Which oil in the twin cam?

[Bruce Crowthorne]

I rebuilt my twin cam 500 miles ago and have started the running in process with mineral 20W 50 oil. I hope that this is letting the engine bed in properly.

But when it is run in which oil suits the Twink best?
I have read comments on here about synthetic causing oil leaks (don't think I beleive that).
Some people seem to think that "original is best" so they say use old mineral 20W 50 - Duckams or similar (I believe things have moved on and improved!)

So should I use fully synthetic or semi sythetic?

Next question - what grade?

In old mineral oils the "cold" viscosity was typically 20. But these days fully synthetics get this down to viscosities of 10 or even 0. My thinking is that I won't have a problem with oil pressure when the engine is cold, but the Twink always runs low oil pressure when it is hot.

How does this affect the Twink?

My feeling is that the lower cold viscosity the better, so I am thinking of a 0W-50 (like Mobil 1 or similar)

Can I have your opinion?
Or even better, who has been running a Twink on fully synthetic for lots of miles and what is your experience?

Thanks
Bruce

[MintSprint]

For what it's worth, I use Mobil 1 20W50 Motorsport fully synthetic and I've never had any problems, but then I don't do massive mileages.

To be honest, though, I'm of the opinion that modern oils are so good, and average Elan owners' milages so low, that any good quality brand of the correct viscosity will probably give trouble-free service for road use.

In terms of viscosity, I'd personally tend to steer clear of low cold viscosity oils (10W or lower), simply because, even if you get all the gaskets and seals oil-tight, they will leak down the valve guides more readily when the car is stood up. Given the quality of modern oils, I'd rather risk a little more cold wear than more of a smoke haze at start-up.

But those are just my personal views...

[steveww]

I am currently using Millers classic sport 20W50 see http://www.millersoils.co.uk/

[freddy22112211]

I don't get a smoke haze on start up with a 0W60 (or any other problem), and I've been using a full synthetic ever since they came out. I guess it's just possible that leaks could be slightly worse, but I can't really see any difference, they could even be a bit less. Engine now 130,000km. Standard Sprint.
Gordon

[Alasdair]

Any 15/40 Diesel CJ4 or equivalent.

[freddy22112211]

Isn't that a bit unfair Alasdair? Two Jags, two Elans, an Elite and a Porsche. Can't I have one?
Gordon

[Alasdair]

I am removing the 930, it is off to auction and, you missed one of the best, the 2CV!

[Allison]

Bruce,

stick with what works! For us its Duckhams. I can't say we've taken it right round the world - but its been to Albania, Austria, Greece, Tunisia, Morrocco, Senegal, India, Nepal and Bhutan and places in between.

Right now the Elan's on the high seas on its way to Kuala Lumpur - with 3 4.5 litre cans of Duckhams on board.

we tried Castrol GTX but it was too thin.

Peter & Allison

[freddy22112211]

P&A,
And what effect does the 'too thin' have?
Use too much oil/engine rattles/engine wears out/or other?
Gordon
13,5kg extra weight of oil on board (where does it all fit?) must slow the car up a tad. And you let other folks drive it on and off the boat?-or is it crated?

[denicholls2]

In my Europa, I use Mobil 15-50. Haven't found a good supply of 20-50 locally but I should look for it.

I agree that lowering the base viscosity is not the way to go on a classic engine. 15 is too low for my liking.

I'll also opine that synthetics do leak more. But the leaks don't create themselves. If there's a noticeable flaw with dino oil, then it will be more noticeable with the synthetic. So it's not that bad. I would not avoid a synthethic over this issue, I'd fix the leak.

[cusword]

I use Mobil Mororsport 20/50, but it's terribly expensive. Does anyone know a cheap source in the UK? I wouldn't use modern thin oil unless you are in the Arctc Circle.

David

[Bruce Crowthorne]

The Mobil "Mororsport" 20/50 sounds good
I accept it will be expensive - but always cheaper than a rebuild!
Where do you buy yours now? I can't say I have ever seen it!

My feeling is that a decent synthetic will practically always be better than an equivalent mineral. Even though our engines won't be hammered, I just hope it increases the factor of safety.

[RotoFlexible]

I know this is a well-worn topic in these forums (fora?) and I expect this article is old news to many, but I found it useful. Fortunately, my engine builder put the good stuff on the cams during assembly and the other good stuff in the oil during break-in on the dyno, so I am off to a good start. Based on the information in the article, Amsoil 20W-50 or Red Line 20W-50 may be good choices.

Disclaimer: I am not an expert in this area; I can't vouch for the accuracy of the information. And yes, the article has a certain "sky is falling" tone in its first part. But it seems unbiased, informed, reasonably well documented, and well written.

[andyhodg]

I am currently using Mobil 1 Motorsport in my +2 no problems with increased leaks. I buy it fro Opieoils.co.uk as that is the cheapest source I have been able to find. They do give a discount for LDC members and members of other car clubs.
Hope this helps - Andy