madhat

Evenin, DTR...

To the point...

When you are at the track, there is a lot of idling and waiting to get up to the line... I don't know about your truck, but mine takes forever to warm up and open the t-stat...

How do I keep from blowing the freezeplugs? If my thermostat is closed when I get to the line, the pressures in my block waterpath is going to be stupid...


????


TIA!

mad

Raspy

Mad,

That's the point I made some months ago about blowing freeze plugs. The t-stat takes a long time to open and, at idle, will never open very far. It takes a long time to warm the engine but it also takes along time for the stat to respond to the heat it senses. By the end of the run you've got a steam boiler about to blow and the stat has not yet responded. You cannot take advantage of the cooling you have in that situation. If it wasn't the freese plug blowing it would probably be the radiator.

If you put a pressure relief on the system to blow off steam you'll create steam pockets in the head and overheat it. So, in a sense, pressure is your friend if you can't get rid of the heat.

A thermostat bypass is needed that you can just open up as you launch. Then you'd get full flow now.

I haven't looked close enough to see how that can be done and, from what I understand you can't just remove the stat to give it full flow. Plus that would prevent it from ever coming up to temp.

What are your thoughts?

jrs_dodge_diesel

I know on the large marine diesels (3,600 shaft horsepower) that we had on my last ship had manual/automatic thermostats. At low/medium speeds and loads the engineers would leave the them in automatic mode, and they would act like a normal thermostat (like the ones in our trucks). But when we had to kick up the speed, they would turn a valve handle that either forced the thermostats open or bypassed them altogether (I can't remember).

Perhaps a way to force the thermostat open before a run would work?

Raspy

jrs,

I sat in the engine room as a throttleman for many hours. Ours were 10 cylinder opposed piston Fairbanks Morse. Older than yours, I guess, and completely manual. Every speed change required adjusting and re-adjusting the valves. We also kept a rotation log that counted and recorded the total shaft rotations per hour. I used to try to hit it right on the correct number each hour. 2/3 speed for one hour equaled X revolutions. Sheesh. Hour after hour. You could always tell a change of the OD in the wheel house because he would change course or RPM.

CamperAndy

There are kits on this site for sale to bypass the thermostat during runs but there is a cheaper way. Just before you stage set your cab heater to full heat. This bypasses the thermostat and will help prevent the back freeze plug from blowing. The heater water supply is from the back of the engine and the return from the heater is back to the inlet of the pump.

Raspy

Trouble is the heater core is way smaller than the radiator.

MoNStrRIg

Ive been sendin my baby down the 1/4 for two years now, never had a problem with mine, and ask Nate (ShakinRedCTD) you can wait a lil bit in staging here in nc. But then again you drive to the strip, and you make your first pass or whatnot, my truck stays warm the entire time there. But I think I'll address it now.....

CamperAndy

Very true but you are only looking to avoid a massive pressure build at the back of the block. Every little bit helps.

glocklove

This is a thought and only a thought, due to the fact I do not know diesels.

How hard would it be change the t-stat before going to the track to a lower temp t-stat? If you did this wouldn't it open up sooner allowing the proper flow? Thus avioding the problem of blowing the freeze plug? Again read line 1 before you take jabs at me...

Raspy

Pressure buildup in any closed vessel is equal everywhere. Just because the rear plug blows it doesn't mean that that is where the pressure is. It means that the plug is the weakest link in the system.

Raspy

That would help some, but doesn't really address the problem of a partially open stat that is very slow to respond to temp changes. The best would be a bypass that could be opened at the start of the run. This would give maximum cooling and maximum flow through the block right when it's needed. It also allows the engine to be up to temp before the run.

paulb

An even coolant temp is very important. On my 02, I will let it idle in drive to make sure that not only the thermostat has opened, but that it has opened a few times. Because the thermostat is typically slow to respond to temp changes, the engine can defuel because it see a spike in temp. The code in an 02 is 0217. It basically means that the ECM has limited fuel because of an over heat condition. Not something you want to happend during a drag race.

On my 05 I installed one of Opie's pressure relief systems. His system reacts to both temp and pressure, and reacts much faster then a thermostat does. I don't worry about having the thermostat open.

Turning the heater on, can help with the pressures, but it also return hot water to the inlet of the pump. I like having cool water there.

In a closed vessel pressures are not the same, if flow through restricted passages is present. This is the case with cylinder #5. When pressures get high in the cooling system, the amount of flow around #5 gets reduced. This cylinder will overhead and score pistons and cylinders. Relieving pressure from the back of cylinder #6 (where the freeze plug normally blows), is not as good of a solution either.

Opie's system reacts to both temp and pressure. This keeps steam pockets from forming, and freeze plugs from blowing. I've only got about 50 1/4 mile passes on the truck since installing it, but so far I really like it.

Paul

madhat

Link or pics, please!

Thanks to all who have responded, I'll comment more later when I have time...

RamWheelsBy4

This is a problem I have not really resolved yet. I suppose the best solution is a full blown bypass system. There are a couple that I know of.

I always try to make sure that my engine is at full running temp and that the t-stat is open before making a pass. This is sometimes impossible depending on the staging lanes. I will run up and down the return roads and around the parking lot if possible until I see the t-stat open. Then go to staging lanes. Not always good enough.

I blew my rear plug about the 1/8 mile marker about three years ago. I did not know it and did not slow down until the 1/4 marker. Needless to say the engine block was HOT, temp gauge buried. Probably did some damage but still running without pulling head to see. That was three years and 60,000+ miles ago. I do have a plate installed over the rear plug that went back in, but that does not remedy the problem or help any other plugs.

Raspy

Ram,

It's just amazing how durable these engines are. I love it.

Try that with an aluminum engine.