Orest

Dan- The engine is out of the car on a stand but the studs are in place. I am going to post pics today and see if it's bad enough to send the whole thing to a shop to get decked.

Blown 87- I will research the hylomar.

Orest

SO my question now is is there a sealer that is safe to use with the stock Porsche gasket (fiberglass)? Hylomar? Copper spray?

Daniel Dudley

A machinists straight edge and a light shining from the back side can tell you a lot. So could a few passes with a perfectly flat whetstone. In the old days, machinists would hand lap things on a routine basis, but if you are not familiar with the technique, you can do more harm than good.

I too am very fond of blue hylomar, but I have never used it on a 928.

blown 87

The spray Hylomar is a lot different than the tube hylomar, it is really thin so you can spray it, it is expensive and comes in a very small spray can.
It is worth every dollar on head gaskets.

The distributor told me that there was a problem with the last batch that was made and it is short supply right now.

Your best bet is to find a machine shop that has some on the shelf that they will sell.

I use a lot of Hylomar at the shop, mainly because it is very good and I do not like RTV.

Back to point, if anything other than redoing the bottom end of your motor will help, spray Hylomar will.

What it really means when you are talking about decking the block is a full on engine build.
You are going to have to take the engine down to the block to clean it after it is machined.

For someone with the skill set of Greg Brown and some others here it is not a big deal, but for the rest of us, doing a rebuild on a 928 engine is a major undertaking.

This is just added on trivia, but what my machinist told me was that not only does a Roloc (and other power abrasives like this) does is that it removes the sharp ninety degree angles where the holes for coolant, oil and combustion chamber, doing this makes a path for the oil, coolant or combustion chamber gasses to start a pathway for leakage.

He said it was kind of like a hydraulic wedge, but even though there was not such thing it was a good mental image.

I have no idea if there is any truth to this.

Orest

I looked at the block again today and decided to just cross my fingers and pray. I cleaned the block with a razor perpendicular to the surfaces and used just a little scotchbrite. There are very minor swirls from the roloc pad, nothing more than a light brushing in my opinion. The pics I took don't really show the surfaces too well so they are not attached.

I also took a straightedge to it and used a feeler gauge (0.004 was the smallest in the shop) and it seems true.

However, the edges overall are what may do me in (referring to blown 87's comment), they appear a little rounded from the roloc.

Hopefully this won't be a problem or maybe it's something I can manage with Barr's stop leak in the future.

I really appreciate all the input from everyone!

GregBBRD

Stock gaskets work dry...anything else seems to "upset" the design of the gasket and makes the sealants built into the gasket fail.

blown 87

I would take Greg's advice.

Orest

Regarding Greg's comment, I heard the same thing from my machine shop. So, last night I put on one of gaskets dry and have left it over night to "preload." I will do the same with the other side and I think (hope) that I am ok. The roloc just put in surface swirl marks but all the surfaces are smooth to the razor.