What is the recommended oil to use in twin cams these days?

[bcmc33]

I have to admit that the oil in my car has not been changed for 3 years.

At just under 2k miles, the oil looks as clean as the day it was put in.

[gordonlund]

I have used Duckhams 20/50 for years in my twinks and change it regularly every year, regardless of mileage which I must admit these day is not a lot. Last years 5,000 miles half of those in Spain and France over two weeks. Keeping oil in an engine too long even for small mileages can lead to problems due to condensation and acid corrosion. Compared to the cost of an engine rebuild, oil is cheap!!

Gordon

[msd1107]

Following up on what Gordon says.

Low mileage and inactivity are the problems.

If possible, during the inactive time, allocate some time each week. Start the car, warm it up, drive at least around the block. This way, not only does the engine and oil get warmed, but rotating parts in the rest of the car get rotated, warmed, and lubed.

You may not find this pleasant in the dead of winter or in the rainy season in a DHC with no top, but at least warm it up in the garage.

If your car is a daily driver racking up, say, 12,000 miles per year, with normal maintenance occurring at 3,000 mile intervals, you change the oil quarterly. The daily driver puts far less stress on the oil than the car driven 500 miles per year. So you should think of doing preventive maintenance quarterly, not annually.

A Lotus driven 500 miles per year is far less reliable than one driven 500 miles per week.

With respect to oil. Before the times of the Elan, oil was single weight, say SAE 30. A car would use SAE 30 in the summer, and SAE 20 or SAE 15 in winter. An older engine consuming oil would use SAE 40 to cut down on oil consumption.

With the advent of multi-grade oils, it became more normal to use higher weight oils (like 20W50) I did this, but the higher weight oil just contributes to higher friction losses. Modern formulations like 0W30 should be sufficient, provided there is sufficient ZDDP or equivalent to minimize tappet scuffing. You may not like seeing a max oil pressure of 30 psi, but you actually do not need much psi, you need flow volume. Modern ideas are to use as low a viscosity as possible (to provide the necessary film strength) and as little oil as possible (more oil volume actually increases losses).

But if it makes you more comfortable using a high psi oil pump, go ahead. It is your car and your peace of mind.

David
1968 36/7988

[GrUmPyBoDgEr]

Following up on what Gordon says.

Low mileage and inactivity are the problems.

If possible, during the inactive time, allocate some time each week. Start the car, warm it up, drive at least around the block. This way, not only does the engine and oil get warmed, but rotating parts in the rest of the car get rotated, warmed, and lubed.

You may not find this pleasant in the dead of winter or in the rainy season in a DHC with no top, but at least warm it up in the garage.

If your car is a daily driver racking up, say, 12,000 miles per year, with normal maintenance occurring at 3,000 mile intervals, you change the oil quarterly. The daily driver puts far less stress on the oil than the car driven 500 miles per year. So you should think of doing preventive maintenance quarterly, not annually.

A Lotus driven 500 miles per year is far less reliable than one driven 500 miles per week.

With respect to oil. Before the times of the Elan, oil was single weight, say SAE 30. A car would use SAE 30 in the summer, and SAE 20 or SAE 15 in winter. An older engine consuming oil would use SAE 40 to cut down on oil consumption.

With the advent of multi-grade oils, it became more normal to use higher weight oils (like 20W50) I did this, but the higher weight oil just contributes to higher friction losses. Modern formulations like 0W30 should be sufficient, provided there is sufficient ZDDP or equivalent to minimize tappet scuffing. You may not like seeing a max oil pressure of 30 psi, but you actually do not need much psi, you need flow volume. Modern ideas are to use as low a viscosity as possible (to provide the necessary film strength) and as little oil as possible (more oil volume actually increases losses).

But if it makes you more comfortable using a high psi oil pump, go ahead. It is your car and your peace of mind.

David
1968 36/7988

David,

I may have missinterpreted your posting?
I have seen engines that have been subjected to many such short runs & the effects can be scary.
Really the engine needs to be run "hot" for as many miles as possible, not a run around the block.
The short run mode introduces condensation into the engine & oil which over time causes rust & sludge to form.
Having gained that experience I dislike starting the engine of my Elan unless I know it's going to get at least a 20 mile blast.
It's the number of cold starts withot a hot run that make the major contribution to the problems I've mentioned.

Cheers
John

[msd1107]

I may have missinterpreted your posting?
I have seen engines that have been subjected to many such short runs & the effects can be scary.

John,

You are correct.

Note that the post was for a DHC in relation to poor weather conditions, where you really do not want to drive. So warm the engine thoroughly in the garage before subjecting youself to the poor weather conditions.

As you point out, it is important to get all fluids up to temperature so that condensation products are evaporated. Driving is the other aspect, that keeps a lubricating film on other rotating components.

This may not be as good as a 20 mile blast up the road.

On a more philosophical note, I have wondered why people in a cold and/or rainy climate buy a DHC.

David
1968 36/7988

[GrUmPyBoDgEr]

On a more philosophical note, I have wondered why people in a cold and/or rainy climate buy a DHC.

David
1968 36/7988

"Mad dogs & Englishmen"???
John

[redskatejbf]

As for `correct oil` for the Twincam and you have the time to read some very interesting posts go to the `search` window and type `zddp`. I use Castrol oil XL 20/50 classic oil.

When I layed up my car for the winter (I do not now) I would lift the back wheels up on wooden blocks positioned between the discs and the wheel/tyre,so that the tyre was just off the garage floor and then run it thro` all the gears up to 4th, and wind open the throttle screw to give about 2500 revs. Turn on the heater fan and go and have a cup of tea. I would do this about every 3 weeks turning on lights etc. just to keep everything working. I would gently apply the brakes to stop the rears from surface rusting, I never had surface rust on the fronts.
John.

[Rob_LaMoreaux]

When the issue of ZDDP came up, I asked Mobil about it even though the design of the TwinCam head means it isn't as important (oil pool on the big wide tappets). They recommended Mobil 1 Extended Performance 15W50.

For all Mobil 1 data see http://www.mobiloil.com/USA-English/Mot ... _Guide.pdf

Rob

[rgh0]

i agree with Rob that ZDDP levels in oil is not really an issue in an Elan

Every now and again I get the urge to talk about all this ZDDP level in oil b****t one more time. I have had a couple of glasses of red wine so here i go again - turn off now if you dont want to read any further

All the data I read about problems with excessive cam or tappet wear happens in 1 of 3 circumstances and the failure mode of each is well understood.

1. New engines
2. High performance push rod engines flat tappet or overloaded overhead cam flat tappet engines
3. Engines with mismatched cam and tappet metallurgy

These have been problems for many years and they are not caused by the recent small reductions in ZDDP in modern oils. Though a poorly designed or built engine that was marginal to begin with may fail a little quicker with a low ZDDP oil than otherwise.

So now for why they fail

1. New enginess - all flat tappet engines require careful running in of the cam to follower surface - to high or to low engine speeds or oils with to low ZDDP can ruin the surface due to galling on break in. Galling is microscopic welding and then tearing out of particles on the two surfaces as they slide over each other. Always use a specific running in oil, these have very high ZDDP levels and other additives to ensure correct break in and to prevent galling. Phosphate coating of the cams and follower and use of a cam assembly lube which has high ZDDP levels all also help. Recently DLC ( diamond like coating) have been also been used to aid in break in especially with steel cams and followers ( see point 3 below) You need to use these running in oils also to ensure good ring bedding. None of the normal oils you can buy are really suitable as running in oil - which is why car builders change the oil after the first 1000km as its been filled with a running in oil. Once the cam to follower surface had been bedded in then the level of ZDDP is not critical in most circumstances and not critical for a road Elan.

2. Push rod engines where the follower is upside down and not as well lubricated,plus they have heavier valve trains and thus heavier loads on the interface and they typically have smaller diameter followers to fit them all in a row - especially on a american V8 or narrow bore long stroke 4 like a B series - suffer the most from low ZDDP levels once run in because the design is marginal in the first place especially for a hotted up engine with modern aggressive short duration high lift cam profiles. Fortunately this is not a Lotus problem. Most modern 4 valve engines have very light valve trains and spring loads and its not a problem in them either. A race elan with very high spring load to handle a 0.5 inch lift 9000 rpm cam may be a problem but even then I doubt it. A road elan with the correct springs is not a problem and the design is far from marginal.

3. The final problem area is mismatch of cam and follower metallurgy and hardness. In the good old day with cast iron cams and cast iron tappet followers this was not a problem as cast iron is very forgiving. But with new lighter better stronger steel cams and followers the details such as alloy composition and hardness difference between the components have a big affect on galling resistance. Again tends to be a problem in modified engines where people are buying after market componentsthat have not necessarily been propelry speciufied tested or mades.

If you have an engine with one of the base case problems then you have a problem whether you use low ZDDP oil in normal use or not and use of higher ZDDP may or may not help get you over the line. So before condeming the oils and the EPA for forcing a reduction in ZDDP levels understand all the issues which may affect your engine wear performance

If your worried and want to be conservative with your twin cam then use the high ZDDP oils as we dont have catalytic converters to worry about. The oil companies now make these again in response to the somewhat overblown concerns that if they exist at all are really restricted to the Amercian hot rod market and hot MGB's - it does not hurt . But if your serious about the best lubrication for your twink its more than just ZDDP levels so spend the $100 plus for 5 litres of Redline. it has high ZDDP levels plus a Polyol Ester base stock that is much better and more stable than other sythetics plus the rest of the additive package also is superior.

Sorry to be so boring

cheers
Rohan

[Carlos A]

Please read "OIL FOR CLASSIC BRITISH SPORTS CARS" by Michael Grant in British Motoring Winter 2009. Online ed at http://www.britishmotoring.net/Archives/2009_Winter.pdf pages 20-23.

Best

Carlos A

[msd1107]

Along this line, Mobile has recently introduced a full synthetic oil with enhanced anti-wear properties by using high levels of anti-wear additives. This is Mobile 1 racing 0-30. They do not recommend this for use on the street, but this is primarily because it poisons catalyst equiped cars. Also, I suspect, detergent levels are less than in other oils. The advantage of this oil is that it has reduced friction properties compared with normal oils, supposedly giving greater power and fuel economy. The disadvantage is that it is frightfully expensive and apparantly can be purchased only online through the Mobile on-line store. Probably, the engine needs to be assembled with attention to minimal clearances, as well as the usual oil leak minimization strategies.

They have another fully synthetic line, Mobile 1 0W-40, designed for street use. This is much less pricy (although premium priced) and is available on-line through Amazon and other outlets.

Provided the engine is not an oil seive, both of these would be a modern fully synthetic replacement for the usual 20W-50 oils more normally used.

David
1968 36/7988

[SJ Lambert]

Rohan

Is this 20W/50 Redline variant the one you use for track work?


http://www.redlineoil.com/product.aspx?pid=8

[rgh0]

Yes thats what i use

cheers
Rohan