Oil Change Interval.

[Southern Star]

I'm sure this will have been covered before, but I can't find the info using the search function, so perhaps I can solicit an answer here? The engine is a BMC 1.5.

 

According to the engine handbook supplied by Leyland Cars, the oil and filters should be changed every 150 hours. According to the C.T. Marine sticker on the rocker box cover, oil and filters should be changed every 75 hours. Since I'm cruising at the moment, this would mean every 10 days. What's the general advice on this? The engine has done about 2,800 hours, and appears to be in good condition.

[alan_fincher]

I can see no reason not to go with the BMC / Leyland figure of 150 hours.

 

I don't think I ever changed ours at any shorter interval than that, and, if I'm honest, sometimes it was a bit over that.

[Sabcat]

I'm sure this will have been covered before, but I can't find the info using the search function, so perhaps I can solicit an answer here? The engine is a BMC 1.5.

 

According to the engine handbook supplied by Leyland Cars, the oil and filters should be changed every 150 hours. According to the C.T. Marine sticker on the rocker box cover, oil and filters should be changed every 75 hours. Since I'm cruising at the moment, this would mean every 10 days. What's the general advice on this? The engine has done about 2,800 hours, and appears to be in good condition.

 

150 hours would be roughly equivalent of a car being serviced at 6000 miles. 250 hours that some say is the rough equivalent of 10000 miles.

 

A lot of people just do an annual service on their boat engine.

[steamraiser2]

250 hrs is the equivalent of 6000 miles given the light duty cycle of a narrowboat. For most people it means an annual oil change. Best to follow the manufacturers lubrication schedule.

[Tony Brooks]

Trouble is that different marinisers seem to give different times. When I last looked into this for a questioner I think I found Calcutt said 150 hours while Thorycroft said 200. (Not 100% sure about which way round). Now we have CT saying 75 but I suspect that is from the 70s or 80s and maybe for mono-grade oil.

 

If it were mine I would go for 200 hours or sooner if the oil was emulsified, really black and thickening with carbon or emulsification.

[David Schweizer]

I am with Tony here, All the workshop manuals I have say every 200 hours, and that is what I have done for the past 18 years, without any problems so far.

[gazza]

Echo the above, 200 hours or annually if less. Filter every change as the cost is so small there is no reason not to.

 

I actually change ours around October/November for the winter, then drain and refil in March/April when we start cruising in earnest, I am fortunate my oil is very cheap

[bigste]

In todays world the problem does not lie with the oil. The filter is the part that will give up first. On modern ocean going ships the size of engine means they need a lorry load of oil. If you think they change oils every 200 hours in mid pacific you should do the same. Otherwise I suggest once a year is more than adequate. If you are a heavy user I´d maybe change the filter twice a year. I´ve been in engineering most of my life during which time I´ve had used oils analysed several times and results concur with the above.

[gazza]

In todays world the problem does not lie with the oil. The filter is the part that will give up first. On modern ocean going ships the size of engine means they need a lorry load of oil. If you think they change oils every 200 hours in mid pacific you should do the same. Otherwise I suggest once a year is more than adequate. If you are a heavy user I´d maybe change the filter twice a year. I´ve been in engineering most of my life during which time I´ve had used oils analysed several times and results concur with the above.

My conclusion is oils cheaper than engine bits

[bizzard]

And yet if you can remove metal particles and moisture from old engine oil ''not too old though'', your left with a nice slippery lubricant, virtually Molybdium disulphide because of the combustion sulpher carbon content. Try comparing new oil and old oil by rubbing between the fingers, the old oil feels more slippery.

[guelrose]

BMC 1.8 (Thorneycroft 108) recommends every 200 hours which I have stuck to (give or take 10 per cent) for the last 12000 hours and 26 years. Fuel filter etc changed at the same interval.

[steamraiser2]

You are not running F1 cars guys. Your operators manual will give you a service interval and an oil spec. Follow it. Simples.

[Tony Brooks]

You are not running F1 cars guys. Your operators manual will give you a service interval and an oil spec. Follow it. Simples.

 

Have you missed the point that three different marinisers of the same engine have given three different intervals? not so simples now, is it unless you are happy to waste money.

 

I know Newage/Tempest marinisations had a full length sump while other used the half length vehicle sump and the smaller sump could account for the shorter interval but as far as I know Calcutt and Thorneycroft both used a full length sump (happy to be corrected on that though). No idea about AMC or CT marine. I think the JG Meaks marinisation used the full length sump as well.

[steamraiser2]

Of course its simple. As I said : follow the manufacturers specified service interval.

[Southern Star]

Thanks for the replies, I will do an oil change towards the end of the month.

 

Another question. Perhaps it should be in a new thread, but rather than clogging up the forum I'll ask here. Assuming BMC 1.5 engine has been reasonably well maintained, how long can it be expected to last in terms of hours, and what generally leads to the need for a re-build or replacement?

[Machpoint005]

Thousands and thousands of hours - but a lot will depend on how hard it is used.

[Theo]

In todays world the problem does not lie with the oil. The filter is the part that will give up first. On modern ocean going ships the size of engine means they need a lorry load of oil. If you think they change oils every 200 hours in mid pacific you should do the same. Otherwise I suggest once a year is more than adequate. If you are a heavy user I´d maybe change the filter twice a year. I´ve been in engineering most of my life during which time I´ve had used oils analysed several times and results concur with the above.

Are you saying that it is the time rather than the running hours which determines when you should change oil and filter. I CC and in the year to last April I did 840hrs. Would it be reasonable in these circs to change the oil and filter every 500 engine hours?

 

What are the consequences of having the oil change interval too long?

 

N

[Theo]

And yet if you can remove metal particles and moisture from old engine oil ''not too old though'', your left with a nice slippery lubricant, virtually Molybdium disulphide because of the combustion sulpher carbon content. Try comparing new oil and old oil by rubbing between the fingers, the old oil feels more slippery.

 

Presumably the oil filter removes the metal particles and a good long run to warm up the oil will drive off moisture so are yo saying that the oil should last forever and you could get away with changing the filter only? I thought that the molecules in the oil degraded with mechanical stresses and that was one of the reasons for an oil change.

 

N

[steamraiser2]

Here we go again! Read the manufacturers recommendations regarding specification, grade and service intervals. Follow that and you will not go wrong.