6 replies to this topic

[Steve@RetroDash]

A work collegue has just bought a 70's mini with 80000 miles on the clock.

on initial start up of the engine he gets a nasty clunking sound which then goes away.It sound like the engine itself rather than a mounting of somesort

any rough ideas of where to start? its a 998cc with drums all round. recent recon engine according to the last owner

[Dan]

Could be big ends knocking at startup due to low initial oil pressure. Does it take a long time for the oil lamp to go out? This could be due to either a tired or stuck oil PRV or a dying oil pump, or general wear. Hard to work out what a sound is without hearing it though.

[Steve@RetroDash]

Could be big ends knocking at startup due to low initial oil pressure. Does it take a long time for the oil lamp to go out? This could be due to either a tired or stuck oil PRV or a dying oil pump, or general wear. Hard to work out what a sound is without hearing it though.

it only lasts a couple of seconds, i'll check the light tommorrow at work.
how easy are these mentioned problems to fix? and sorry whats a PRV? i'm useless with engine components

thanx for the reply

[Dan]

Pressure relief valve. That's what sets the maximum oil pressure in the engine. If the spring's gone a bit weak then it'll be low on pressure in general, and if it's sticky or got grit in it then it won't be re-seating properly so the pressure won't come up as quickly as it normally would.
If it's the valve then it's easy to service, the pump means engine out at least and if the big ends themselves are gone then it's a re-build.

That's if that is the actual problem though, may well not be.

[1984mini25]

I had the problem of the oil pressure relief valve sticking due to the spring being worn (too short)

Replaced it with the uprated ball and spring, had no probs so far


Take the OPV out (just above starter motor and is 26mm or 1") and look at the cup for wear (sticking) if so replace like i did

[AlexM]

Do you have to take the engine out to change the oil pump?

[Dan]

Well strictly speaking it is possible to change it in the car but I wouldn't recommend it. The pump is buried quite deep inside the transverse A series, to get at it you have to remove the clutch/flywheel and the flywheel housing completely. Getting it back together and keeping it oil tight is nasty in the tight space. Maybe other people find it easy enough to do it that way but I don't really, so I always at least inspect and prefer to replace the pump whenever the engine is out.