Decoke yes or no

Technical Area Routine Servicing
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  1. My model of MX-5 is: __mk2 California
  2. I’m based near: __blandford forum
  3. I’m looking for technical help or recommendations on: __decoke engine
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Have the engine Terracleaned. As a MX5 Owners Club Member you can get a discount. Look on line for your nearest garage that does it. Costs about £100. Cleans engine, intake and exhaust from carbon deposits. Lowers emissions output and improves MPG.

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For the quickest result, yes.

Or cheaper, a couple of tankfuls of V-Power and a couple of Italian tune-ups on the second tank.
:grinning:

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Hey Richard, what do you mean here by a couple of Italian tune-ups? And also would V-power solve carbon deposit problems?

Cheers,
Nathan.

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And does Terracleaning (or Terrace C as my autocorrect wants to call it) work? Is there any measured evidence to support it, or is it snake oil?

Italian tune ups = giving a motor a good work out, have blast to burn out the cobwebs.

V power (as well as other fuels ) contain cleaning additives that help prevent build ups. May also clean where build ups have already occurred due to using cheaper fuel with less effective additives (as a generalisation, Tesco momentum has been shown to cause more build ups than a branded alternative).

Hard to imagine any mild chemical addressing serious carbon build ups though. Walnut blasting is the answer for direct injection engines, like my b58 BMW unit. Not sure what areas on the MX5 are prone to coke?

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I’ve seen a few good demonstrations of terraclean online by taking before and after emissions readings etc which shows it performing very well. Interesting chemistry behind it as well, lots of detailed information on the web so certainly not “snake oil”.

@McTrucky can you link me to the info re Tesco Momentum causing coke build up? I use that fuel pretty much exclusively so would be interesting to read about that!

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There was a comprehensive test done by Millbrook that was published on line, but has since been taken down. Google Millbrook Tesco Petrol Test and you will find it. If I could attach a file here I would upload it, but I hope this link takes you to a copy.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://f30.bimmerpost.com/forums/attachment.php%3Fattachmentid%3D1460676%26d%3D1468877098&ved=2ahUKEwjjpsXfuP3rAhUGhlwKHaj0BjoQFjABegQIBRAB&usg=AOvVaw1wMJY8Cv2jLjtHEuxJ50E-

There is a lot of reading…

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Thanks very much for that :slight_smile: I work in automotive so am used to long monotonous test reports!!

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No worries.
It was a few years ago, and formulations may have changed; but it reinforces my view that sticking to one brand of fuel is worse than regularly swapping brands - which means the effect of weakness in one brand’s offering does not accumulate and strengths can all be exploited. It is rare for me to have more than a couple of tank fulls in a row from the same place.

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That does make for interesting reading, very basic summary being that fuel consumption for momentum was marginally worse than standard 95, or either fuels from “a competitor”, and a similar story for carbon deposits.

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This topic got me pondering.
I’m all for a clean and efficient engine but wonder, does mileage play a part?
My NB has average mileage for it’s year but it’s 21years young.
Could removing and carbon build up possibly have a detrimental effect?
Could it affect compression or create rough running?
The only time I’ve ever attempted this was on an old MK1 Ford XR2. I used Red-Ex in a tankful of petrol and it never ran right again. That experience makes me wary.

Cheers,
Guy

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Going back many years I did many a decoke on 60s, 70s and 80s cars, not to mention more than a bit of porting work with the grinder. They were much simpler engine designs in those days in those days, of course, so doing one over a weekend was easy. Er, no, RedEx was never a substitute for a ‘proper’ decoke and valve grind. The big benefit of this work was restored compression as the valves always needed grinding in and they always ran far better afterwards. The deposits in the combustion chambers and the burned valve seats was a consequence of the various compounds in leaded petrol. Decokes seem to have faded away with modern engines, materials and unleaded fuel. With reduced combustion chamber deposits, I suspect the only real reason a cylinder head needs removal these days is if compression is low (easily checked) and the valves and seats need work or valve guides need replacement. I’d always make sure the valves were reseated should a head ever be removed for any reason.
JS

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