Title : Dolomite 1850, Sprint and TR7 Block
Author : Mark Larmour (SPRINTPARTS)
The Dolomite 1850, Sprint and TR7 engine blocks can all be interchanged. The only difference between the blocks is that the early series casting has a smaller water outlet from the water pump area to the cylinder head face. The later series blocks also have larger water jackets around the cylinders.
During engine rebuilds remember to check the top of the block, (head face) to ensure that it is flat.
To improve bearing life it is recommended to have the crankshaft Nitrided. Nitriding hardens the crankshaft journals, which not only protects the crankshaft but also improves the life of the bearings.
Timing chains are relatively cheap, and in a 16-valve motor they are under fairly high stress, so it is always worth while to replace a timing chain whenever a motor is dismantled.
Don’t over tension the timing chain during reassembly. Over tensioning of the chain can cause the chain tensioner to fail, ie the rubber slipper face to separate from the tensioner foot.
If you are using standard conrod bolts, be very careful not to over tension them during torquing. Factory spec’s are 38 to 46 ftlb, DO NOT exceed these figures, as the bolts WILL stretch.