View Single Post
KTL KTL is offline
KTL's Avatar
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 15,990
Send a message via Yahoo to KTL
You've got quite an autopsy going on this engine. Nice job so far!

Looks like somebody chose to seal the cylinders to the heads with the orange loctite 574 goop? That's not necessary...... Also no reason to use that white teflon paste goop anywhere in these engines.

I would consider replacing the rocker shafts since they show a lot of markings. When you consider the fit is such a close one, you don't have a lot of room for wear. Plus the shafts aren't that expensive and Pelican has two good alternatives (Mahle & Febi Bilstein) to the original Por$che part

The bores in the cam housing need to be cleaned up so your shafts will seal well. Need to be careful with what you use and not disturb the surface too much. Wrapping a socket with super fine grit sandpaper does a nice job of cleaning them without disturbing the precision fit. Or you could try a hone and be very gentle with it.

You can get a grape hone that is 5/8" size (the rocker shaft bore is 18mm which is 5.67/8ths) and rotate the hone by hand to clean up the crud. Be sure to lubricate the hone with some oil.

The cam housings are easily the most neglected and abused part in these engines. I have seen so many boogered up cam housings over the years and I just don't understand why. It's baffling to me that people don't treat them with more care, given how much influence this piece has on oil leaks. Let's think about it:

-Both valve cover gasket surfaces
-Oil return tubes
-Camshaft paper gasket surface (more on this later)
-Rocker shafts
-Head sealing surfaces
-Oil spray tube

All of those places I listed have a high chance of creating a leak and still people do crazy stuff like clean them up with a scotchbrite pad, stamp numbers in a machined surface, gouge them with tools, etc. Just don't understand why so much carelessness

Regarding that camshaft paper seal location. Make sure before you reinstall the housing, to flatten the gasket location on each housing and also flatten the gasket side of the thrust plate (the piece that bolts in from the chain box side) because you'll be surprised how NOT flat that area is. Especially on the cam housing. It's easy to do with some wet-sand paper and a flat surface like a pane of glass.

And when you mate the heads with the cam housing, you hardly need any sealant. Only the round areas near the valves and the stud holes need sealant. All the rest of the machined surface doesn't need anything. It's just a waste of sealant and makes for unnecessary cleanup work (removal of old sealant) the next time someone takes it apart.

I think the CP pistons are a nice alternative to the usual JE pistons that have been used for years. The CP pistons appear to have all the features JE offers, and many of them at no addtional cost. Like for instance the JE pistons cost a lot more if you want the reduced skirt (they call it FSR- Forged Side Relief) and CP pistons are standard that way with their X-forging. Plus the flyer below says their pistons include a piston pin circlip (wire lox) tool. SWEET!
Kevin L
Present: '86 Carrera, '79 911SC widebody conversion rolling racecar shell
Past: '87 Carrera
Old 11-22-2017, 08:24 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)