302 SBF Dart block potential cooling system issue

Todd Gross · 07-11-2016, 10:09 PM

I have a Stock customer that I upgraded his engine over the winter and changed out his filled OEM 302 block with a Dart SHP block. It dynoed fine and all looked well, but recently he has been noticing on his data log that as the car goes down the track the cooling system temperature continually drops. It starts in the range of 120f, drops down to say 70f, then on deceleration goes back up to the 120 range. It appears to be building a vapor pocket. The bad thing is this caused the rings to butt on the forward cylinders causing damage. After tearing down to repair the ring issue we checked over the heads, gaskets and so on. We went to great lenghts to verify all the air was bled out and the water pump was functioning properly. The temp still goes down during the run. It utilizes a 35GPM Electric Water Pump ( std direction flow ) and uses water w / Purple Ice additive.
I spoke with Dart and they had not run into this.
Everything on this engine is the same as what it was on the previous block with zero issues last season.

Anybody been down this road?

Thanks-
T. Gross / JPE Inc

07-11-2016, 10:09 PM	#1
Todd Gross Member Join Date: Mar 2016 Location: Crete, IL Posts: 167 Likes: 260 Liked 54 Times in 24 Posts	302 SBF Dart block potential cooling system issue I have a Stock customer that I upgraded his engine over the winter and changed out his filled OEM 302 block with a Dart SHP block. It dynoed fine and all looked well, but recently he has been noticing on his data log that as the car goes down the track the cooling system temperature continually drops. It starts in the range of 120f, drops down to say 70f, then on deceleration goes back up to the 120 range. It appears to be building a vapor pocket. The bad thing is this caused the rings to butt on the forward cylinders causing damage. After tearing down to repair the ring issue we checked over the heads, gaskets and so on. We went to great lenghts to verify all the air was bled out and the water pump was functioning properly. The temp still goes down during the run. It utilizes a 35GPM Electric Water Pump ( std direction flow ) and uses water w / Purple Ice additive. I spoke with Dart and they had not run into this. Everything on this engine is the same as what it was on the previous block with zero issues last season. Anybody been down this road? Thanks- T. Gross / JPE Inc