Joe Stevens
New Member
Hello. REAR CRANK SEAL CHANGE WITH BMC 2.2 ENGINE IT SITU? If I just separate the PRM gearbox from one of my pair of BMC 2.2 engines (supplied by Newage Marine Ltd back in 1972) but leave the bell housing on, will I be able to reach through and remove the rear crank seal… perhaps using self tapping screws to pull it ….and then tap the new seal in?
I think I can easily split the asssmbly at the orange line in the photo. If I had to split the assembly at the yellow line in pic I'd be past the rear mounts and would need to somehow support the engine. Not sure I trust the Macwester Pelagian fibreglass hull to take the weight even with a board slid under a jack. Getting the engine craned right our means destroying the cockpit roof and masses of other work so am keen to avoid that.
I think I can deduce that the rear crank seal is almost certainly the problem as I can see the errant reservoir of oil between engine and gearbox by borescope through inspection plate. Leak was minor a few years back and I could catch and return the oil but it is now severe. A run of only an hour puts 2L of oil in the void under the starter wheel and the oil then gradually leaks into a drip tray that I have to keep right under the gearbox/engine join - the oil drip point is not in doubt.
I think crankcase pressure and breather issues are unlikely to be the cause. The pair of engines I have are identically well maintained and set up. They have done the same hours. The other one is not leaking at all.
Helpful chap with old engine records looked up my engines (Newage refs are 25P/D189 and 25P/D199) and thinks it may well have a fairly standard Leyland rear crank seal, NZK3472, which I have ready on site.... but we can only know for sure once the area can be eyeballed.
This old pair of engines still have great compression and run very well so it would be lovely to do the fix.
I have stripped and rebuilt a 1980s Toyota land diesel engine of similar size successfully, so whilst I have more than average skills I am a newbie on doing it on boats and am not a professional engine expert. Any wisdom, helpful challenge, or guidance would be very welcome indeed.
Yours in hope.
Joe Stevens
I think I can easily split the asssmbly at the orange line in the photo. If I had to split the assembly at the yellow line in pic I'd be past the rear mounts and would need to somehow support the engine. Not sure I trust the Macwester Pelagian fibreglass hull to take the weight even with a board slid under a jack. Getting the engine craned right our means destroying the cockpit roof and masses of other work so am keen to avoid that.
I think I can deduce that the rear crank seal is almost certainly the problem as I can see the errant reservoir of oil between engine and gearbox by borescope through inspection plate. Leak was minor a few years back and I could catch and return the oil but it is now severe. A run of only an hour puts 2L of oil in the void under the starter wheel and the oil then gradually leaks into a drip tray that I have to keep right under the gearbox/engine join - the oil drip point is not in doubt.
I think crankcase pressure and breather issues are unlikely to be the cause. The pair of engines I have are identically well maintained and set up. They have done the same hours. The other one is not leaking at all.
Helpful chap with old engine records looked up my engines (Newage refs are 25P/D189 and 25P/D199) and thinks it may well have a fairly standard Leyland rear crank seal, NZK3472, which I have ready on site.... but we can only know for sure once the area can be eyeballed.
This old pair of engines still have great compression and run very well so it would be lovely to do the fix.
I have stripped and rebuilt a 1980s Toyota land diesel engine of similar size successfully, so whilst I have more than average skills I am a newbie on doing it on boats and am not a professional engine expert. Any wisdom, helpful challenge, or guidance would be very welcome indeed.
Yours in hope.
Joe Stevens
