• UPDATED INFORMATION & ADVICE - PLEASE READ NOW

    'I didn't know/I wasn't told' will not be a valid defence if you fail to comply and lose your access to the off-topic area, core topic areas, or the entire YBW forum as a result. Full details can be found here, please read before you proceed.

Md7a oil?

stu9000

Active member
Joined
8 Mar 2008
Messages
762
Location
near kingston upon thames, surrey
Having read martyng's post on oil I am wondering what type of oil I should be buying for my aged but historically well looked after MD7a engine. I had her looked over when I bought the boat and the engineer was v complimentary. So I need to do it right and maintain that treasured reliability.

Having read around I still an wondering

- what oil should I buy?

- can I use the same oil in the engine, sail drive leg and reverse gear?

- where should I get oil filters? Surely own brand type is OK.

She is a dry boat.I imagine I'll do about 50 running hours over the season (fairly wild guess).

Thanks all

S
 

Bobc

Well-known member
Joined
20 Jan 2011
Messages
8,497
Mineral 20/50 oil and after-market filter will be fine.
 

Minchsailor

Well-known member
Joined
2 Dec 2014
Messages
1,148
Location
N of Ardnamurchan, winter South of Oban
I had one of these in my last boat. You don't want an oil that is too good. These engines are very robust, low stressed massive bearings with quite generous clearances compared to more modern types. Any generic 20/40 or 20/50 should be OK. Can't speak for the saildrive.
 

Topcat47

Well-known member
Joined
2 Jun 2005
Messages
4,933
Location
Solent, UK
Do NOT use synthetic or semi-synthetic oils. You can get older spec lubricants from agriculture; engineers but a CD spec 20-50 mineral oil will do fine.
 

Jokani

Active member
Joined
21 May 2014
Messages
743
Location
March
This is what was recommended to me by a Marine Engineer to use in my MD2B, which agrees with the above advice, I also used the same oil in the gearbox.

 

lw395

Well-known member
Joined
16 May 2007
Messages
42,084
This is what was recommended to me by a Marine Engineer to use in my MD2B, which agrees with the above advice, I also used the same oil in the gearbox.

I guess he doesn't like your engine very much....
 

bedouin

Well-known member
Joined
16 May 2001
Messages
30,214
Until recently I had an MD2B - that really didn't like multigrade. I switched to SAE30 and it worked fine.

The problem I had was that the oil pump would not prime (reliably) with the lighter oil. I suspect I was trying 10-40 and it may be that 20-50 could work - provided the oil pump primes it won't do any harm,
 

VicS

Well-known member
Joined
13 Jul 2002
Messages
46,357
This is what was recommended to me by a Marine Engineer to use in my MD2B, which agrees with the above advice, I also used the same oil in the gearbox.

I guess he doesn't like your engine very much....
That is a non detergent oil to only API spec SA. It is suitable only for vintage petrol engines and even then requires very frequent oil changes.

I'd definitely suggest looking for a different Marine engineer
 

Jokani

Active member
Joined
21 May 2014
Messages
743
Location
March
Sorry for the bum steer on the Comma, and thank you for putting me straight Vic.

It's one of the reasons I like this forum so much, it's gives protection from people (like me) who think they know something.

Enjoy the rest of the weekend all.
 

stu9000

Active member
Joined
8 Mar 2008
Messages
762
Location
near kingston upon thames, surrey
Stu:
this web page, written by a regular forumite, has lots of good information on oils for yacht engines: https://coxengineering.sharepoint.com/Pages/Oilforyachtengines.aspx

Vyv's a pretty modest chap on here, but if you read his brief biog on the 'About Us' page of his website, you'll get a sense of the authority with which he writes.
A well written and informative link. Thanks.

So, if I have this right, I want a mineral oil with a TBN of 4. API CD.

I understand this can be hard to find?
 

Tranona

Well-known member
Joined
10 Nov 2007
Messages
34,200
A well written and informative link. Thanks.

So, if I have this right, I want a mineral oil with a TBN of 4. API CD.

I understand this can be hard to find?
CE and CF are easy to find. This is the spec of basic diesel oils sold in supermarkets and will be fine in your engine.
 

macd

Active member
Joined
25 Jan 2004
Messages
10,605
Location
Bricks & mortar: Italy. Boat: Aegean
A well written and informative link. Thanks.

So, if I have this right, I want a mineral oil with a TBN of 4. API CD.

I understand this can be hard to find?
Yes, CD is evidently hard, but by no means impossible, to get hold of. (It's a while since I've shopped for oil in the UK.) This thread might trigger some sourcing suggestions. (Edit: there you go, Tranona's already on it...)
Vyv has often written that CF-4 is an acceptable substitute, and does on the page you read. He might be along in a while to amplify.
 

VicS

Well-known member
Joined
13 Jul 2002
Messages
46,357
CE and CF are easy to find. This is the spec of basic diesel oils sold in supermarkets and will be fine in your engine.
But is it not the high TBNs of oils of these API specs that Vyv objects to ? Or rather the effects of the additives giving the high TBNs on older engines
 

stu9000

Active member
Joined
8 Mar 2008
Messages
762
Location
near kingston upon thames, surrey
But is it not the high TBNs of oils of these API specs that Vyv objects to ? Or rather the effects of the additives giving the high TBNs on older engines

Indeed.

"the TBN of API CD is 4, of API CE it is 10.5 and for API CF it is 16."

"There is a great deal of evidence to show that use of an oil with a TBN that is too high for the duty can lead to several problems, particularly high wear rates of cylinder bores"

Quotes from
https://coxengineering.sharepoint.com/Pages/Oilforyachtengines.aspx

Ill have look round. Can't be that hard to find surely

S
 

vyv_cox

Well-known member
Joined
16 May 2001
Messages
23,283
Location
France, sailing Aegean Sea.
For your engine I would buy API CC from Morris Lubricants. http://www.morrislubricants.co.uk/ They don't make API CD but there is little difference between the two. I use their API CC 20/50 in my BMC 2.2 diesel, as do hundreds of canal boat users, their main market.

I would definitely not use a 10W-40 viscosity oil in an older boat engine. The only purpose of these low viscosity oils is fuel economy in car engines designed to take them, with hardened crankshafts and aluminium bearings. Older yacht engines have no need for the fuel economy and will suffer increased bearing wear and maybe worse using thin oils.
 

bedouin

Well-known member
Joined
16 May 2001
Messages
30,214
Yes, CD is evidently hard, but by no means impossible, to get hold of. (It's a while since I've shopped for oil in the UK.) This thread might trigger some sourcing suggestions. (Edit: there you go, Tranona's already on it...)
Vyv has often written that CF-4 is an acceptable substitute, and does on the page you read. He might be along in a while to amplify.
In fact our local car shop stocks this (only hold a couple of cans though) - apparently it is still commonly used in agricultural machinery.
 
Top