Tightening Cam Caps - How?

[Spetz]

Hi guys,

I'm going to be installing my cams back into my 6A12 Mitsubishi MIVEC motor (so, quad cam V6).

I have the instruction manual and know the sequence and torque setting.

My question is do the bolts need to be free from oil or is a bit of residue oil on them fine?

I am just wondering how this will affect the torque specs

 

[Trav]

Clean threads with a small amount of oil on the bolts is normal practice.

Edit: Start with the inner holders and tighten them slowly and evenly working your way out a little at a time.

 

[Spetz]

Thanks as always Trav.

Yes I have the sequence and torque settings in the engine manual and plan to go up in 3 increments to the designated torque specifications.

 

[asand1]

The manual should indicate whether oil should be present. Is the a little icon of an oil can near the torque specs in the illustrated protion of the book?

 

[Spetz]

The manual does not mention anything about tightening with oil nor are there any oil can icons

 

[Trav]

Correct, no manufacturers recommendation is published for this and a lot of other things for this Mitsubishi engine. Clean lubed threads will provide the smoothest bolt tightening and insure proper torque and bolt retention. When no manufacturer specific recommendation is given its always best to use industry accepted standard as oil lubed threads will generally not throw the torque reading out of min/max range for the bolt or threads.

Quote:
To achieve an accurate torque measurement, we need to overcome as much friction as possible using the least amount of "extra" force. The prime area for friction occurrence are the threads (more specifically, the top side of the threads) and the 'flat' underneath the nut or bolt head. To combat against friction, we use a lubricant on these areas. Without a lubricant, the threads will drag and create friction and that will "inflate" the torque value, which will result in less clamp load than you intended or measured.


They also go on to mention info about moly lubes which you wouldn't use unless specified by the manufacturer, ditto thread lockers as they can also effect torque values. In your case lubing the threads with oil on those bolts is the safe bet.

 

[Number_35]

Originally Posted By: Trav
Correct, no manufacturers recommendation is published for this and a lot of other things for this Mitsubishi engine. Clean lubed threads will provide the smoothest bolt tightening and insure proper torque and bolt retention. When no manufacturer specific recommendation is given its always best to use industry accepted standard as oil lubed threads will generally not throw the torque reading out of min/max range for the bolt or threads.

Quote:
To achieve an accurate torque measurement, we need to overcome as much friction as possible using the least amount of "extra" force. The prime area for friction occurrence are the threads (more specifically, the top side of the threads) and the 'flat' underneath the nut or bolt head. To combat against friction, we use a lubricant on these areas. Without a lubricant, the threads will drag and create friction and that will "inflate" the torque value, which will result in less clamp load than you intended or measured.


They also go on to mention info about moly lubes which you wouldn't use unless specified by the manufacturer, ditto thread lockers as they can also effect torque values. In your case lubing the threads with oil on those bolts is the safe bet.

Great advice about something I'd always wondered about. Thanks Trav!

OP, when I reinstalled a cam in my old Mazda JE engine, I followed the tightening sequence in the shop manual and also, as you've suggested, tightened things up in several passes. It's been 2+ years since, and no problems so far.