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Scavenge pump housing to cam tower leak

I have a small but persistent leak between the scavenge pump housing and the cam tower. The scavenge pump is not leaking. It is dry at the seals and the seals are new. The oil is going past the paper gasket. Rtv was later applied with a new paper gasket and this held longer but not long.

Would a thin o ring, like 1.5mm thin instead of the paper gasket be a safe more effective long term solution?

Any suggestions?


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84 911 Carrera, 78 930 RoW no option sunroof coupe, 64 Corvette, 71 911T, 73 911E, 67 Bronco, 2001 Boxster, '80 SC
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Old 10-16-2016, 09:44 AM
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I'm not sure??? but is that your seal on the end of the cam in the first picture? It looks mangled! If so you might start there.

Rahl
Old 10-16-2016, 11:02 AM
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Yes, but it is just the oil on it. I am going to try some curilT as suggested by a friend (jpnovak) and the paper gasket.
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John- I blame and thank the longhood boys of Austin
84 911 Carrera, 78 930 RoW no option sunroof coupe, 64 Corvette, 71 911T, 73 911E, 67 Bronco, 2001 Boxster, '80 SC
"Illegitimi non carborundum"
Old 10-16-2016, 11:05 AM
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SunnyD, this also works great on paper gaskets (in addition to metal-to-metal applications that it's mainly intended for).

https://www.amazon.com/Permatex-80019-Aviation--Gasket-Sealant/dp/B000HBM3QQ/ref=sr_1_1?s=automotive&ie=UTF8&qid=1476641356&sr=1-1&keywords=aviation+gasket+sealant
Old 10-16-2016, 11:11 AM
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Quote:
Originally Posted by 356911930 View Post
I'm not sure??? but is that your seal on the end of the cam in the first picture? It looks mangled! If so you might start there.

Rahl
I was thinking the same thing it looks like it's out of alignmnet. But it might just be the picture angle.
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Old 10-16-2016, 11:57 AM
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Is this area supposed to be dry? The motor was recently rebuilt and this seal looks good other than it is not sealing? I am not sure how tight of a seal this is supposed to be. After all there is a paper seal on the housing and a wiping seal on the scavenge pump so I can only assume it is normal for some oil to be there.
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84 911 Carrera, 78 930 RoW no option sunroof coupe, 64 Corvette, 71 911T, 73 911E, 67 Bronco, 2001 Boxster, '80 SC
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Old 10-16-2016, 12:02 PM
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Only supposed to be one seal, and that's the one in the scavenge pump housing. No seal in the cam carrier.

It that a converted SC cam or something other than 930?




.
Old 10-16-2016, 12:16 PM
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If you look at the cam in the end of the cam tower it looks like it is not centered and something is off. Like maybe the Pump drive lobe is bolted on the end of the cam and not actually part of the cam and is missaligned. This would make any seal leak. but like i said it might just be the camera angle making every thing look cockeyed.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
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Old 10-16-2016, 12:18 PM
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It's the angle. The cam is a Elgin Super SC cam in a 930, different grind than the previous cam.
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84 911 Carrera, 78 930 RoW no option sunroof coupe, 64 Corvette, 71 911T, 73 911E, 67 Bronco, 2001 Boxster, '80 SC
"Illegitimi non carborundum"
Old 10-16-2016, 12:36 PM
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Someone here told me a while back to use the gasket and loctite 574 on that joint. Also the one behind the cam tower. When i did that on the cam tower and that joint it never leaked again. When i pulled everything apart for the next rebuild it came apart just fine.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
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Old 10-16-2016, 12:42 PM
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If it's an SC cam and you added the drive extension with the two allen bolts then there's a good chance the oil return holes in the cam are blocked. It sort of looks like the two holes in the drive extension appear to be blind.
Old 10-16-2016, 01:12 PM
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Note the hole in this 930 cam journal at the 12:00 position. This is needed to drain the oil back from the cavity between the cam and the scavenge pump which is constantly fed from the oil bleed around the cam journal.

SC cams have two oil return holes and the added stub on the end of your cam may be blocking them.

Old 10-16-2016, 01:29 PM
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Use Hondabond 4 or Yamabond. Easily gotten at most any motorcycle shop. The last time I disassembled that, I replaced the inside reddish rubber seal seen in your second picture, too...
Old 10-16-2016, 01:29 PM
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Thanks all. I will use something like yamabond or curilT and see if that works.
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84 911 Carrera, 78 930 RoW no option sunroof coupe, 64 Corvette, 71 911T, 73 911E, 67 Bronco, 2001 Boxster, '80 SC
"Illegitimi non carborundum"
Old 10-16-2016, 02:02 PM
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what is that grey thing on the outside of the cam? a seal?

I replaced mine with a dry gasket and have no problems, also replaced seal in pump and large rubber Oring
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Old 10-17-2016, 05:52 AM
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I use titeseal on this sort of gasket, just a light smear on each side, works great.
Old 10-17-2016, 08:06 AM
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"SC cams have two oil return holes and the added stub on the end of your cam may be blocking them."

My SC cam had two holes in it, I tapped them to attach the pump drive boss, are you telling me I have to pull the %&*$*($ cam now to drill two more oil drain holes? It makes sense to relieve the oil pressure in the cavity between end of the cam and the scavenge pump. I could try drilling a small hole thru the center of each bolt on the lathe which would help but would weaken the bolt. I could fab a drill guide that bolts to the cam tower and drill it in place and with grease on the bit and try to get any chips out on the inside thru the valve covers. A better idea - drill two more holes in the drive boss on the drill press, bolt it to the cam and use those holes to guide the bit thru the cam.

Last edited by boosted79; 10-18-2016 at 06:03 AM..
Old 10-18-2016, 05:58 AM
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Yup you need to drill two more oil holes in the end cam journal if you threaded them and put bolts in them. Two new holes opposing each other 180 degrees apart so the cam remains as balanced as it was before.

Someone said there is no cam journal oil seal in that end of the cam tower... that is incorrect, there is an oil seal in the cam tower - you can clearly see it in a picture above where the scavange pump is not installed on the cam tower and Ken is right, it looks mangled.
There's a chance the fine round tension spring in the groove in that oil seal is gone now after a camshaft has possibly been pushed in and out of it without care and oiling it first. If it's not there anymore look around on the floor or replace the seal.

My '87 4 bearing cam tower has an oil seal down at the scavange pump end too. There is also another oil seal riding on the same cam journal in the scavange pump housing so there are two of them at that end of the left side cam.
That may be your oil leak.
Old 10-18-2016, 10:17 AM
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"Someone said there is no cam journal oil seal in that end of the cam tower... that is incorrect, there is an oil seal in the cam tower"

I can assure you there is no seal in the cam tower on my '79, only in the housing that holds the scavenge pump. Maybe Porsche added one in later years?
Old 10-18-2016, 10:44 AM
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I guess they did because mine has one. You can clearly see the oil seal in the picture at the top of the page.
It also looks like some one jammed a screwdriver into it at 4 o clock and tried to pry it out of the cam tower bending the stamped out steel frame of the seal under the injection molded rubber part.
whatever...

Old 10-18-2016, 10:54 AM
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