Temple Cloud Posted March 20, 2022 Share Posted March 20, 2022 I've just got my first Caterham with a 1.7l Ford Xflow engine producing the usual supposed 135bhp and absolutely love it.However, not that I'm an expert in these things, I think I'm hearing the occasional high frequency pinking sound, though it may be related to something totally different. I haven't driven a carburettored car for about 40 years and never driven an xflow before so I'm not used to the sounds they make.I've been using 95 RON fuel but I'm thinking it may be better to go up to 97 instead and wondered what other's opinions were on the matter.Any views would be most welcome. Thanks Link to comment Share on other sites More sharing options...
GulfSeven Posted March 20, 2022 Share Posted March 20, 2022 I can't help about the octane rating, but Caterham recommends super-unleaded in a x/flow for the lower ethanol content:https://www.caterhamcars.com/en/latest/can-i-use-e10-petrol-in-my-caterham Link to comment Share on other sites More sharing options...
GaryK Posted March 20, 2022 Share Posted March 20, 2022 I use Esso or Tesco Super if I can't get it. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 20, 2022 Member Share Posted March 20, 2022 A stethoscope can be very helpful in locating unusual noises.Jonathan Link to comment Share on other sites More sharing options...
Temple Cloud Posted March 20, 2022 Author Share Posted March 20, 2022 Thanks for that. Really useful. My local garage has SU so I'll use that from now even though I'll need a mortgage to pay for it... Link to comment Share on other sites More sharing options...
OldAndrewE Posted March 20, 2022 Share Posted March 20, 2022 Agree with what has been said above. I use Shell V power in my classic Mini and will be using it in the X flow when it is back together. There are 2 issues, both mentioned above. There is the ethanol issue mentioned by GulfSeven above and for that reason alone it is worth using Super Unleaded.There is also the pinking/pre-ignition issue and Super Unleaded will certainly help in this. This will be governed by things like compression ratio and ignition timing. Using super unleaded will allow you to get the ignition properly set up for performance rather than be set at a compromise to allow use of standard unleaded.From your other post you are obviously after performance from the car and to save a bit of money by buying cheaper fuel would be seem to go against this.Enjoy the car Link to comment Share on other sites More sharing options...
East Kent AR Posted March 20, 2022 Share Posted March 20, 2022 As I understand it, 95 Ron has 10% Ethanol, while Super Unleaded being 98/99 Ron has 5%. I would only ever use Super Unleaded in your 7. The 10% Ethanol will rot all your rubber seals. Piers Link to comment Share on other sites More sharing options...
john milner Posted March 20, 2022 Share Posted March 20, 2022 To save money it is worth crunching the numbers on a bottled octane booster. My guess is that it will be more expensive but you may get lucky.Demon Tweeks Link to comment Share on other sites More sharing options...
GulfSeven Posted March 20, 2022 Share Posted March 20, 2022 I use Esso or Tesco Super if I can't get it.Same. We're in the right location for E0, and conveniently get 2p/l off at our local Esso too. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 20, 2022 Member Share Posted March 20, 2022 10% ethanol in petrol shouldn't cause problems to rubber or any other polymer components recently designed for use in cars. Resistance to this has been in the standards for a few decades.But:1 Sevens might contain custom or DIY parts that don't meet those standards. There is one suggested example of this.2 Sevens last a long time, and fuel line components will wear out and should be inspected and considered for scheduled replacement.Jonathan Link to comment Share on other sites More sharing options...
East Kent AR Posted March 20, 2022 Share Posted March 20, 2022 Jonathan - Your right about modern engines, but the Ford Xflow cannot be considered as modern. It will have twin Webber 40 DCOE's in Super Sprint form.Piers Link to comment Share on other sites More sharing options...
Beagler Posted March 20, 2022 Share Posted March 20, 2022 Is the ignition timing correct. Is it electronic. Are the plugs the correct grade/heat range. Is the fuel mixture weak causing overheating. Is there excessive carbon buildup in the engine ( a borescope down the plug hole would help) there aare quite a few reasons for pinking.but as you say a change of fuel may solve it. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 20, 2022 Member Share Posted March 20, 2022 "... but the Ford Xflow cannot be considered as modern. It will have twin Webber 40 DCOE's in Super Sprint form."Yes. Do carburettor service kits now contain E10 resistant rings, seals etc?Jonathan Link to comment Share on other sites More sharing options...
rkeywood Posted March 20, 2022 Share Posted March 20, 2022 I stick with zero ethanol Esso Super but did ethanol proof things a while back. The Weber kits were ethanol resistant when I had my carbs refurb'd 3 years ago. Even on E5 Super I'd still be inclined to use an additive like Millers EPS if carbs and fuel lines haven't been changed. I'd also think about a lead substitute as well unless hardened valve seats are fitted. Classic Valvemaster does the job and includes ethanol protection so kills 2 birds with one stone. Link to comment Share on other sites More sharing options...
Temple Cloud Posted March 20, 2022 Author Share Posted March 20, 2022 Yes, I'm now sticking with 97 RON petrol. Having listened to the sound again it's not actually pinking at all but a lose metal clip vibrating over certain RPM lol.That said I'll get the guys at Interpro to take a look at the tune and also convert her to electronic ignition which I seem to get the feeling will help too.One interesting thing however happened today on a run down towards Salisbury, going up a long hill on a three lane road (2 my side, 1 the other), I soon ran out of puff at around 80mph and the sound I got was like I was having fuel starvation. This cleared once I was back on the level. Don't know if this is something that is common to 7s....But slightly odd... Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 20, 2022 Member Share Posted March 20, 2022 There are several reports of fuel starvation, with problems with the breather tube probably most common. (And there's a Workshop Notice.)Usual first investigation is to keep the engine running, remove the filler cap, and listen for an intake of air and improved running.Jonathan Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted March 20, 2022 Area Representative Share Posted March 20, 2022 I think I am correct in saying that if it is a factory build or kit Super Sprint with 135 bhp, then I would expect it to have electronic ignition as standard. My 1985 Super Sprint was fitted with it as standard. Someone will be along who knows.Losing power going up a hill sounds like fuel starvation. I would have a look at the fuel pump and if it still has the original fitted, change it to a new one. Maybe the float levels in the Webber's, but getting beyond my knowledge.Good luck finding the issue.Piers Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted March 21, 2022 Share Posted March 21, 2022 Depending on the gear you are in and the steepness of the hill, 80mph may be an appropriate maximum speed you can reach. I would say due to the age of the car, 120bhp is probably a more realistic engine output due to wear and tear, so power available at the wheels would only be about 100bhp. At 80mph about 40bhp is needed at the wheels to overcome drag and rolling resistance on a flat surface. An additional 45bhp would be needed to sustain 80mph on an 8% gradient. 85bhp would only be available in an appropriate gear above about 5000RPM, which can probably only be achieved in 4th gear. Link to comment Share on other sites More sharing options...
Temple Cloud Posted March 21, 2022 Author Share Posted March 21, 2022 Thanks for all the info. I must say this is turning out to be a brilliant forum with such fast and knowledgeable responses.I'll certainly investigate the breather tube and I'm quickly coming to the conclusion from lots of posts that the bhp isn't as advertised and is probably much closer to 110 than 135. Hopefully a tune by an expert will take her up a bit but I'm fast becoming more realistic regarding out and out speed....but of course where these cars win hand over foot are the bendy bits. I've never driven a car with such outstanding road holding. And I come from a lifetime with some great sports cars.As an aside and in response to Piers300, as she's a Q plate she's no doubt an enthusiast's build and by the looks of things doesn't have electronic ignition..Thanks again for all the help. Fantastic... Link to comment Share on other sites More sharing options...
rkeywood Posted March 21, 2022 Share Posted March 21, 2022 Does it have a mechanical fuel pump? Link to comment Share on other sites More sharing options...
Temple Cloud Posted March 21, 2022 Author Share Posted March 21, 2022 TBH I have no idea lol. I'll have to check. I really know very little about these Ford engines but am learning Link to comment Share on other sites More sharing options...
rkeywood Posted March 21, 2022 Share Posted March 21, 2022 Just follow the fuel line back from the carbs - if it's a mech' pump then it'll be on the block. If electric then it'll be remote in the engine bay or beside the fuel tank. There'll probably be a filter regulator in the line as well. Where are you based? Link to comment Share on other sites More sharing options...
East Kent AR Posted March 21, 2022 Share Posted March 21, 2022 This is a photo of a factory build 1985 Super Sprint. The electronic ignition unit can be seen under the steering shaft to the left of the air inlet filter. Hope this helps you Piers Link to comment Share on other sites More sharing options...
Temple Cloud Posted March 21, 2022 Author Share Posted March 21, 2022 Thanks for that. I'm having the car put on a rolling road and tuned by a Ford expert next month so I'll be able to ask all these questions and get his advice then but it's great getting all this info so quickly on this forum. There's obviously a great knowledge base to tap out there. Locationwise I'm about ten miles south of Bristol in North Somerset Link to comment Share on other sites More sharing options...
p.mole1 Posted March 29, 2022 Share Posted March 29, 2022 Just a note on E10 fuel for anyone using carburetors. They may require a spot of re jetting as the ethanol can cause lean running. You better off just avoiding it Link to comment Share on other sites More sharing options...
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