torque for cylinder head and camhousing nuts

[jchatfield]

I am confused on the proper torque settings for the cylinder head nuts vs the camshaft housing to head settings.

Issue #1: On page 154 of the book, it says" torque the nuts in a crisscross pattern as shown in Figure 11. Start with the low torque value listed in Appendix A, and then repeat the pattern at the full torque value." Figure 11 is the camshaft housing tightening pattern. However, when I refer to Appendix A on page 200, there is only one torque reading for "camshaft to cylinder head nuts" is 18.4 ft/lbs, but right below that spec, is one for "cylinder head nuts" with an initial setting of 7.4ft/lbs and a final setting of 23.5 ft/lbs.

Are these two figures backwards or am I misinterpreting something here?

Issue #2: The very next paragraph on pg 154 -155 starts with, "Now tighten down the barrel nuts on the head studs.....When the engine has been fully assembled and run for 1,000 miles, you will re torque the heads again." So, similar to issue # 1, what torque setting do I use and, can all of these head studs be reached with the camshafts installed?


The reason I am asking these questions: The PO of my car had the motor rebuilt 3 years ago by Motormeister (I did not know about this forum or their reputation when I bought it!) and it has been leaking oil right where the camshaft housing meets the heads. I just want to take a shot at re torquing all of these connections to see if that will stop the leaks, which, BTW, are not coming from the rocker shaft seals. If I retorque these items, won't that potenntially take my valves out of proper adjustment?

Thanks in advance for any assistence you could provide.

Finally, my two cents on MM - they did a $6,000 rebuild on a 72 2.4L T motor, which included a new case, Solex cams, rebuilt Webers and fly cutting the heads. The negatives - it leaks oil and the Webers were overcarbed (34mm venturi, 60 idles and 160 mains) and was clearly not set up as a "turn key" job. A lot of Weber learning and an MSD ignition later, it runs pretty good. On the positive side, the car makes good power and has even, good compression.

Jim Chatfield
1972 911T

[dtw]

To add to your question Jim:
-For the re torque at 1,000, what is the proper way to do this? Do you back each head stud nut off a bit so that a nonstatic torque can be obtained? Or do you just check the torque from the exisiting position?
Thanks Wayne

[kstylianos]

For the "cam tower to head", 18ft/lbs is the correct torque. I noticed this discrepancy here also, but figured the step procedure mentioned was for the head studs (24ft/lbs).

I tightened the "cam tower to head" using a step procedure also, started at 10 ft/lbs, using the crisscross pattern, then went through it again at the final torque at 18ft/lbs.

Then tighten the head/tower 'unit' to the cylinders using the recommended step pattern 7.4 ft/lbs then to the final 24ft/lbs.

Can't remember off the top of my head if the "cam tower to head" bolts are accessible w/ the cam in place. Some most definitely are, just cant visualize if you can get to all of them. The head stud barrel nuts are definitely reachable. I believe the recommended procedure to check head stud torque is to just check, not to re-torque (don't loosen and torque back to spec).

[Wayne 962]

Originally posted by jchatfield
...it has been leaking oil right where the camshaft housing meets the heads.

This is a bad oil leak that can typically only be fixed by dropping the engine. Fortunately, sometimes the leak appears to be here, but is actually leaking from somewhere else (like oil return tubes). Do a dye test and see if you can identify where it's coming from...

-Wayne

[jchatfield]

I'll do the dye test, but if the cam housing to head area is the source of the leaks, what is the fix once the engine is dropped?

[jchatfield]

I'll do the dye test, but if the cam housing to head area is the source of the leaks, what is the fix once the engine is dropped?

[Wayne 962]

Remove the cam towers, clean them off (and the heads), and reseal...

-Wayne

[jchatfield]

Thanks Wayne. Great Book! Good luck with the BMW version.

Jim