Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) 1969 Plus 8 - oil filter thread size?

Hoping that the gurus can 'splain this for me. Checking around various manufacturers websites, all the oil filters recommended for the 1969 Plus 8s (i.e. Purolator L30005) have a 13/16"-16 thread. My '69 +8 uses a 3/4"-16 thread (i.e. AC Delco PF2). What gives?

There are essentially three types of filter fitted to Rover V8s: those from 1968 to 1976, 1976 to 1993 and 1994 onwards used on the serpentine engines. These used different threads but please don't ask me what they are but a google search will reveal the answer.

A not infrequent modification on early engines was to use an SD1 front cover that incorporated a larger oil pump and had a proper crankshaft oil seal rather than the rope seal of the earliest Rover V8s.

It is possible that your car has a later SD1 cover fitted. One way of identifying this is to see if a conventional oil seal is fitted and also compare the depth of the pump housing.

The best front cover for distributor based Rover V8s is the interim serpentine front cover fitted to Land Rovers from 1994 to around 1998. These retain the distributor but have a much improved crankshaft driven oil pump; unfortunately, the crankshaft woodruff keyway length needs machining longer and the poly-V belt driven waterpump and alternator are driven in the opposite direction so it is not a straightforward swap.

Thanks David, I'll bet you've hit it on the head. Probably an SD1 cover.

If it is, it has a higher capacity oil pump than the original. Has your distributor got points or has it an electronic distributor? The spigot drive between the distributor and the oil pump gear is different between the pre-SD1 and SD1 setups.

As David says the 13/16" thread is for Rover P6 based engines up to 1976, the 3/4" thread is for SD1 engines.
Irrespective of the oil pump gears and front case, the pump base which mounts the oil filter is fully interchangeable between the two versions, so, it maybe is that a previous owner changed only the base.
Equally, as David suggested, the previous owner may have changed the complete front cover, oil pump and oil pump base. If that was done, then either the distributor will have been changed or modified, this is because the orientation of the peg and slot between the oil pump drive and distributor also changed between the P6 and SD1 engines.
So, working from the top down, (assuming a Lucas distributor), is the distributor, still on points, or a modified points base, if so, probably only the oil pump base was changed.
If the distributor is a Lucas electronic one, or a modified electronic one, then probably the whole front cover was changed.
The only way to be sure is to pull the distributor and check whether it has a peg or a slot.
P6 engines, slot in oil pump drive, peg on the end of the distributor drive gear.
SD1 engines, peg on end of oil pump drive, slot in the end of the distributor drive gear.
In the alternative, don't bother with any of the above and just fit the 'right' oil filter!

Absolutely correct - the oil pump base is interchangeable!