BC

https://rennlist.com/forums/showthre...hreadid=134452

2V4V

Not terribly shocking.

Sad, but not terribly shocking.

BC

No, not shocking, but not good at all. In fact, quite troubling. Troubling because we have no other choice then to go wet sleeve all the way to the webbing.

Looks like the money would be better spent with a deck plate.

Flint

Sorry, but I'm wondering just what the lady in Danno's avatar is doing to his car. Seriously, I'm actually rather disturbed by that picture...

TroppoShark

Flint,

Isn't it obvious?

She's there to hide some of the number plate...

heinrich

Flint I agree, very disturbing. There's clearly a problem, she should be 100 lbs heavier, wearing jeans and sporting a tattoo on her forehead with some sort of star. And she should be sitting on her wife's Mack Truck.

Seriously ... what disturbs you so about a classily-dressed pretty lady and a pretty car together?

2V4V

Heinrich,

I'm with ya man. (Though honestly she does look slightly uncomfortable in the pose...)

Brendan,

I'm sure you read through the hole (pun intended) thread. My personal read has pretty much been my experience for a while (lots of learning from other's issues) -

If thou bores out to the ragged edge and sleeves, thou shalt pony up for the best freakin' machine work available. Or forget it. In fact, if you've gone to the trouble of pulling a powerplant out of car (esp. any exotic) WTF are you trying to save $200 on machine work for? Collect bottles, get a paper route, work a McDonald's for a week, sell your plasma, whatever - just spend the money. Please, please, please. A good Porsche machinist is your best friend, and not an option. Borrow a truck and drive all day if you have to, just get it done right - or be ready to do it over. and over. and over.

Thou shalt use OEM pistons - I know, this'll get me flamed but I tell you after watching, listening, and being involved with this stuff for quite a while, there are SOME things that I just don't like the odds on. If it works for you, great. I've seen some Ross stuff that worked very, very well. But personally, I don't like the worry. I'll pony for the Mahle/Kolben.

The mixing of aftermarket pistons of "one-off" dimensionality with cylinder liners from a different manufacturer and then a hogged out Alusil block guarantees a bunch of different rates of thermal expansion.

This can lead to less than positive results. These unhappy results can become more common when you shove 20+ PSI of boost down it's gullet on a semi-regular basis.

On one of the other threads Devek Marc and I are disagreeing a bit about the limitations of an open deck block. Regardless of the other aspects of that discussion, the science in the area cylinder design seems to pretty consistently suggest that the *prime* cause of major cylinder deformation is the different rates of thermal expansion for different metals.

Different block, liner, and piston material would seem to me a very risky proposition on the face of it, until one had done some really hardcore calcs, and even then, I would be very concened for a *street* engine. Race motor? Sure. Who cares. But a street engine is tortured in ways a race powerplant never is, and is expected to do a LOT of hours between rebuilds. If set up 100% right, it might work fine. But what if it's not 100%?

Like I said, there are ways to make it work. There are folks who have had success at this combo plate. But it is NOT to be taken lightly, and frankly, 3 different rates of expansion and a thinnish tube to put it in, seems like a lot of risk for a (relatively) small displacement increase.

But that's just my take,

Greg

Lagavulin

There is a LOT of heart-ache in that 951 thread. The best we can do is do as gbyron does:

Based upon that, the bottom line is, we have one crappy block to work with if we attempt to get some real horsepower out of it. And to me, it just doesn't look like it's worth the time, trouble, and pain attempting to rectify it.

Closing the deck? According to one of the posters in that thread, it costs $1000 for four cylinders, so make that $2000 for eight cylinders. Who knows what happens to the block with all that heat from welding anneals it. No doubt the block will have to be heat-treated afterwards.

Depending upon how serious one would be, THE engine to drop into a 928 would be Ford's 4.6L 32v:
http://www.seanhylandmotorsport.com/

Now here's what a V8 block should look like!:
http://www.seanhylandmotorsport.com/shm_block.shtml

What a foundation to build high horsepower upon!

By the way, I'm with heinrich; I wouldn't mind that beautiful woman hovering over the hood of my car!

H2

I don't mind the Ford engine concept (Chevies are generally better) but you can by a Chevy adapter kit for the 928. I'm not that serious yet I guess but if the engine ever blows it's an option.

By the way, isn't that a lap dance? She likes the car better than the owner.

Harvey
'85S 32V...and not a street rod yet.

"Depending upon how serious one would be, THE engine to drop into a 928 would be Ford's 4.6L 32v"

Fastest928

Lag says: "Based upon that, the bottom line is, we have one crappy block to work with if we attempt to get some real horsepower out of it. And to me, it just doesn't look like it's worth the time, trouble, and pain attempting to rectify it. "

What is this...a change of heart about the "robustness" of the 928 block for high horspower?

I was waiting for that highly touted 7.0 l to show its face...or the 48 psi boosted 928...darn, now the block is a wimp and we are told to replace it with a ford! Nothing wrong with Ford, I spent some years working for Ford..great company...but...

What is the new projected limit?

Marc
DEVEK
NOT agreeing with the "bottom line"

2V4V

Lag,

Why the panic? Perhaps I wasn't clear about my meaning. This is stuff at the ragged edge. I wouldn't worry about the block too much pumping a bunch of boost into it. I DO worry about hogging it out too far and jamming a liner in it, then boosting it. No matter what the powerplant, it's seldom a 100,000 mile motor in the end.

Marc has gotten more than decent HP out of the block. He even does it with a stroker. Block seems to hold up just fine.

Many folks have bored out their 928 and run it NA with positive results. So far the supercharged folks are doing fine.

It's the *combination* of a "bored to the fringes" block, a liner of differing material, pistons of a third material, and (I would wager) way more than 12 PSI boost, that is the dicey recipe.

Greg

Lagavulin

Fair enough; but I never said anything regarding the robustness of the 928 block. My remarks were always aimed at the crank and rods. But that 'point' really doesn't matter anyhow now; given the choice, I'd much rather replace wimpy rods and/or crankshaft versus having to fix/replace the block.

With that said however, I still have yet to see a grenaded 928 rod or crank outside of the 2/6 failures. So I still stand behind that portion of the remark I made earlier.

Has anyone seen the block/cylinders of the Porsche TAG engine? I'm willing to bet it was not an open deck design. Now that engine was putting out some 'real' horsepower'!.

I believe that was Huntley, and at the time, he said he was going to post a dyno sheet.

Hmm, never heard of that one. Perhaps that was one of your ideas?

If you'll re-read the post, I said that with respect to 'high horespower'; I haven't seen a NA 928 engine do that yet, nor do I expect to any time soon. I guess it all depends upon one's definition of 'high horsepower' though; to me, it starts at 700 rwhp, or about 825 crank hp. Some may even consider that low horsepower, like the Supra guys.

100 crank hp/L (..chp/L) NA is nice horsepower for sure. But to keep that number in perspective though, otherwise stock street Z06's are putting out 90chp/L with just an exhaust and cam change, and that's with being 'shackled' with a totally un-sexy 2v head. On the other hand, a completely stock Honda S2000 does 109chp/L right out of the box.

The block pictured in the link is currently in a 1500 hp centrifugally supercharged Mustang which has now made several hundred 1/4 mile runs without breaking ANYTHING; now that's a strong engine in every sense of the word! For that block combo, it looks like 'the sky' is the limit.

Hey, makes for an interesting discussion, jabs and all!

You are on the right track, but cylinder ballooning can occur with a stock cylinder and bore size, especially if one is running 20+psi of boost.

Tony

http://sambandit2.home.comcast.net/mevsmike.wmv

YOU BETCHYA! I tell ya I cant wait to see the new Cobra Rs...
The power these guys make with the stock motors is pretty impressive.


I would just like my engine to HOLD together at 20psi!!:

Jim bailey - 928 International

Greg nicely stated " that is the dicey recipe " . I think we have all ordered a favorite food at a new restaurant only to find that some how that particular cook managed to screw it up . Add in the fact that the food was "cheaper " , the cook never made it before , and you were trying to tell him HOW to do it based on what YOU read on the internet ................. It is even more interesting if you are the supervising chef and you haul it around and have several different cooks add their own seasonings . When testing the envelope the only way to KNOW is to go too far , figure out what happened , then back up a bit . Highly modified "race" engines benefit from being built by professional mechanics with a history of building highly modified race engines who have tested the envelope BEFORE !! Anyone can take an engine apart , most can put one together , some can get it to then run ................ most should learn from the experience . And I do understand that with shops charging $100 / hr or so there is a huge incentive to learn ! Now where is Andy with that blower ?

David Floyd

The Performance Developments deckplate is not welded in but the block is machined and the plate pressed in.

https://rennlist.com/forums/showthre...ight=deckplate

That Ford block is a work of art.