Landseer

My only point was the hg failure contributing to hydrolock as being a common report here.

Cause doesn't seem to be a cracked block on these heavy-walled engines, just corroded interface.

And the automatics have a driveshaft/coupler design issue that has resulted in a large number of failures of thrust bearings and resulting cataclysmic engine failures due to effects of resulting preloading.


You might contribute as much or more than any of the amateur and pro mechanics here. These cars seem to have strengths where others have weakness, and sometimes vice versa.

Kiln_Red

Just one more reason why I am happy to own an earlier car.

Kiln_Red

I'm actually in the middle of doing head gaskets on my car. Landseer, I have been following the other thread that you referenced here. Since I've been disassembling my own engine I found this thread very compelling. Here is a photo of my engine bay at the moment. That engine is coming out before I go any further. It was challenging enough pulling those cam carriers out. I can't imagine going in would be any easier.

Landseer

That's some serious work to get the heads off in the car. Where are you in TN? What are the details on the car? The one in the avatar my headed to Bristol this week.

Kiln_Red

It would honestly be a breeze if it weren't for the cam towers. That's been the only curve ball so far, so to speak. I'm lazy though. If I see ANY occasion at all where I find that something MAY be easier done on an engine stand, then by George, that beast is coming out of the hole.

I'm about 30 miles north of Nashville actually. The vehicle is an '84. It had been my daily driver until about 3-4 weeks ago when the water pump quit. I figure, "What the hell?" The car is 26 years old. I'm not going to just put another pump & a new TB on it without going the whole 9 yards. I've owned the car since '96. Finest car I have EVER driven. I love the 928.

Vilhuer

There are at least three ways to crack stock 928 block.

1. Head gasket failure where coolant can leak into combustion chamber. This leads to water washing oil away from cylinder wall which in turn causes friction between piston and cylinder bore. As piston expaqnds from heat it will crack cylinder tower, usually from 6 o'clock position as water pools at bottom. I have seen crack where it started from the middle of stroke and did not reach all the way to the top. Cylinder wall to piston diameter difference is so small in these engines that it doesn't take much to crack them.

2. Piece is cracked away from lower front corner of the block due to AC or alternator hitting something. As they are bolted to block its block which cracks as its weakest link which can give in.

3. Block cracks around thrust bearing area due to TBF.

Besides above there are other possibilities too. Using wet steel sleeves in place of Alusil cylinder towers can cause center of V to crack.

Kiln_Red

Not saying it isn't possible, but I would have to see it to believe it I guess. The scenario you describe where you have seen/heard of blocks cracking as a result of water in the compression chamber is the same type of scenario where I have seen it cause ring groove, but never cracking. Again, not saying it isn't possible. Only very shocked that there are apparently known incidents of this in a 928. Perhaps the fact that the 928 has no cylinder liners changes the dynamic on this conversation as it is the only engine I've ever seen with that design.

Vilhuer

I have two GTS blocks in garage which are perfect example of this.

Landseer

You (and me, too) have stumbled upon ground-central for 928 knowledge.
These guys are the real-deal. If Vilhuer says it, you can believe it. Enjoy!

While you are here, do an advanced search for posts by rennlister Dwayne. He did some very high-quality write-ups that pertain to the 84. And then there are the better part of 9 years of archives here, too.

terry gt

A fourth way is to drop a bolt in the intake , split the liner right down from the top