[WiLLs SuPra]

So..I'm a tad confused on what might be the issue? IF anyone can chime in or help me out..it would be greatful!!! So the car just finished an aristo engine swap..from a N/A-T setup..and everything goes smoothly in the dyno and on idle. It went through 2-3hrs of tuning on the dyno..and nothing. The PS pump however, is making all sorts of noises, when turning the steering wheel. We just figured the pump is going out..and that can be replaced later on...It will sometimes go on/off. So we tried to keep rotating the wheel..to maybe release some air in the system. After 1hr of doing so..it still does the same thing. So we wind up taking it for a spin..and within 3-5 minutes of min-moderate boost levels..the water pump housing cracks.

We reinstalled a new one..and same result. It is a USDM TT water pump, and the belt and tensioner looks good. All the goodies are there..a/c, alternator..etc.etc. The clutch fan..has however been extended (studs) to bolt the NA radiator fan. We put plastic washers on it. What might be the issue? **2-3hrs of dynoing..and all is fine**

 

[Dego Red]

Where did the crack occur? Do you have any pics? I can only think of two things, so maybe someone else will have more experience:

1) Did you torque the bolts on the water pump, or is it possible they were over tightened?

2) More importantly, where exactly was the fan clutch "extended"? Between the clutch and the fan? My thought here is if it wasn't exactly centered or there's a variation in balance, etc...the force & vibration on the water pump is going to be multiplied and quite possibly outside the range of the pump's survival. And it may not be visible or felt at idle (ie - a tire out of balance at 55mph vs how it feels at 10mph).

In development of 13L-16L engines that live in the neighborhood of 2000+ft-lb, I can tell you vibration is a bitch and can wreak havoc. I'm not saying that this IS your problem, but I'd move the fan where it belongs for now. It's not worth the risk, and considering the power some of these engines are making, we don't exactly have cooling issues that require help from the shroud.

HTH, and good luck.
Mike