Is Redex safe to use in the Renesis?

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Is Redex safe to use in the Renesis?

Post by warpc0il » Fri Oct 20, 2017 11:27 am

The previous answer to this question has always been a simple "No" based on this history...

Redex used to be a single product, originally sold alongside petrol pumps, by the shot, as an upper cylinder lubricant.

Later it was sold in bottles over the counter.

The Redex company was bought by Holts and they continued to make the original product, that was safe for rotary engines, and was recommend by some RX7 specialists.

However, around 2006, Holts changed the formula, making it unsuitable for rotary engines and the RX8 Owners Club had a letter from Holts making this clear.

Over the last few years Holts had extended the Redex brand to include a whole range of fuel additives and related products, such as an octane enhancer, which they do consider as safe for rotary engines though they admit that it has not been tested on the Renesis.

The latest version of the Redex Upper Cylinder Lubricant - what what most people recognise as "Redex" - remains unsafe for rotary engines.

I've just done some digging regarding the Redex letter from Holts.

It was received by the original OC Spin Doctor ( my predecessor - also named Dave) who scanned it and posted on to the forum.

Unfortunately, Dave later had a falling out with the then OC Committee and not only resigned his position but abused his forum access powers to delete any and all of his existing posts, plus any other posts where he had been quoted.

This was the situation I inherited when I took over the role in 2010 and we scrabbled around recreating the FAQ's etc.

Some members had downloaded stuff from the forum and (a least one) said that they had a copy of the scanned letter - which I remember reading but hadn't downloaded. However, this has yet to resurface.

The letter itself didn't go into much detail, it just stated that the formulation of "Redex" (then the only product sold under that brand) had been changed the previous year and that it was no longer suitable for use in rotary engines.

The current range of Redex branded products not longer includes the UCL, so this debate may be mute unless someone comes across a bottle in their garage or some New Old Stock being sold off e.g. ... 2810389160

There was also an oil system treatment flush sold under the Redex brand. This and ALL OIL FLUSHES are unsafe for the Renesis engine because over 40% of the oil capacity is not drained when the oil is changed, mainly due to having dual oil coolers and their associated pipework.

If you've just bought an RX8 and want to be sure that the engine oil is as good and clean as possible then change the oil twice, running the engine (better still, driving the car) for at least 20 minutes in between, replacing the filter on the second change.

The good thing is that the design of the rotary engine means that there are no piston rings for combustion by-products to leak passed and contaminate the sump oil. It is the residue of these by-products that oil flushes were designed to remove.

There was also a Lead Replacement additive sold under the Redex brand. This was supposed to slightly increase the octane rating of the fuel but mainly it provides a replacement for the lubrication properties that lead used to provide to the intake and exhaust poppet valve seats of piston engines.

Owners of classic cars were concerned that valve seat damage would be caused when unleaded fuel was introduced. Some classic cars could be retro-fitted with hardened valve seats to prevent damage, while others chose to use an additive to compensate.

Needless to say, the Renesis engine doesn't have poppet valves and therefore such an additive is irrelevant.
These users thanked the author warpc0il for the post (total 2):
mrspiller (Fri Oct 20, 2017 12:07 pm) • Shagrington (Fri Oct 20, 2017 10:36 pm)
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