I am going to change to a different engine oil

[kyliesmith.com]

I have been putting Mobil One 20w50 mineral based oil into the car for last two years as recommended by local Lotus mechanic. I was thinking of changing to Castrol 10W60 synthetic for better engine protection. The car has 78,000 miles and valves guides are due to be done soon. So ideally I need something just as thick or something much better for engine protection and not going to burn up easily.

There are various oils to chose from on LEW but nothing to suggest for mileage for my car - or I missed it .

Should I just stick with the same or go to something else?

Ta,

K

[WayneB]

Hello Mrs.Adams

With the synthetic oil you will find that any previous oil burning (via the valve guides) or oil leaks will get worse than with a mineral oil, as the synthetic flows alot more readily when cold.

They did do a Mobil 1 synthetic in a 20w-50 (which I was using), but it has been reciently discontinued (in North America)

I noticed that when I started using it (instead of Valvoline 20w-50 mineral oil), my aluminium sump would drip oil (it exposed a porosity in the casting)

I would stick with the mineral oil till you have the engine overhauled if I were you.

[Vulcan Grey]

I have been putting Mobil One 20w50 mineral based oil into the car for last two years as recommended by local Lotus mechanic. I was thinking of changing to Castrol 10W60 synthetic for better engine protection. The car has 78,000 miles and valves guides are due to be done soon. So ideally I need something just as thick or something much better for engine protection and not going to burn up easily.

There are various oils to chose from on LEW but nothing to suggest for mileage for my car - or I missed it .

Should I just stick with the same or go to something else?

Ta,

K

I would think a 10W-60 would be too thin, unless you drive in below freezing temps alot...

I originally used a 20W-50 (per Lotus recomendations) Havoline racing (non-synthetic), and it was too thick in the winter, engine sounded horrible. About 30,000miles ago I switched to Mobil 1 15W-50 synthetic. No new leaks resulted, I did go around a replace various cam tower o-rings and seals since I've owned the car. It sounds much better in the winter here (sub freezing) and has fine oil pressure in the summer (up to ~105degF)

I am now rebuilding the engine and the wear was not bad at all for a 74,000mile engine (4 owners). There was no damage, I was doing a preventative rebuild.

There was heavy varnish, probably due to the non-synthetic for the first 40,000miles.

Never burned oil, compression had just started to fall off.

I would stick with a 15W-50 minimum though.

Edited September 29, 2006 by Vulcan Grey

[kyliesmith.com]

Hello Mrs.Adams

With the synthetic oil you will find that any previous oil burning (via the valve guides) or oil leaks will get worse than with a mineral oil, as the synthetic flows alot more readily when cold.

They did do a Mobil 1 synthetic in a 20w-50 (which I was using), but it has been reciently discontinued (in North America)

I noticed that when I started using it (instead of Valvoline 20w-50 mineral oil), my aluminium sump would drip oil (it exposed a porosity in the casting)

I would stick with the mineral oil till you have the engine overhauled if I were you.

Hello mate

The guides will probably be done next year, so yeah probably stick with the same to prevent these leaks. till the engine is sorted.

I would think a 10W-60 would be too thin, unless you drive in below freezing temps alot...

I originally used a 20W-50 (per Lotus recomendations) Havoline racing (non-synthetic), and it was too thick in the winter, engine sounded horrible. About 30,000miles ago I switched to Mobil 1 15W-50 synthetic. No new leaks resulted, I did go around a replace various cam tower o-rings and seals since I've owned the car. It sounds much better in the winter here (sub freezing) and has fine oil pressure in the summer (up to ~105degF)

I am now rebuilding the engine and the wear was not bad at all for a 74,000mile engine (4 owners). There was no damage, I was doing a preventative rebuild.

There was heavy varnish, probably due to the non-synthetic for the first 40,000miles.

Never burned oil, compression had just started to fall off.

I would stick with a 15W-50 minimum though.

I think your right 10W60 might be too thin. In Auckland NZ it only get down to 10degC during the day in winter months

[esprithk]

I had similar experience.

first I used Castrol RS 20W/50 synthetic. it is too thick during Spring time Feb/March, which is about 15-20 degC . (Hong Kong never gets under 6degC)

now I switch to Redline 15W/50 synthetic. (and Redline 75W90NS synthetic for transmission)

Edited September 30, 2006 by esprithk

[esprits4de]

I just checked my file, Castrol RS 10W60 is what I have used , as per Lotus recomendation for Germany, for the past 20000 Km.

I note that the Oilpressure comes on 5-10 sec. after ignition, and in warmed up mode will be just above the red sector at idle.

I cange the oil + filters every year or 5000 KM.

So far no notable disadvantages.....

[kyliesmith.com]

Thanks guys. I am going to get a compression check done, do an oil change next weekend and put same stuff in it - Mobil 1 20W-50 (mineral). Will monitor oil consumption real close too and see if I am burning anything.

[esprithk]

found this interesting information

(1) about "Synthetic"

In the late 1990s, Castrol started selling an oil made from Group III base oil and called it SynTec Full Synthetic. Mobil sued Castrol, asserting that this oil was not synthetic, but simply a highly refined petroleum oil, and therefore it was false advertising to call it synthetic. In 1999, Mobil lost their lawsuit. It was decided that the word "synthetic" was a marketing term and referred to properties, not to production methods or ingredients. Castrol continues to make SynTec out of Group III base oils, that is highly purified mineral oil with most all of the cockroach bits removed.

(2) about "GROUP III base oil (highly purified mineral oil)

Viscosity Index over 120 and have essentially no paraffin and wax in them.

Edited October 4, 2006 by esprithk

[rydning]

Hi

If your engines are leaking it gona be worse after a while any way.

Regardless of what kind of oil you are using.If you cant live with some smal leaks.Get new seals and put silicone gasked all the plases where this engine have paper gaskeds that gona help a lot.........

Remeber this is a 35 year old engine design......I gess non of the engines from the 1970 ties are complete sealed.

[Vulcan Grey]

Hi

If your engines are leaking it gona be worse after a while any way.

Regardless of what kind of oil you are using.If you cant live with some smal leaks.Get new seals and put silicone gasked all the plases where this engine have paper gaskeds that gona help a lot.........

Remeber this is a 35 year old engine design......I gess non of the engines from the 1970 ties are complete sealed.

Do not use silicone gaskets where the paper gaskets are! Most silicone sealants will damage the O2 sensor down stream. For example, a silicone seal in the intake manifold will hurt the O2 sensor even after the combustion and turbo.

I use Loctite 518 anerobic gasket eliminator (also known as Permatex anerobic gasket maker) for the cam tower and plenum seals. The water pump can be sealed with or without a paper seal, using Hylomar. Or for overkill you can use the Loctite 518.

[Artie]

Do not use silicone gaskets where the paper gaskets are! Most silicone sealants will damage the O2 sensor down stream. For example, a silicone seal in the intake manifold will hurt the O2 sensor even after the combustion and turbo.

I use Loctite 518 anerobic gasket eliminator (also known as Permatex anerobic gasket maker) for the cam tower and plenum seals. The water pump can be sealed with or without a paper seal, using Hylomar. Or for overkill you can use the Loctite 518.

Are you using sealant on the paper gaskets when reassembling the engine? I usually just reinstall with the paper gaskets. Are you getting vacuum leaks without the sealant?

Artie

[rydning]

Do not use silicone gaskets where the paper gaskets are! Most silicone sealants will damage the O2 sensor down stream. For example, a silicone seal in the intake manifold will hurt the O2 sensor even after the combustion and turbo.

I use Loctite 518 anerobic gasket eliminator (also known as Permatex anerobic gasket maker) for the cam tower and plenum seals. The water pump can be sealed with or without a paper seal, using Hylomar. Or for overkill you can use the Loctite 518.

The intake and plenum does not have papergasked the way I see it.Its in a material I dont know the English name on.

And I dont have any problem with oil leaks in the plenum and intake gasked at least......................

But In other plases where there is oil it will be better to use silicone in my opinion.

I gona try silicone next time I have the cam towers of because its not sealed with that anaerobic gasket I did use last time.

[Artie]

The intake and plenum does not have papergasked the way I see it.Its in a material I dont know the English name on.

And I dont have any problem with oil leaks in the plenum and intake gasked at least......................

But In other plases where there is oil it will be better to use silicone in my opinion.

I gona try silicone next time I have the cam towers of because its not sealed with that anaerobic gasket I did use last time.

Okay, that's what I thought! I have been lucky enough to only have had a leak at the oil pump shaft seal which I fixed whilst replacing the timing belt a few months ago.

Art

[rydning]

I did also use anaerobic gasket in my thermostat housing,and I have a smal leak there also now(may be I`m cursed to not use anaerobic)....So I gona stick with Loctite red silicone gasket in the future to seal oil and water,thats the one I have best and perfect result with.And I dont use silicon to seal the intake.If you cant use the stock gasket there you can use window seal/glue to this,so you dont get any loose silicone gasket in the engine.

OIL: I use Shell helix ultra Racing 10w/60 with good result.Use the best you can affort,dont save money on using cheap oil.Thats not gona pay off..........

But no oil is gona help if you have a oileak in the engine.

Edited October 10, 2006 by rydning

[Artie]

I did also use anaerobic gasket in my thermostat housing,and I have a smal leak there also now(may be I`m cursed to not use anaerobic)....So I gona stick with Loctite red silicone gasket in the future to seal oil and water,thats the one I have best and perfect result with.And I dont use silicon to seal the intake.If you cant use the stock gasket there you can use window seal/glue to this,so you dont get any loose silicone gasket in the engine.

OIL: I use Shell helix ultra Racing 10w/60 with good result.Use the best you can affort,dont save money on using cheap oil.Thats not gona pay off..........

But no oil is gona help if you have a oileak in the engine.

Well, my assumption would be that any loose silicone in the engine would just eventually get burned in combustion. Also, I use permatex "the right stuff" silicone sealant for oil and water passages/pumps. I have used this sealant for years on rotary engine oil pans and pumps(these engines are prone to eating gaskets and sealants) with very good result!

Art