Grandpa#3

Hello Gents, I need some help. I am tearing down a 1992 968 to replace rod bearings and WYIT things. I have heard the 92 rods are p/poor at best and should be replaced with 951 Turbo Forged Rods. I can't remember the year has the best Rarst Rods. Any help will be greatly appreciated.

Cheers ,
Larry

supes6

I have a set of 86 951 rods for sale if you're interested, just shoot me a pm.

odurandina

according to Porsche the stock rods from '92 to late '94 changeover shouldn't be re-used when replacing the rod bearings. the early 968 rods can safely facilitate torquing the bolts down only once (at the factory).. but. the late '94~95 upgrade rods have more meat to support the rod bolts and should be used instead, and can handle changing the bearings/rod bolts multiple times. but they are pricy.

one possible solution if you want beefy, virgin rods without getting taken to the cleaners by Porsche....

http://www.jdmultimate.com/product/i...SCHE&Model=968



.

MAGK944

iirc all 968 rods are lightened and forged. And doesn't the 968 run a different stroke to 951's so interchangeably would not be possible.

944meister

The carrillo rods odurandina posted fit all 944/968, so if the stroke is not the same then there would be a difference with the crankshaft. On a side note, are S2 rods good for replacing bearings multiple times right? They don't have the same issue?

Grandpa#3

Check out the link, Odurandina, posted above. Going from that the Connecting Rods measure the same, so the 86 951 turbo rods can be used as well as the 83-84. I am an old retired gent on a fixed income, so I can no longer afford to spend what I used to spend. If I went with the Corrillo Rods, $1340 + S/H, Rod Bolts and nuts $300, bearings $80 and on, it all adds up fast. I have to plan well ahead just what maintenance has to be performed and save up for it. I kind of cringe when someone says they are all caught up and have nothing left to do on their Porsche. If you do not have tinkeritous in your blood an older Porsche is not for you.

Cheers,
Larry

67King

Can you document that? I have a very, very hard time believing any OEM would ever produce something like that.

There's also a less expensive high quality alternative:
http://wossneronline.com/forged_pist...roducts_id=315

MAGK944

Interesting, never knew that, learn something new here every day.

If 944/968 rods are the same with different cranks then the piston pins must have been relocated on the 968 also, correct?

Jfrahm

The early 944NA rods, 944.103.101.3 RARAST are nice forged rods and supposedly got used in the late 951. The early 951 rods are supposed to be somewhat stronger, 944.103.110.0 RARAST. They weigh exactly the same as the 101.3 rods (I weighed them.)

Some have found 110.0 rods in later 951 engines and I do not know where the cutoff was. I have found the 101.3 in 1986 NA motors, I do not know where the cutoff is there either. Many said it was much earlier than 1986.

Rods to avoid are the non RARST 944 rods that replaced the 101.3, and the 968 1R rods. The cast 944 rod seems fine in 944NA motors but but not strong enough for boost.

The 1R rods have been bent in 968 and 928GTS engines but there seems to be little info on how this was accomplished. Normal street use does not seem to be a problem. They were replaced with a rod that had more meat in the transition between the beam and the big end.

There are S2 and 2.7NA rods out there too I think, I do not know anything about them.

I recall a TSB that said to replace all the 1R rods in any engine that had a rod cap taken off or something to that effect. There is supposed to be good data on the 968 engine numbers that got the 2R rods. My blue car is supposed to have the 2R rods but i have not looked.

-Joel.

odurandina

the early 968 rods are one time use only. late in the '94 production run, they dumped the early rods for beefier ones.

i would have already changed my rod bearings by now if i didn't need to get the late run connecting rods which cost a small fortune from Porsche.


btw, cunningham maded a slightly shorter stroke rod for the 968 that's great for supercharging or turbocharging without having to tear down the motor.


ebay has the carrillo rods for $972....

http://compare.ebay.com/like/170780374439?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&_lwgsi=y&cbt=y

67King

I understood that is what you wrote, but I was trying to ask where you came across that position. I have a very, very hard time believing it.

odurandina

they did indeed dump the rods for the much improved version. i'm still looking for documentation, but the problem is Porsche is so murky (in general) about the 968 and most of their cars for that matter... but this in fact, did occur. when automakers upgrade critical engine parts, it's fairly normal for them to keep mum about it and move on.

https://rennlist.com/forums/968-foru...d-failure.html






.

Jfrahm

As per:

https://rennlist.com/forums/8284636-post6.html

Changeover as of Oct 1 1993, engine numbers:

42 R 00 98 M44/43

42 R 50 621 M44/44

67King

Sounds like internet rumor mongering to me. Porsche may have chnaged the rods for any myriad of reasons. Having done engine development for an OEM, I've seen it countless times. Could have been a supplier issue, they could have gone from forged to PM, could have been a cost issue. I don't mean to come across as a jerk, and I did search for something like that before I asked you where you found it. I'll have access to the shop manual on Monday, if I recall, I'll check.

But the simple fact of the matter is that for a rod to be machined, it has to be assembled to proper torque, then bored, then taken apart to be put back on. The process by which they are manufactured is why you don't mix and match caps with rods - their fitment is unique because of how they were machined. And periodic checks of production engines are quite normal, meaning it would have to be disassembled to have the dimensional check done, then re-assmbled. So at the very LEAST, for a rod to have been machined, it was assembled to torque once before it was ever put in an engine. And it is also the industry standard to design systems so that the fastener fails, preserving the base part.

Anyway, again, not trying to sound like a jerk. The assertion that the early rods were inferior doesn't sound inconcievable (though one anecdotal failure wouldn't deter me from using them if I were to need to break into my engine - but that is just me). It is the notion that torquing them down once renders them useless that I am questioning.

67King

Bingo, that's what I was looking for. Very surprising. From reading that, it sounds like a post-launch issue was found. Perhaps I had inferred Odurandina's point incorrectly, as I thought the assertion was that it was somewhat intentional. Thanks for posting that!