bushings, all from Pelican. I used OEM Porsche pads and a cam chain from Pelican. Used my torque wrench at 7 fl/lbs for most everything. 15 on the cam holders.
- new timing and balance belts, plus cam seal, front main seal and balance shaft seals and tensioners. The cam and upper and lower balance shaft seals were from Pelican, the main seal was OEM Porsche. It was dry but I thought I'd replace anyway. The timing and balance belts, as well as the tensioners are Conti brand. Last record of service was 50k miles ago from the dealer. Everything removed seemed to be marked OEM Porsche. I bought the p9201 tool, but didn't seem to need it for the timing belt. The balance shaft belt was set to 3.5 using the 9201 tool. When I removed the original bal belt is was very very loose. Not that way now, but still loose; not at tight as the timing belt. I have to say the 9201 tool is very touchy and very expensive.
- new timing belt tensioner from Pelican. I installed and pulled the pin and it seemed to snug the timing belt up nicely.
- remanufactured water pump and new gasket from Zims. New thermostat from Zims.
I also used a OEM Porsche 968 flywheel lock so I didn't move the engine at all. TDC mark on the cam gear stayed fixed the whole time and the crank shaft did not move.
I am planning on hooking up the battery and turing the key tomorrow. Did I forget anything? Any suggested "double checks" ?
Questions:
- the 9226 tool came with cam timing tools, but didn't seem to line up with my cams. The car ran fine before I pulled everything, and I know didn't change the timing from the original. The cams are in the same position as before as is the gear. Any idea what these two p9226 tools are for? The 928 possibly?
- Torque on the crank shaft bolt? I think I did 155 ft lbs but will triple check tomorrow.
- Torque on the cam gear cheesehead bolt (behind the rotor) ? I think I did 50 ft lbs but will triple check again tomorrow.
- Torque on the balance shaft gears? 33 ft lbs?
- Any further advice on the timing and balance belt tensioning? The timing seems to be non-adjustable and based on the pressure applied by the new tensioner, agree?
- What's the order of the spark plug wires on the distributor cap? Going down, I think it's 3, 1, 2, 4 - agree? I checked the forum and couldn't find it.
You help is appreciated!
Scott
- new variocam plastic tensioner pads and chain. I bought the 9226 tool to help remove the cams. I marked the old chain with the cam gears and the tops of the cams so that I didn't change the timing or spacing. The old plastic tensioner pads were only slight worn, maybe 1mm on both top and bottom. Last record of service was approx 50k miles ago. I also installed a new cam cover gasket kit, with spark plug holes and cover bolt rubber bushings, all from Pelican. I used OEM Porsche pads and a cam chain from Pelican. Used my torque wrench at 7 fl/lbs for most everything. 15 on the cam holders.
- new timing and balance belts, plus cam seal, front main seal and balance shaft seals and tensioners. The cam and upper and lower balance shaft seals were from Pelican, the main seal was OEM Porsche. It was dry but I thought I'd replace anyway. The timing and balance belts, as well as the tensioners are Conti brand. Last record of service was 50k miles ago from the dealer. Everything removed seemed to be marked OEM Porsche. I bought the p9201 tool, but didn't seem to need it for the timing belt. The balance shaft belt was set to 3.5 using the 9201 tool. When I removed the original bal belt is was very very loose. Not that way now, but still loose; not at tight as the timing belt. I have to say the 9201 tool is very touchy and very expensive.
- new timing belt tensioner from Pelican. I installed and pulled the pin and it seemed to snug the timing belt up nicely.
- remanufactured water pump and new gasket from Zims. New thermostat from Zims.
I also used a OEM Porsche 968 flywheel lock so I didn't move the engine at all. TDC mark on the cam gear stayed fixed the whole time and the crank shaft did not move.
I am planning on hooking up the battery and turing the key tomorrow. Did I forget anything? Any suggested "double checks" ?
Questions:
- the 9226 tool came with cam timing tools, but didn't seem to line up with my cams. The car ran fine before I pulled everything, and I know didn't change the timing from the original. The cams are in the same position as before as is the gear. Any idea what these two p9226 tools are for? The 928 possibly?
- Torque on the crank shaft bolt? I think I did 155 ft lbs but will triple check tomorrow.
- Torque on the cam gear cheesehead bolt (behind the rotor) ? I think I did 50 ft lbs but will triple check again tomorrow.
- Torque on the balance shaft gears? 33 ft lbs?
- Any further advice on the timing and balance belt tensioning? The timing seems to be non-adjustable and based on the pressure applied by the new tensioner, agree?
- What's the order of the spark plug wires on the distributor cap? Going down, I think it's 3, 1, 2, 4 - agree? I checked the forum and couldn't find it.
You help is appreciated!
Scott
Last edited by metrocpa1; 06-26-2011 at 10:26 AM.
06-27-2011 | 02:58 AM
#3
RL Community Team
Rennlist Member
Rennlist Member
Joined: Jun 2004
Posts: 11,014
Likes: 20
From: San Francisco Area
From memory... the crank bolt is 155, cam bolt is 48-52, and the BS bolts are 33 lbft.
The timing is indeed adjustable. Check out this DIY: https://rennlist.com/forums/968-foru...oner-pads.html
It sounds like you were thorough. Like C Anderson said, turn it over by hand first. Then, prime the oil pressure by removing the fuel pump relay and cranking until you see pressure on the gauge. If you used assembly lube on the cams then you could skip this step but why not do it anyway?
Pics!
The timing is indeed adjustable. Check out this DIY: https://rennlist.com/forums/968-foru...oner-pads.html
It sounds like you were thorough. Like C Anderson said, turn it over by hand first. Then, prime the oil pressure by removing the fuel pump relay and cranking until you see pressure on the gauge. If you used assembly lube on the cams then you could skip this step but why not do it anyway?
Pics!
06-28-2011 | 04:14 PM
#4
Burning Brakes
Joined: Dec 2003
Posts: 1,037
Likes: 11
From: Chicago, Il
Looks good.
I agree 100% with Porschman. "IF" you broke loose the bolt that fixes the cam timing during disassembly, you will probably have to retime the cams at some point, but this does not affect starting or running the engine, since the timing adjustment is very small.......and impacts performance more than anything..
There is a cam lobe template in the shop manual. You should trace this out onto a piece of cardboard or onto a thick sheet of wood and then hand fabricate the template. The purpose of the template is to make certain tht the lobes on the #1 cyclinder are correctly positioned when the engine is at TDC.
Also, there should have been two "colored" links in the cam chain which when installed on the cams tie the cams together for indexing. Once installed in the head, you will confirm the alighnment using the template I mentioned in the previous paragraph.
Other than those few things, it sounds like you did a thorough and excellent job.
If you have not done it yet, just to check, hand rotate the motor through two complete revolutions of the crankshaft which will rotate the cams through one revolution. Do this to distribute the cam assembly lube (assuming that you did lube the cam bearings during assembly), and to double check the timing belt and balance shaft belt alignments.
As a final check of everything even though you used a flywheel lock), pop the plug off the front side of the flywheel sheild to determine that you are "ON THE CORRECT TIMING MARK". at TDC there are three parallel lines marked on the perifphery of the flywheel that should be observable through the view port on the bottom of your motor.
If you are having trouble locating the port, it is a hole, about 0.75" in diameter, that passes through a sheet metal shield that covers the front/bottom side of the flywheel. This shield can be seen from below the car and it is directly adjacent to the back side of the oil pan and the whole is located at the 6o'clock position. The plug (if there still is one installed) is of rubber and can be pried out with a small screwdriver.
Once you locate the view port and pop off the plug, you should see the center scribed line (of three parallel radial lines) in the middle of the view port and should just be able to make out the other two scribed lines (one on each side of the center scribe mark).
TDC, alignment of the timing gear sprocket with notch in cam gear cover, orientation of both balance shaft timing marks with the plastic prongs on the rear plastic belt cover, and a double check of the viewport, and you should be good to go. Just insert key and fire her up!
There is a cam lobe template in the shop manual. You should trace this out onto a piece of cardboard or onto a thick sheet of wood and then hand fabricate the template. The purpose of the template is to make certain tht the lobes on the #1 cyclinder are correctly positioned when the engine is at TDC.
Also, there should have been two "colored" links in the cam chain which when installed on the cams tie the cams together for indexing. Once installed in the head, you will confirm the alighnment using the template I mentioned in the previous paragraph.
Other than those few things, it sounds like you did a thorough and excellent job.
If you have not done it yet, just to check, hand rotate the motor through two complete revolutions of the crankshaft which will rotate the cams through one revolution. Do this to distribute the cam assembly lube (assuming that you did lube the cam bearings during assembly), and to double check the timing belt and balance shaft belt alignments.
As a final check of everything even though you used a flywheel lock), pop the plug off the front side of the flywheel sheild to determine that you are "ON THE CORRECT TIMING MARK". at TDC there are three parallel lines marked on the perifphery of the flywheel that should be observable through the view port on the bottom of your motor.
If you are having trouble locating the port, it is a hole, about 0.75" in diameter, that passes through a sheet metal shield that covers the front/bottom side of the flywheel. This shield can be seen from below the car and it is directly adjacent to the back side of the oil pan and the whole is located at the 6o'clock position. The plug (if there still is one installed) is of rubber and can be pried out with a small screwdriver.
Once you locate the view port and pop off the plug, you should see the center scribed line (of three parallel radial lines) in the middle of the view port and should just be able to make out the other two scribed lines (one on each side of the center scribe mark).
TDC, alignment of the timing gear sprocket with notch in cam gear cover, orientation of both balance shaft timing marks with the plastic prongs on the rear plastic belt cover, and a double check of the viewport, and you should be good to go. Just insert key and fire her up!
