Cylinder head torque setting confusion

I have only ever used the calibrated arm muscle and an appropriate length spanner - not too long. Just the way the factory used to do it. With a bit of experienceyou can be pretty accurate. Bear in mind that torque figures vary significantly for dry and lubricated threads. Using a spanner and feel you can judge the resistance and get it right - neither under nor over torqued.

Both oldbrits and RGM have notes covering this area. The RGM values are,

Torque's.

All 3/8 head bolts 30 lbs./ft

All 5/16 head bolts 20 lbs./ft

The two 5/16 nuts at the front from the top 20 lbs./ft.

The 3/8 nuts tightened from the underside 30 lbs./ft.

The oil feed banjo bolts 12 lbs./ft (be careful these snap easily)

The exhaust cover nuts 8 lbs./ft again be careful, the studs snap easily.

But beware, lubricant reduces these safe values and the calibration of the torque wrench may be correct. If you use a torque wrench, it is important to check it one in a while. I use a spring balance to check mine. load, (lbs)* length, (feet)= torque in lbs/ft.

you can see why more experienced mechanics than I rely on feel.

Previously charles_bovington wrote:

Both oldbrits and RGM have notes covering this area. The RGM values are,

Torque's.

All 3/8 head bolts 30 lbs./ft

All 5/16 head bolts 20 lbs./ft

The two 5/16 nuts at the front from the top 20 lbs./ft.

The 3/8 nuts tightened from the underside 30 lbs./ft.

The oil feed banjo bolts 12 lbs./ft (be careful these snap easily)

The exhaust cover nuts 8 lbs./ft again be careful, the studs snap easily.

But beware, lubricant reduces these safe values and the calibration of the torque wrench may be correct. If you use a torque wrench, it is important to check it one in a while. I use a spring balance to check mine. load, (lbs)* length, (feet)= torque in lbs/ft.

you can see why more experienced mechanics than I rely on feel.

The two at the front are the newer style sleeve nuts. They are 3/8 thread even though the hex is 5/16 BSF spanner. They look like the old rear brake drum sleeve nuts but have a flat seating area instead of tapered. The manual says 30 ft/lbs for 3/8 threads. I think this is regardless of hex size. It is quite easy to take them out and verify that they are 3/8 but even my ancient Atlas heads have 3/8 in that position so I don't think that has ever changed.

I just checked the RGM web site. I think they are contradicting the manual unless you read "3/8 head bolts" as "3/8 cylinder head bolts" and not "3/8 hex head bolts". They do not say "cylinder head studs" which would clarify a little. These are the ones the OP is talking about:

"The 3/8 nuts tightened from the underside 30 lbs./ft."

Which are in fact 5/16 hex.

Someone knowledgeable should contact them and straighten this out. (More knowledgeable than me). Here is the document:

http://www.rgmnorton.co.uk/csi/1245184/f/pdf/cylinder_head_kit_notes.pdf