Dan@SharkWerks

Hi guys,
Some of you may be aware of coolant pipe issues on GT1-block equipped models (GT3, GT2, Turbo), where coolant pipes come apart while driving and the rapid loss of engine coolant can cause spins/crashes at race tracks when slippery coolant sprays all over the rear tires.

The problem exists on the GT1 motor because there are a couple coolant pipes in these motors that are not a single cast piece: the larger cast pieces have extruded inlet/outlet tubes that are connected using an adhesive. There is no metal-to-metal friction or press-fit to keep these tubes in place, so after enough heat cycles the adhesive will soften/loosen up and the tube will come out of the cast block (with the hose still attached), resulting in a rapid loss of engine coolant.

Regardless of how the vehicle is driven, it seems this problem may eventually effect all 996/997 Turbo, GT2 and GT3 models including the 2010+ GT3 and GT3RS.

We have heard of many cases of this, and in fact the last time we were at Infineon Raceway, Alex and I were talking to someone about it when the exact problem happened to a 997 GT3 right in front of us -- a large steam cloud evacuated the rear of the GT3 and it spun on the hairpin! Luckily he missed the other cars and the barriers.

Here's a video showing how the tube comes apart:
http://www.youtube.com/watch?v=RH56CkzC-QE

Here's a diagram showing where the problem happens on 997 GT3 models:


Here's a picture from a 996 Turbo's coolant pipe. Both of these tubes you see are slip-fit into the cast piece and fixed in place using an adhesive:



We first saw this in early 2006 when we started building 996 Turbo engines. In fact, our 996 GT3 suffered from this exact problem earlier in its life.

James has a technique for fixing this, something we do for all 3.9L motor builds and any time a GT1 motor is removed from the car.

This week we had a 2011 GT3RS (project that was documented earlier) whose lucky owner will have plenty of track time with her. He decided that rather than wait until it might happen, he would rather be on the safe side and fix the problem now, preventing a scenario where the coolant might cause a high speed crash at a local track.

The bumper is removed exposing the Shark Werks GT3 Bypass Exhaust:


And despite the car's super low mileage, its factory fresh and perfectly running motor is removed from the car:





With the motor removed from the car, James locates each of the potential problem areas and drills a small hole through the cast piece and into the tube (that normally would come flying out at some point in the future). Then he threads a bolt through both pieces and using loctite secures the bolt in place. This locks the tube together, preventing it from coming apart regardless of heat cycles.





The coolant pipes will now act as a single piece.


All the tubes are buttoned up...



And the motor is lifted back into place, the remaining details addressed.



And here she is, now ready for an enjoyable weekend around the track at 8000 RPMs.




For more of this car, check out the whole project here.

TRAKCAR

Thanks for posting

And Porsche does not do this because...................??!!

DRPM

+1 TRAKCAR

FFaust

Cross-posting my comments from the 996 GT2/GT3 section cause I know some of the 997 guys don't come over there often

Thank you Dan. This is a truly ubiquitous problem; we've all seen it or experienced it first hand I'm sure.

While talking to Alex last week, the topic came up as I wondered aloud about the logistics of sending in the various manifolds for you guys to do your magic. But, the logistics would be complex, the cost too high, and the hassles of crossing the US/Canada border excessive.

However, reading your post just now, inspiration hit. Here is what SHARKWERKS needs to do:

- You need to build and sell a kit with hardware, sealant, and clear instructions so that owners of GT1-blocked cars WORLDWIDE could carry out the modification locally. Heck, you could even include drill and tap As far as I am concerned... name your price!

Who knows if this will be a huge money maker but I doubt that it will cannibalize your local business, so there is no downside for you. Plus, if nothing else, think of the goodwill such a move will create and it would certainly, ONCE AGAIN, put SHARKWERKS at the top of the Porsche Performance supplier list.

You guys have my address, so please ship me the first kit

cfjan

During the drilling and tapping process, how does one prevent the debris from going into the system? All coolant was drained prior to the drilling, I guess?

FFaust

Added benefits v. tig-welding:

- Cleaner Look
- Potentially less issues with P warranty
- No need for a welder; any mech worth his weight can do this mod
- Easier to coordinate since the guy who drops the engine can do the mod (see previous point)
- "Undo-able" if ever needed for any reason
- Some couplings can be done without removing engine
- Various manifolds need not be disassembled for access or to safeguard from heat damage
- Cheaper

rodjac

Last year I had Sharkwerks fix the coolant tubes on my GT2. I have tracked a GT3 and then a GT2 for five years without any problem. But i started worrying about the coolant leak happening on a high speed turn and decided to get James to fix it. It isn't cheap since he has to pull the engine but is well worth ir for the peace of mind it buys.

P.J.S.

what are the downsides to this?
I cannot think of one and it seems way easier than welding...

I just copied this thread and sent it to my tech

often times the best solutions are the simplest - thank you very much for posting

911S4

Thank you very much for posting this fix Dan, its really impressive to see the step by step process, and you guys do some incredible work.

Thinking into this a bit more, would it be advantageous to run a tap with the same thread pitch as the bolt your using into the cast aluminum coolant manifold in an effort to provide more bite and surface area for the red locktite to properly adhere to in an effort to reduce the likelihood of the threaded bolt vibrating or working its way out eventually?

FFaust

Only possible issue IMHO, is that you might have the tip of the bolt sticking out into the coolant flow, which might cause some kind of internal buildup down the road

The coupling wall is so thin that it would be hard to get the bolt length perfect so that it is long enough to lock the coupling but short enough not to protrude... Unless it's no big deal if the bolt does stick out too much on the inside.

911SLOW

It's a quick fix and will hold better than the glue and prevent a sudden release of all fluids, only concerns would be that the coolant might become contaminated while drilling and tapping, and that the bolt won't prevent minor leaks if glue fails.

Maybe if motor is out welding or threads would be a better idea anyway?

Nizer

Also, this solution prevents catastrophic loss but if the glue degrades over time wouldn't leakage ultimately occur around the press fit joints?

911rox

Ultimately, a trickle of coolant can be detected and repaired... A gusher can hurt you or others... Benefit with this method is you can back those screws out, re-glue and do them up quite easily... Downside- its going to cost a crapload if they constantly fail and the engine is continually being dropped...

Biggest problem is that neither welding or tapping is ideal... They both have their issues... And who knows which is the lesser of two evils???

Electric Lizard

Admission of defect, acceptance of liability.

Nizer

I prefer a solution that doesn't lead to an engine drop, whether it be from catastrophic failure to trickle leakage around the bonds.