Engine rebuild
10-22-2016, 04:10 AM
#1
Engine rebuild
Hi, I've successfully done a rebuild on an 83 SC motor. How different and more challenging would be rebuilding a 993 Turbo motor?
apologies for the very broad question.
Thanks
apologies for the very broad question.
Thanks
10-22-2016, 11:20 PM
#4
Rennlist Member
10-23-2016, 11:15 PM
#5
10-25-2016, 08:12 PM
#6
Burning Brakes
The actual "core engine" is very similar to the earlier 911 engines. Its the accessories that are different. So, the camshaft drive for the power steering pump comes to mind.
I rebuilt my 3.6 last year, and used the Pelican book on rebuilding 911 engines for most everything. What does differ is the chain tensioners. Easier on the 993. Also, the cams do not use sprockets for adjustment. So, to set the timing on the cams, you either need to beg, borrow, or steal a set of the alignment tools. Or, buy them for about $1200. Or, do what I did, and "back date" the cams to the old configuration that uses a sprocket to lock in the setting. Do that, and your cams will be timed exactly how you did the 911 motor you previously rebuilt. To backdate, your cams have to have the Woodruff key slot on the front of the cam to take the sprocket. If your cams do not have that keyway, then it is really inexpensive to have a machine shop cut them into your cams.
Lastly, the 993 uses hydraulic valve lifters, so you do not need to adjust the valves. Just prelube the lifters and install. No adjustment required. However, having said that, if you elect to back date your cam timing mechanics, you will have to temporarily install a standard inlet rocker arm on the #1 and #4 cylinders so that you can set the clearance required to set cam timing which is 1.0 mm. Once you have set your cam timing, simply replace the rocker with the hydraulic equivalent. You can pick up all the pieces needed to backdate the valve timing for about $100 and then use your dial indicator setup used to time your early 911 motor.
Bottom line. If you did an earlier 911 motor, you can do a 993 3.6. There are just a few more steps.
I rebuilt my 3.6 last year, and used the Pelican book on rebuilding 911 engines for most everything. What does differ is the chain tensioners. Easier on the 993. Also, the cams do not use sprockets for adjustment. So, to set the timing on the cams, you either need to beg, borrow, or steal a set of the alignment tools. Or, buy them for about $1200. Or, do what I did, and "back date" the cams to the old configuration that uses a sprocket to lock in the setting. Do that, and your cams will be timed exactly how you did the 911 motor you previously rebuilt. To backdate, your cams have to have the Woodruff key slot on the front of the cam to take the sprocket. If your cams do not have that keyway, then it is really inexpensive to have a machine shop cut them into your cams.
Lastly, the 993 uses hydraulic valve lifters, so you do not need to adjust the valves. Just prelube the lifters and install. No adjustment required. However, having said that, if you elect to back date your cam timing mechanics, you will have to temporarily install a standard inlet rocker arm on the #1 and #4 cylinders so that you can set the clearance required to set cam timing which is 1.0 mm. Once you have set your cam timing, simply replace the rocker with the hydraulic equivalent. You can pick up all the pieces needed to backdate the valve timing for about $100 and then use your dial indicator setup used to time your early 911 motor.
Bottom line. If you did an earlier 911 motor, you can do a 993 3.6. There are just a few more steps.
10-26-2016, 12:51 PM
#7
Seared
Rennlist Member
Rennlist Member
The actual "core engine" is very similar to the earlier 911 engines. Its the accessories that are different. So, the camshaft drive for the power steering pump comes to mind.
I rebuilt my 3.6 last year, and used the Pelican book on rebuilding 911 engines for most everything. What does differ is the chain tensioners. Easier on the 993. Also, the cams do not use sprockets for adjustment. So, to set the timing on the cams, you either need to beg, borrow, or steal a set of the alignment tools. Or, buy them for about $1200. Or, do what I did, and "back date" the cams to the old configuration that uses a sprocket to lock in the setting. Do that, and your cams will be timed exactly how you did the 911 motor you previously rebuilt. To backdate, your cams have to have the Woodruff key slot on the front of the cam to take the sprocket. If your cams do not have that keyway, then it is really inexpensive to have a machine shop cut them into your cams.
Lastly, the 993 uses hydraulic valve lifters, so you do not need to adjust the valves. Just prelube the lifters and install. No adjustment required. However, having said that, if you elect to back date your cam timing mechanics, you will have to temporarily install a standard inlet rocker arm on the #1 and #4 cylinders so that you can set the clearance required to set cam timing which is 1.0 mm. Once you have set your cam timing, simply replace the rocker with the hydraulic equivalent. You can pick up all the pieces needed to backdate the valve timing for about $100 and then use your dial indicator setup used to time your early 911 motor.
Bottom line. If you did an earlier 911 motor, you can do a 993 3.6. There are just a few more steps.
I rebuilt my 3.6 last year, and used the Pelican book on rebuilding 911 engines for most everything. What does differ is the chain tensioners. Easier on the 993. Also, the cams do not use sprockets for adjustment. So, to set the timing on the cams, you either need to beg, borrow, or steal a set of the alignment tools. Or, buy them for about $1200. Or, do what I did, and "back date" the cams to the old configuration that uses a sprocket to lock in the setting. Do that, and your cams will be timed exactly how you did the 911 motor you previously rebuilt. To backdate, your cams have to have the Woodruff key slot on the front of the cam to take the sprocket. If your cams do not have that keyway, then it is really inexpensive to have a machine shop cut them into your cams.
Lastly, the 993 uses hydraulic valve lifters, so you do not need to adjust the valves. Just prelube the lifters and install. No adjustment required. However, having said that, if you elect to back date your cam timing mechanics, you will have to temporarily install a standard inlet rocker arm on the #1 and #4 cylinders so that you can set the clearance required to set cam timing which is 1.0 mm. Once you have set your cam timing, simply replace the rocker with the hydraulic equivalent. You can pick up all the pieces needed to backdate the valve timing for about $100 and then use your dial indicator setup used to time your early 911 motor.
Bottom line. If you did an earlier 911 motor, you can do a 993 3.6. There are just a few more steps.
Great response.
Andreas
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10-27-2016, 10:54 AM
#8
Another BIG difference between the SC and 993/994 is the cylinder head bolt tightening sequence. The 3.6 engine require you to torque to a value, then turn an additional 45 or something degrees.
The 964 top end rebuild posting on PelicanParts DIY page shows this.
Overall, I would think the 993 is easier than the 911 without the timing and valve adjustment stuff. Certainly if you can rebuild your SC, you can do the 993.
The 964 top end rebuild posting on PelicanParts DIY page shows this.
Overall, I would think the 993 is easier than the 911 without the timing and valve adjustment stuff. Certainly if you can rebuild your SC, you can do the 993.
