Hypertech Powerstat Installation question…

[steve]

I am installing one of their thermostats in the new 2.8 I am building. And I originally put it in place with the gasket and found out that it would not fit. This was because the gasket has a hole in it smaller then the diameter of the thermostat and the thermostat has a rubber ring/gasket (I think) around the exterior of the thermostat that makes it fit snugly in the opening and also makes it thicker. The added thickens with the rubber ring and also the added thickness of the over lapping gasket makes it so I can not tighten down the filler neck tight to the intake without a gap. How can I fix this? This is the correct thermostat for my situation or at least it is suppose to be. Could I install it with out the gasket relying on the rubber trim ring to make the seal? Is that what the rubber trim ring is for? Or should I just install the gasket and the thermostat with the ring and disregard the gap? I can also take off the rubber trim ring easy enough, but then the thermostat does not fit snugly in the hole. Should I do that and just use the gasket? What do you guys think? Thank you ahead of time for any help you can give me.

[Sam]

You must use the rubber ring for it to properly seal the water neck. If it doesn't fit exaclty like the stock one did, you have the wrong thermostat. You should be able to drop the stat/ring assembly directly into the recess for the stat. Then, the water neck should tighten down over it without a gap. The rubber ring will seal it. Sometimes an extra gasket is used on the water neck for a back up, but it isn't always necessary. If yours came with the extra gasket for the water neck, replace it with one. Put it back just like it was, just with a new stat.

By the way, if you are running a 160 stat, that's too cool. You need a 180 if you are going down from a 195.

[steve]

The gasket I am using with it came from a full engine gasket set I got for building my motor. It did not come with the stat. So you are saying I don't need the gasket then? Would you suggest any silicone sealant? Also why do you warn against the 160? That was the only one they had available for my application. And I should need it when I get my new chip to prevent detonation. And also thanks for you input I appreciate it.

[Sam]

My truck only uses the rubber ring and it doesn't leak, so you sholdn't have to use one of the paper ones in conjunction with the rubber one. The 160 stat is too cool because most all computer controlled engines run rich until they reach 160 or so, then they correct the air/fuel mixture up to operating temp. If you run a 160, you will be running rich some of the time and be wasting gas and maybe fouling plugs. I called hypertech about this once and they told me that a 180 was fine to use when using their power programmer III on my 2000. Your overall mileage will drop considerably with a 160 because the higher the operating temp, the better the mileage. Obviously, you can't run it too hot or you will begin to knock or harm the engine. that's why i run a 180. the factory installs the 195 for improved mileage purposes, but in Mississippi, it's too hot for a 195.

[steve]

Sam my new engine is far from stock and will need a custom made chip to control it. Should the chip be able to compensate for all the fuel air ratios you are talking about? The motor is also a 2.8 turned to 3.4 so its cylinder walls are thinner because of being bored out. Wont this effect the engines cooling so it will be better to have a cooler thermostat? The questions I have about this engine are endless. This is the first engine I have ever attempted to build and I did not pick an easy engine to build. I appreciate greatly the help you have given me and any one else on this site that helps. Thanks again.

[steve]

Any one else has any input? I would be very happy to hear it if you got any. Or does every one agree with Sam?

[Sam]

I'm not an engine guy, but I have just heard that most computer controlled engines run rich until they get up to around 160, then all the sensors start to work properly. If you install a 160, some of your sensors will not be at the correct operating temp to be correctly functioning. A 180 stat will keep your engine cool enough to be safe, but also keep all the computer stuff working right. If this is a race motor, then you can just toss the thermostat and run it without one. You can have it custom programmed to whatever you want, but engine management sensors just require that the operating temp be over 160 so that they are all functional. If it's street driven, then the 180 will be best. That's about all I can tell ya. One example (depends on exhaust temp) is the oxygen sensor. It has to be warmed up by the exhaust gases before it reads correctly. Same type of principle with the engine sensors. The 180 will be cool enough and also safe. Seeing as you're in CT, you should have no problems with cooling the motor.

[steve]

I would have no problem getting a 180 thermostat, but I can not find one at that temp. The only one I could find was the 160 for the 2.8. The 2.8s do not have many options when it comes to performance parts unfortunately. If you know were I can find a 180 I would be very appreciative. And also my motor is being built for the street.