911 camshaft oiling update - anyone done this ?
06-15-2010, 10:46 PM
#31
Drifting
Are you mentioning about the cam line restrictors?
If so, the PO of my Targa had the restrictors installed the my motor and never had any issues.
Oil pressure is about 4 bar at start up.
During a hot summer day with 90 plus temps oil pressure is at 2 bar at idle after a long high speed fun run with temps only reaching close to 220 if stuck in traffic.
This is with 9.8 compression.
John
If so, the PO of my Targa had the restrictors installed the my motor and never had any issues.
Oil pressure is about 4 bar at start up.
During a hot summer day with 90 plus temps oil pressure is at 2 bar at idle after a long high speed fun run with temps only reaching close to 220 if stuck in traffic.
This is with 9.8 compression.
John
06-15-2010, 11:11 PM
#32
Rennlist Member
Sorry, "pre-mod" meant before I installed the cam oil line restrictors. What an amazing difference! My numbers are now very close to yours, except for idle pressure (hot); mine is just under 1 BAR. I'll take it, because pre-mod I never had idle pressure in hot weather (with the engine above 200F it was always zero), and a new sending unit might bring it up a little further.
Heck, one 110F day coming back from L.A. on the freeway I saw 260F oil temp, and couldn't get more than 1.5 BAR of pressure, even at 3800 rpm in 4th. That was about 8,000 miles ago, so it's obvious that I didn't do permanent damage, but it scared the hell out of me!
Heck, one 110F day coming back from L.A. on the freeway I saw 260F oil temp, and couldn't get more than 1.5 BAR of pressure, even at 3800 rpm in 4th. That was about 8,000 miles ago, so it's obvious that I didn't do permanent damage, but it scared the hell out of me!
06-15-2010, 11:42 PM
#33
Rennlist Member
Heck, one 110F day coming back from L.A. on the freeway I saw 260F oil temp, and couldn't get more than 1.5 BAR of pressure, even at 3800 rpm in 4th. That was about 8,000 miles ago, so it's obvious that I didn't do permanent damage, but it scared the hell out of me!
Great thread.
Now I'm going to be sure to check my 88 and see if has the update.
06-16-2010, 10:57 AM
#34
Rennlist Member
20W/90 would have served me well on that trip to L.A.!
I never thought far enough ahead, based on what I've read, that the adapter modification might raise oil pressure enough to open the piston squirters at 3,000+ revs hot. Simply amazing!
My car ('82 SC) has 204K miles (no rebuild), and it looks like the original oil pressure gauge sending unit is still fitted. I think that I'm going to change that part (the gauge needle bounces a little at hot idle after it settles in at about 0.8 BAR) and see if the overall readings change.
06-16-2010, 03:12 PM
#35
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Going to do this mod this weekend if i get the parts. Will someone please describe where to look for the cam line and fitting? Is it on the front of the engine, as in same orientation as crank seal or is on top of the engine?
Also, my engine has right at 100k miles. Should i go ahead and replace the cam lines as well?
Also, my engine has right at 100k miles. Should i go ahead and replace the cam lines as well?
06-16-2010, 04:21 PM
#36
Rennlist Member
I will try to post my Tutorial if someone can tell me how to transport a Word doc with pictures to here (in a reasonable amount of time).
Last edited by Peter Zimmermann; 06-16-2010 at 05:30 PM.
06-20-2010, 10:09 AM
#37
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Ok. I did the mod yesterday.
Conditions:
Engine Temp: warm, on 1/3 marker
Speed: idle, 880 RPM
Engine Oil: Castrol GTX 20w-50 (I know, this oils sucks, but changed oil to M1 20w50 VTwin right after this)
Oil pressure:
Before Mod .......After Mod
0.4-0.5 bar .......1.1 - 1.2 bar
A couple of comments:
1. Being that the line you have to install the fitting for IS the lube oil supply to the cam housing, remember that cleanliness is very important. Any crap that goes inside the hole, if it's not clean, will be fed to the cam and valve train. So to that end, clean the area thuroughly. I used non-chlorinated brake cleaner and then wiped down with a terry cloth.
2. I was expecting some oil to come out, so I placed some towels underneath the fitting as I was removing it, but hardly no oil came out. So this is not a messy job at all.
3. If you are going to do the mod, then I would recommend replacing the oil lines. I didn't replace mine, but I wish I had. Rubber and hoses do degrade over time. It's a good "while you're in there" upgrade. I will do mine in the near future.
4. If you are thinking of doing this update and already have good pressure (1 bar or better) at idle with engine warm, then I don't think I would do it. Reason being, if you already have good oil pressure, then you already have a good balance of flow to the cams versus the crank/rod bearings.
Conditions:
Engine Temp: warm, on 1/3 marker
Speed: idle, 880 RPM
Engine Oil: Castrol GTX 20w-50 (I know, this oils sucks, but changed oil to M1 20w50 VTwin right after this)
Oil pressure:
Before Mod .......After Mod
0.4-0.5 bar .......1.1 - 1.2 bar
A couple of comments:
1. Being that the line you have to install the fitting for IS the lube oil supply to the cam housing, remember that cleanliness is very important. Any crap that goes inside the hole, if it's not clean, will be fed to the cam and valve train. So to that end, clean the area thuroughly. I used non-chlorinated brake cleaner and then wiped down with a terry cloth.
2. I was expecting some oil to come out, so I placed some towels underneath the fitting as I was removing it, but hardly no oil came out. So this is not a messy job at all.
3. If you are going to do the mod, then I would recommend replacing the oil lines. I didn't replace mine, but I wish I had. Rubber and hoses do degrade over time. It's a good "while you're in there" upgrade. I will do mine in the near future.
4. If you are thinking of doing this update and already have good pressure (1 bar or better) at idle with engine warm, then I don't think I would do it. Reason being, if you already have good oil pressure, then you already have a good balance of flow to the cams versus the crank/rod bearings.
Last edited by Tango635; 06-21-2010 at 07:17 PM.
06-20-2010, 01:29 PM
#38
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This update has been around for some time now. It is explained fairly complete in Dempsey's 911 engine rebuild book on page 83. I installed them when I completed a rebuild on a '82 3.0. The oil pressure reads noticeably higher at idle than before the rebuild. I attribute the pressure increase to the new fittings as no other changes were made to the lubrication system more than cleaning and checking clearances.
I'd make the upgrade in any case.
I'd make the upgrade in any case.
06-21-2010, 03:16 AM
#39
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AMAZING! I know that my Tutorial is promised to another site, with an MIA IT guy, but in the mean time I can tell you that I just drove my car. 100F ambient. Cruised a few miles, not exceeding 50 mph, to Stockdale hwy, where I was able to increase speed to between 60 and 70. The oil temp went to 210F and stopped. Similar pre-mod experience was 220-225F in the same conditions.
I then headed for a local neighborhood where I could cruise around for a few miles, which pre-mod would take my car up to 240F+. Today, while able to keep the revs between 3200 and 3800, I was able to keep the oil piston squirters open (with oil pressure between 3.2 and 3.4 BAR at 3500 rpm) more often and longer. After many stops and starts, the oil temp slowly crawled up to 220F, pre-mod the car might have seen 250F.
This is why my car has spent it's last five summers in the garage. Now, I can't wait to take it for a 40-mile ride at 70+ mph on Highway 99, just to see what happens. Last time I did that I saw temps of 250F, and oil pressure no higher than 2.5 BAR (too low to open the piston squirters). I will probably wait for the first 105F+ day to do this, so stay tuned.
It would appear, at this point, that Porsche developed these oil pressure "check valves" to allow operating pressure to be high enough to better control operating temperature (because of open piston oil squirters, used since 1970). If that assumption is fact, then the modification is pure genius. I now consider, after only one hot-day test, that my car, for the first time, is safe to drive in Bakersfield, CA, in the summer. Hot-diggity!
I then headed for a local neighborhood where I could cruise around for a few miles, which pre-mod would take my car up to 240F+. Today, while able to keep the revs between 3200 and 3800, I was able to keep the oil piston squirters open (with oil pressure between 3.2 and 3.4 BAR at 3500 rpm) more often and longer. After many stops and starts, the oil temp slowly crawled up to 220F, pre-mod the car might have seen 250F.
This is why my car has spent it's last five summers in the garage. Now, I can't wait to take it for a 40-mile ride at 70+ mph on Highway 99, just to see what happens. Last time I did that I saw temps of 250F, and oil pressure no higher than 2.5 BAR (too low to open the piston squirters). I will probably wait for the first 105F+ day to do this, so stay tuned.
It would appear, at this point, that Porsche developed these oil pressure "check valves" to allow operating pressure to be high enough to better control operating temperature (because of open piston oil squirters, used since 1970). If that assumption is fact, then the modification is pure genius. I now consider, after only one hot-day test, that my car, for the first time, is safe to drive in Bakersfield, CA, in the summer. Hot-diggity!
This is a different (and positive) take on the mod than I have read before. I may need to rethink my position but I still wonder though if this mod is really a good thing for earlier cars with the stock oil pump. After all, this mod was introduced after Porsche installed larger capacity pumps in the cars.
Several years ago there was a flurry of posts on the topic here and at the Bird. The subject is complicated. You can see one thread here: http://forums.pelicanparts.com/porsc...ml#post4452810 that leads you to other very interesting threads as well.
06-24-2010, 07:25 PM
#40
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Interesting. I to may have to rethink this.
I think of the heads as being oil cooled. Expecially the exhaust valve steems so my thought till now was the more the better.
I see is as a good mod for a street motor. Not yet sure about on a track dog.
The biggest risk to the cam is a cloged port at the oil bar. When this happens the cam lobe goes flat. Had it happen on a 91 Turbo and an 85 MBZ.
I think of the heads as being oil cooled. Expecially the exhaust valve steems so my thought till now was the more the better.
I see is as a good mod for a street motor. Not yet sure about on a track dog.
The biggest risk to the cam is a cloged port at the oil bar. When this happens the cam lobe goes flat. Had it happen on a 91 Turbo and an 85 MBZ.
Last edited by KeithC2Turto; 06-24-2010 at 07:27 PM. Reason: spelling
