Engine temp too cold!!!

[psdperformance]

I just took my freshly rebuilt 455 old motor for a test run on sunday and could not get the water engine temp up above 100 degrees. What do i need to control water/engine temp so i can get my engine to run at optimum engine temp even in a cold lake??
Thanks chris

[460 jus getn it]

I just took my freshly rebuilt 455 old motor for a test run on sunday and could not get the water engine temp up above 100 degrees. What do i need to control water/engine temp so i can get my engine to run at optimum engine temp even in a cold lake??
Thanks chris
what was the water temp like where u were at? i was out at one of our lakes here in az and my temp stayed at 105 all day long.

[psdperformance]

the water temp was very cold i do not know what it was but my engine temp
never got above 100-110 ules i was idling it got a little warmer. i was just wondering if ther is any way to restrict the water flow to the motor to warm the engine to say 160-180 degrees and keep it there all day.

[napabob]

the water temp was very cold i do not know what it was but my engine temp
never got above 100-110 ules i was idling it got a little warmer. i was just wondering if ther is any way to restrict the water flow to the motor to warm the engine to say 160-180 degrees and keep it there all day.
I have this very simple system, standard on my jet boat, that controls the water intake into my engine. If the lake water is cold, like this past Sunday at Lake Berrryessa, I just turn the valve down until I start getting readings of 150 running at 4K and 165-70 at idle.
http://www.harmanmarine.com/newsite/Library/pp/12.pdf
I have TT exhaust and I do not know if it will work on your boat.

[Sanger Jet]

the water temp was very cold i do not know what it was but my engine temp
never got above 100-110 ules i was idling it got a little warmer. i was just wondering if ther is any way to restrict the water flow to the motor to warm the engine to say 160-180 degrees and keep it there all day.
Install a Ball Valve between the pump and the engine. Available at local hardware store.

[460 jus getn it]

Install a Ball Valve between the pump and the engine. Available at local hardware store.
thats what i have also just a plain old ball valve. at idle my temp rose up a little but at 3000rpm i was at 100-110. id say you are ok your temp will rise as the outside temp gets warmer.

[redi4fun]

Rex marine has just what you need. Better than trying to use any type of valve to control the water temperature. Look here:
http://www.rexmar.com/page160.html
I have one on my jet boat and it works great. ;)

[Shark In The Pond]

Rex marine has just what you need. Better than trying to use any type of valve to control the water temperature. Look here:
http://www.rexmar.com/page160.html
I have one on my jet boat and it works great. ;)
I just installed one last week on my Jet and I like it !

[Hallett19]

I just got a plastic valve from Home Depot and put it in my feed line from the pump and I just close it off a bit and it runs fairly consistently. At idle it will get to about 190 and at wot it stays around 160-170. I usually just leave it wide open so it runs cooler so my oil doesnt get too hot.

[sanger rat]

Hallett19 I would not run anything made of plastic on your water lines. Hate to see a boat sink becuse of a 2 dollar part. Get something made of brass.

[Back Forty]

Get a thermostat. You won't regret it. What cooling set up do you have now?
Mine runs 140* and at idle after a hard long run will get as high as 160* and then settle back to 140*.

[Hallett19]

Hallett19 I would not run anything made of plastic on your water lines. Hate to see a boat sink becuse of a 2 dollar part. Get something made of brass.
Its a hardcore piece of gear. It rated at almost 200 psi and is made of some hardcore stuff. Thats what bilge pumps are for, right ? :)
I actually think I am going to change that setup to a pressure regulator soon.... not sure.

[NELSON#109]

get a thermostat kit, with the bypass. they are the best. ur water temp will be consistantlt between 160 & 170. ur oil temp will be between 140 & 160. mine was a gill, but it is the same basic design Rex, CP, and eddie are selling. theyre all good products. like someone else already said, you wont regret it. controlling your temp with a valve IS A BAD IDEA, and even thow most peps are doin it that way, its not good. the only valve you should be adjusting is one from the therm housing to the header. if you want some sweet pics of a good set up, send me an email..... stinson50k@adelphia.net.. make sure you tell me u want pics of water plumbing.. ill hook u up.

[LVjetboy]

"get a thermostat kit, ur water temp will be consistantlt between 160 & 170..."
In my case the Rex bypass thermostat regulated water temp between 160 (cruise) to 190 (idle) Interestingly enough, Rex's description of operation here...
REx Thermostat (http://www.rexmar.com/page160.html)
matched my water temp range very close. Notice a 30 degree variation, not 10 degree.
"...ur oil temp will be between 140 & 160.
That I'd also challenge for typical lake jet operation (ie occasional cruising not a quick 1/4 mile pass) Unless you run a cooler, I'm thinking oil temp will likely exceed 160 at cruise...by maybe 100 degrees. I've run both thermostat and no thermostat on several jets. I've also measured oil temps (mechanically and electrically) approaching 300 either way, thermostat or no...even with water exit temperature at 120 as I posted in another thread but got no feedback. So I'll float the question again...
First: How do you define "Engine temp too cold" By water temp alone? By oil temp? Or some combination of both?
Another interesting point is: With no thermostat I still get about 30 degrees variation between cruise and idle. Which begs the question...how does the thermostat benefit engine health?
Let's hear from those out there running a Rex thermostat. Do you measure water and/or oil temperature? Are you also seeing a 30 degreee water temp flux between cruise and idle as Rex's link indicates and what I measured or only 10 degrees as Nelson109 posted? And those of you who've measured oil temp at cruise w/o a cooler...anyone running 250+ degrees?
Finally: If water temp cold and oil temp hot...what is the measure of an "Engine running cold" or for that matter, jet boat engine temperature goodness?
jer

[Danhercules]

I am no motor goru by any means but here what makes sence to me.
In a closed system, like a car, when the motor is warm, the water temp goin inn the motor is what, lets guess 120*. then comes out at 160-190. Thats a 40 to 70 of a spike in temp. Thats if the water goin in the motor is 120. I bet its hotter. So, the water is taking a bunch of heat out of the motor.
At the river, the water is 65 to 70. The water commin out of my boat is 110 to 120, Its still raising the water 40*. So , I would say, the motor is runnin the same temp. If you collected the water thats 120, and put it back in the motor, what you think it would come out as?
When a car is "cold", the water commin out is near the same goin in, its the spike in temp that makes me not worry about my runnin temp in my boat.

[Squirtcha?]

Here's a bunch of information regarding engine cooling on jetboats. You'll read about pros and cons for both thermostatically controlled and the more common gate valve method.
Per usual with the message board, you'll have to come to your own conclusion, but it'll make for some interesting reading. If you've got the money to spend, and you feel that engine running temps are that critical...............
Get some popcorn and a cold beer (or whatever).
Jetboat cooling (http://www2.***boat.com/forums/showthread.php?t=17610&highlight=egg+shaped)

[LakesOnly]

In a closed system, like a car, when the motor is warm, the water temp goin in the motor is...120*. then comes out at 160-190. Thats a 40 to 70 of a spike in temp.
At the river, the water is 65 to 70...The water commin out of my boat is 110 to 120, Its still raising the water 40*. So , I would say, the motor is runnin the same temp. If you collected the water thats 120, and put it back in the motor, what you think it would come out as?
When a car is "cold", the water commin out is near the same goin in, its the spike in temp that makes me not worry about my runnin temp in my boat.
No, you're car is running at 160* and your boat is running at 120*.
When somebody says that their motor "run's at 180*," they are referrring to the water temperature in the coolong system of their engine.
A closed cooling system in an automobile has several factors which help the coolant do it's job, including a thermostat, coolant (sort of), pressurization, etc, If that thermostat is designed to be fully open at 180*, then under typical operating conditions it will maintain an operating temp in the neightborhood of 180* regardless of whether the water being drawn in by the waterpump is 100* or 145*.
The two examples you give do not necessarily prove that both engines are operating at the same temperature; it only shows that both engines are coincidentally raising the temp of the cooling water by the same amount in that case.
LO

[Danhercules]

Is oil temp the answer then. It would be close to a car, no coolin system. So if the jetboat was running "cooler" then a car, the oil would be cooler. Or how bout a temp senson drilled in to the block, sensing the temp of the metal block itself.
I cannot touch my heads for more than a few seconds when my boat is warm. Same as car. So, the temp of my boat motor is running approx the same as a car, even though the water is cool. I think is cause the water goin in is cooler.

[psdperformance]

WOW this is what i like about this forum many different opinions and great advice this is my first jetboat and was not used to seeing 100 degree temps on the guage. I am currently not running a valve or a thermostat in my boat but if the cool water temps don't make that big of a difference than maybe i shouldn't worry about the water temp per say only the oil temp?? when i looked at the guage i thought the engine temp and oil temp was 100 deg. wich in my mind was a bad thing as i know the average engine needs temp to run efficiently. I will buy the t-stat kit from rex marine should i buy an oil cooler as well?
Thanks Chris

[NELSON#109]

ok, 1st off, i think oil temp, is more important than water temp, sorta. adition to what i posted above. i ran the water straight off the pump, no valve. i did use a regulator for a short time, but it didnt make a differance, so i took it off. i had the water temp sender in the top of the intake manifold, & i had a temp sender in the front of the oil pan. both senders were electric. i ran them both to the same temp gage, through a two way toggle switch. one way for water temp, the other for oil temp. the numbers i posted were consistant at every lake, or river i ever boated in. it didnt take more than a few minutes to warm up either. this system worked very well. 90 percent of the plumbing on the boat was 1/2 " stainless hardline, with a little braided stainless. if your not convinced, you can ask the current owner & see what #'s he shows. he goes by the name STILLGOIN. he posts every now and then. this was on a healthy 461 chevy. again, i have pics if you want them. i dont make anything by you doin it this way, so it should be obviouse that im not blowin smoke. i just know that ive tryed all of what has been recomended and many other things, and the bypass therm, was the only one that worked & it worked well. if i was to do another one, id do it just like my last.
jus a quickie. those that defend the straight through cold temps, are right for the most part, people have been cooling boats that way for many years. a 100 to 120 water temp isnt that bad. your oil temp is what you want to get up a little, but not too much. the reason i installed a sender in my oil pan, is because i was going to use the therm bypass & was worried it would send the oil temp to the moon. before i had the therm, i never knew what the oil temp ran at. i wanted a little more water temp, but didnt want the oil too temp to high. as it worked out, the oil temp never went to high, and i was able to get good water temp at the same time. every person i have talked to that has run a ther bypass sytem, loves it. i have talked with several people who havent tryed one, because they were afraid too cook the oil. which again is why i put a temp sender in the pan.
i dont think your gonna kill your moter with cold water temps, but ever little thing helps, and i think a consistant 160 to 170 is healthier than 100 to 110, pluss your oil temp is also more consistant. i ran my old boat mostly in so cal, central cal, and on the river. good luck

[Back Forty]

Something for the non Olds crowd to remember is that the Olds heads have siamese exhaust ports for the two center ports. Running car temps i.e. 190* may be a serious problem when you consider that cars run closed cooling systems. The boiling point of the coolant is much higher at 16 psi.(car) This may not sound like a problem when you have 20 plus psi in your block while going down the waterway however as soon as you come off plane you have very low pressure and the possibility of boiling water near the two center exhaust ports comes to mind. There's a reason why most factory marine setups with open cooling systems run a thermostat down around 140 to 160*
I'm using a mercruiser 140* stat in my berkley thermostat setup. Something to consider at least.

[CARLSON-JET]

Good point made on the olds issue AND block pressure @ idle BackForty :idea: R.B.

[LVjetboy]

Oil Temperature Data posted Sun Jun 3 15:12:30 2001 RJB? Can't remember now:
"Many posts ago we had a thread on oil coolers. Someone stated jet oil temp runs 100 deg above engine coolant temp...a claim I found hard to believe. Well, I was wrong.
Under certain conditions the oil temp can run near 100 degrees above, so here's the story:
Bought a mechanical oil temp gage (autometer, 140-280) and tested it against a meat thermometer in boiling water. Both matched w/in 3 deg from 140-210. Installed gage probe in oil gallery located above oil filter on my BBC...contacting oil just after it leaves the filter on the way to the bearings. Tested over two days last week with air temps of 105 and lake temps at 76 F. Idling out harbor, coolant water temp rose quickly and stabilized at 170, oil temp was just coming off the peg at 150. After complete warmup, did steady cruise (appox. 2 miles each check):
40mph/water 170/oil 205/delta = +35
50mph/water 170/oil 220/delta = +50
60mph/water 175/oil 240/delta = +65
70mph/water 175/oil 258/delta = +83
73mph/water 175/oil 265/delta = +90
When I backed off on speed, oil temp dropped back down.
Idle(after hard run)/water 190/oil 210/delta = +20
So, even though the water temp dropped to a fairly steady 170-175 during cruise, the oil temp continued to climb as engine load increased to 90 above coolant at full throttle.
Oil cooler in my future? Eventually, maybe. Except for the oil temp cruise tests, the oil temp stayed in the 200-230 range the entire weekend. This is because most of my boating is a quick runs around for battery charge or impromptu race, then floating and chillin' with the stereo. I rarely cruise anywhere at max speed and normally stay within a mile or two of the marina. But for someone with different boating habits, and much longer cruise times...an oil cooler with thermostat control may be a consideration. May also be good to have the extra temperature protection of a synthetic."
Update: Since then I've upgraded to a 540. Still see the same oil temp trends without a Tsat. More thoughts to come.
jer

[Danhercules]

NOw the question is, with water temps at 100 to 130, whats the oil temps? if its the same, dose that mean the motor is still runnin the same temp?
What about testing the acual temp of the motor. The metel. Not the oil or water. Its that not the TRUE motor temp?
Jer, waitin to see more. Good post.
The added pressure in a car motori is interesting too.

[Back Forty]

What about testing the acual temp of the motor. The metel. Not the oil or water. Its that not the TRUE motor temp?
Thats a complex question. Remember there isn't a "constant" thoughout the block and heads. There is however a source(s) for the heat being conducted throughout the block and heads. This goes back to the siamese exhaust ports on the Olds and boiling water rather than transfering heat from the heads to the coolant being pushed through the passages. many variables. I'm sure it can be left simple. If the engine is living without any damage then the setup is working... My lake barge may be tame and pretty much stock but I run for long periods of time over 4000 rpm’s (AA impellor) with my 455 which has a 12x3” oil cooler (no temp sensor). I’ll say that my 455 is making a nice 350 hp + at those rpms. Here is a nice conversion. HP x 0.746 = kW
350 HP x 0.746 = 261.1 kW 261,100 Watts.
Apply this to a time structure and begin considering what volume of lake water will do the job. This is a complex scenario but can be kept simple for our situation. I have no idea what is really going on in these Olds heads but I do try to be aware of the possible conditions without being to much of an egg head. If the subject engine is alive and well with no noticable problems, wear or damage then consider things right.
Thats my opinion.
I like my 140* thermostat and big ol' oil cooler for the lake heap... My 8 hour trip from Cinci to Louiville and back last summer on the Ohio River comes to mind. :rollside:

[LVjetboy]

"Now the question is, with water temps at 100 to 130, whats the oil temps? if its the same, dose that mean the motor is still runnin the same temp?"
Well, with my new engine (540) running at 120 deg F and 4 qts more oil I see similar oil temps as I posted with the mild 454. If I cruise over 50-60 mph I get the light (250 F) and the needle climbs towards 300 F. Not unexpected because neglecting other changes, the same speed with either engine requires the same thrust or engine power output. And unlike the car, a jet boat works harder at these speeds...maybe benefiting from extra cooling. But this engine's at bit different than the 454. Aluminum heads for one thing.
As BackForty posted, complex. The obvious question, is the average metal temperature the measure of goodness? Or temperature fluxuation range? Or average oil temperature? And so on. I'm not saying the answer to these questions will affect everyones jet. My 454 survived many cooling schemes and high oil temps.
Just questioning.
jer