V8 Crankshaft and bearings

CRANKSHAFT, MAIN AND BIG-END BEARINGS

Crankshaft end - float - check

1. Set-up DTI to measure end float.
2. Move crankshaft forwards and zero gauge.
3. Move crankshaft rearwards, record end-float reading obtained.
Crankshaft end-float = 0.10 to 0.20mm.
4. Remove DTI.

NOTE: Crankshaft end-float is controlled by thrust faces on upper half of centre main bearing shell.

Big-end bearings - remove

1. Remove sump.
2. Remove 2 bolts securing oil strainer.
3. Remove strainer, remove and discard gasket.
4. Suitably identify bearing caps to their respective connecting rods.
5. Remove 2 nuts securing each bearing cap.
6. Remove bearing cap and bearing shell.

Keep bearing caps and shells in their fitted order.

7. Fit a length of plastic tubing over each connecting rod bolt.
8. Push each piston up its respective bore and remove shells from connecting rods.

Keep bearing shells in their fitted order.

Big-end bearings - Inspection

1. Check big-end bearing shells for wear and damage.
2. Renew big-end bearing shells as necessary.

NOTE: Big-end bearings are available in 0.254 mm and 0.508 mm undersizes.

Big-end bearings - refit

1. Fit bearing shells to each connecting rod.
2. Lubricate bearing shells and crankshaft journals with clean engine oil.
3. Pull connecting rods onto crankshaft journals and remove plastic tubing.
4. Fit bearing shells to each big-end bearing cap.
5. Lubricate bearing shells and fit bearing caps ensuring reference marks on connecting rods and bearing caps are aligned.

NOTE: Rib on edge of bearing cap must face towards front of engine on RH bank of cylinders and towards rear on LH bank of cylinders.

6. Fit bearing cap nuts and tighten to correct torque.
7. Check connecting rods move freely sideways on crankshaft. Tightness indicates insufficient bearing clearance or misaligned connecting rod.
8. Check clearance between connecting rods on each crankshaft journal.
Connecting rod clearance = 0.15 to 0.37 mm.
9. Clean oil strainer.
10. Clean gasket mating faces on strainer and cylinder block.
11. Fit gasket to strainer, position strainer, fit bolts and tighten to correct torque.
12. Fit sump.

Crankshaft - remove

1. Remove flywheel or drive plate and ring gear assembly.
2. Remove timing cover.
3. Remove timing gears.
4. Remove big-end bearings.
5. Starting at centre main bearing and working outwards, progressively slacken then remove

10 main bearing cap bolts.
6. Remove 5 main bearing caps and bearing shells, retain bearings with their caps.
7. Lift out crankshaft and rear oil seal. Remove and discard oil seal.
8. Remove 5 bearing shells from cylinder block and retain in their fitted order.
9. Remove and discard side seals from rear main bearing cap.
10. Remove Woodruff key from crankshaft.

Crankshaft - inspection

1. Clean crankshaft and blow out oil passages.
2. Support crankshaft front and rear bearings on vee blocks, and using a DTI, measure run-out on centre main bearing.
Maximum permitted run-out = 0.08 mm.
If run-out exceeds permitted maximum, crankshaft is unsuitable for regrinding and should be renewed.
3. Measure each journal for overall wear and ovality.
Main bearing journal diameter = 58.409 to
58.422 mm Maximum out of round = 0.040 mm.
Big-end bearing journal diameter = 50.800 to 50.812 mm
Maximum out of round = 0.040 mm.
If measurements exceed permitted maximum, regrind or fit new crankshaft.

NOTE: Ovality checks should be made at 120° intervals around each journal. Crankshaft main bearings are available in 0.254 mm and 0.508 mm undersizes. When fitting 0.508 mm undersize bearings, centre main
bearing, which controls crankshaft end-float, has thrust faces increased in thickness by 0.254 mm. Therefore if 0.508 mm undersize bearings are fitted, 0.127 mm must be machined off each thrust face of centre main bearing journal to maintain correct radius.

Crankshaft dimensions:

Bearing journal radius - all journals except rear main
journal A = 1.90 to 2.28 mm.

Rear main bearing journal radius B = 3.04 mm.
Bearing journal diameter C :
Standard = 58.400 to 58.413mm.
0.254 mm undersize = 58.146 to 58.158 mm.
0.508 mm undersize = 57.892 to 57.904 mm.

Bearing journal width D :
Standard = 26.975 to 27.026 mm.
0.254 mm undersize = 26.975 to 27.026 mm.
0.508 mm undersize = 27.229 to 27.280 mm.

Bearing journal diameter E :
Standard = 50.800 to 50.812 mm.
0.254 mm undersize = 50.546 to 50.559 mm.
0.508 mm undersize = 50.292 to 50.305 mm.

Crankshaft spigot bearing - renew

1. Carefully extract old spigot bearing.
2. Clean bearing recess in crankshaft.
3. Fit new bearing flush with, or to a maximum of 1.6 mm below end face of crankshaft.
4. Ream bearing to correct inside diameter.
Spigot bearing inside diameter = 19.177 + 0.025 mm.
5. Remove all traces of swarfe.

Crankshaft - refit

1. Clean main bearing caps, bearing shell recesses and mating surfaces of cylinder block.
2. Fit upper main bearing shells, with oil holes and grooves, in cylinder block, ensuring flanged shell is fitted in centre position.
3. Lubricate bearing shells with clean engine oil and position crankshaft in cylinder block.
4. Fit main bearing shells to bearing caps.5. Apply EXP16A (Marston Lubricants) lubricant to threads of main bearing cap bolts.
6. Lubricate main bearing shells and fit numbers 1 to 4 bearing caps, fit and lightly tighten bolts.
7. Fit side seals to rear main bearing cap.

CAUTION: Seals must protrude approximately 1.5 mm above bearing cap face.

8. Apply Hylomar SQ32M jointing compound to bearing cap rear mating face on cylinder block.
9. Lubricate bearing shell and side seals with clean engine oil, carefully fit bearing cap assembly.
10. Fit bolts and lightly tighten.
11. Clean seal location and running surface on crankshaft.
12. Engine numbers without suffix B: Clean seal
protector LRT-12-010 and lubricate with engine oil.
13. Engine numbers with suffix B: Clean seal protector LRT-12-095 and lubricate with engine oil.
14. Lubricate oil seal lip with engine oil.

NOTE: Seal protector LRT-12-095 illustrated.

15. Position seal protector to crankshaft.
16. Engine numbers without suffix B: Fit oil seal squarely using hand pressure only until fully seated in recess.
17. Engine numbers with suffix B: Fit seal using tool LRT-12-091.
18. Tighten main bearing cap bolts to correct torque.
19. Fit Woodruff key to crankshaft.
20. Check crankshaft end-float.
21. Fit big-end bearings.
22. Fit timing cover and gears.
23. Fit flywheel or drive plate and ring gear assembly.