Triumph Repair: TR7 engine bottom end, hydraulic gauge, head gasket

Question
QUESTION: Howard,

 I'm about to put the oil pan back on my 1976 TR7 engine block (had to replace the gasket, engine still in car) I was wondering if there's anything I should do with the crankshaft exposed like torque the crank bearings ?  Or is that something best done only once when the engine was originally assembled ?

  Thanks,

  Steve.

ANSWER: Hi Steve,

It is not usually necessary unless you removed any of the bolts or nuts. The reason it is not necessary like the re-torque of a head is because a head gasket compresses as the head expands and contracts from the heat cycles. The rods and mains don't have any gaskets to compress.

Howard

---------- FOLLOW-UP ----------

QUESTION: Howard,

  That makes perfect sense.

  I did notice the big ends of the con rods had a little bit of play side to side on the crank, but the crank itself seemed pretty solid.

  Thanks again,

  Steve.

Answer
Side to side movement is normal as that is how the piston, rings and pin are lubed. You should not feel any up/down movement as that clearance should be only .0015" to .002" which you should not be able to feel with oil in the bearings. The crank itself should not have much more then .005" movement end to end. These clearances can be roughly checked by testing the oil pressure with a hydraulic gauge put in place of the oil idiot light sending unit. The oil pressure should read about 25 to 35 PSI at idle with warm oil and from about 45 to 65 PSI at 2000 RPM. Anything less then that indicates a problem, possibly a worn bearing or a pressure regulator valve.

Howard