Re: Head bolt Torqueing
Posted: Tue Jun 30, 2015 9:21 pm
I gave an inadequate answer.
I said that when I assemble bolts etc I oil the threads. This is for general stuff. But some fixings such as head bolts may be required to be dry. Depends on what the makers say.
On less ambitious engines such a A series BMC the main thing is that head nuts are all the same torque. If an A series is torqued to say 60 ftlbs then if only done to 55 it will be OK. Obviously its best to go by what BMC say. In the case of A series it wouldn't make much difference if dry or oiled.
By general stuff I mean bolts that hold the headlights in etc. Not important stuff ĺike big ends.
Car makers often don't state whether dry or oiled. My car's workshop manual has default torque settings which go by the bolt size and thread. Only ones not listed are wood screws and self tappers.
Putting engines together and keeping oil off threads is awkward.
A much more important thing to look out for is oil in blind threaded holes. The stud or bolt can hydraulic the component and crack it.
The wheel nuts on my car ard phosphor bronze and should be oiled and tortured to 50lbs.
Steel road wheels when torqued up slightly spring in around the nut. This helps the nut stay tight.
Aluminum alloy wheels don't have this feature so extra care is needed.
Incidently if a bolt is torqued up with a click torque wrench and then checked later as mechanics tend to do then each time the wrench clicks the bolt goes slightly tighter and its possible to add say 5ftlb with out realising. On an A series it won't matter. But some engines are fussy buggers.
I use a bendy arm wrench. They don't need calibrating.
Dashed bad luck with paint in the wheel holes.
Thats racing for you.
A good indication of how tight a wheel nut should be is the lenght of the factory supplied wheel nut wrench.
I said that when I assemble bolts etc I oil the threads. This is for general stuff. But some fixings such as head bolts may be required to be dry. Depends on what the makers say.
On less ambitious engines such a A series BMC the main thing is that head nuts are all the same torque. If an A series is torqued to say 60 ftlbs then if only done to 55 it will be OK. Obviously its best to go by what BMC say. In the case of A series it wouldn't make much difference if dry or oiled.
By general stuff I mean bolts that hold the headlights in etc. Not important stuff ĺike big ends.
Car makers often don't state whether dry or oiled. My car's workshop manual has default torque settings which go by the bolt size and thread. Only ones not listed are wood screws and self tappers.
Putting engines together and keeping oil off threads is awkward.
A much more important thing to look out for is oil in blind threaded holes. The stud or bolt can hydraulic the component and crack it.
The wheel nuts on my car ard phosphor bronze and should be oiled and tortured to 50lbs.
Steel road wheels when torqued up slightly spring in around the nut. This helps the nut stay tight.
Aluminum alloy wheels don't have this feature so extra care is needed.
Incidently if a bolt is torqued up with a click torque wrench and then checked later as mechanics tend to do then each time the wrench clicks the bolt goes slightly tighter and its possible to add say 5ftlb with out realising. On an A series it won't matter. But some engines are fussy buggers.
I use a bendy arm wrench. They don't need calibrating.
Dashed bad luck with paint in the wheel holes.
Thats racing for you.
A good indication of how tight a wheel nut should be is the lenght of the factory supplied wheel nut wrench.