GT40 Heater install

[Hlymons]

Looked around and could not find good pictures of the engine hookups for a GT40 heater install. If anyone with a heater could take a few picture I would appreciate it.

BTW here are some good heater install links

http://www.planetnautique.com/index....heater+install


http://www.planetnautique.com/index....heater+install

http://www.wakeworld.com/MB/Discus/m...21/282619.html

http://www.planetnautique.com/index....heater+install

http://www.planetnautique.com/index....amp;pic_id=811

[Sinkoumn]

RE: GT40 Heater install

Here's a write up I did when I installed mine a few years back:

I had the chance to go up north and partially install my heater this past weekend, here's the general overview of how to install the heater:

First I had to find the water temp sensor on the raw water pump:

Different angle:

Mas:


Here is the main components that I had to purchase at the hardware store because they are not included with the kit (the main purpose of these is so that there is hard plumbing coming off the block and to also allow my to completely shut down the heater water flow path should something go wrong):

**Note, I had to purchase a 3" bronze straight pipe extension because the 90degree elbow hit the silver mount when I tried to install it originally**

Once I took the temp sensor off (pictured above), I installed my hard pipe chain leading to a 2" shutoff valve and a hose barb:

Different angle:


Here is the pathway in which I ran the heater tubing, the heater unit itself was mount directly behind the kick panel (red square) - this requires at least 50ft of heater tube believe it or not:


I mounted the heater unit directly flush behind the kick panel so that the heater outlets faced underneath the walkthrough (two hot tubes will be installed under the walkway/playpen):

Mas:


I had some extra carpet, so I made the panel to hold the two hot tubes and installed it under the playpen (they will stretch all the way to the back seat):



The only thing I need to do is install the Y-adapter into the raw water intake hose and install the final ball valve for the water return.
Here is the best picture I have of that (the water return is the black hose running through the ball valve on the lower left), you can somewhat see the Y-adaptor that I installed into the raw water intake line (green striped tube that runs into the water screen filter):


And here is how to use the Y-adaptor:


Last thing to do is wire up the switch, I decided to use a three position rocker switch that I got at a local MC dealer (they were about $5/ea if I remember correctly):

Mas:


Hope that helps a few people! :grin:

[Hlymons]

RE: GT40 Heater install

This is great thanks,
Is the Y adaptor the way you plumb it so there is less heat loss during Idle or is it the other way around? Also I have a DD and was looking last night and it looks like the Y adaptor is going to be a tight fit.


Thanks Again

[M3Fan]

Re: RE: GT40 Heater install

This is great thanks,
Is the Y adaptor the way you plumb it so there is less heat loss during Idle or is it the other way around? Also I have a DD and was looking last night and it looks like the Y adaptor is going to be a tight fit.


Thanks Again

On your DD boat the Y pipe will splice in right before your raw water pump- basically right underneath the crankshaft pulley in the 1" RW feed hose. Plenty of room there. It increases the amount of heat during idle. You want the Y pipe. Incidentally FWIW I do not have the Y pipe and still get incredible heat at all RPM ranges, but the EFI boats run a 160 stat which may have something to do with it.

[Hlymons]

RE: Re: RE: GT40 Heater install

Thanks M3,
BTW
Your Fifteenoff site is great, sent the URL to a friend yesterday that was having trouble with his 32mph run.

[SquamInboards]

You can also tap into one of the block drains (whichever one doesn't have a knock sensor) so you don't have to mess around with the temp sensor, with all the adapters and extra parts in an area with so much else in the way.

[Hlymons]

So are you (SQI) saying to use the y-adator for one and the block drain for the other? That seems too easy. There must be a reason eveybody goes with sensor "T" method. Anyone anyone Bueller!

[ally606]

I installed my heater using the same take off on the block but just used a regular T adaptor down by the raw water pump. The only problem I have had is that the temp sender now reads around 30F lower than it should, hovering around 120F at idle and up to 125F when running, it does spike to around 140F after a blast but that increase is to be expected. I've replaced the stat twice with 160F units, replaced the sender, replaced the gauge, metered the wiring between the two and checked the feed voltage - all good.

For the life of me I can't understand why I am now getting lower temp readings. I've used a laser thermometer on the block and am getting readings of between 140F and 15oF so I'm pretty happy that the engine is not running cool, has anybody else had temp gauge issues after installing a heater? Sorry to hijack this thread

[8122pbrainard]

You can also tap into one of the block drains (whichever one doesn't have a knock sensor) so you don't have to mess around with the temp sensor, with all the adapters and extra parts in an area with so much else in the way.

The block drain is the proper place for a tap. Just like "ally606" has stated, you will get lower temp readings with the relocated sender. Bad idea messing around with the sender.

[ally606]

where are the block drains on the GT40 that I should tap into? I'm used to working with carb'd Chevy motors so am new to the injected engine and all the sensor paraphernalia that goes with it. Any pics would be useful. Cheers.

[M3Fan]

My theory on tapping the temp sensor port on the intake mani is because basic convection will force the hottest water to the top of the engine, or perhaps that's the last stop for the water on its way out the T-stat. As far as I know, the T tap with the temp sensor is the factory installation so it can't be that bad. Also, with the Y adapter or not, the feed is (almost always) coming from the intake mani and the return is either the block, circ pump, or Y pipe. I've never seen both block drains tapped for a heater, or an block drain combined with a Y pipe.

[ally606]

thanks M3Fan. That takes me back to my first question which I'm struggling to answer, why am I getting a temp drop when my instal is pretty much identical to others? I'll try blocking off the heater and run the engine to see how it affects the cooling temp.

[8122pbrainard]

Another having a low temt reading problem on CCfan just poted this morning.
http://www.correctcraftfan.com/forum...12219&PN=1

[KenG]

I've never seen both block drains tapped for a heater, or an block drain combined with a Y pipe.

It seams to me if you tap into both block drains for the heater you will get little or no circulation through the heater core, both fittings flowing the same way. The coolant temp sender should be just as accurate an inch or so from the manifold as it is in the manifold.

My last boat had the GT 40 and factory installed heater, it was Y'ed into the sender, worked great. Returned at the front block drain on drivers side.

[ally606]

ah, you caught me out!! It was me that posted the question on CCfan, hoping for a combined wealth of knowledge to solve my problems (boat problems, not personal...).