Leven Fuel Cap
Leven Fuel Cap
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Discussion

Cats

Original Poster:

1,000 posts

190 months

Sunday 24th January 2010
quotequote all
Hi Folks - I'd appreciate an opinion.
I've had Trevor now for 4 months and had no issues whatsoever, just a huge stupid grin all the time I get in it.
I thought I would buy a bling Leven fuel cap. Put it on the car the other night took him for a quick blast and noticed that the idle was staying a little higher than usual before settling down. I didn't think too much more about but thought it was probably coincidental.
Being a lovely day today I thought I would go for a blat down to the coast, as you do. Filled him up with V Power and off we went.
I have noticed before that I used to get the odd "boing" from the fuel tank but certainly no running issues. Today I noticed that the "boings" were far more regular and when cruising at a steady speed (any speed) the engine was holding back with what would appear to be a fuel starvation sympton. As soon as I accelerated the car would pick up with no problems and the lumpiness would disappear for a few more miles but would happen again when going steady.
Obviously I thought that the new cap had something to do with this so I removed it completely and the issue disappeared. I put it back on and the problem happened again so obviously the new cap is the cause. Ultimately I put the cap on but didn't turn it fully home and this seemed to be ok.
My worry is that would this be safe if the worst happened in an accident and the car turned over?
Having compared the Leven cap with the old one the latter appears to have a notch in the rubber washer whereas the Leven unit does not.
Having read about the issues that some Chimaeras have with fuel tank breathers and the carbon can, I understand that many owners resort to not fully tightening their fuel cap.
My questions are :-
a)Have other people who have bought a Leven cap suffered similarly or have I got the wrong cap?
b) Do I need to get the breather assembly checked out?
c) Does it really matter as I guess the old cap was venting with a 10 year old washer anyway. I would prefer to tighten the cap fully as I would have thought that this is the way it should be.
Any thoughts or opinions would be greatly received.
Thanks
Cats

biper

2,095 posts

233 months

Monday 25th January 2010
quotequote all
I had a simular thing happen yesterday. I went to fill up and when I opened the filler cap there was a huge whooshing out of the tank, it was quite concerning as this had never happened before. I could have sought of understood it if the weather was hot. Or is it becuase the car has been stood for two or three weeks.
biper

V8 GRF

7,298 posts

226 months

Monday 25th January 2010
quotequote all
The Leven cap does seal very well and suggestions have been made in the past to cut a small nick in the seal ring or drill a small hole in the neck to allow the tank to vent. I think you'd have more things to worry about than a little bit of dripping fuel if you turned the car over....


LevenTech

207 posts

286 months

Monday 25th January 2010
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The official line on fuel caps is that they must seal to prevent fuel vapour releasing in to the atmosphere. The car has a system to capture the fumes and burn them in a controlled way. How this works is well documented so I will not go in to it again. On TVR's this system frequently fails resulting in the petrol system pulling a vacuum. The 'bong' is the fuel tank springing back to shape when the cap is released. There are options 1) new venting system costing lots of money. 2) slightly vent the cap. 3) Make other modifications. We suggest that owners with this problem vent the cap as a quick easy solution. On early caps (PC1) notch the gasket, on later cars (PC3) notch the sealing ring. We are talking small notches here just to let a little air in. If any owners have one of our caps and need to know how to vent it plaese call us.

Hedgehopper

1,541 posts

260 months

Monday 25th January 2010
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If your fuel tank is suffering from negative vacuum I suggest you don't ignore it. Years ago my Opel Manta tank collapsed (it looked like someone had jumped on it) after having the same problem, the only previous clue to that was a reduction in top speed.

Badmutha

656 posts

209 months

Monday 25th January 2010
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I also have a Leven cap and if I run with less than 1/4 tank of fuel the revs will keep surging up to 1500 then back to 900 again at idle. When I lift off when driving I can feel the engine pulling more than it should so it is still happening when the car is moving, although it doesn't seem to be surging. The problem is solved when I release the cap. I'm now going to 'nick' it!

Edited by Badmutha on Monday 25th January 17:10

Cats

Original Poster:

1,000 posts

190 months

Monday 25th January 2010
quotequote all
Thanks guys that all makes sense
Cats

fog66

368 posts

214 months

Monday 25th January 2010
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I have the leven cap and have had no discernable issues, however it would be useful if we could get a picture of one that has been modified. Anyone feeling in a David Bailey mood?

rigga

8,783 posts

217 months

Monday 25th January 2010
quotequote all
fog66 said:
I have the leven cap and have had no discernable issues, however it would be useful if we could get a picture of one that has been modified. Anyone feeling in a David Bailey mood?
Yea no issues as yet here,but be good to know whats the cure should anything start happening.

cjwbrown

10 posts

92 months

Tuesday 10th January 2023
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Hi all Im looking for a replacement fuel cap for my 97 griff 500. Im located in new zealand and although I ordered one from the UK during Covid it never arrived and the subsequent emails I sent were not answered ( still had it charged to my CC though smile
Is it standrad from another car . What is the leven one and am i able to buy one or something similar down here in NZ
Hope someone can help


regards

Chris Brown

Belle427

10,784 posts

249 months

Tuesday 10th January 2023
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There isn't anything special about it to my knowledge.
Are you able to find a generic non locking one at parts stores with you?

cjwbrown

10 posts

92 months

Tuesday 10th January 2023
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Hi

Im trying . Ill have another go tomorrow.
thanks

Jordie Barretts sock

6,018 posts

35 months

Tuesday 10th January 2023
quotequote all
Hi Chris, i bought one of these for my Chimaera.

https://www.racetechdirect.co.uk/car-parts/car-car...

They do the standard black tin one as well I think.

If a fellow Kiwi needs a hand, let me know.

Edited by Jordie Barretts sock on Tuesday 10th January 11:58

Wiltshire Lad

307 posts

85 months

Tuesday 10th January 2023
quotequote all
Jordie Barretts sock said:
Hi Chris, i bought one of these for my Chimaera.

https://www.racetechdirect.co.uk/car-parts/car-car...

They do the standard black tin one as well I think.

If a fellow Kiwi needs a hand, let me know.

Edited by Jordie Barretts sock on Tuesday 10th January 11:58
Bought the same item for mine - no problems.

cjwbrown

10 posts

92 months

Tuesday 10th January 2023
quotequote all
Thanks Jordie

Its a long way from here to there and i did buy one but it never arrived ( not from Racetec but tvr parts) I was hoping to find something here in NZ

Ill keep hunting


Cheers
Chris

Jordie Barretts sock

6,018 posts

35 months

Tuesday 10th January 2023
quotequote all
Happy to post it/DHL it to you from up here bro.

Fenderer

137 posts

118 months

Thursday 12th January 2023
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I had loads of issues like this with mine. People used to drill a small hole in the cap which is a nasty fix.

A better one is to junk the carbon canister system which doesn't work properly anyway and at the end of the pipe that inlets into the canister box, put in a small bleed valve which vents to atmosphere. You can then blank off the vacuum line to the plenum and have a complete seal on petrol tank cap which is what you are supposed to have to prevent spillage if the car turns over plus it won't fill your boot with petrol fumes as mine kept doing.

PabloGee

680 posts

36 months

Tuesday 21st February 2023
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Interesting to read about the concerns if the car flips over (I'm really hoping I never experience that).
Mine has the original cap, and I replaced the cork seal with a new cork seal.

I don't get any smell of fuel in the car, and no issues with starvation or popping (it would concern me quite a lot if I was).
I wouldn't say it's a perfect seal, but it's surely no different from drilling holes and cutting nicks?