Porsche 944 turbo road to racecar.

[doctor ed]

Cut losses and buy this?

https://www.racecarsdirect.com/Adver...48/porsche-948

Oooo.... that's about 45mins away from me....

[Roy928tt]

After sleeping on this. It's cheap arse Americans.... We don't have much of a problem with freezing engines in Australia, but other countries do. I'll bet, that is the root cause of the cracks, a lack of anti freeze.

It was one of those things the American 928 owners were anal about, and applies equally to the 944 but one wonders if the cheaper Porsche falls into the hands of less discerning owners who give no fucks....eventually the neglected car is bought by a Porsche engine workshop. Who remove the engine and wreck the rest. The engine kicks around under a bench till someone in Australia needs an engine built....because they didn't supply a donor engine.

As for checking for such damage. from my time on the 928 forum I don't recall any block failures from freezing, so it wouldn't be something I'd be concerned about. Timing belt failures, yes, and torque tube clamp creep/engine thrust bearing failures, yes, corroded head gaskets, yes, but not cracked blocks from freezing.

[PXL265]

But to me testing the block would be standard practice.

I know it's not in the same league, but my old shitty L series blocks I used were always checked for cracking before being built and sonic tested to see how big we could go if they were going to be bored out.

I hope you can get something back out if the engine builder for not checking what a lot of people would consider basic prep.

Really feel for you with the time and dollars you have invested in this car, and hope you can come back to have another crack in the future.

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[Uncle]

That's just fucked. Gutted for you Pat.

[fnlow]

this thread makes me believe in curses! feel for you mate!

[da9jeff]

After sleeping on this. It's cheap arse Americans.... We don't have much of a problem with freezing engines in Australia, but other countries do. I'll bet, that is the root cause of the cracks, a lack of anti freeze.

It was one of those things the American 928 owners were anal about, and applies equally to the 944 but one wonders if the cheaper Porsche falls into the hands of less discerning owners who give no fucks....eventually the neglected car is bought by a Porsche engine workshop. Who remove the engine and wreck the rest. The engine kicks around under a bench till someone in Australia needs an engine built....because they didn't supply a donor engine.

As for checking for such damage. from my time on the 928 forum I don't recall any block failures from freezing, so it wouldn't be something I'd be concerned about. Timing belt failures, yes, and torque tube clamp creep/engine thrust bearing failures, yes, corroded head gaskets, yes, but not cracked blocks from freezing.

Nothing to do with over ~3x the standard power output? Even though the boost was only 16psi or whatever, boost is only a measure of restriction. 600hp is still 600hp worth of load on the motor.

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[Mini]

This sort of shit drove me away from racing after spending many tens of thousands so I feel for you. In the end we broke it all up and parted it out and got a small percentage of what we had spent back. You never go into motor sport expecting anything but a money pit but stupid stuff like this is over and beyond the normal expectation.

[Roy928tt]

Nothing to do with over ~3x the standard power output? Even though the boost was only 16psi or whatever, boost is only a measure of restriction. 600hp is still 600hp worth of load on the motor.

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From what I see of the 928 engine, I wouldn't consider that the slightest issue at all.

A 3.2 litre 4 valve per cylinder engine will produce 600hp ( I mean if you had a 3.2 litre RB or JZ you would want that sort of output) relatively easily and the Porsche bottom end is more than capable of withstanding the forces involved. We are seeing with the 928 engine 1000 rwhp on essentialy stock 5 litre engines...

[333pg333]

That's the problem with using old Alu blocks. You have no idea of the history. I started the build with this motor 10 years ago but it got shoved to the back burner as I dealt with other motors. I had invested a fair bit of cabbage on this block and head even back then. So at the end of 2015 I decided to finish it. It got out of hand and the builder tried to design in as much preventative engineering into it so that we'd have decent longevity. (Inject Irony here) The builder did apparently have it crack tested and water pressure tested but as the brief wasn't to deliver a fully built, tested & run in motor, then it wasn't put under pressure oil wise. So in reality how can a builder ever be held accountable if they don't actually sell you a fully built (inc intake, exhaust, ECU) tested on dyno, motor? I don't know when he crack tested it. I have invoices showing this from back in 2007. I believe he had it tested for water pressure more recently. Add that it was bored slightly. 104 - 105mm, it has had large headstuds installed and a Timesert type thing installed inside there. Deckplated too. However he said that the process of press fitting the deckplate doesn't require much force. Add to that the motor is on solid engine mounts. Why did the crack in the other side of the motor suddenly happen and we had hardly even done 1 lap and it wasn't at full noise. Maybe this thing was just going to continue to crack all over. Still, you'd have thought that it would have shown up somewhere in the 10 years it took to be finished and delivered.

Massive shame for a number of reasons. Apart from cubic dollars on my part and never driving the thing, it just started to show some promise as far as an efficient motor goes. 500whp @ 10psi is strong in anyone's book. Pretty much all the competitors at WTAC run 25psi+ 'gate springs and use 35psi as their boost base. Just would have been fun to see what it could do. Not sure about a .28 but I reckon there was a .29 in it. Will probably never know.

[fatz]

Commiserations old son

Grab some scotch

Smash it down

Throw the feet up and yell KUNT lousy

Least she didn't burn down to the cage

Everything can be fixed

[333pg333]

Thanks all for the kind words of support.

I'm working with the builder and people here to see what we can come up with. At this stage we can't lay blame at anything without having a closer look.
Possibly treating a 25+ year old block to Nikasil treatment may have affected the metallurgy of the block? This is the first one that he has done like this.

Back to the Scotch...

[nuk1ear]

Very sorry to hear mate. Hope to see things come back to life in the future after some reflection has been made and you feel more comfortable to get back into it.

On a side note, you could always get one of these, Insane $$$

[Roy928tt]

LOL yeah they made use of the wide bore spacing, they are very close to Chev Big Block bore spacing, you can swap Porsche 928 heads onto a Chev big block....

Strangely, it would seem as if it is quite less stressed than an equivalent 4G63, each cylinder is making similar power but the cylinders in the "Porsche" are larger, therefore bigger valves so likely lower boost pressures....

I think there is probably some wisdom in limiting revs to 8500, there has to be some weight of piston and rod swinging around in there, 8 litre V8 at 8500 rpm, anybody? I'm also guessing they have deleted the balance shaft that Porsche fitted to these engines!

[333pg333]

Working with the builder now. Of course nobody wants to repeat the problem. May have been something to do with the block itself (ie no idea of history-overheating etc). May also have been to do with serts put in place prior to the very large headstuds. The crack in the block was a lot larger than we thought, or could see, with it installed. Once out, it became apparent just how big this crack was. Problem is now he has tested a number of blocks and they all flex quite a lot under certain loads. Therefore, were we unlucky (well d'uh...middle name etc) and could we get away with just going again on another block and enjoy success that some others have had at similar power levels? Or think about billet? How much would a simple billet block be...more than I have at the moment.

So at this stage I'm doing absolutely nothing and trying not to think about the car at all. It's sitting in a dark corner with the Aero removed as I sold that just to make it to WTAC among other parts. Sad state of affairs really. $$$ spent per lap is impossible to calculate. There's no number large enough to write down for such fucked up lunacy!

...

[LINCOLN]

Sadface. My condolences