Pismo10

After years of reading about crossovers, sounds like they are more trouble than they are worth

Donzi1979

iTrader: (1)

n^^^ I fought this exact same cross over set up for a year and then gave up and put a recirculation pump on with stock t=stat housing. Water temps now come up quicker and much more stable (mercury did this for a reason) as does the oil temp, although it doesn't look as cool as a cross over. When my motor had a procharger it benefited from the cooler water temps, but now in the stock configuration the recirculation pump and stock t-stat housing is the only way to go in my opinion.

Bavanew

I think I know what the problem is.

Originally, when I took delivery of the boat, my main concern was to make sure that my water temperature wasn't fluctuating, as that was one of the problems when the boat was first water tested following the engine build. It would climb to 1155/160 then plummet to 100 when the thermostat would cycle. Since I've had the boat, the water temp has always remained constant within a few degrees of 100. However, it was only a few weeks ago after reviewing the diagnostic report that I recalled that the water temp had previously been capable of reaching 155/160 degrees. I had been so focused on monitoring for temperature spikes that it never occurred to me that the temp was 50 degrees lower than it was at post build.

Once realized, I assumed that the thermostat was faulty or there were too many holes drilled into it, as it was the build shop who drilled the holes into it to regulate the temperature.
However, replacing the thermostat made absolutely no difference. Yesterday, I decided to review the diagnostic report, again. A second problem that the build shop had reported was that the port side head was 30 degrees hotter than the starboard side. (I had forgotten about that) To resolve that issue, they welded a washer/resistor into the starboard side water inlet of the block, which allowed more water to flow into the port side. Apparently that resolved the issue.

In hindsight, I think I know what the problem is.

Look at the facts:
Prior to drilling a hole into the thermostat and adding a restrictor/washer, the water temp was reaching full operating temp. (Even the dyno report shows 160 degree temps)
Drilling one 1/4" hole into the thermostat would not create enough water bypass to impede the temps by 50 degrees. I know this because most of the users who have chimed in have said that they have three 1/8" holes drilled into their thermostats and can still achieve full operating temp. Secondly, I replaced the thermostat and drilled one 1/8" hole, and my temperature never increased.

It is possible that by restricting the starboard side water jacket, that they were able to even out the head temps. However, I think the primary reason why one head was 30 degrees hotter is because the thermostat wasn't drilled yet, which resulted in an airlock in the port side head. I think they added the washer/restrictor to start off with, which may have assisted a little bit, but they still hadn't drilled the thermostat, and I think once they drilled it, that's what truly made the difference in eliminating the hot spot on the head. Because there is more volume of water entering the block from port side, I believe its inertia allows a portion of it to keep traveling right on through the starboard side, then out and up the the crossover bypass.

I'm going to remove the restrictor in the spring and start from there. If the flow of water entering the port and starboard jackets is equal, then that should balance the forces withing the block, thus preventing a continuous exchange of water.
I'll keep everyone posted.

Dannydean

iTrader: (1)

More than likely you got the wrong headgaskets installed. You dont have enough restriction to keep the water in the block long enough to build heat.

RBeyer

Agreed I never got over 100 water temp on a hot day, had oil thermostats to ensure oil temp ran great for 6 years for me and I hear it's still going.

Full Force

iTrader: (5)

Mine has had them since new in 1987.... they fine.

Full Force

iTrader: (5)

ICDEDPPL

iTrader: (1)

This guy likes solving non issues, I wish I had that kind of time.

Bavanew

Regarding the issue being a non issue, well, that's your opinion. It was an issue for me.
As for wishing you could have that kind of time, well, seeing as you took time from your busy schedule to leave a non-constructive comment, it seems to me you have plenty of time on your hands.

Bavanew

I have aluminum heads, therefore, they dissipate heat rather quickly at idle, so the idea was to keep them warmer for a smoother idle.
When I tuned my carb, I tuned it after the engine was was at full operating temp (Obviously). However, after coming off plane and letting the engine idle for roughly 5 minutes, the RPM's would drop about 180-200 from where the idle was set. That's strictly as a result of cooler head temps.
My objective was to increase water temperature as a means of eliminating the idle issue and to promote a faster rise in oil temperature.

As indicated in one of my final posts from last fall, I said I was going to remove the welded restrictor/washer from the crossover, as I suspected that might be the issue.
Anyway, I did so two weeks ago. I put the boat in the water, fired up the engine, warmed it up to 110ish, increased the RPM to 1,200 for about 3-4 minutes, and lo and behold the water temp rose to 144-145 and stayed there. That has never happened before. When I reduced the RPM to idle (850) the temp lowered to about 125-130 after 3 to 4 minutes and stayed there.
RPM dropped less than 50 as appose to the 180-200 that would typically drop. I can live with that!

I didn't have time to go for a ride (left it on the trailer), so I'm not sure how it's going to behave during a run, I'll find out this weekend. So far so good!