CLUTCH OIL SEAL FOR INJECTION AND 1992 ON HIF38 CARB MODEL

Primary Gear - Bush Replacement

With the cost of new primary gears spiralling ever upwards, and the availability of good, serviceable used ones, fitting new bushes to existing gears is becoming a more common solution. For some reasons for bush failures and rectification to stop it re-occurring, see article Primary gear - Bush problems. Since there is no useful information given in any of the workshop or DIY manuals on this subject, following is my approach to dealing with the issue. The first thing to get to grips with is which bush is which. This has added an element of confusion to many conversations I have had with folks on this subject, so - the FRONT bush is the one nearest the engine block, the REAR bush is the top-hat one nearest the flywheel. This is because the front of the engine is actually the radiator end - quoted in 'in-line' engine-speak. The REAR bush is the same on all primary gears - be they for small or large bore engines. The FRONT bush is different for each though; the small-bore one is smaller in diameter as there is no step in the crankshaft where the primary gear runs.

Primary Gear - Bush problems

Although not of immediate interest to many road-runners/street-burners, mainly accorded to the racing scene, it seems to be a perplexing problem to a very large number of folk around the world, and has burned up plenty of telephone time. Distilling the myriad of 'the symptoms go like this' descriptions down from various languages it has been put to me in - the end result was always the same. The bushes at one end or other, and sometimes both, had failed in their duties. Incidentally - some of the confusion when trying to sort the problem descriptions was down to misunderstandings about which end of the primary gear is which. To put the record straight, the end nearest the engine is the FRONT end. Consequently the end nearest the flywheel is then the REAR end. The two biggest outstanding symptoms were severe oil leaks onto the flywheel/clutch assembly, and difficulty/impossibility in selecting gears.

Primary Gear - Setting end float

A fairly crucial part of how the primary gear operates is its tolerances and running clearances. End float is a continual problem as folk either ignore it through ignorance or lack of accessible information on how to do it, or belief special tools are needed.

Terminology: DTI - Dial Test Indicator Also, later factory assembled engine units (from about 1992 onwards) were built up using whatever thrust washers were available, since Rover were not making regular orders for all shim/washer sizes due to the forthcoming end of production. Consequently, many units left Rover with incorrect (usually too big) clearances. The primary gear was no exception. Too much end float and clutch disengagement is adversely affected, the gear floating up and down the crankshaft in unison with the clutch plate. The result is a graunching gear change since the plate isn't clearing the flywheel and pressure plate surfaces fully. Too little end float and the gear is likely to be pinched tight as it gets hotter in operation.

Primary Gear – Bush Problems

Although not of immediate interest to many road-runners/street-burners, mainly accorded to the racing scene, it seems to be a perplexing problem to a very large number of folk around the world, and has burned up plenty of telephone time.

part numbers: 13H2934, LUF10005, CE12, 22G109, DAM8889, DAM8887

With the cost of new primary gears spiralling ever upwards, and the availability of good, serviceable used ones, fitting new bushes to existing gears is becoming a more common solution. For some reasons for bush failures and rectification to stop it re-occurring, see article 'Primary gear - Bush problems'. Since there is no useful information given in any of the workshop or DIY manuals on this subject, following is my approach to dealing with the issue.

The first thing to get to grips with is which bush is which. This has a...