MPDano

I've never had anything Powdercoated, whats the cost in your project?

Giovanni

LOL, if we have issues with cracked blocks, then what about Chris Harris' opinion on RMS issues with 996 engines or maybe he has never heard of that.

Vilhuer

There are basically three ways how 928 block will crack.

1. AC is hit on something and it will tear piece away from block.
- Can happen in any car which is low and driver isn't careful.

2. Head gasket goes and car is still driven. This will eventually heat up piston so much than it will expand enough to crank cylinder bore.
- 924S, 944, 951 and 968 have this exact same problem.

3. Crack originates from main bearing area of the block and goes up towards heads.
- This is rarest failure mode by far and it only effects very few cars. Problem comes serious issue only if cylinder towers are removed and wet steel sleeves put into their place or possibly in very high boost applications which use stock block.

996 RMS is by far larger problem than block cracking is for 928.

Shark Attack

doesnt someone have a contact us link for him so we can straighten him out?

dr bob

My block is waiting to crack. Yours are too. What's the question? So long as we are still waiting, no worries.

The 'big one' here in SoCal is a constant threat. No matter how much the ground moves in the next major earthquake, there's always going to be the risk of a bigger one sometime further in the future. Important questions: When? How Big? Same applies to 928 blocks. Mine is likely to crack when it goes to the recycler to be made into beer cans. When? How Big? Someday. BIG, maybe even a keg...

Bill Ball

I knew there was a reason I shouldn't have bought this car! Where was Chris Harris when I needed him 8 years and 116K miles ago?

Mike Simard

This is a classic example of how misinformation becomes accepted fact. The comment refers to the "block thoughts" thread here on RL and is not based on examples of sleeved 928 engines but 944s.
The Chris Harris article may be based on reckless ignorance but the "block thoughts" post was intentionally intended to discredit an idea. It was dishonest to do so by citing examples of a completely different engine and presented in the way it was. The poster had an agenda and used his stature among the community to lend weight to unsubstantiated implications that would never have been accepted without facts if they were presented by anyone else.
The fact that someone as respectable and intelligent as Erkka repeats the premise shows how big the effect of a rumor or bad information can be. I've seen the same thing stated elsewhere too and the block thoughts thread was the source.
When the future Chris Harrises write an article on 928 racing engines and the subject of sleeved ones comes up, what do you think will be said?

Z

Does anyone have any actual information on this type of block cracking occurring on a wet sleeved 928 engine? I mean actual information, not speculation as may have been posted in the past. I'm aware of three 928 engines that have had cracks of the kind being refered to, but none of them were wet sleeve engines. All three of the ones I'm aware of that cracked were stroker motors, and the cylinder towers were NOT machined out and replaced with wet sleeves in any of those. Are there wet sleeve 928 engines out there that have actually run yet and experienced the problem? I only know of one 928 engine that's had wet sleeves installed and been run. As far as is known at this point, that engine hasn't had the problem. If there are other wet sleeved 928 engines out there somewhere that have been run and have had the cracking occur, I think everyone would be interested in any details, especially since these blocks aren't being produced anymore and wet sleeving could be a way to save some otherwise worthless ones.

Dennis Wilson

Prior to the 928, previous made all-aluminum blocks were prone to cracking or warping if overheated. Case in point is the 61 Buick. The Porsche engineers compensated for this on the 928 by doubling the coolant and oil capacities and changing their molding techniques during initial develpment. IIRC this subject is covered in Projeck 928 or Up-Fixin V or both. Needless to say, there is little or no truth in this rumor.

Dennis

hacker-pschorr

13 years after production ends!!!! What a joke.

TAREK

I don't know where all/any information on cracked blocks could be statistically significant, in comparison with actual data on blocks still not cracked. For example, my 86.5 has more than 300,000 miles on engine and tranny and still going strong...or should I say uncracked?

pmotts

There is some contact info in this thread

https://rennlist.com/forums/showthre...ghlight=harris

Vilhuer

Block cracking he speaks of has very little to do with steel sleeves so they are irrelevant and I shouldn't have brought them up. He must refer to either hiting AC to something or head gasket related block failures. If he is worried about those then he really shouldn't buy any Porsche anyway. Both problems can be easily avoided.

918-S

I cracked one. Dropped a valve, valve lodged in the head and the piston split the cylinder.

I've dropped valves on Big Block Chev engines too. The same thing happens. Block cracks.

Nicholbry

I originally posed this topic (unaware that another had been started -sorry) because, as many of you know, my car is out in CA at Greg Brown's shop getting a rebuilt motor installed (TBF). I was just wondering if there was something that I could do, buy, add-on, remove etc. to my engine while it is out of the car to prevent this or increase the engine's longevity. The block going in had 90K mi., although it was disassembled completely, will have new bearings (w/ proper tolerances), and pistons were machined to w/in 1 gram of one another for better balance. Greg Brown is top notch, no doubt.

I know we like pics, so here's a couple Greg sent me of the work in progress.

* 3rd picture is the original weight of the pistons; they've since been machined. Kind of interesting to see such a wide variance, but I'm no mechanic so maybe this is normal.

* 5th pic shows how badly coated the pistons were (that's not charcoal) - good thing we opted to break the block down