hey greg! glad you didn't give up!!

IIRC, your deck ht will vary based on how much resurfacing you needed to do, and what you've changed in the assy - my block was taken down .025" due to a nick on top of one of the bores, heads were resurfaced a bit (affecting volume too), and so the 968 style pistons stuck out quite a bit/had too much compression for street gas... so I just used a custom piston/CH to cure it, although you could use custom rods or change the crank spec, whatever(deckplate?)

good idea brenden, I won't go to summit for $400 rods either... but http://rds.yahoo.com/S=96062885/K=ra...ww.pauter.com/ makes a really cool thin profile custom rod for $1250 and 2-3 weeks... any HP you want too...

I just used 5.85's cause I was going to use custom pistons anyway, I wanted to cram as much displacement as I could for my NA thing (ie max stroke and rod angle ok for NA), carrillo seemed bulletproof enough & most importantly - greg liked'em

might ck out http://www.hekimianracing.com/conrods.html too - he's really a motorhead to the extreme... 10k HP stuff...

Lag - that 6.1 FI motor is off the hook!!!! cant' wait till the dyno posts and it stomps some asphault - make our 928's represent, yo!!!! so that's what happens when motorheads get snowbound!!! cant' imagine what would happen if you moved to alaska!!!

 

The exhaust driven compressor is really a hard deal to beat...Marc, I say skip the parasites and hang some hybrid T3/T4s on that thing and lay down some seeeerious mid range and top end power. Once the Goldmember is gone, I'm in the market for an S4...but it must be a 5-speed. All the plumbing is sketched out...in my head! Putting into reality might be a different issue altogether though! Your mental images go to pot when you are up against the space constraints of the shark's engine bay.

No wife, lots of tools and lots of free time=something interesting next year!

 

off on a tangent a bit here but...

A picture or two of the underside of that twin turbo in the PAC NW would save a bunch of time!
Is that guy "mum" on what he has done or is he pretty open about it. The headers and fitment are the hard part...hes doen that already. Tuning is easy!
417 rwtq on 7psi

 

You know what? I gotta say it. John - what happened? I thought you were just engaged? Then married? And now no wife?

 

Bredan it just seems like yesterday that he got married........in the time it takes to "fix" a car people can meet ,fall in love ,get married,fall out of love, get divorced, and buy a new house.........

 

yeah..in the time Brendan has fixed his car....the Berlin Wall has...

uh..nevermind

Just riding you a bit Brendan. . Jim started it.
Do it once do it right and take all the time yo need to do it...thats what i do even though "Patience is a thing i cant wait around for" seems to fit my mode of operation sometimes .
I think quite a few of us will benefit from what your doing

 

I've had a kid and moved a few times I guess.

 

Hi Rob, do you know what width your conrods were? Please update us as to where you are with your project?

Cheers Greg

 

Adam:

Just looked at this thread. Good stuff. The psiton that you have pictured is not a 968 piston, but an S2 piston. The 968 pistons are completely different. They are not full skirted, only the S2 version is. Indeed, the S2 version piston has problems clearing the counterweights and also is prone to hitting at the bottom of the stroke......you might want to check this carefully. Indeed, both pistons have offset piston pins. This means that if you do not machine "intake" valve reliefs into the "exhaust" relief area on all eight pistons, the pistons will end up "upside down" on the 5-8 side of the engine. That really screws up the rod angle on that side of the engine. Porsche ignored this problem on the early model 928's, but made the valve reliefs all the same so that the pistons could be turned the "correct" direction on both sides of the engine on the S-4 models, forward.

 

So if I'm getting it, if you turn the piston around the conrod wont be so close to the inside boss area of the piston? Do you also concur that the rod width is 0.940" ?

Cheers Greg

 

just plain ol' carrillo A-Series SBC stuff (cataloge pn C - 35 <A 65850) widths PE 1.060", BE .940", BE BORE 2.2250", wt- 550g, 2.1" main bearing/.927" pin, 220,000 psi tensile more or less http://www.carrilloind.com/story.html...

IIRC, the A series was developed for oval track racing and had a fairly low wt/thin profile compared to the regular carrillo stuff, but was limited to about 600-800hp depending on how much wt you're swinging & how fast... under about 7K rpms w/my 435g JE's was not an issue, and the rods are light!! carrillo has good tech support, so it's easy to find out for your app to be safe... I used the 7/16" bolts/larger bearings, FWIW... IMHO there are lots of good rods out there & lots of religion w/wrenches on them too... the 7/16" bolt carrillos did require clearancing the block a tad though/not a big deal in non-structural area (I hope/famous last words)... I hear the olivers/pauters don't require any block grinding w/3.75" stroke, FWIW...

otherwise, not special by any means/just seemed to work out...

motor is done! looks quite inconspicous, somewhat pretty - but still silent... just awaiting final WYIT hose roundup for accessories/trans, then wrap up exhaust from the 3" random cat/xpipe section on back, tune'er up and shazzam!! no more $$$ won't be a record setter in this crowd but hopefully it'll be a decent daily driver...

don't feel bad brendan, as whitie at moldex told me when I pestered him for the crank one time too many: "you can have it right, or you can have it fast - you choose and while you're deciding - quit bugging me!!" (well, maybe it was my 4th call that week which pushed him over the edge)... besides you can learn from everyone elses mistakes!!!

hope this helps... back to regular programming...

 

GregBBRD wrote:

>>The piston that you have pictured is not a 968 piston, but an S2 piston.

I don't know if I concur with that. The full skirt is a Mahle, the partial skirt is a KB. I've seen both come out of both motors in my hunt for used pistons. Do you have a way to settle the confusion for good? Both pistons had a 944 part # I believe.

 

...Wow Tony. Thanks for the vote of confidence. I did plan to get as many pics and pages on a site as I could once I proved what I did (am doing) works.

I haven't mentioned it much, but I have a GTS crank ready for a third engine with custom rods and pistons for higher boost. I guess thats not very adventurous though.

 

rob,

just reading your thoughts about 'proprietary information' vs an open forum where enthusiasts share, i wouldnt think that the information itself needs to be hoarded although im sure others will have a different opinion. to me it seems that not only do those who find things out first get to make mistakes but they also get to perfect technique, what does it hurt them to share there experience and welcome others to step up and have a go? at least they can say that they not only have the information or pioneered the technique but that they can reproduce it reliably too. i mean its one thing to talk about how these engines go together and another to actualy build one. in my opinion i would choose an engine builder on competance rather than budget, up to a point. if there was a shop out there that said they could build me a 928 engine and had done this before reliably i would be impressed more than to take my block to the local engine reconditioners, even if they both had the same set of specifications to work with.

for you guys in the USA this is kind of a moot point as you have ready access to the big three (and superchargers!) in a way that is better than 928'ers in other parts - we are the ones who would most benefit from a greater flow of information.

i think there are two other potential areas of concern with a lack of shared info, one is competition to improve technique/practice and the other is that this information may become extinct with time if limited to very few individuals. as an example of how fragile this market is look at whats happening currently with twinscrew superchargers, it only takes one of the 'big three' to drop out for some reason and there is a third of our retail/support network gone!

more than that, i view my relationship with vendors of parts and services as an open one in which i am not sworn to secrecy unless specificaly informed!
"does raise an interesting dillema however - at times I know a lot (ok really only a tiny, tiny, tiny, tiny bit) more than I dare tell, out of respect for the Deveks, Precision's, competitors, etc that have spent countless hours fine tuning specs on these things and the propriatery nature of some OEM stuff as well...

however I'm conflicted due to my natural tendency to help out and the essence of these forums which is to share info - so I tend to just leave bread crumbs and hope I don't offend by going too far or not far enough...apologies to all for that...

don't know where the line is, but perhaps on another thread it'd be interesting to hear/poll pro wrenches, and end users alike to see where/or if such a line even exists..."

 

Those are the best mistakes to learn from!

Nice informative post BTW.