Motor never warms up. Advice wanted
 

I have just purchased and installed a 468 and 3" oil cooler. The motor has a crossover instead of a water pump. Water lines run from the sea water pump to the oil cooler, from the oil cooler to the crossover and then from the thermostat housing to the Eddie Marine Exhaust. My water temp guage never rises off the peg. I do not have an oil temp guage yet but plan to get one. I can make several hard passes after running for 1/2 hour or more, and the temp guage never rises at all. The sensor is new and the guage worked fine before the engine swap. After running hard, I can lay my hand on the block or heads and they are only luke warm. I am concerned I am not warming the engine enough to get the oil to proper temp. Is this a valid concern? Wouldn't I be down on horse power running this cool? I haven't looked to see if there is a thermostat but I am suspecting there is not one. Can you even use one when the only outlet is the 1" hoses going to the exhausts? It would seem if you used a thermostat it would shut off water to the exhaust, and that can't be good. I would appreciate any advice you have.

Do you have an oil temp gauge? You certainly want to be up over atleast 160 or 165 oil temp. Optimal temp is higher. Maybe 200's or so, all depends who you ask. If you are getting good oil temp and the water temp guage is still not reading, maybe re-check the guage and sender, there might be an error there I would think. Oil temp and no water temp sounds goofy, and water temp increases much quicker than oil temp does. Be sure you did not cross the oil temp and water temp guage wires...so the water guage is actually reading the oil temp and vice versa.

Just my minor .02, plenty of other more knowledgeable guys on here will chime in soon I'm sure. One more thing, do you have a water pres reading?

Good luck

Ray the main thing is the oil temp ,it needs to warm up to work and rid itself of condensation ,water temp is ok if its cool 140*or less and not hot ,,,but your right for all out HP you need the hot water but thats in cars as we have more detonation to worry about :D

The boat is a Baja Hammer, and just has the basics in guages such as oil pressure, Volts, Temp, gas, speedo, and tach. No oil temp or water pressure guage. My temp guage starts at 100, and the needle never rises up to that. Does anyone know if the plumbing system I refered to with the crossover would normally use a thermostat, or would that prevent cooling water from getting to the exhausts while it was closed? The 310 MPI I just took out would run at about 170 degrees when fully warmed up. I can see I need to get an oil temp guage but if it is not getting warm enough, is there anything I can do short of removing the crossover, installing a water pump and replumbing?

165* for oil is way too cool! you need to be above the boiling point of water, like around 220* or your gonna eat your engine from the inside out.

Over cooling your oil is a major no-no.

oil T-stat is a must.

Water T-stat can only work if you have water bypass on the crossover to the exhausts. With your plumbing, you cant run a t-stat.

220BR...I agree, I was talking about a safe low end operating range not optimal or full time temps.....I run mine at about 215 or so....It needs to be up to atleast 165ish to put the motor under any significant load is what I was getting at....much hotter for normal running.

Thanks....seeya

Good luck Ray...:)

The problem with the engine temps is the crossover. You are flowing too much water too quickly through the block so it can't build temp. That is why merc runs the circ pumps-to add some restriction. The circ pump also helps to ballance the flow between both sides of the engine. If you had clear hoses going to your exhaust, you'd notice that the flow is unbalanced. All the water will go to one side and then switch and go to the other side. I believe that this has to do with steam pockets building in the exhaust and then collapsing. Adding the circ pump would be the easy solution to both of these problems.

Presuming that you want to keep your crossover, do you have any holes drilled in the thermostat? You need a couple of 1/8" holes to help get a little flow through the block when the stat is closed. The problem otherwise is that the block will heat up and thermostat will open allowing cold water in, thus closing the t-stat. You also need to slow the water flow that is going through the engine. I used a pair of 20gpm flow restrictors on my engine. With my cross over, I see 120-130 degrees of temp. The problem then is pressure. Because you are restricting the water flow, the system now builds pressure. I used a 3/4" dump valve and it's not big enough. At around 50mph I'm already seeing 30psi of pressure. My dealer has a dump valve that uses a 1-1/2" port and it's supposed to work real well. That's going to be my next project.

Of course, you could always just add the stock circ pump. But that would be too easy.


btw-where is your temp sender? Is it after the t-stat? Try installing it in the manifold crossover. Use the port that serves the bypass. Then route the bypass after the t-stat from the crossover to the thermostat housing. This will allow water to reverse and bypass the engine while it's warming up. It will also allow a small amount to recirculate and help the engine to warm up.

Damn! It is getting complicated. I would like to retain the crossover, but I am beginning to wonder if it is worth it. I want to try however, so I am going to work on these suggestions. I talked to my builder and they did not put a thermostat in as the water in the South, where they are, is about 85 degrees. We are about 65 here right now. They suggested a thermostat with holes drilled in it. I take it that trial and error is the only way to know how big or how many holes to drill. If I do use a thermostat, what degree should it be and how many and how big should the holes be. I have had another suggestion to put a restrictor in. Moroso apparantly makes them. Any one go this route? Mcollistin says I need an oil thermostat. Sounds like a good idea, but it sounds like more plumbing and obviously more money. Cheaper than an engine, I know. Does everyone use one of these? I can see I need to get the temp guage. Cord has really thrown me a curve with this water pressure thing. I thought the primary need for a water pressure guage was to make sure you were getting enough water at speed. How much pressure is too much pressure? Does everyone with a crossover have dump valves to bleed off pressure? Not doubting you Cord, just trying to understand. I am beginning to think the benefit of the crossover on a non supercharged engine is just looks. Thanks for the help guys, I am learning.

cross over is great !!!! its not nessary to have a water thermo and yes the moroso restrictors work great !! you need an oil thermo. anyway !!!!! you can get a cheap yet good one from summit racing or jegs or a killer one from eckhart or c.v products in high point N.C.
same stat eckhart buys his from them ,,,but anyway just do that stuff and it will be great



KEEP THE CROSS OVER :D :D :D :D

Does your crossover have a bypass from the inlet to the t-stat housing?
I just put my engine in with a crossover w/bypass.
It has a thermostat (140*) with three 3/16"holes drilled in it.
I've only ran it for initial break-in. 20 minutes @ 2000rpm on the hose.
Water temp came up to 130*. The oil temp wasn't hooked up yet but the filter was pretty warm to the touch. But not real hot.
I'm using a 6"long 2 1/8" oil cooler.I'll let you know what the oil temp is next time I run it.
Your oil cooler is much bigger, I think you should use a oil t-stat also.
Summit sells the "PERMA-COOL" for about $30.

15 psi of water pressure in the block is safe (the motor is designed for a 12psi radiator cap in automotive applications).
Above 25psi in the block, you're asking for trouble.

Ok, what makes the water pressure get high in the first place? I still have the standard water pick up coming in the sides of the lower unit. My X dimension is not high so I have not modified the lower unit for low water pick up. My speed is about 80 now. Speedo says more but haven't GPS'd yet. Is the extra speed what gives the extra pressure? I am having trouble visualizing why water pressure would rise to dangerous levels as a result of using a cross over. I am sure I am missing something here, so help me out. My Cross over does not have a bypass. it has a 1/2 in. pipe thread fitting in the crossover that I assume is where you would install a sensor for water pressure. There is a smaller pipe thread fitting in the top of the thermostat housing. I could probably plumb a bypass using those, but then would loose the place for a water pressure guage. There is another plug in the top of the manifold oposite the one used for the water temp sensor. Would a water pressure guage be appropriate there? Thanks for the help guys.

That is where I run my sender.....works fine for me.

You probably DONT have water pressure troubles right now. You will, though, if you add a Tstat.

Stockers don't have pressure problems cause the water neck has spring loaded popoffs that send water to the risers to dump pressure instead of force feeding it into the block like a crossover does. If you run a crossover and a TStat then you need to run blowoffs to the riser fittings.

Ray, One neat little tool that you can use to check the accuracy of your temp gauges is one of those little heat sensing guns with the red laser pointer-----just point and shoot. It takes ALL the guess work out of finding out what kind of temps you are running. Last year I thought one of my engines was running too warm and I had just installed a BRAND NEW Gaffrig water temp gauge! It showed that I was running about 200*, but when I put that heat sensing pointer on the thermostat and water lines, it showed that I was running about 155* and I am running 160* thermostats. It will tell the temperature of just about ANYTHING! We took readings off my block in various spots, water thermostat and water lines, oil thermostat and oil lines, oil cooler and the lines going in and out of the cooler. I have tubular headers and we even shot each individual tube to get a reading of each one. It is about the best thing since they invented the areosol can!!! Just point and shoot and instantly you get a digital reading. Takes out all the guess work! I did this with my engine hatch off and ran the boat under normal load conditions out on the lake. I drove and watched the gauges on the dash while my cousin sat in the back and took readings! It's a GREAT little tool!

cont'd from post #16....

...I am running 160* thermostats. We also took readings off various spots on the blocks, oil thermostat, oil cooler and oil lines. I also run tubular headers and we took readings off of each individual cylinder. We took readings of the discharge water, electrical wires, fuel lines----EVERYTHING! We did this last year by removing the hatch off my boat and running it under normal operating load conditions---like we normally run the boat. I drove my boat and watched the gauges on the dash while my cousin sat in the back and took the readings from the engine. Just point and shoot whatever you want a temp reading from and you will instantly get a readout on the digital display. It's the greatest thing since the areosol can!!! It quickly and easily takes all the guess work out of temperature readings. They're about $100 or so.