Did 84 911's share SC's weak points?
10-25-2002, 11:41 AM
#1
Racer
Thread Starter
Join Date: Jan 2002
Location: Washington, D.C.
Posts: 319
Likes: 0
Received 0 Likes
on
0 Posts
Did 84 911's share SC's weak points?
I've read about the clutch, chain tensioner, head stud and pop-off valve upgrades for the SC's. Did any of these apply to the '84s?
10-25-2002, 12:19 PM
#2
Technical Specialist
Rennlist
Lifetime Member
Rennlist
Lifetime Member
[quote]Originally posted by Jaxon:
<strong>I've read about the clutch, chain tensioner, head stud and pop-off valve upgrades for the SC's. Did any of these apply to the '84s?</strong><hr></blockquote>
No, they do not apply. The oil-fed chain tensioners were standard starting in 1984. Pop-off valves are only relevant to CIS-based systems - the '84+ uses Digital Motronics or DME.
The 84+ DME engines, however, did have some problems with valve stem and valve guide wear.
<strong>I've read about the clutch, chain tensioner, head stud and pop-off valve upgrades for the SC's. Did any of these apply to the '84s?</strong><hr></blockquote>
No, they do not apply. The oil-fed chain tensioners were standard starting in 1984. Pop-off valves are only relevant to CIS-based systems - the '84+ uses Digital Motronics or DME.
The 84+ DME engines, however, did have some problems with valve stem and valve guide wear.
10-26-2002, 12:49 AM
#4
Intermediate
Join Date: Aug 2001
Posts: 46
Likes: 0
Received 0 Likes
on
0 Posts
Jaxon,
My understanding is that the valve guide problem affected 87 and later Carreras. My 86 has 114K miles and very low oil consumption. I had compression check during the PPI and it was good. Mechanic said another check was to drive the car at 4,000 rpm and let up on the gas. If there's blue smoke it means valve guide wear.
I did those two checks but if you want to make really sure pay a little extra during the PPI and have them do a leak down test. Had good 1 - 2% leakage in my case and 84 and 86 are of the same vintage, you should be OK if engine was well cared for.
Another thing to check although it tends to affect SCs more than Carreras is head stud condition. Sometimes they break. Not the end of the world but still expensive to fix.
Pete
86 Carrera
My understanding is that the valve guide problem affected 87 and later Carreras. My 86 has 114K miles and very low oil consumption. I had compression check during the PPI and it was good. Mechanic said another check was to drive the car at 4,000 rpm and let up on the gas. If there's blue smoke it means valve guide wear.
I did those two checks but if you want to make really sure pay a little extra during the PPI and have them do a leak down test. Had good 1 - 2% leakage in my case and 84 and 86 are of the same vintage, you should be OK if engine was well cared for.
Another thing to check although it tends to affect SCs more than Carreras is head stud condition. Sometimes they break. Not the end of the world but still expensive to fix.
Pete
86 Carrera
10-26-2002, 02:22 AM
#5
Instructor
Join Date: Jun 2001
Location: SoCal
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
As I understand it, the valve guide wear is a potential for any year 3.2. Also, head stud breakage is relevant for 3.2 as well as 3.0 engines. Since the 3.0 engines are older and on average have seen more miles, there are more cases of snapped studs.
10-26-2002, 01:12 PM
#6
Addict
Rennlist
Lifetime Member
Rennlist
Lifetime Member
Add the rod bolts as a concern on 3.2s. The 3.0 used 10mm rod bolts and the bottom ends were known for being bulletproof, but when Porsche designed the 3.2 rods, they went with a lighter 9mm bolt. All the performance engine gurus I have talked to say that for prolonged high RPM operation, the rod bolts should be replaced with ARP or Raceware in the 3.2 and up engines.
TT
TT