Oil Change Advice

[AndyC]

20W/40 is on the thin side when hot. Not a major issue per se, but you will lose more oil past the rings and down valve guides when hot compared to the 15W50 Mobile one.

I'm using 5W/50 Valvoline racing fully synth in mine.

Well, he is even further north than you (I guess I really am in the South), so from my memories of Scottish weather, his oil will be kept relatively cool. I had thought wow 40 is thin, but then realising the location changed that to, wow 20 will be quite thick at startup if used in the winter.

[Lotus-e-Clan]

Good point about the cold North Andy!

Past couple of weeks I've been rebuilding our SMART roadster Engine...timing chain wear due to a blocked chain spray nozzle (common issue due to a design gaff).

It's done 110K miles, had only Molbil 1 or MBenz-branded fully syth every 7000 miles. I was amazed how clean the engine was inside -just a light tan tinge to the crankcase.

If the slack timing chain hadn't chaffed the timing chest cover (releasing swarf!! ), I would have got away with just changing the timing chain, sprockets and spray nozzle. But the swarf scored the bearings- otherwise the bearings showed hardly any wear, nor did the bores nor rings. It's going back into service with bores and rings untouched. thanks to, I believe, the use of fully synth oil.

BTW the filter is changed every 7000 miles too, which begs the question why the swarf got to the bearings and wasn't caught by a relatively clean filter. I'm pretty sure it's due to cold winter starts. The filter bypass valve opens when cold oil is too viscous to pass through the filter matrix, hence unfiltered oil reached the bearings.

Anyway I wouldn't use anything but fully synth - apart from running-in new bores, and I'm steering away from thick cold grades these days too (I favour 5W for the Lotus and Clan).

[TrevorK]

That's interesting, Pete. I remember when BL upped their oil change intervals, they did it by fitting bigger oil filters as they were the factor limiting it to 6,000 miles beforehand.

[Esprit2]

Compared to modern engines designed specifically to minimize the use of ZDDP, the Lotus 9XX engines depended upon a high level of ZDDP (specifically the 'P', phosphorus) for anti-wear protection. For civilized daily driver use, an oil with 1200 ppm (parts per million) of Phosphorus is adequate for a vintage Lotus. But if you prefer vigorous driving, then more Phosphorus is better. In general, high performance oils with more Phosphorus cost more.

A few people have mentioned Valvoline VR1 20W50. It's a good oil with 1300 ppm Phosphorus, it will take care of your 9XX for spirited driving, but might be marginal for full-throttle track days. And of the oils in the 1200-plus ppm end of the scale, it's relatively inexpensive.

Then there are some high performance, 'supercar' oils, some with 1600-plus ppm of phosphorus, some of which get really pricey.

"IF" you normally use an expensive, high performance, high-phosphorus oil, and "pay the price" for it, then good on you, you're taking excellent care of your 9XX. Then, within the 1200 to 2500 ppm spectrum, Mobil 1 15W50 (1200 ppm) and Valvoline VR1 (1300 ppm) ARE the less expensive oils.

The point isn't to use the cheapest oil on the shelf, maybe with only 600-800 ppm phosphorus. The point is, within the realm of oils that are appropriate for use in the vintage 9XX Lotus engines (1200 ppm phosphorus and up), chose one of the less expensive oils for flushing. If you normally use the cheapest 1200 ppm oil available, then you're already there.

I normally use Mobil 1 20W50 V-Twin Motorcycle oil (1600 ppm). It used to be a automotive oil, Lotus highly recommended it, but it contains more than the maximum 1200 ppm phosphorus that the API now allows on this side of the pond (USA). So Mobil simply re-branded it as a motorcycle oil... it's the same great stuff. For flushing, I'd use Mobil 1 15W50 (1200 ppm), which is less expensive. It is my "cheap" oil, but you first have to define "cheap"... compared to what?

I NEVER put an 800-1100ppm oil into any vantage Lotus engine... from a Coventry-Climax to a 918 V8. They can't make those low-phosphorus oils inexpensive enough to make them appropriate for use in a vintage Lotus engine, including the 907 & 912.

Modern Lotus Toyota engines are designed to a different set of rules, and require different oils. Any Lotus with a pre-Toyota engine is "vintage", and requires 1200 ppm phosphorus or higher.

Phosphorus is the "P" in ZDDP. Since "P" is less than the total, complex molecule, it takes more than 1200ppm ZDDP to deliver 1200ppm Phosphorus. If your favorite oil company only talks about how much ZDDP is present in their oil, then they're not answering your questions about phosphorus content. You need to know if their oil contains 1200+ ppm "PHOSPHORUS". If they won't tell you, then move on to another company.

When you buy by 'price', the low price you care about must still be within the range of oils that have 1200ppm phosphorus or more. And "MORE" phosphorus can get rather expensive. All things are relative, and 'cheaper' isn't always the cheapest.

Regards,
Tim Engel

[pistolpete]

Compared to modern engines designed specifically to minimize the use of ZDDP, the Lotus 9XX engines depended upon a high level of ZDDP (specifically the 'P', phosphorus) for anti-wear protection. For civilized daily driver use, an oil with 1200 ppm (parts per million) of Phosphorus is adequate for a vintage Lotus. But if you prefer vigorous driving, then more Phosphorus is better. In general, high performance oils with more Phosphorus cost more.

A few people have mentioned Valvoline VR1 20W50. It's a good oil with 1300 ppm Phosphorus, it will take care of your 9XX for spirited driving, but might be marginal for full-throttle track days. And of the oils in the 1200-plus ppm end of the scale, it's relatively inexpensive.

Then there are some high performance, 'supercar' oils, some with 1600-plus ppm of phosphorus, some of which get really pricey.

"IF" you normally use an expensive, high performance, high-phosphorus oil, and "pay the price" for it, then good on you, you're taking excellent care of your 9XX. Then, within the 1200 to 2500 ppm spectrum, Mobil 1 15W50 (1200 ppm) and Valvoline VR1 (1300 ppm) ARE the less expensive oils.

The point isn't to use the cheapest oil on the shelf, maybe with only 600-800 ppm phosphorus. The point is, within the realm of oils that are appropriate for use in the vintage 9XX Lotus engines (1200 ppm phosphorus and up), chose one of the less expensive oils for flushing. If you normally use the cheapest 1200 ppm oil available, then you're already there.

I normally use Mobil 1 20W50 V-Twin Motorcycle oil (1600 ppm). It used to be a automotive oil, Lotus highly recommended it, but it contains more than the maximum 1200 ppm phosphorus that the API now allows on this side of the pond (USA). So Mobil simply re-branded it as a motorcycle oil... it's the same great stuff. For flushing, I'd use Mobil 1 15W50 (1200 ppm), which is less expensive. It is my "cheap" oil, but you first have to define "cheap"... compared to what?

I NEVER put an 800-1100ppm oil into any vantage Lotus engine... from a Coventry-Climax to a 918 V8. They can't make those low-phosphorus oils inexpensive enough to make them appropriate for use in a vintage Lotus engine, including the 907 & 912.

Modern Lotus Toyota engines are designed to a different set of rules, and require different oils. Any Lotus with a pre-Toyota engine is "vintage", and requires 1200 ppm phosphorus or higher.

Phosphorus is the "P" in ZDDP. Since "P" is less than the total, complex molecule, it takes more than 1200ppm ZDDP to deliver 1200ppm Phosphorus. If your favorite oil company only talks about how much ZDDP is present in their oil, then they're not answering your questions about phosphorus content. You need to know if their oil contains 1200+ ppm "PHOSPHORUS". If they won't tell you, then move on to another company.

When you buy by 'price', the low price you care about must still be within the range of oils that have 1200ppm phosphorus or more. And "MORE" phosphorus can get rather expensive. All things are relative, and 'cheaper' isn't always the cheapest.

Regards,
Tim Engel

Tim,

That is so interesting never new that , it is funny how we all think our oil is the best and actually have no idea what's happening inside our engine , but we base it on 20w 50 or something and the cost. you have helped narrow down what we should be really looking for. SO I currently use VR1 20w50 and so I need to change this before my trackday or stay of the loud pedal.. ummmmm..

Ok I will change oil.

SO when you flush. do you run the engine for a brief time , a few hours before changing oil again?

Thanks again

[Lotus-e-Clan]

That's interesting, Pete. I remember when BL upped their oil change intervals, they did it by fitting bigger oil filters as they were the factor limiting it to 6,000 miles beforehand.

I think classic car owners should pay more attention to the real-world operational effects of using modern oil filters. I'd like to see more options for classic car owners than there is currently.

For example: A two stage filter might prevent unfiltered oil reaching the bearings on cold starts:

• Stage 1: a coarse, old-fashioned, filter matrix that allows very cold 20W/50 (or 10W/60) to easily pass down to -40C. This would never trigger the 1st stage matrix bypass valve in cold weather (unless the filter is beyond dirty!) - then all incidental swarf would be caught by the matrix on cold starts -thus limiting damage and wear, saving money when it's time for a rebuild.
  
  Stage 2: a fine, modern, filter matrix designed for thinner modern oils (0w/30 to 10W/40), that would allow very cold thin grades to pass at -40C. Thicker 20W/50 or 10W60, will pass the fine matrix once warmed beyond that common British cold weather zone of 0C to 10C.

Obviously each matrix stage would have its own bypass valve.

Alternatively, if filter manufacurers were honest about the operational suitability of their matrix densities for all engine grades at all ambient temeratures and sold two grades of filter (modern and classic), fussy types like me could build a system comprising TWO in-line filters in series - the first one a Classic grade followed by a Modern grade to catch the finer stuff when the oil is up to temperature. The downside would be the cumulative pressure drop across 2 filters - but that would be a small price to pay for better filtering.

Currently, modern filters are very fine because they're spec'd for thin modern oils. Most classic cars owners are left to believe that modern filtering sytems are better than they used to be ... yes great for preventing wear in modern cars but not great for classic car owners who use much thicker oils.

We classic car owners have been left in the dark.

[Esprit2]

(Snip)... SO I currently use VR1 20w50 and so I need to change this before my trackday or stay of the loud pedal.. ummmmm..

Ok I will change oil.
SO when you flush. do you run the engine for a brief time , a few hours before changing oil again?

Track days can vary from driving faster than local speed limits allow, to faux-racing... 'pedal to the metal'. How aggressive do you drive? For many more casual track days, the Valvoline VR1 20W50 will work just fine. Back when I used to autocross my Esprit S2, I'd flog the crap out of it, including taking it to 8000 rpm. I used a premium oil that has 1600ppm phosphorus, and sometimes it's sibling oil that has 1750ppm. So, how hard to you drive at a track day? Just hard enough to get a ticket on the street?... VR1 is fine. Flat-out?... then you might want to consider an oil upgrade.

I'm in the USA, where the API (American Petroleum Institute) as a lot to say about what goes into oils. On your side of the pond, there are other standards. The API has set an upper limit for the amount of phosphorus that can be in a "Certified" motor oil. But for vintage cars driven hard, sometimes a NON-Certified oil with more ZDDP/ phosphorus is just what it needs.

To that end, some more "sporty" oil companies have re-branded higher ZDDP oils as "motorcycle" or "racing" oils... NNWWSNM (Monty Python -- nudge, nudge, wink, wink, say no more). You have to be able to read between the lines and choose which NON API Certified, high phosphorus oil is right for your car.

Many of the available "Racing" oils are what I call "Boutique Racing Oils". They're non-certified oils with higher levels of ZDDP/ phosphorus that exceed the API's maximum limit. A 'true' racing oil has none of the street additives that are necessary for prolonged (normal) oil change intervals. It's presumed that 'racing' oils will be changed after every event, and the interval will only be a few hundered miles. "IF" you use a true racing oil in your street engine, it will protect the engine's wear-parts just fine. However, it should be changed every 500 miles or 3-months, whichever comes first. For most private owners, that's not acceptable.

The "Boutique Racing Oils" contain a full compliment of the required 'street' additives, and they can be changed on a normal long interval... like 3000 miles/ 6 months. They're really street oils that just happen to have more ZDDP/ phosphorus than the API allows... NNWWSNM.

So, when we're talking about Valvoline VR1 Racing Oil (or Mobil 1 Racing oil, or Castrol Racing oil...), it's really a 'Boutique Racing Oil'... ie, just a premium street oil with more ZDDP than the API allows. There's nothing magically "Racing" about it that will provide "Race Protection"... other than the extra ZDDP. It's a sporty oil company's marketing department's attempt to put a high ZDDP oil in the hands of vintage and hotrod car owners... NNWWSNM. Dial your expectations accordingly. And flavor it as necessary for your part of the world.

Valvoline VR1 is available in both mineral oil and full synthetic versions... read the label carefully. Then there's a third choce, VR1 NSL (Not Street Legal). More marketing terminology... NSL has nothing to do with being legal according to the law. But it is a genuine racing oil with NONE of the street additives. It will protect your engine's wear surfaces, but change it ever 500 miles or 3 months. That recommendation comes straight from Valvoline, it's not just my opinion. And it applies equally well to other 'Racing' oils.

*~*~*~*
Flushing Oil:
Some of the crud & corruption that accumulates inside an engine during normal use, and sets-up to hard goop during prolonged storage/ non-use, can require real muscle with brushes and solvents to clean them out during an engine re-build. It isn't just light fluff lying about, so don't expect that simply pouring in a cheap oil then draining it will do much of anything to clean the engine as it 'flows through'.

The dirt/ sludge/ crud you're most worried about is that which has collected in all the myriad internal oil passages, in the bearings themselves, and in the external plumbing to the oil cooler and back. Just pouring oil into the sump doesn't circulate it all through the engine to flush dirt & sludge out of all the critical places.

So yes, when you 'flush' with clean oil, you do need to run the engine for a while. And 'a while' isn't five minutes or an hour sitting in your shop during an oil change. Put the car back on the road and drive it. Not for a full 3000 mile normal change interval, but for something arbitrarily shorter... like the 500 milles mentioned above. But even that presumes you 'drive' the car enough to accumulate the miles in a reasonably short time. If it's a Garage Queen that barely sees 500 miles per year, then you may have to re-think what it means to 'drive' the car for a short (500 mile) oil change interval.

"IF" the flushing oil that drains out is really dirty after that short use interval, then you might want to consider repeating the flush/ drive again. Fresh oil and filter... the whole bit.

When you're satisfied with the flush results, then thoroughly drain the oil (give it plenty of time... go have lunch), install another new filter, and refill with fresh xxW50 or xxW60 oil that contains a minimum of 1200ppm of phosphorus, or more if you like to drive the car hard.

*~*~*~*
Getting off-topic relative to your questions...

The main, rod and cam bearings use what is called a "plain" bearing. Two smooth metal surfaces (journal and bearing shell) separated by a hydro-dynamic layer of pressurized oil. Think of it as surfing an ocean wave. As long as there's sufficient forward (rotational) velocity, the hydro-dynamic fluid layer can 'float' the journal away from the bearing shell, and the two never touch. "Sufficient velocity" depends heavily upon the viscosity of the oil used. Chose the wrong viscosity oil, then the two metal surfaces make contact, and things become very expensive in a heartbeat.

Plain bearing design is a balance of several factors, and an engineer made choices that are now built into the engine. There's a lot more involved (it's complicated), but the short list of factors for the 907 engine (for ALL vintage Lotus engines) is 1) large bearing clearances, 2) a high viscosity/ thick oil, and an oil pump that has 3) a high flow rate with 4) relatively modest oil pressure. In vintage times, that was sometimes referred to as a 'racing' bearing design, and Lotus built 'racy' street engines. That config was built into the 907 engine, and now it's NOT up to you or any oil salesman to switch to a 0W30 that is somehow magically better for your 907... It's NOT.

Lotus recommended 20W50, but xxW50 will suffice, and the engine also likes a xxW60. But you go to lower viscosity oils (xxW40, xxW30, or xxW20) at your own peril... or the peril of your engine. And you'll immediately notice a lower oil pressure that results from using a thinner oil. It's not adequate compensation to simply modify the oil pump (shim the Pressure Relief Valve) to increase it's pressure output, since the bearings still have wide clearances that are not compatible with thin oils (it just squirts out of the wide gaps faster than you can pump it in.

Modern engines that use water-thin "high efficiency/ high fuel mileage" oils, like 0W20, are designed and built to work with those oils. They have very narrow/ tight bearing clearances, an oil pump with modest flow rate but HIGH pressure... and the THIN oil. That's "NOT" what your 907 has, so don't go there !!

Regards,
Tim Engel

[MetBlue]

Thanks for the insight Tim.
Finding this thread really informative. All so logical and obvious when it's pointed out, but not something you'd think about in such detail normally.
Tony

[DavidOliver]

Good to hear from you Tim, as usual most informative and easy to understand.
Here in Spain it is hard enough to get a better oil, sales go on price. So I do not bother asking about Phosphorous levels.
I am not aware of the Spanish API equivalent. For my Elite of 40 years ago I used SINT 2000, an AGIP oil, pretty good.
I recently asked for Castrol Edge to be offered a thin Motorcycle Edge, not accepted obviously.

For my Excel it is very easy to drain the oil cooler and pipes by removing from the car, the cooler is the most likely point to collect old oil.

Also as a detail, on the Excel I found that oil collects in the side panels of the sump under the splash plate and does not circulate so sets up a heat mass and a couple of wasted pints of unused oil. I drilled a 3mm hole in the webbing to relieve the oil stagnating there.

Dave the cog.

[Pete Boole]

Also as a detail, on the Excel I found that oil collects in the side panels of the sump under the splash plate and does not circulate so sets up a heat mass and a couple of wasted pints of unused oil. I drilled a 3mm hole in the webbing to relieve the oil stagnating there.

Dave the cog.

That sounds like a great tip Dave - I'll look at that further.

Pete

[pistolpete]

There seems a gap between VR1 ( £50) and moving to higher levels of phosphorus such as Mobil 1 v twin ( £130.00) I struggle to find the info on ZDDP it seems they hide the info or just talk about other more important factors . !!!!

So we have been talking about this forum recently, (v facebook group), among other issues I think this kind of insight and knowledge and helpfulness is why this group is so great. Maybe you could post it on facebook to see if it melts there server

Thanks

Pete

[Esprit2]

I struggle to find the info on ZDDP it seems they hide the info or just talk about other more important factors . !!!!

Most oil companies don't make the 'Product Data Sheets' for their oils readily available to the public. Mobil 1 used to (I've not looked for it recently) publish a chart of all their oils and what's in them. Some companies will verbally tell you what the ZDDP/ phosphorus content is if you call and speak with a Tech Rep. A Valvoline Tech Rep will answer questions, and will send a Product Data Sheet if you ask for one.

Just my experience...
Mobil 1 is very open about what is in their oils.
A Valvoline Tech Rep will answer questions if you call call & ask, but very little is volunteered.
Castrol won't divulge anything.
More oil companies are like Castrol than like Mobil 1

.Phos. / Zinc. . . Current motor oils with high Zinc / Phosphorous (ZDDP) levels:
2400p / 2500z Redline Racing Motor Oils (typical, “all have2200 ppm Phos” minimum)
1750p / 1850z Mobil 1 0W-50 Racing Oil (contains full street additive package).
1600p / 1700z Mobil 1 20W-50 -- old, discontinued, now re-named…
. . . . . . . . . . . . Mobil 1 20W-50 V-Twin Motorcycle Oil (same good stuff)
1400p / 1500z Brad Penn®, Penn Grade 1 Hi-Perf Oils, 20W50
1383p / 1483z 3 Qts Mobil 1 15W-50 plus 2 qt Mobil 1 0W-50 Racing Oil
1310p / 1410z 4 Qts Mobil 1 15W-50 plus 1 qt Mobil 1 0W-50 Racing Oil
1300p / 1400z Mobil 1 Extended Life 10W-60. Not sold in North America,
1300p / 1400z Valvoline VR1 Racing Oil, API SF/CD (FULL street additives).
1300p / 1400z Valvoline VR1 NSL (Not Street Legal) Racing Oil (NO street additives)
. . For street use, NSL should be changed every 3 months/ 500 miles" <<<<
1266p / 1379z Amsoil HDD Series 3000 Synthetic 5W-30, combined Diesel / Gasoline.
1266p / 1379z Amsoil ARO 20W-50 Synthetic, street, gas/ Diesel, for API SL/ CI-4 Plus
1265p / 1378z Amsoil AMO 10W-40 Synthetic, street, gas/ Diesel, for API SL/ CI-4 Plus
. . Note: “FOR” API SL applications, but "NOT" API certified due to high ZDDP
1235p / 1370z Amsoil TRO 20W-50 Synthetic Racing Oil, gasoline hotrod, race, 'big' cams
1200p / 1300z Mobil 1 15W-50
1200p / 1300z The minimum phosphorus I'll put into a vintage Lotus engine. "Vintage" Lotus is every Lotus built prior to the current Toyota powered Elise, Exige & Evora... ie, the 918 V8 or older.

Just FYI...
1560p / 1625z the 1980-88 API SF = highest ZDDP/ phosphorus levels ever spec'd by the API.

Regards,
Tim Engel

[Esprit2]

I've got no idea what's going on with the multiple posts. I've deleted the long, redundant content.

Would an Admin please delete this post.
Tim

[Esprit2]

I've still got no clue what's going on...

Would an Admin please delete this post.
Tim

[Lotus-e-Clan]

Thanks Tim. Every day's a learning day.

Relieved to read that my current oil (Valvoline) is on the OK list.