Cam shaft woes :(
#21
02-13-2011, 12:45 PM
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Location: PHX some of the time
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#22
02-13-2011, 01:08 PM
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Location: Damon /Houston, Texas
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you only need 4 cylinders on base circles, and just cut the cam apart in 4 sections and put them all on the base circles for the exhaust cam, and then reweld them...
But seriously, you have to install the cam in proper postion and then rotate the engine to the base circle for each cylinders exhaust lobes on that engine bank. Check clearances with a feeler gauge,then remove the cam after recording clearances. this is assuming that some are out of spec. If theyre all in your done, and consider yourself lucky. Otherwise remove the cam again and set all the out of spec clearances with the correct lash shims.
But seriously, you have to install the cam in proper postion and then rotate the engine to the base circle for each cylinders exhaust lobes on that engine bank. Check clearances with a feeler gauge,then remove the cam after recording clearances. this is assuming that some are out of spec. If theyre all in your done, and consider yourself lucky. Otherwise remove the cam again and set all the out of spec clearances with the correct lash shims.
#23
02-13-2011, 02:11 PM
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#24
02-13-2011, 03:19 PM
#25
02-13-2011, 03:45 PM
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#26
02-14-2011, 02:42 AM
Veteran Member
Sort of like going window shopping for a XJR, starting up the old car to leave, and having the idiot light for the alternator that was just fixed last week glowing at you in the old car ... all the way home.
Today it's a different story. Idiot light doesn't come on at all when the key is turned to position 1.
Maybe the old car was just mad at the possibility of being replaced.
#27
02-14-2011, 06:15 PM
Join Date: Oct 2007
Location: PHX some of the time
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you only need 4 cylinders on base circles, and just cut the cam apart in 4 sections and put them all on the base circles for the exhaust cam, and then reweld them...
But seriously, you have to install the cam in proper postion and then rotate the engine to the base circle for each cylinders exhaust lobes on that engine bank. Check clearances with a feeler gauge,then remove the cam after recording clearances. this is assuming that some are out of spec. If theyre all in your done, and consider yourself lucky. Otherwise remove the cam again and set all the out of spec clearances with the correct lash shims.
But seriously, you have to install the cam in proper postion and then rotate the engine to the base circle for each cylinders exhaust lobes on that engine bank. Check clearances with a feeler gauge,then remove the cam after recording clearances. this is assuming that some are out of spec. If theyre all in your done, and consider yourself lucky. Otherwise remove the cam again and set all the out of spec clearances with the correct lash shims.
I had forgotten the old cut and weld camshaft trick. 
The suggestion about having the cams on base circle was for tightening the bearing caps not checking the shims.
#28
02-14-2011, 09:21 PM
If you lock the crank in the '45 degrees after TDC position' with the 'crank-lock-tool' no piston will touch a valve and you can rotate the exhaust cam 'round and round' until your hands get tired. You can install and remove the exhaust cam 'over-and-over' (EVENLY) until all the follower bucket shim lash specs are correct.
I have used the special tool to depress the buckets and it is easier to remove the exhaust cam than to try to catch the edge of the buckets for more than a few lobes.
The intake cam is a little harder to remove/install so the special tool might be the way to go. It is still difficult to use and not worth buying unless you work on alot of engines.
Here is a TSB for the S-Type 3.0 engine but the tool is used the same way for the V8.
bob gauff
I have used the special tool to depress the buckets and it is easier to remove the exhaust cam than to try to catch the edge of the buckets for more than a few lobes.
The intake cam is a little harder to remove/install so the special tool might be the way to go. It is still difficult to use and not worth buying unless you work on alot of engines.
Here is a TSB for the S-Type 3.0 engine but the tool is used the same way for the V8.
bob gauff
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Sean B (02-15-2011)
#29
02-15-2011, 07:08 AM
Veteran Member
If you lock the crank in the '45 degrees after TDC position' with the 'crank-lock-tool' no piston will touch a valve and you can rotate the exhaust cam 'round and round' until your hands get tired. You can install and remove the exhaust cam 'over-and-over' (EVENLY) until all the follower bucket shim lash specs are correct.
I have used the special tool to depress the buckets and it is easier to remove the exhaust cam than to try to catch the edge of the buckets for more than a few lobes.
The intake cam is a little harder to remove/install so the special tool might be the way to go. It is still difficult to use and not worth buying unless you work on alot of engines.
Here is a TSB for the S-Type 3.0 engine but the tool is used the same way for the V8.
bob gauff
I have used the special tool to depress the buckets and it is easier to remove the exhaust cam than to try to catch the edge of the buckets for more than a few lobes.
The intake cam is a little harder to remove/install so the special tool might be the way to go. It is still difficult to use and not worth buying unless you work on alot of engines.
Here is a TSB for the S-Type 3.0 engine but the tool is used the same way for the V8.
bob gauff
#30
02-16-2011, 08:12 AM
#31
02-17-2011, 01:09 PM
#32
02-18-2011, 05:21 AM
Veteran Member
Good luck, and keep us updated, rooting for you here!
#33
02-18-2011, 08:52 AM
I believe ANY 4.0 exhaust cam for the 'A'bank will work. I sold an S-Type head to someone for installation on a 1999 XJ8. He used the exhaust cam in the head and installed his intake cam for the AJ27 4 lobe CMPS (S-Type AJ28 uses 5 lobe)
He only had to adjust the valve shims for the intake cam.
bob gauff
He only had to adjust the valve shims for the intake cam.
bob gauff
#34
02-18-2011, 04:56 PM
Veteran Member
#35
02-19-2011, 07:04 PM
The good news is that retiming is pretty straightforward as long as you have a flywheel locking tool and a camshaft locking tool.
#36
02-20-2011, 02:49 AM
Veteran Member
Quite right. Must have had brain fade on that one.
#37
02-21-2011, 04:58 PM
#38
04-25-2012, 04:34 PM
@jagscott
A possible contributing factor is the cam orientation.
You did the first cam with the cam oriented so that the base circle was facing the cam buckets. Less spring pressure.
Then you attempted the second one without moving the cam to a similar relaxed position. There is more pressure involved.
For anyone else following along, the missing step is to finish the first side by undoing the zip tie and releasing the retaining pin. Then, bump the starter to get the next cam into working position. WITH THE FUEL PUMP DISABLED.
The cam bearing looks fine. You could smooth it out a little bit with emery cloth wrapped around a cylindrical object.
Most overhead cam repair procedures note that the lifter buckets wear to the cam lobe it is matched to. Therefore, if someone does not ship the entire head, get the lifter buckets and shims, and make sure they are labeled at disassembly.
In the meantime, put the bearing caps back into proper position with finger tight bolts so that you do no lose the original positions.
When you are finished, you should have: old head, old valves/springs, replacement cam, buckets.matched to replacement cam.
You will need to check all the valve lashes on the exhaust valves on the replaced cam. A little loose=noise. A little tight=burned valves.
A possible contributing factor is the cam orientation.
You did the first cam with the cam oriented so that the base circle was facing the cam buckets. Less spring pressure.
Then you attempted the second one without moving the cam to a similar relaxed position. There is more pressure involved.
For anyone else following along, the missing step is to finish the first side by undoing the zip tie and releasing the retaining pin. Then, bump the starter to get the next cam into working position. WITH THE FUEL PUMP DISABLED.
The cam bearing looks fine. You could smooth it out a little bit with emery cloth wrapped around a cylindrical object.
Most overhead cam repair procedures note that the lifter buckets wear to the cam lobe it is matched to. Therefore, if someone does not ship the entire head, get the lifter buckets and shims, and make sure they are labeled at disassembly.
In the meantime, put the bearing caps back into proper position with finger tight bolts so that you do no lose the original positions.
When you are finished, you should have: old head, old valves/springs, replacement cam, buckets.matched to replacement cam.
You will need to check all the valve lashes on the exhaust valves on the replaced cam. A little loose=noise. A little tight=burned valves.
#39
04-25-2012, 05:42 PM
Would it not be easier(and more accurate) to rotate the engine by means of the crankshaft bolt until the second cam to be removed is under the least pressure from the valve springs(using the mark 1 eyeball method) - or am I mis- understanding this. I need to know because I'm tackling my tensioners this weekend
Vector
#40
04-25-2012, 07:13 PM
Veteran Member
