What are the MG TF engine bolt torque specs?

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orlando.martinez

Torque Values for XPAG and XPEG Engines

Engine

Gudgeon pin clamp 25 lbft
Rod big end bolts 25
Main bearing cap nuts 63
Flywheel to crankshaft bolts 50
Clutch pressure plate bolts 19
Oil pickup pipe to sump bolts 6
Camshaft locating plate bolts 6
Camshaft sprocket bolt 50
Timing chain tensioner bolts 6
Sump to block bolts 19
Timing chain cover bolts 19
Crankshaft pulley bolt 50
Cylinder head nuts 50
Rocker tower bolts (8 mm) 16
Rocker tower bolts (10 mm) 43
Oil pump to block bolts 6

Other
Water pump pulley nut 10 lbft
Generator pulley nut 35
Transmission output flange nut 65
Rear axle hub nut 170-200
Front axle hub nut 40-70
Wheel lug nuts 50

The following thoughts are offered by Carl Cederstrand, a well known M.G. enthusiast and life-long engineer.
I would like to add a comment on tightening head bolts. Measuring the torque is Donald Duck way of setting the clamping force. The torque varies with the smoothness of the threads and with any grease or oil on the threads. A better way is to set a dial indicator in contact with the top of the stud and then tighten the head nut until the stud is elongated by an amount that indicates the desired clamping force. This is the way it is done in Germany and it is a superior technique.
When tightening head studs on our T-Series use a torque wrench that has a dial indicator so that it gives a continuous torque reading. As one tightens the nut, the torque reading increases. Then suddenly the torque no longer increases as the nut is turned. Stop! You have reached the elastic limit of the stud. Further turning of the nut will only snap off the stud!
I always limit the torque I apply on the head nuts to 90% of the recommended factory value. The factory suggested value does NOT allow for the smoothing of the threads that occurs with use. The 90% value has worked fine for me for decades.
Best wishes,
Carl Cederstrand

Author: orlando.martinez