Why should aluminum heads be tightened only when cold?
Why should aluminum heads be tightened only when cold?
Aluminum heads should only be torqued when cold. Iron heads can be re-torqued when hot. It seems like the head bolts may expand in length when warm more than the iron head. Otherwise the head gasket may settle some when it gets warm.
Does temperature affect torque specs?
It increases as temperatures get higher, like in the 400 to 500 deg. C range. So a beam-type torque wrench will read a bit lower than it should at a lower temperature. The change for temperatures most humans live in would be around 2%.
Should I reuse cylinder head bolts?
Damaged Head Bolts Bolts with any signs of damage, no matter how slight, should never be reused. Not only will the bolts eventually fail, but when they do, there is the potential for them to cause damage to your cylinder head.
Do you put oil on head bolts?
Motor oil will be fine. It’s cheap, plentiful and what Honda recommends using. Head bolts are usually torque to yield and usually require replacement after use.
How many foot pounds do you torque the head bolts?
Many cylinder heads require multiple torque sequences to achieve proper tension. For example, a 10-bolt cylinder head may require you to tighten them all first to 42 foot-pounds in a specified order, then to 75 foot-pounds in the same order. Improper sequencing or torquing of the bolts may result in damage.
Does cold affect torque wrench?
When a wrench is stored below freezing, you run the risk of developing condensation that can cause the internals to rust, affecting the accuracy and performance of the tool. Before the torque wrench is used, either in hot or cold temperatures, it should be exercised to get the internal parts and grease moving around.
Does temperature affect torqued heads?
If one is torquing an alloy head using steel bolts/studs, temperature can make a very small difference. When I owned an Austin 7 Special with an alloy head, I would put the head into the refrigerator (the head on A7 is quite small!), get it cold, then fit it as rapidly as possible.
Do you check torque when hot or cold?
So if you check the torque when hot and they cool the torque changes to a lesser number generally. Or am I reading this wrong, never heard of checking torque when hot. Well of course I usually deal with under head valve engines that require a re torque at least 3 times minimum when stone cold.
When to re-torqued the heads?
Re-torquing the heads was standard procedure when I worked on diesel engines in heavy equipment. It would be done right away after getting the engine up to temperature, checking for and correcting any leaks or anything else that needed attention.
Does cool cooling the head increase torque?
Cooling the head allows one to apply a reasonable torque, which then is increased slightly by the expansion of the head. That is the theory, but whether it makes much difference, I cannot say. Cars Owned::Wade-blown TR6 Supercharging.
