Lagondaforum

Subject: Oil additives

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I've just changed the oils in my LG45 and it got me thinking about all the new additives on the market claiming to be just the ticket for our older cars.

I've always been very wary of engine flush on older engines in case they loosen something that has built up over years which could block an oil way or some such. On a newly rebuilt engine though I wonder whether it might be a good idea to flush first.

There is also a number of products such as Molyslip which claims to reduce wear of gearboxes and rear axles. Not for limited slip diffs, overdrives, or auto boxes but supposedly good for all others. Supposed to reduce whine if experiencing it.

My naturally suspicious mind tells me that a good quality oil will be more than adequate but I thought I’d throw it out there.

Anyone have any knowledge - good or bad?

David

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Subject: Re: Oil additives

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Hi David,
I did use some moly type additive in my V12 that did absolutely nothing. The problem I had was oil consumption, which eventually reached a staggering 100mpg yes per gallon. I used Redex oil treatment (completely different to the more usual petrol treatment), and that really did improve the oil consumption to a more manageable level.

For a newly rebuilt engine, the filter should catch anything untoward. That said, flushing oil would do no harm, and indeed could be beneficial as an aid to initial running in. The one issue I can think of is, how much flushing oil will be left in your engine after draining? The more left, the more it will dilute your fresh oil. Certainly worth draining the filter, as a good pint or more would otherwise remain.

Laurence

Subject: Re: Oil additives

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Hi Laurence,

Thanks for your comments.

I might try an engine flush next time although I last changed the oil after just 1,500 miles and it was still in really good condition so I was probably being over-cautious anyway. I’ll do the next one after another 2,500 miles and see what it’s like. I take your point about residue.

I’d still be interested to hear other people’s views if they want to join the discussion.

Interesting that the moly additive did nothing but it sounds as if you had/have a very specific problem with oil consumption that the moly products possibly aren’t really claiming to help with. 100mpg oil consumption! WOW! I’m glad the Redex has bought that down to manageable levels.

In hadn’t considered the moly products for being used in engines. The one I’ve seen was specifically for gearboxes and axles. As I mentioned in my original post, I suspect they’re not of great benefit. A good modern oil, changed regularly, must surely be sufficient.

An interesting topic.

David

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Subject: Re: Oil additives

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Hi David,
I think the moly additive I tried was one of those supposed to stop leaks and effectively remetal the cylinders. Compression test before and after proved they were false claims.
The V12 was taken off the road in 1983 as I was concerned that continuing to drive it would cause damage. Since rebuilt, I have the old pistons etc and many rings are missing entirely, and others only partially there!
I recall there's a school of thought in the VSCC just to use cheap oil, but change frequently. Bear in mind also that oil manufacturers claim that they have scientifically formulated their products, and have included all additives they feel necessary.

I'm tempted to use a synthetic gear oil, which my Peugeot seems to thrive on!

Laurence

Subject: Re: Oil additives

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Hi Laurence,

I use Penrite GB40 gear oil which is a 25w75. I think the important point is regular changing. The box only holds about 3 litres so it’s pretty cheap. Just awkward to get to the filler.

The only problem I see with modern synthetic oils is that the various additives could well include cleaning chemicals such as chlorine (bleach)which could harm bronze bearings.

David

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Subject: Re: Oil additives

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Not sure if the Molyslip product you are referring to is the same that is available here in Canada but I suspect it is and I can tell you from 35 years of using this product in the differential in my 1936 modified Ford panel truck it is the "bee's knees" I fully rebuilt the differential all those years ago and being a "quick change" racing unit with coupling gears the noise emitted was horrible. On advice from the manufacturer, Frankland in Florida I added some Molyslip and the problem was solved . Well over 200,000 hard miles and all gears and bearings remained as new. That said I would not put it in an engine.

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Subject: Re: Oil additives

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Thanks Barry. That’s a glowing endorsement if ever I saw one.

I think I’ll try some in my gearbox and see if I notice a difference.

How’s your car coming along?

David

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Subject: Re: Oil additives

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Well David , I am sad to say I threw in the towel . I do not regret the experience and enjoyed doing what I could but found the obstacles overwhelming for my amateur skills .In spite of this I renewed my membership as I think the club is one of the best I have ever been involved with. Maybe there is a Rapier in my future,although it would have to be "turn key" or close to it!
There is a positive note to this story in that the car is in England with an enthusiastic club member and I am sure it will be restored to it's former glory ! Stay tuned ! Cheers,Barry
Meanwhile, back to working on old motorcycles ,my first love.

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Subject: Re: Oil additives

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HI Barry,

I'm sorry to hear that the Lagonda was too much for you, but well done for realising it and passing it along the line. All too often unfinished projects languish in damp workshops and deteriorate. That's far worse. I look forward to seeing her when the new owner has completed what you started.

Glad you kept your membership going.

David

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