Fully synthetic oil versus semi synthetic oil

[Andyf]

My god just seen 5lts for £12.21 + vat, i paid £13.75 for 1 ltr of Castrol power 1, i will be changing to groundsman.

Cheers Ian

Where ?

he posted a follow-up thirty minutes later to say he'd paid £24 coz of p&p

[Andyf]

Synthetic and semi-synthetic both provide better protection at low temperature, which is when most wear is likely to occur, i.e. start up from cold, let alone the tremendous protection that is provided to high speed running engines. .

why is that?

[Warkton Tornado No.1]

The choice of oil that we use is very important. It is always an emotive subject & we tend to have our favourites, not always based upon comparing like for like.

I don't doubt that mixed in the correct ratios for the particular state of tune, it could be proven that vegetable based oils can contribute to producing as much power as the best fully synthetics.

As far as I am aware, there are very few two stroke oils specifically produced for, say, an air cooled 'race' engine, yet I feel that, as it says on the tin, such an oil is likely to fit the parameters my tuned engines require.

Further narrowing of choice is made due to the convenience factor. Shell make an oil for air cooled kart engines but it is hygroscopic, so I personally won't be using that.

By all accounts, I may have been really fortunate that big ends haven't burnt out with the stuff I use, but I have to say that the crankshafts I've used have been built by some of the best in the industry, IMHO. That's not dismissive of any other crankshaft builders, but my choices are often based upon "who I wouldn't use" but I also do check runout etc & have been satisfied with my choices.

However, I listen to other opinions, specifically those that build reliable, powerful engines. I continue to use my choice of oil @ a ratio that I feel appropriate, even though my oil of choice has received negative comments. The negative comments have not made me change my mind concerning the brand, but struck a cord as far as mix ratios. For example, in a reed valve engine that I built & is the most extensively tuned & powerful yet (for me!) the crankcase is ported in line with the rod, so that is IMO an obvious aid to big end lubrication. Yet, more power will need more oil, regardless of that fact. So, I am grateful to have received comments about the oil I use because it was a good reminder of an obvious fact.

Just bear that in mind, whatever your choice. Also, never forget the effect of changing the mix ratios will affect carburation

[Martin s]

I've just bought 20 litres for £73.18 inc. vat & delivery. £3.65 a litre, couldn't refuse.

[Warkton Tornado No.1]

As there are many fans of different oils, Rock's Groundsman in particular, I wondered if anybody was aware of the flashpoint

Rock publish details for their excellent Synthesis (150°C) which I have used on track & my current (Exol) is 140° C. To my mind, those flashpoints are safe & where you need to be for a tuned engine which inevitably will run hotter in producing good power without backing off/retarding ignition to the point where flexibility is lost.

Not all of us choose to run substantially retarded fixed ignitions, or even retarding ignitions. I find that 19 DBTDC is a good compromise on the engines I build for road use.

[steeleyscoot]

I have used Groundsman Semi-Synthetic for some years and had no issues in tuned and standard engines.

This is the cheapest place I found for it currently even when VAT and shipping is taken into account (cheaper than Garfitts who I have used in the past)

https://globalhygiene.com/product/rock- ... -oil-5ltr/

Cheers.

[Warkton Tornado No.1]

As there are many fans of different oils, Rock's Groundsman in particular, I wondered if anybody was aware of the flashpoint

Rock publish details for their excellent Synthesis (150°C) which I have used on track & my current (Exol) is 140° C. To my mind, those flashpoints are safe & where you need to be for a tuned engine which inevitably will run hotter in producing good power without backing off/retarding ignition to the point where flexibility is lost.

Not all of us choose to run substantially retarded fixed ignitions, or even retarding ignitions. I find that 19 DBTDC is a good compromise on the engines I build for road use.

As this thread suddenly came back to life, I thought I'd seek the answer to my own question.....

According to TC Fixings that publish the specification for Groundsman 2 stroke, the flashpoint is only 96°C

[coaster]

I've always bought my Groundsman from Garfitts, gone up in price recently from £4 to £5 a litre but still cheap compared to others. Current prices are £21.09 5l and £79.99 for 20l, + VAT on both of those.

+ 1, must get some more in

[alex_hughes]

I've used the Groundsman for about ten years, covered thousands of miles - I really like it and I didn't have any concerns about using it, though I would say that my engines are modestly tuned.

However, Lambretta Paranoia is now creeping in... what is the relevance of the flash point please?

[Tractorman]

Oil is very much a personal preference thing. I have been using groundsman for several years without problems. I think Rock oil are catching on because it has gone up in price recently.

[Warkton Tornado No.1]

I've used the Groundsman for about ten years, covered thousands of miles - I really like it and I didn't have any concerns about using it, though I would say that my engines are modestly tuned.

However, Lambretta Paranoia is now creeping in... what is the relevance of the flash point please?

I think it's best to consider all the varying aspects of a two stroke oil & suggest that the following link is a good read:

http://www.dragonfly75.com/moto/oil.html

[GRTDKAD]

I’m in the Fully Synthetic minority by the looks of it.
Running a JBT TS1 and a Rayspeed built RB25 it’s not worth scrimping over oil. It just removes a variable if ever one of these engines fails.

Recently took a delivery from Opie Oils of Castrol POWER1 Racing 2T Fully Synthetic: 5x 1litre for £45.80 and £7ish for delivery. Worked out at £10.54 per litre delivered.
Quite happy with that.

[Tractorman]

I’m in the Fully Synthetic minority by the looks of it.
Running a JBT TS1 and a Rayspeed built RB25 it’s not worth scrimping over oil. It just removes a variable if ever one of these engines fails.

Recently took a delivery from Opie Oils of Castrol POWER1 Racing 2T Fully Synthetic: 5x 1litre for £45.80 and £7ish for delivery. Worked out at £10.54 per litre delivered.
Quite happy with that.

Just as riders who spend much less a litre and have no oil related problems are happy.

[Warkton Tornado No.1]

I’m in the Fully Synthetic minority by the looks of it.
Running a JBT TS1 and a Rayspeed built RB25 it’s not worth scrimping over oil. It just removes a variable if ever one of these engines fails.

Recently took a delivery from Opie Oils of Castrol POWER1 Racing 2T Fully Synthetic: 5x 1litre for £45.80 and £7ish for delivery. Worked out at £10.54 per litre delivered.
Quite happy with that.

Just as riders who spend much less a litre and have no oil related problems are happy.

As I understand it, an oil such as Groundsman will be adequate if certain conditions are maintained. Due to factors such as lubricity, shear & flashpoint, the mix ratio will need to be richer than other, fully synthetic oils.

That needs to be factored into any costings applied.

I cannot see any reason for changing from the oil that I use. The engines that I have built & used it in have proved reliable & powerful with no indication of exasperated wear. The oil can be used with ratios as lean as 50:1 in one cast iron bore barrel that comfortably pulls TV200 top gearing which confirms torque, but I'd estimate about 25 BHP if a figure needs to be given. Obviously, the fact that less is used means less trips to fetch it or delivery costs