Change to synthetic oil or stick with mineral for old car

[kylie]

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 to give you an idea on engine wear inside. So ideally I need something just as thick or something much better for engine protection and not going to burn up easily without puffs of black smoke. 10W60 too thin?

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,
Kylie
89 Turbo (Carbed)

[anonymous-user]

A personal view. If it ain't bust, don't fix it. Stick with the same old.

There are stories doing the rounds about the dangers of a switch to synthetic later in an engine's life. In particular, some say the lovely synthetic can dislodge all sorts of old gunk and grunge which is coated around your engine causing it to clog narrow oilways and lead to early destruction of the engine. Can't comment on whether this is true or false but personally I consider it a risk not worth running. I favour slightly more frequent oil changes as the engine gets older but using the same type of oil as before.

Edit: I thought Mobil 1 synthetic 0w-40 was the oil of choice for 1980s Esprits?

Edited by 5 USA on Saturday 30th September 00:10

[ErnestM]

I would say stick with the old stuff until/unless you have a rebuild. At that point (provided the rebuild is a complete one - rings, etc) you can switch to synthetic.

ErnestM

[kylie]

Sounds great to me. Will stick with the old stuff.. Thanks

[falcemob]

Why are the guides due to be done at 78K, are they worn or has someone told you this is the time they need doing?

Edited by falcemob on Saturday 30th September 07:33

[cross-eyed-twit]

yeah, full rebuild switch to 10w60 synthetic, its the recommended oil for my S4 (same engine 910, right?) The sticker on the boot lid says so, Lotus recommends castrol RS 10w60, now I think its called something else, bleedin' marketing people...

My car has 83000 and still goes well, don't know about worn bits though there are bound to be the way I drive

[lotusse89]

falcemob said:

Why are the guides due to be done at 78K, are they worn or has someone told you this is the time they need doing?

Edited by falcemob on Saturday 30th September 07:33

BTW I'm in the middle of a rebuild and my guides were fine at 74,000 miles. I would have thought the silicon-bronze exhaust guides would have worn faster.

[kylie]

lotusse89 said:

falcemob said:

Why are the guides due to be done at 78K, are they worn or has someone told you this is the time they need doing?

Edited by falcemob on Saturday 30th September 07:33

BTW I'm in the middle of a rebuild and my guides were fine at 74,000 miles. I would have thought the silicon-bronze exhaust guides would have worn faster.

Mmmm this is intersting and possibly saving me $$$ in the near future anyway. Before I got my carbs cleaned and rebuilt it was a little smokey on start-up and running a little rich but not burning oil. I was told that one of the reasons was a need to replace the guides by the local lotus mech. I decided to get the carbs done first as it was clear that it needed a tune-up. After this no more smoke on start-up. Therefore I may not have to get the guides done then in the near future then?

So how will I know an engine rebuild or guides need doing? Look for blue smoke next time? Increased oil consumption for regular driving?

[falcemob]

kylie said:

So how will I know an engine rebuild or guides need doing? Look for blue smoke next time? Increased oil consumption for regular driving?

I'm not sure what engine is fitted to these cars but as a general engineering guide I would have thought you would be looking at double the present mileage for a rebuild unless you are racing the car.
General signs would be oiled plugs, excessive oil consumption, blue smoke. These can also be linked to worn pistons/rings etc. It just isn't worth pulling the engine apart just to check the valve guides, just wait until you have a problem that requires a partial or full strip down.
As someone said earlier, "If it ain't broke, don't fix it".

[lotusse89]

falcemob said:

kylie said:

So how will I know an engine rebuild or guides need doing? Look for blue smoke next time? Increased oil consumption for regular driving?

I'm not sure what engine is fitted to these cars but as a general engineering guide I would have thought you would be looking at double the present mileage for a rebuild unless you are racing the car.
General signs would be oiled plugs, excessive oil consumption, blue smoke. These can also be linked to worn pistons/rings etc. It just isn't worth pulling the engine apart just to check the valve guides, just wait until you have a problem that requires a partial or full strip down.
As someone said earlier, "If it ain't broke, don't fix it".

The engine is a 910 2.2L 4 cylinder with turbo. They do go over 100,000 miles easily. However, many seem to have a problem around 74,000 miles or so. It's a highly stressed little 4 cylinder, which uses some interesting technologies for cylinders (forged aluminum with Nikasil plating), and valve guides (silicon-bronze exhaust), and sodium filled exhaust valves. These are all relatively soft. The silicon-bronze valve guides in Ferrari V8's are known to wear out much faster than sintered steel. But they do transfer heat much faster than steel or cast iron.

The Esprit 910 engine also requires a large amount of disassembly just to check and shim the valves fairly often. Then when you add that its a 15 yeal old engine, not driven as much as a daily driver, you have to replace seals and o-rings.

In the case of my 74,000 mile engine, it was running fine and made good power, but the compression was on the low side (even for my mile high altitude) and the connecting rod bearings were starting to wear. I also had a problem with the belt wandering towards the end of the cams. So I decided to do a preventative rebuild before anything major happened.

IMO, waiting until something really goes wrong with these engines is the wrong thing to do. The parts are fairly expensive (pistons, cylinders, head, block, and crank) and not worth destroying, trying to wring out ever last mile.

[kylie]

Agreed, I like to do the preventative maintenance too, but if told to hold off for a while for something major like this I will.
I had it planned for next year anyway. Will get another compression check too. Last one was done 6000miles ago.

Edited by kylie on Sunday 1st October 20:47

[anonymous-user]

falcemob said:

....General signs would be oiled plugs, excessive oil consumption, blue smoke. These can also be linked to worn pistons/rings etc. It just isn't worth pulling the engine apart just to check the valve guides, just wait until you have a problem that requires a partial or full strip down.
As someone said earlier, "If it ain't broke, don't fix it".

For sure, blue smoke = worn engine. The question is "how's the oil getting into the cylinders?". With worn bores/piston rings you'll get blue smoke all the time. Even without much smoke someone driving behind you in a convertible or with windows open should be able to smell the oil burning. With worn valve guides the blue smoke is often most obvious when the engine is first started. That's because while you're parked oil has a chance to trickle down the valves so there's more in the cylinder when you first start than when the engine's running normally.
Broadly speaking the first thing to do is monitor yopur oil consumption. If it's increasing the next thing is a compression test. Poor compression is a sure sign that something's not right and the test will tell you which cylinder or cylinders are at fault. Unless you have a very specific and limited cylinder head issue a total rebuild is often the best long term solution.

Edited by 5 USA on Sunday 1st October 20:52