Too scared to do the thermostat upgrade??? Poll...

[krazzz]

I am about to do the thermostat upgrade with the 1/4" spacer which requires the removal of the thermostat housing studs from the head. I pulled the housing and I have been spraying PB Blaster on the studs for the last 2 days. Now I have cold feet. I have very limited access over the studs so if I break one when trying to get it out I will be in a world of hurt trying to drill them out. I do have an nice stud puller (the kind that looks and works like a drill chuck.) It just makes me nervous when trying to remove something that have been a part of the block for 44 years. I am looking from advice from those who have gone before me. I am most concerned about downtime from sailing. I currently do not have a thermostat and I am running about 100 to 110 degrees. If I shut it off and check the temp a few min later it will be 120 degrees so that is probably closer to the actual temp.

Should I:
1. Do the job, it isn't hard and low risk of breakage.
2. Run the rest of the season and worry about the thermostat when the boat is laid up?
3. Don't worry about running too cold and be thankful I don't have the opposite problem?

[Trés 30]

2¢

Option 2, all day long (and a little of 3).

If you're concerned about the studs after 44 years, you may find other things needing attention that will likely cost you more downtime.

[JOHN COOKSON]

Have you been tapping on the studs with a hammer while you've been shooting them up with PB blaster?
When you try to remove the studs if there is any way with your limited access you can tap and torque at the same time it will incerase your chance of success. Maybe a crew member can help. Or some sort of impact wrench perhaps.

TRUE GRIT

[krazzz]

Option 2, all day long (and a little of 3).

If you're concerned about the studs after 44 years, you may find other things needing attention that will likely cost you more downtime.

I'm just concerned because it is a part that hasn't likely been removed in 44 years and has a good chance of becoming "one with the block." The boat hadn't been in the water in 15+ years when I bought it so I had a lot of catching up to do. In the past 2 years I have rebuilt the carb, installed a Moyer fuel pump, rebuilt the water pump, new alternator, new gauges, and added electronic ignition. It runs like a top with no issues. Now that I got all the bugs out of it I am working down my list to the lowest priority stuff. Since running too cold is a minor problem to worry about I have put it near the bottom of my list. After this is only the "nice to have" upgrades left such as the longer dipstick and quick oil change kit.

[krazzz]

Have you been tapping on the studs with a hammer while you've been shooting them up with PB blaster?

TRUE GRIT

You know I forgot about the tapping with a hammer trick. I will start doing that.

[smosher]

There's another way to increase the engine temp and thats with a bypass valve.
Moyer sells the kit. I have one and no Thermostat, I use it to keep the head temperature front to back as close as possible. Eventually the water temp gauge gets to 120 after running for at least an hour with ocean temp in the 60's

If your going by the water temp gauge and its in the usually position, it's misleading as its where the cooling water enters the head. The rear of the head by #4 will be the hotter.

depending on power level and water flow it will take awhile for the A4 to get upto temp.

My vote would be not to do it at all,

Steve

[Dave Neptune]

A comment

Steve, a bit of a side-bar here. In regards to your comment as to the proximity of the temp sender to the bypass when not using the t'stat. I found a good solution. I brought my bypass feed to the manifold via a tee and plugged the hole on the t'stat housing. I get good temp readings and the adjustments on the valve are "quickly responded too" by the gage now. I have run this set-up for about 5 years now. Quicker warm ups and I can run warmer 130+ with minimal fuss adjusting the valve.

I did post some pics of it a while back but do not remember the thread.

Dave Neptune

[smosher]

Hi Dave, Why do you think it behaves this way?

Simple enough to do and sounds like a very good change to make

Steve

[krazzz]

Hey Dave,
If you find the post please share the link. I would love to see the pictures. I would be perfectly content not having a t-stat if I could get it up to 130 degrees.

[Dave Neptune]

krazz, hope this works.

http://www.moyermarine.com/forums/showthread.php?t=6699&highlight=bypass

Dave Neptune

[hanleyclifford]

I like Dave's system. Thermostats in general are not a good idea because they operate on a principle of restriction whereas a bypass system uses the principle of diversion, which preserves velocity and flow, which is good for the block and the pump.

[capnward]

stud removal not necessarily required to upgrade thermostat

I like the Indigo FWC thermostat I recently installed, which mounts separately from the engine. It diverts the flow back to the pump until the coolant temperature reaches 180*, then it diverts it into the HX. There is no restriction in the flow, and flow is not diverted from going into the block. I do not have a bypass from the side plate. The thermostat housing on the front of the head has been empty since the last engine rebuild in the late 90's. For years I used the Honeywell mixing valve that Indigo used to sell, but when it melted internally during an overheating episode caused by FW pump water seal failure (which never happened with the old grease-cup style water pump), I decided to get a thermostat that wouldn't melt. Usually these t-stats are mounted at the exit of the manifold, but I have mounted the Indigo unit directly on the HX upper end, and it keeps the operating temperature just under 180*, if I can believe my gauge.
My only problem is that when I shut down the engine when it is near 180* and turn it back on before it cools down, the temperature alarm, whose sensor is on a tee fitting at the exit of the manifold, sounds when the gauge temperature is 180*. The alarm is supposed to go off at 200*. The gauge sensor is on the front of the head. Apparently hot coolant left stationary in the hot engine builds up enough heat to trigger the alarm sensor, but not enough to make the temperature gauge read too hot. I also had this problem when both sensors shared a tee fitting on the front of the block.
I'm glad I haven't had to worry about removing thermostat housing studs from the head. After I removed the ruined mixing valve, and before I installed this new thermostat, I had a manual valve and bypass that diverted coolant away from the upper end of the HX, into a tee at the lower end, and back to the pump, partially bypassing the HX. With this I was able to reach a temperature of 130 to 150*, but thought this was not hot enough. Now I don't have to mess with a bypass valve, which seems to me to restrict flow as much as a thermostat.

[smosher]

Dave, you reversed the flow through the manifold, does this eliminate the hot spot ?


Thanks


Steve

[joe_db]

I hate to plug the "other firm", but I would use the Indigo thermostat before I tried to get a stud out of a decades old engine. I would even use no thermostat at all and use a manual valve until I got around to removing the engine and doing this work at a shop or in my garage.

[Dave Neptune]

Steve, the hot spot is just the end of the exhaust manifold and is not covered by a water jacket. Some manifolds are ported at each end for alternate exhaust set ups and are blocked by a blind plate the gets hot too. All normal!!!!

Dave Neptune