8-71 TI Temp

[scottinsydney]

Its not often we can go faster than 900RPM in our local boating area and the engines never warm up. Rarely do we go above 1500RPM
.
Dieselpro has 160, 170 and 180 degree thermostats... would the 180 degree be my best choice? Any issues using a higher thermostat?

 

[Briankinley2004]

What ratio do you use on the NAPA Kool? Thinking of going that route next time I change mine as we dont get below freezing either and if so I have block heaters.

 

[kelpy]

Your heat exchangers will get scaled up in fresh water just like in sea water though to a lesser extent. Get them cleaned and resealed and you problem should go away. Never let those engines get above 190 degrees - not even for a second.

 

[SKYCHENEY]

The red Detroit stuff. I let it run in the slip for a while and they both came up to about 150 on the thermostat housings. Maybe that got it... Won't know anything until I run it.

No, I haven't flushed the closed side. What kind of coolant are you guys running?

DD Powercool and I check the SCA level yearly.

 

[SKYCHENEY]

Its not often we can go faster than 900RPM in our local boating area and the engines never warm up. Rarely do we go above 1500RPM
.
Dieselpro has 160, 170 and 180 degree thermostats... would the 180 degree be my best choice? Any issues using a higher thermostat?

Changing thermostats will not bring up the temps if you're only running 900rpms. Stick with 170's and at least you're good when you do run 'em up.

 

[scottinsydney]

Thanks. What thermostats would the fzctory have installed when they were built?

 

[SKYCHENEY]

Thanks. What thermostats would the fzctory have installed when they were built?

All marine DD's should run 170's. Others may disagree but I've had several mechanics tell me that. If you give a DD dealer your serial number, they can tell you what the original part was.

 

[Boatsb]

What ratio do you use on the NAPA Kool? Thinking of going that route next time I change mine as we dont get below freezing either and if so I have block heaters.

Theres a recommended concentration on the jug that I follow. I usually keep it a bit high so when I fill with distilled a bit theres no big drop.

 

[Capt Chad]

I pulled the intercooler off today and backflushed them. All I found out of normal was oil. So I inspected the Turbos and found too much end play on the shafts.

Even at the slip I noticed one engine was 20 degrees hotter on the exhaust ports on the manifold than the other side.

Have you guys seen an overheat caused by Turbos going out? Too much exhaust restriction?

 

[racclarkson@gmail.com]

What ratio do you use on the NAPA Kool? Thinking of going that route next time I change mine as we dont get below freezing either and if so I have block heaters.

Or just go with Power Cool premix. About same price as concentrate. If your system is tight and you use overflow tanks you should never have to top off.

 

[scottinsydney]

I ran the motors up to 1450 rpm which is the absolute maximum I will ever go for the next 20 years due speed restrictions. Used my IR gun on the thermostat housings and recorded about 167 degrees for both engines. Why can I not necessarily use replacement 180 degree thermostats? My thoughts are they will solve the issue of running cool engines. Nobody will drive the boat except myself. The old thermostats can be stored for a future owner.

 

[racclarkson@gmail.com]

I ran the motors up to 1450 rpm which is the absolute maximum I will ever go for the next 20 years due speed restrictions. Used my IR gun on the thermostat housings and recorded about 167 degrees for both engines. Why can I not necessarily use replacement 180 degree thermostats? My thoughts are they will solve the issue of running cool engines. Nobody will drive the boat except myself. The old thermostats can be stored for a future owner.

No reason. Do it.

 

[SKYCHENEY]

You state that you normally run at 900rpms. The 180's will make absolutely no difference in temps at that rpm because they will not even start to open same as the 170's or even 160's. Do as you wish but you will likely see no change. To get the temps up, you need to run them at higher rpms.

 

[Briankinley2004]

Put one in forward and one in reverse and advance throttles to 1800. I bet you come up to temp and dont violate the speed restrictions. I personally agree with Robert on this

 

[scottinsydney]

The farmers in Australia refer to spinning a car around in a paddock as "Circle Work!" Perhaps I could try this on my boat in front of the Sydney Opera House. I'd be sure to be breath tested by the water police.

Anyway, the issue at hand is IF the engines will generate enough heat at 900RPM to increase the coolant temperature to around 180 degrees?

If anyone has a parts book, the blue tag on the engine says SN 12VA077581 and the thermostat is #76.

Cheers.

 

[Photolomy]

What is the full range of RPM's for 8V71TI engines in a 53' boat, and what should the temp be throughout?

 

[kelpy]

167 deg. at 1450 RPM or so sounds about right.

Changing thermostats to increase the operating temperatures at low load/RPM is as fruitless as changing injector size to get better fuel economy. Detroit Diesels just don't work that way.

 

[Capt Chad]

Well, I pulled the heat exchanger because it was the only thing I haven't had apart. It looked like it was brand new... I pit it all back together. I lot it to check for leaks. I have water spewing out of the week holes in the inner cap on the outgoing side of the cooler. I know something happened to one of the o rings. Anybody ever had this happen?

 

[Scarlett]

Wait a minute Scott, I seem to remember someone else driving your boat a few weeks ago, and by the way enjoying it a lot. John

 

[KPTIM]

On the thick plate / spacer on the out going side of the heat exchanger.
That plate has to go on facing the correct direction.
If you put it on reverse / backwards water will come out of those small weep holes.
It is very easy to install it wrong.

The other cause for this is if you use the wrong after market O-rings and also can happen if you do not replace the crush ring that goes between the two O-rings.