Crossover temp problem HELP
 

I need some help with this one. I just put my motor in my boat and i installed the crossover system that was on the old motor. The old motor ran at about 180 deg. but when I pulled the thermostat housing off to use it on the new motor I found that the thermostat was stuck closed?
So i put a new 165 in the new motor and now when I ran the new motor I get no temp or 120 deg. max. cant get ant temp in the motor and the oil temp is staying way to cold. Getting milk in the oil. Now I have tried putting back the old stuck thermostat and still no temp. Cant run the
motor like this any ideas how to get the water temp up. It has a bypass system. How does a stuck closed thermostat still allow the motor to run cold????

This would my concern " Getting milk in the oil."

How do you know the thermostat is "stuck"? Are you taking it out and boiling it in water to see if its opening?

What kind of crossover setup and how is it plumbed? 180* is a bit hot for my liking on a typical carb'ed marine engine, but.......what engine are we talking about?

you are not going to get enough condensation in crankcase to milk up oil in this short a time. you have a bigger problem than engine temp issues. find the leak. first culprit, intake manifold gaskets. second culprit, head gaskets or the heads themselves. you say your motor and your old motor. what is the new motor? somebody else's old motor? were the heads run in salt or brackish water for any length of time? are they mk4 heads on a gen 5 block? how old are exhausts, though they usually hydrolock engine, not water the crankcase.

Here is some more info, I own a boat that I built a 600 ci big block that made 720 hp ran it for 2 seasons no problems.This motor had a reg. circulating pump. Then I bought a 29 fountain that had a stock 502 that I wanted to swap motors and sell the other boat with a stock motor. During the winter I rebuilt the 600 ci motor changing the cam, intake, and heads ( the heads were run on this motor so I know they bolt up and no leaks. ) The headers are dry. So now when I put the 600ci motor in the fountain I used the crossover set up that I took off the fountains stock 502 that was running with no problems and that motor was running at 150 water temps.

Sorry but for some reason it did not post the whole post. Now I cant get the 600ci motor over 110 deg. the oil temp does not even move. Today I changed the oil and bypassed the oil cooler ( which I presure tested ) now the engine temp is still 110 but the oil temp came up to 140 still not hot enough but better, the milk is a lot less and the oil level never rises. If it was leaking water into the motor the oil level woud be rising. Also the motor was run on a dyno, warmed up cooled down gone over and warmed up a few pulls and let cool down no milk ran great. Dont understand how a motor can run so cold with a stuck thermostat, I put one in just to see and still no heat.

Randy are you sure the motor is not getting hot. With some of these cheap bypass setups the inlet water can bypass the motor and go right into the exhaust. May want to verify temp with gun or run it and place your hand all over the cylinder head especially front and back if it is really no temp the head will feel cool to the touch.

BB I have been checking the motor after a run and the block and heads are ice cold. After I shut it down I see the temp gauge go up from the heat soak but as soon as I start it the temp drops right down to about 120. Driving me nuts.

Could you be running in a lot colder water than you usually do or did ?

Crossovers, even with t-stats, in my area usually still run too cold both engine and oil for a part of the year. Work okay when lake warms up.

This sounds like the situation.

I hope thats the case, but why would the thermostat not let the motor heat up??? Maybe not to full temp but some temp. Just got off the phone with Keith Eickert help line said to put more holes in thermostat, thinks I may have air pocket problem?? Going to give it a try will let you know what happens........

Sounds like you got the same tech that works for all the performance parts companies. That makes no sense at all.

Well I took a new 145 thermostat and drilled 4 small holes in it, I now get 130 deg. water temp and 145 oil temp, thats with out an oil cooler. Seems that the holes worked or at least help. Dont know how but it is getting better. The milk in the oil is almost gone, I did change it but its not coming back and the little that was left seems to be going away.I know 145 oil temp is to low but till I can get water temp higher I dont know how to get the oil hotter. Like I said before I bypassed the cooler so even a thermostat controlled oil system
would not help. Im guessing.

Makes sense to me. You need a small amount of water to be allowed to circulate to prevent air pockets in the block. Reason cars dont need holes drilled in the thermostat, is because they have a bypass that routes coolant back into the circulating pump while the thermostat is closed. Circulation of coolant exists, it just isnt going thru the radiator. Mercury's system functions in a similar manner with the circulating pump on the front of the engine.

With a crossover, there is no way to keep water circulating thru the engine, to help bleed off any air pockets, without drilling holes in the thermostat. The main problem with these systems, when running a water thermostat, is maintaining an acceptable amount of water pressure in the engine block when the thermostat is closed. If the bypass on the crossover is too small, you will likely see high water psi in the block.

What type of thermostat are you running?

You can buy the high flow robert shaw thermostats with the holes drilled in them already. Stewart sells them, they drill three, 3/16 holes in them.

http://www.stewartcomponents.com/ind...&product_id=55

He's not trying to lower the temperature he trying to raise the temperature. Drilling holes in the thermostat is not going to raise the temperature of the engine it will lower the temperature. As did with his New thermostat. Drilling holes in a 140 thermostat got him 130 degree motor.

I just want to say thanks guys for the help, its great to have a place like this to turn to for some help.
Drilling the holes in the 140 thermostat got me to 130 with out the holes it was about 115 or 120 so the holes helped. I had a 165 thermostat with one hole in it still would not come above 120, guess it needed more bleed holes?????? The boat has a pressure relief
valve between the oil cooler and the crossover tube, is that the right spot for it?

You guys are not going to belive this.I called another well know marine high performance shop and told them what was going on with my water temps. told them I could not get water temp over 130 and oil over 140. They told me the water temp is to
HOT and the oil temp is perfect????? They said water temp should be 100deg. and oil temp 140 and they should never go higher. All there engines ( custom and full race ) are built and set up to run that way. I am thinking that is to cold for me I would like to see 140 to 150 water and 190 to 210 oil temp. Is that about right. I also have some thing that I have been thinking about trying to get my temps up and will try it over the weekend. Will let you guys know how it works.

I know many engine builders who have had success running temps like that.

I personally, do not run any water stats in my engines, but I do run oil stats. It does take a while to get some oil temp, but once warmed up , my oil temp stays around 190ish. Water temp, never comes off the peg.

Prior to this setup which has been the last 3 years, I had no oil thermostats, or water stats. It was rare to get much oil temp at all on the gauge. The engines were setup this way, from 2005-2011. When I tore into them, the bearings looked like you can put them right back in the engine, and nothing showed any signs of abnormal wear. Sometimes, I'd get a little bit of milky foam on my breathers, but never anything in the oil, and looking into the valve covers, springs and rockers were clean and milk free always.

Not saying any of this is the right way, or wrong way, just saying whats worked for me over the years.

OIl temp is the most important with performance motors and things built a little loose.

I'm no Borgie (oil expert) but I've been told and have read and have had success with min oil temp of 180 and max of 220. That said, I'm fine with a little more oil temp than that max, but I am a nervous nellie with oil temp lower than that min.

I remember on a few stock merc "black" engines, that simply had water thermostats, low oil temps were pretty common. At least on the engines I've seen around here boating in cold lake michigan water. My buddy had some 365 mags, bone stock, oil temps rarely ever went over 150-160*. He ran that boat like he stole it, full throttle everywhere, 38'fter. He sold it with over 900 hours on the engines, and they still ran great, and held 30+lbs of hot oil pressure after a hard run.

I think back then, mercury spec'd oil cooler size to the engine package and it generally worked. They did not however, have control over the temperature of the water that would be passing thru the oil cooler. Big difference when you're pumping 55 degree water thru the oil cooler, or 90 degree water thru the oil cooler. Bottom line, they were pretty long lasting engines. Actually, longer lasting than most of the modern marine engines today!

Sorry it took so long to update this but been busy. Well its fixed,cant belive it but the problem was a leaking intake gasket. Pulled it apart and changed the gasket and, no more milk, got some temp in the water and the oil. Boat is running great so far. Still have not run it wide open for any length of time but did push it for a quick run. Saw 91 at 5800 for a few seconds, still have to dial in the jetting and timming also the prop but so far im pretty happy.