[ds968]

No luck in identifying my engine number.. That aside, it was my understanding the new rods went only into late 94 ( Oct production date ) or later models, not in late 92, or 93 or even early 94 .. Is that not correct ? [img]style_emoticons/<#EMO_DIR#>/huh.gif[/img]

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[Cloud9...68]

That's interesting, if it's true. I wonder why it would have taken so long to realize they had a problem. Also, I wonder what type of rods were in, say, 951's, which of course had the capability of producing way more power than a 968's NA 3.0. My suspicion is that rod failures must be exceedingly rare - due to their inherently catastrophic nature, I would have thought the issue would have been at least as well publicized as, say, the pinion bearing problem. And yet I never even heard of it after six years of diligently following the 968 forums. Even with the D1R racing supercharger, which is of course designed to add power primarily in the mid range, my uneducated guess is that the early rods are pretty safe. But if you can afford it, upgrading is probably a good idea. It kind of falls outside the realm of "cheap insurance," however...

And as far as identifying the engine number, yeah, it seems pretty hopeless without some serious dismantling. Thanks for checking, though.

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[ds968]

I also tend to think "early rods" failure is more more myth than fact.. there is some hearsay, to the tune of " I know someone who definitely had this problem " but nothing absolutely verified by the "victim" himself/herself that I can see anywhere ( unlike all the other well documented maladies of our cars have suffered, such as Pinion Bearing, clutch hose, HCV, DME relay, etc. and similar common issues..) until I see at least half a dozen cases posted from people who actually had rod failures, to validate this is indeed a weak link, and not just an isolated incident a friend of a friend heard about, I remain a skeptic [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]

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[Cloud9...68]

I tend to agree. Although, why would Porsche go to the trouble of re-designing them if there was no problem? My personal theory is that the early rods will tend to fail as a weak link, but only if there is another simultaneous triggering issue, like a rod bearing failure (which these engines are somewhat prone to).

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[mrmister]

I think the 951 rods were beefier, buy don't quote me on that. I want to say the rods being put in my car are a modified 951 rod. Cost me about a grand for the rods and the machining.....plus the installation costs.

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[Cloud9...68]

Mrmister,

The whole connecting rod discussion aside, your car is truly amazing. Along with Flash's, of course, it looks like yours is one of the finest examples of what this car is capable of becoming. Enjoy it when it's all finished.

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[mrmister]

Hey thanks a lot man, I am glad you think so. I am trying to do a real nice build. It is all coming together. Pete sent this over today!

   

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[rxter]

That is starting to look familiar. fast car...

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[flash]

lol - i love seeing this stuff - they're going to be all over the country in a couple of weeks - we have 4 up and running, and 2 more being installed right now - very cool indeed

i think we need to get one installed in something besides a black car though - not sure what that's about

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[rxter]

The fastest drivers always buy black (when they are not buying yellow).

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[mrmister]

Looking at potential routes back home. I want to go south this time and was also thinking of hitting up the Porsche driving school in Leeds, Alabama. I got to drive a new 911 4S on a short little track yesterday with one of the instructors. Pretty fun car to drive.

   

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[ds968]

That's because black cars need a SC just to keep up with NA cars of another color.. black paint attracts heat, that slows the car down considerably.. and there you are - a perfectly sound theory ! [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img]

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[mrmister]

You are right about one thing, we have the hottest cars [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img]

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[Monstrous4Banger]

951 used forged rods. Pretty sure 968 doesnt because its NA...no need, although I could be wrong, mine hasnt been broken down for the conversion yet. NA 944's dont afaik. Low boost levels are ok, but if you want to push even moderate boost levels, install forged rods. Thats how Ive always been schooled any way. Ive heard of the rod failure in 968's, but was my understanding that it was rare.

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[flash]

rod failure is fairly rare in the 968 - as far as we can tell, it is a stretching problem, due to insufficient material at the bolt boss, which occurs as a result of high rpms - it does not appear to be a bending or twisting problem under load, which is the more traditional mode of rod failure

that being said, rs barn just had one in the shop with rod failure - it was on a supercharged car (different kit)

but, that is also why i kept the redline to stock on the tuning, limited the boost, and put the boost curve lower in the rpm range - that is also what will make it less than what anybody would want on the track though - if this kit is to be taken out on the track, you will have to relearn how to drive the car, and keep the revs down and focused more within the boost curve, which levels out at about 5k - peak power is under 6k

basically, revving it up to redline like you would have before, will not serve you well - i have been having to relearn the car as well

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[Scott Collins]

Inquiring minds want to know...

If the rods were not an issue, why did Porsche strengthen them after '92?

(I have a '92, so it matters to me if I go supercharger down the road...)

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[Cloud9...68]

"Inquiring minds want to know...

If the rods were not an issue, why did Porsche strengthen them after '92?"

My theory is that while rod failure can and has happened, something else has to go wrong to cause them to fail, for example, a rod bearing "welding" itself to a crank journal. This is one reason I'm planning to replace my rod bearings this fall, just as a precaution. Plus, my oil pressure at idle on a hot day is a tad lower than I'd like to see it. Actually changing out the rods is almost prohibitively expensive, at least for me.

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[flash]

they were an "issue" in that they could fail under the right (or wrong) circumstances

our current thinking, regarding supercharging, is that as long as the revs are kept down, there is actually LESS stress on the rods - the idea here is that you will not need to go to redline to get max power any more, thereby decreasing the potential for rod stretch - this is not proven at all, and is only a theory, but seems to be shared by many

for what it's worth, i'd still change the rods, and plan to do that myself if i find that i have the early ones - i still have not checked my engine number yet to tell yet or not, and the memo shows "as of 10/1/93, engine #42R0958 - #42R50621"

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[ds968]

" If the rods were not an issue, why did Porsche strengthen them after '92?

We can speculate as to why Porsche decided to change the rods, but I think if that decision would have been indeed triggered by an actual failure, it would have had to happen in the first year or so of this car being on the road, and not be just an isolated incident but a number of failures pointing to a real problem, you'd think a recall would have taken place and/or there would have been a lot of exposure on forums , etc. Not sure they decided to reinforce the rods because of a problem which manifested itself, but rather someone simply looking at the design and function on paper and thinking.." hey we can improve this " with next model year..

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[PorscheG96]

Jared, take the 40 back home from the east Texas/Louisiana area because 10 is complete sheiBeville. I hated 10 all the way from Texas to California. 40 is far more interesting especially in the northern AZ area.

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