Carrera rod bolts

john_colasante · 07-05-2002, 06:39 AM

Wayne's talk of the Carrera rod bolt problem got me thinking. If one does a valve job on a Carrera 3.2 would it not be a good time to put in ARP rod bolts without splitting the case? If so can you just reuse the same rod bearings and slap in the bolts? Seems like a quick fix expecially for a car that sees alot of higher RPM use.

makaio · 07-05-2002, 06:45 AM

Yes you could just do that. But I would replace the bearings while I had the chance.

Wayne 962 · Wayne 962's Garage

Once you get the engine torn down that far, you really might as well freshen up the bottom end. It only adds a bit more effort to the whole task...

-Wayne

marcesq · marcesq's Garage

Question: Was the 3.2 rod bolt problem resolved by '89 or was it resolved once and for all with the coming of the 3.6

Thanks

Superman · 07-05-2002, 11:54 AM

When I did my recent top-end job, I removed the rods without splitting the case. From this position, you might as well replace the rod bearings. It can be done.

However, I did agonize over whether to split the case and renew the main and intermediate shaft bearings. I decided to split the case, and I am glad I did. Some of those bottom end bearings, while serviceable, were worn and I'm glad I replaced them. Also, you will hardly believe the tiny amount of additional energy it takes to do the bottom end, once the cylinders are off anyway. The bottom end overhaul was the funnest, and easiest, part of the entire rebuild. It could be done in an hour.

And yes, if I had a 3.2 that was going to see some high rpms, I'd upgrade those rod bolts.

speeder · speeder's Garage

This reminds me of a question I've been wondering for awhile; are brand new bearings and rings preferable to ones that are still in good condition and worn-in to their mating parts? I am not talking about rings and bearings that show significant wear, that is a given I think, but when I tear-down my SC motor with 115k miles for head studs and oil leaks, this might very well be the case.

I know that it is difficult to answer w/o seeing the parts in question, but assuming they look great? TIA.

Wayne 962 · Wayne 962's Garage

Again, I agree - the bottom end is really easy once you get that far.

As for the 3.6L engines, the answer is NO! THE PROBLEM WAS NOT FIXED. 3.6L engines have this same problem as well. One of the pics for my new book is from an exploded 3.6 engine. Rod bolt came loose and went right through the case. Let me see if I have a pic:

Nope, can't find it...

-Wayne

RoninLB · 07-05-2002, 12:19 PM

I did the Raceware rod bolts..most pros do the ARP..the intermediate shaft bearings showed wear after 90k miles..IMO, a stock rod bolt that sees a missed shift may not destruct the rod for another 5k or 10k miles.....Ron

Wayne 962 · Wayne 962's Garage

Agreed. I specifically recommend RaceWare, only because I have a set. I hear that ARP is very good as well. Stock rod bolts = trouble...

Now, this doesn't mean that you have to place your car in storage for fear of stretching a rod bolt. Just don't rev it past 6300 and you should be okay. When you rebuild it, use the RaceWare (or ARP) rod bolts...

-Wayne

Doug Zielke · 07-05-2002, 01:55 PM

Quote:

Originally posted by speeder
This reminds me of a question I've been wondering for awhile; are brand new bearings and rings preferable to ones that are still in good condition and worn-in to their mating parts? I am not talking about rings and bearings that show significant wear, that is a given I think, but when I tear-down my SC motor with 115k miles for head studs and oil leaks, this might very well be the case.

I know that it is difficult to answer w/o seeing the parts in question, but assuming they look great? TIA.

Exactly what I'm thinking.
Recently, the Blue Bomber gave me a little "present" at 75k miles.....a broken head stud on the #6 cylinder. Not a real big deal, as the motor has no other issues, good compression and no oil burning. Runs strong and mechanically quiet as it always has. Considering this, there is no way I'm going to fix what ain't broken. My plan is 24 new steel head studs and gaskets as required. De-carbonize the piston tops and combustion chambers. Install new SSI's. Button her up, and drive!

Superman · 07-05-2002, 02:24 PM

That's not a bad plan Doug (I say that because it was my initial plan as well), I will just watch to see if you have the sense of restraint you will need to deny the various temptations you will encounter.

I'll also suggest you replace twelve, rather than twenty-four head studs. The intake-side studs on your engine are already factory steel units. It is the twelve exhaust-side studs that are Dilivar and prone to breaking. Folks like to throw stones at OEM Porsche studs, but after asking questions (and asking and asking and asking), I came to the conclusion that the factory steel studs used on top are about as reliable as the fancy expensive ones, except in a race-built (high horsepower) motor. I saw no reason to replace more than 12 studs, and I saw no reason to spend more than about $11 per stud. If I had the money and time to do it all over, I would use that money to replace the rocker shafts and bushings before I would buy head stud overkill (ARP, Raceware).

Oh, and by the way (I've warned all of your before) three of my heads were banging on my cylinder tops, even though only one stud was broken. This means it is a good idea to check the torque on those head studs periodically. I checked the right-side nuts this weekend, and found three that were not perfectly tight.

Doug Zielke · 07-05-2002, 02:40 PM

Quote:

Originally posted by Superman
I'll also suggest you replace twelve, rather than twenty-four head studs. The intake-side studs on your engine are already factory steel units. It is the twelve exhaust-side studs that are Dilivar and prone to breaking.

\

I was hoping you'd chime in here, Jim.
I fully understand the steel/Dilivar thing. What prompted me to say I'll replace all 24 with new steel studs, is I'm unsure about mixing old with new. Don't you think the old studs may be a bit weak after 75K miles of heating and cooling? The steel studs are relatively cheap, too, so why not replace 'em all?
If I'm really wasting money/time here, please speak up.

Superman · 07-05-2002, 02:53 PM

I think John Walker said he has never seen a factory steel stud break. Now, perhaps he exaggerated, or perhaps that's me doing the exaggerating, but his point is that in his experience those factory steel studs are pretty darned reliable. He steals them from his inventory of old cases, whenever he needs one. I would have been happy to install 12 used ones, but there was no source so I got them from the dealership.

RoninLB · 07-05-2002, 03:23 PM

IMO, probably the most logical install is steel on intake and Raceware/ARP on exhaust...I had to do expensive on all 24 because of the different worlds I travel to..Ron

widebody911 · widebody911's Garage

I had 2 broken stock studs on my 3.6L, and used RaceWare replacements, as well as RaceWare rod bolts. Having the bottom end gone thru on my rebuild didn't add a tremendous amount to the final bill, and what it gave me in peace of mind was well worth the $1000 of hardware.

Wayne 962 · Wayne 962's Garage

I'll weigh in on this. For the 3.0L engines, you only need to replace the lower studs. The top ones are fine. Turbos need to replace all 24...

-Wayne