head torque method?

H

hotrodcbx

Senior Member
I was on the Speedway website looking for head gaskets and noticed a PDF on how to install and torque aluminum heads on a flathead. Everything was pretty much as most of us know except the torque method. They recommend after the initial torque to fire up the engine with NO COOLANT. Let it heat up, warm to the touch, let it cool to ambient and re-torque. Do this 3 times. Anyone heard of this dry start torque method?
 
First I would say there's not many experts at Speedway Motors especially when it comes to most things related to the Flathead. The idea of firing up a flathead with no coolant for any reason is not a good idea ever. Having built a number of flatheads here's how I do it. First I torque each head bolt or nut in three steps. Example 25 first 40 next and finally 55 or 60 depending on the hardware being used. Now prior to starting the engine the coolant is added now the engine is fired up and run until its warmed up then I shut it down and walk away. The next day I check the torque once that's completed I repeat the above warm up procedure. Now on the third day check the torque again and tighten anything found at this point the checking process is now completed. The above has worked for me perfectly with coolant.
Ronneroadster
 
This method was from a gasket company. I do my torqueing just like you do Ronnie, always leaving a day between re-torqueing. I highly questioned the method too...
 
I realize that this sequence all appears to apply to aluminum heads but what is the consensus on torquing cast iron heads and what did the factory do ?
 
You are not going to hurt an engine running no coolant until it is warm to the touch. I see what the person is doing here. With all the weeping you read about on new installations, by doing the heat cycle the way they suggest the way they suggest everything stays dry until its done. It's thinking outside the box. Before you lecture me on the perils of running an engine with no water remember you are doing nothing different than what an air cooled engine does.
I'm not endorsing this method but just trying to explain what the logic is.
 
I have to agree with Frank Miller. Run the engine until warm to the touch not HOT to the touch.

Frank Miller said:
You are not going to hurt an engine running no coolant until it is warm to the touch. I see what the person is doing here. With all the weeping you read about on new installations, by doing the heat cycle the way they suggest the way they suggest everything stays dry until its done. It's thinking outside the box. Before you lecture me on the perils of running an engine with no water remember you are doing nothing different than what an air cooled engine does.
I'm not endorsing this method but just trying to explain what the logic is.
Click to expand...
 
Frank Miller said:
You are not going to hurt an engine running no coolant until it is warm to the touch. I see what the person is doing here. With all the weeping you read about on new installations, by doing the heat cycle the way they suggest the way they suggest everything stays dry until its done. It's thinking outside the box. Before you lecture me on the perils of running an engine with no water remember you are doing nothing different than what an air cooled engine does.
I'm not endorsing this method but just trying to explain what the logic is.
Click to expand...

Excellent logic for an air cooled engine but of course its the only way to do it for an air cooled engine! For a Ford flathead V-8 its completely WRONG. Now hot to the touch that's not really very accurate so beware of burns.
Ronnieroadster
 
There is absolutely nothing damaging or "wrong" about a quick, dry, (no coolant") run with ANY engine. I do not usually do it except for very high performance drag race engines which never use coolant. But it is not WRONG or otherwise impractical to make a short warming run up dry. I would avoid doing this dry startup where initial cam break-in is being established because the initial run-in time is important and should not be interrupted.
 
Running a STREET engine dry on initial fire up is a recipe for disaster.
The critical temperature of valve seats, valve stems and top rings can easily be reached long before any outside surface of the engine is warm to the touch.

Any comparison to air cooled engines in this respect is irrelevant, They have cooling fins instead of water.
 
One very minor suggestion (and it is not mentioned here) I always back the nut off a bit then retorque it. I believe the reason for this approach is to beak the nut loose of anything which could effect the true torque value you want to reach. Yes No???? I've always done this regardless of what I needed some precision on but I could be wrong.
 
Veeder said:
One very minor suggestion (and it is not mentioned here) I always back the nut off a bit then retorque it. I believe the reason for this approach is to beak the nut loose of anything which could effect the true torque value you want to reach. Yes No???? I've always done this regardless of what I needed some precision on but I could be wrong.
Click to expand...



Using lube on the threads and head surface will eliminate the need for that step if your doing the torque dry. I prefer the stuff made by ARP.
Ronnieroadster
 
For any fastener that requires a certain amount of torque, the thread, nut thread, nut face and any washer faces should be lubricated. If it needs to be torqued to a higher value later after being in use, it should be broken loose slightly before going up in value. This is because the static required torque value in many cases will be higher than the target value and thus give a false reading.
The only exception I know of is if you are using CcL4 (carbon tetrachloride) for lubricant. The static and moving torque numbers will be almost identical in that case.
I don't recommend you fool with that stuff though. It will give you bad vibes.
 
Regarding a short run with a dry coolant system--some of these responses have not been stupid. However, they have lacked education. I have seen HUNDREDEDS of full power runs, with zero coolant, leaving the engine hotter than a coal fired furnace and not show any on the listed, theoretical, damage. This is not to endorse such, high temperature, dry runs. However, it is intended to add some common sense and practical knowledge to the original question and some of the comments.
 
JWL said:
Regarding a short run with a dry coolant system--some of these responses have not been stupid. However, they have lacked education. I have seen HUNDREDEDS of full power runs, with zero coolant, leaving the engine hotter than a coal fired furnace and not show any on the listed, theoretical, damage. This is not to endorse such, high temperature, dry runs. However, it is intended to add some common sense and practical knowledge to the original question and some of the comments.
Click to expand...

You are absolutely right. The clearances run in those engines and the big oil presssure keeps them alive. Stuff that doesn't work for a street engine.
 
Pete said:
You are absolutely right. The clearances run in those engines and the big oil presssure keeps them alive. Stuff that doesn't work for a street engine.
Click to expand...
Earlier you said it was the valve seats and stems. Those clearances are pretty much the same from a Model T to a drag car.
 
You must log in or register to reply here.
Back
Top