Hitchcocks Forum

Hello, could any one tell me the torques for the crankcase of a 1958 Constellation?
Thank you!

Torques of what please? (We are not psychic.)

I am a bit psychic, as it happens, but it's not helping here, I'm afraid. If you mean the nuts on the studs holding the cases together, don't go too mad on them - they certainly don't need to be as tight as the cylinder head nuts. Just nip them down, plus approx. 1/2 turn should do. In numbers, maybe 8 lb/ft? Regards, Paul.

I'm psychotic; you know? Mentally tele-pathetic, read other peoples mail...

Thank you for the answers! Yes I mean the 5/16 an 1/4 Nuts on the studs which hold the cases together.

Alexander, you should know that when these bikes were made torque wrenches and settings were only for very special applications like aircraft engines. They were never quoted for motorcycle engines like these. We have arrived at some settings that work through experience but only for cylinder head bolts/nuts (23 ft/lbs) and big end bolts (22 ft/lbs). Royal Enfield used very fine threads into the alloy of the crankcases and so if you are trying to assess torque values for these they need to be even lower than might seem wise. Remember, torque settings are usually used on fasteners that need to be all the same as each other to prevent distortion, that's one of the reasons why they are particularly needed on cylinder heads. When assembling the crankcase halves this is less important so don't strive for too much accuracy and give some respect to 60 year old components!

REgards, Mark

When torqueing up 26TPI threads it needs to be remembered that what seems a reasonable torque say 30ft lbs can be putting nearly 2 tons of tension on the bolt.

Thank you guys. Today I assembled the cases. I used the tourque wrench to be sure that the crankcase bolts are evenly tightened (I gave the 5/16 nuts about 10 lb/ft (less to the 1/4s) - think/hope thats fine).
Kind Regards Alexander