CamTower 12mm bolt torque specs?

[EricB]

Engine: L24

The 5 cam towers that hold our camshaft in place are themselves held in (partly) by 12mm bolts. In all the step by step assembly pics in both the Haynes and Datsun Service Manuals they skip the part where they attach those to the cylinder head and also ommit any kind of torque specs either.

Does anyone know the info I require?

And no (in case I was unclear above) I am not referring to the head bolts which are torqued down 20, then 40, then 60ft-lbs.

thank you.

-e

[hmsports]

From the book "How to rebuild you Nissan/Datsun OHC Engine" by Tom Monroe...

...gradually tighten to 25-33 ft-lb (3.4-4.5 kg-m).

Now, there are steps to follow to make sure the cam towers are aligned so the cam turns freely otherwise you will risk galling the cam bearings. If you need this outlined, let me know and I will type it in for you.

Rick

[Phred]

Danger!!!

The Cam Tower bolts you refer to are 8mm dia. x 1.25 pitch.

The hex size is 12 mm. IMPORTANT! DO NOT torque ( or attempt to torque) these bolts to 25-33 lbs. You will strip the threads out of the head!! Remember, your head is aluminum, and the bolt is steel. These bolts are the same dia. as those holding the front cover and oil pump on. Datsun Factoty Manual calls for 11.5 lbs. for them. I have assembled many racing Z heads with high lift cams and higher than stock spring pressures, and all have survived with only 15 lbs. of torque on the cam tower bolts. I have heard some engine builders only used 12 lbs. torque. So consider 12lbs. min. & 15 lbs.max. Also never torque bolts into aluminum dry. Put a little lite engine oil on the threads and under the head, then torque. If, when approaching 15 lbs, the bolt feels "soft", STOP.

Phred

[hmsports]

I'm sorry for misleading you. Thanks to Phred for straightening things out.