linderpat

looking for guidance from the gurus on a 16 valve top end refresh. My car is a 78, so very little rubber on top. I have done the 32 valve job, and there are lots of good pictorials and write ups for those, but not much for the early and "easy" engines. Still, what are the "gotchas" I have to worry about? Also, some random questions:

• do you put sealer on the gaskets between the spider legs and the manifold or do they go on dry?
• what about the other paper gaskets - dry or with sealer?
• what sealer do you use - silicone RTV, something else?
• to remove the cis system under the spider, do you pull off every gas line or just pull it all out as a single unit after you pull out the injectors at the other end of each line?

Thanks for the insights.

Ducman82

Spider gaskets go on dry
I use a slight amount of Honda bond on the water bridge gaskets
Not sure on the voodoo stuff that is cis

jwillman

Just did mine.

Disconnect all the lines at the fuel distributor (FD), fuel injectors and the start valve at the front of the plenum/ air gallery.

You can then pull the injector lines off and out of the car to make room.

I pulled the throttle body out separately has it had the decel valve attached.

I left the FD attached to the MAF and attached to the air guide housing and pulled those off as a unit.

The air guide housing is held on by 4 nuts on rubber mounter bumpers that thread into the top of the engine. All four disintegrated when trying to get the nuts off as the rubber was completely perished. Order new ones. They are cheap but had to use a cut off saw to grind a slot in the top to get then out as there is nothing to grab a hold of once the top part separates.
https://rennlist.com/forums/928-foru...t-removal.html

There are also orings at the base of the throttle body and FD.

Search youtube for 928 CIS injector removal. There is a DIY tool for injector removal that makes it a snap. Only call out is the brass coupler is not 1/2 inch to 1/2 inch. Should be 3/8s to 1/2. Got all the stuff at lowes.

linderpat

Thanks Jim. Were there any crush washers to replace with each fuel line from the distributer? I did order those rubber bumper fastners. O-rings, etc. The fuel injectors have been out recently, so I'm good with that job too. Those other linked threads are very helpful.

jwillman

There are 2 each crush washers for each of the 8 injector feed lines as well as feed or return line on the side. Any banjo bolt will likely need two, one top and bottom.

linderpat

looks like a lot of folks are doing a top end refresh right now based on the threads. Anyway, mine is progressing. I'm doing the water pump, timing belt, and full top end refresh. Pulled the water pump, and it looks good. Metal impellor but genuine Porsche unit. Still good, only 5 years old; no play in the spindle, and I can't see it where it was leaking. I will keep it as a spare, I think it has lots of good life in it still (I'll sell it if anyone wants it). Pics below.
Also, posted below are pics of my valve at cylinder 5 - does this look like too much carbon build up?

linderpat

bump on the carbon valve question above. Is this normal?

Guy

Normal? Depends on conditions that the car was driven under, mileage etc. I have seen way worse in domestic engines.

Of course, being new to the 928 world, I can only tell you that mine was the same. You can try a tad of water detonation to clear it up.

dr bob

Ed, that's pretty mild in the big scheme of things. There's a little bit on the edges but that's hardly abnormal. The phrase "Italian Tune-Up" just jumped into my head from the ozone. Who knows where these random thoughts come from?

linderpat

Ha - Dr Bob - I have done that procedure too, but not yet this year!

BC

As long as you replaced the fuel hoses, and Italian tuneup with e85 cleans those valves.

linderpat

did the fuel hoses 4 years ago. Why e85? I try to run efree as much as I can. Is there an additive like Techron that would do the job? I'm learing of putting the 15% ethonal in my car. Most around here are 10% ethanol.

linderpat

Here are some pictures of the top end refresh process. This phase is now done. Just need to finish the timing belt project. Bit off alot here. I have no idea if my car will run once I am done, but it will sure look great

linderpat

more pictures

linderpat

top all done; now to finish the timing belt job.