Mod Details
PremiumNo Difficulty
Mod ID1908
Creditevilution
For
Linkhttps://evilution.co.uk/mod/451-cylinder-head-bolts.htm Copy to ClipboardYou know how to tighten cylinder head bolts right?
You have to sneak up on them. You have to do it in stages.
Important Bolt Information
Always use new bolts each time. This is because they are stretch bolts which deform when fitted. If you reuse the old bolts, they won’t be clamping with the correct pressure and have a high likelihood of snapping during the tightening procedure.
Smart also recommend that you oil the threads of the bolts
Tightening Pattern
Tightening Procedure
25Nm + 90° + 90°
Err What?
If that’s confusing you, you shouldn’t be working on an engine, however, let me hold your hand. Do it in this order (in case you don’t know how numbers work) to these specs.
| Bolt Number | Tightening Specification |
| 1 | 25Nm |
| 2 | 25Nm |
| 3 | 25Nm |
| 4 | 25Nm |
| 5 | 25Nm |
| 6 | 25Nm |
| 7 | 25Nm |
| 8 | 25Nm |
| 1 | 90 Degrees |
| 2 | 90 Degrees |
| 3 | 90 Degrees |
| 4 | 90 Degrees |
| 5 | 90 Degrees |
| 6 | 90 Degrees |
| 7 | 90 Degrees |
| 8 | 90 Degrees |
| 1 | 90 Degrees |
| 2 | 90 Degrees |
| 3 | 90 Degrees |
| 4 | 90 Degrees |
| 5 | 90 Degrees |
| 6 | 90 Degrees |
| 7 | 90 Degrees |
| 8 | 90 Degrees |
Do yourself a favour and use a paint pen to mark the bolt you just worked on. That way, you never lose your place and torque the same bolt too many times or not enough.
For example, I will torque bolt 1 to 25Nm and then put a paint dot on the head. Repeat for the other bolts. I’ll then torque bolt 1 to +90 degrees and put a 2nd paint dot on it. Repeat for the other bolts. Finally I torque bolt 1 to the next +90 degrees and put a 3rd paint dot on the head. Repeat for the other bolts. That way you can see which one you’ve done last and where you are in the order.
Degrees! Is That Celsius or Fahrenheit?
Angular degrees.
