Oil circuit upgrade in '79 sc...thanks Noel...

[ascarswell]

Does anyone have any idea of what is involved, both parts wise and labor, with the upgrade to oil circuit in my '79 sc? According to the article Noel copied from Rennlist, the pressure relief valve & sump screen need to be upgrade. I don't even know what these parts look like, let alone what's involved with upgrading them. Any help would be greatly appreciated! Thanks again, Noel, for your excellent diagnosis! I'm impressed!

Thanks.
Adam

Originally posted by ascarswell

On top of that, when it lost power on the back stretch with about 5 minutes of the 30 minute session left, I pulled into the pits and noted that, with the car stopped and idleing, the oil level guage was all the way down to NOTHING, yet after it cooled a bit, the guage's needle bounced right back up to full indication. HMMMM....

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Reply from Noel:

Adam, I believe you have a 1979 SC. What you describe is an issue with the 78-79 cars that have never had the oil circuit upgrade done. What happens is that the oil pump can't pickup oil during high corning G situations and it basically fills the engine sump with oil, thus pumping the oil tank dry.

Check out the tech articles on Pelican and Rennlist for more info. I think the SC FAQ on rennlist covers it. Let me know if you can't find it and I can send a link.

Check your receipts to see if your cars has this upgrade. If not, I would suggest getting it done before you go back to the track.

BTW, the oil circuits on the 1980+ models were upgraded at the factory.

Noel


__________________
Noel

1980 Porsche 911SC w/


Here is the quote from the SC FAQ, which can be found at:

http://tech.rennlist.com/

"There were several upgrades made to the 1979 and 1980 oil circuits to prevent oil cavitation and the sump filling up with oil, which caused a sudden loss of engine power under hot driving conditions. The first fix, a new pressure relief valve, was
incorporated after engine number 628 2539 (non-CA) and 658 1060 (CA) in 1979. In 1980, there was a new sump screen design which helped the pump in picking upcrankcase oil. It's recommended that both these be fitted to pre-1980 SC's, however, they are not needed on earlier 2.7 engines. While not critical to idling and going to the corner store, these two upgrades should be made if you intend to drive your early 911SC with vigor. There was one additional oil-related change made in
1983, and that was a change to a new screened oil pickup and sump plate without an oil drain plug. At the same time, Porsche made this the replacement for 1977-1982 engines, where a new oil pump or sump plate is required. There is a good discussion of this, including references to PCNA dealer bulletins, in "911 lubrication System Upgrades" by Allan Caldwell in Porsche Panorama, p. 12, December 1999."

['78 SC]

Adam,

The updated (meaning it was redesigned two decades ago) sump screen is an easy install. Just replace it when you do an oil change. The difficulty is finding the part, since it is NLA. (I'm assuming you checked to see which screen you currently have.) Used ones do come available occasionally when owners upgrade to later design oil pumps with the integral screens on the pickup. Check out the thread here and search on "venturi" and "sump" for more background.

The relief valve upgrade is inexpensive. Check our sponsors for parts. The installation is not difficult, but you may struggle some removing the slotted plugs that retain the pressure relief valves and springs. Wayne's engine book walks you through the process.

Good luck.

[Noel]

Adam,

You're making me blush.

You might want to search out the article in Pano referenced in the SC FAQ quote. I have all of the Up-Fixen der Porsches (Archives of past Pano tech articles), but they stop at 1998, so your best chance of getting that article is to call the PCA to see if they have a reprint. You could also solicit a copy of that article from the folks on this board, as many may keep their old Pano's (Sorry, I don't).

A call to Porsche North America could also help.

Good luck,

[Noel]

Adam,

I just check the PCA website and you can order back issues of Pano for $3.