GregBBRD

Kyle removed an engine from a 130,000 mile '91 GT the day before yesterday and popped the heads off, yesterday.

This is what I'm used to seeing....


'91GT 130K #5-#8 head with gasket still attached.




#7 cylinder with burned exhaust valve. Note that the combustion chamber is "steam cleaned" from water getting into cylinder.



Because Fred will want to see the head gaskets, separate.



Close up of the worst part of #1-#4 head gasket.



Close up of the worst part of #5-#8 head gasket.



Close up of #5-#8 cylinder head. Note the dark areas (where the pointer is pointing) where coolant has been migrating under the fire ring. Note the areas at the bottom of the combustion chamber where the this is also occurring.

Entire #1-#4 head, looking at combustion chambers. Note the black areas around each combustion chamber where coolant was migrating under the gasket.


Entire #5-#8 head, looking at combustion chambers. Note that #7 cylinder is the only cylinder where there is no trace of water intrusion under the head gasket. Yet it was the cylinder with the coolant in it that got steam cleaned!


Fortunately, the Porsche dealer in South Carolina was smart enough to know two things:
1. They did not have anyone with the technical expertise to fix this engine.
2. They knew that "cranking the engine over" could result in even bigger issues...and took steps to prevent this from occurring.

Because of their great insight, this engine does not appear to have a "split" cylinder that I have to deal with!
Kyle is taking this engine the rest of the way apart, today.

And pulling an '89 GT engine (with original head gaskets) with the same grief.

There's a message about head gaskets and coolant that I keep repeating on this Forum, somewhere in this thread.....

oups59

What 60,000 more miles can do .... This is mine removed from a 1988 with 115,000 km ( 72,000 miles).

Do you need to shave those heads?

GregBBRD

The GT heads pictured in my post will require welding and shaving.

While I can't see if your head has pits, your heads do have some signs of water intrusion, under the fire ring.
I'd certainly suggest that you have them taken apart and shaved, at a minimum.
Being 35 years old, I'd think that replacing the valve stem seals would be in order, anyway.

.....While not the toughest job, getting the heads off and back onto an '88 engine isn't exactly a quick and dirty job.
I doubt you will want to do it again.....

Darklands

My Shop told me if the engine was sometimes filled not with G48 the damage is even worse.
Porsche Clasic ask him if he has good Blocks, I think Gregs advice is wise to save the engines and reduce costs.

Rob Edwards

Is it Cancer?

Darklands

Arthrose? What's the meaning in english ?

NoVector

I'll put $10 on G-05 to win.

FredR

Thanks for taking the time and effort to post.

This is a classic case of what I have been advising about. Look at the transfer ports in the head- clean as a whistle and no corrosion - obvious that coolant per se did not cause this attrition.

The gaskets have also been attacked from the head side.

Was there any localised corrosion on the top mating surface of cylinders 7 &8 adjacent to the gasket damage by any chance?

It would be interesting to see the heads after the initial layer of gunge is removed to expose the corroded surfaces- doubtless there will be pitting present.

Darklands

The Mantra is: if you don't know the Status quo of your engine, change head gaskets.
than change every two years the right coolant.
We did after an head gasket failure after 30 years an complete refresh on my S2 from 84. I was lucky not to break a cylinder.

GregBBRD

A fair amount of white corrosion around the tops of the sides of the cylinders, which I've largely scraped off, at this time.
There is definite pitting on the heads.
However, this is not a revelation, but a given, these days.
It's very, very rare for us to not have to weld on a set of heads, these days.

GregBBRD

This engine was filled with "pink" factory Porsche coolant, when we received the car.
Doubtfully, anyone knows what was in there, in the past.

GregBBRD

As in, "Vot are you selling this year....Cancer"?

Not as bad as the last GTS we did.
And not terminal, but will definitely require some radiation treatment, from a TIG torch.

karl ruiter

I recently did my '88 heads, which were somewhere in between yours and what Greg is showing. Lots of pitting, but only a couple of spots intruding on the fire ring area that required welding. If a head has been off I always surface it and put a new head gasket, because that's just how my daddy raised me up. More importantly, on my '88 I was hoping just to lap the valves but the machine shop said the guides were so badly worn that the valves were floating around up enough to damage the seats. Compression was good, and they were valves were sealing, but it would not have lasted. Which, I think, is the downside of those miles. So you might want to look at that. The ODO on this car broke at 6x,xxx miles, so it is TMU. I am guessing, just based on the guides that it is more like 100K miles.

GregBBRD

Add in a "wee bit" of silicone bead dust from blasting and powder coating the intake manifold at some point in time:


Piston ring end gap....some damage from silicon beads

Telltale piston scratches from silicon beads.

And every camshaft having pits:

Typical GT camshaft pits.

.....And it won't be done, by the end of next week.

GregBBRD

I wish you all could rub our finger through these areas and feel the grit.
Amazing.

However, I one doesn't know what they are looking at, on the pistons, this engine could be re-assembled with the grit still there!



"Grit" inside intake manifold....mixed with oil, forming riverettes of grit.

"Grit on the inside of the intake manifold...mixed with oil, forming little riverettes of grit.

Grit mixed with oil, plastered against the internal butterfly.


The people that are fixing these engines, right now are the lucky ones.
At least there are currently some parts available!