54 replies to this topic

[Spider]

I know you've had it on the RR and probably spent a few bob there, but that looks to me like it's running quite rich. I can't see a different heat range plug helping with that.

[69Cooper]

Thanks Moke Spider, that's what someone else has said, suspected wrong idle jet, might need to re-visit my tuner!!!!!!!!

[Dusky]

Does it "burble" under heavy Braking?

[69Cooper]

Don't know, never checked, why?

[69Cooper]

Quick Update, got the NGK PMR7A's, swopped them over and it's alive again, but for how long only time will tell

[Dusky]

Webers can overfuel a lot when breaking/ heavy acceleration if there is too much clearance between the bronze choke mechanism barrels and the housing. A common fault

[69Cooper]

Hi All,

 

I know it's been quite a long time since I started this thread but still having issues, so much so I'm thinking of removing the 7 Port Head, really frustrated with it.

 

Update:

I took it to a different Rolling Road (Dyno Hub to be precise) had a Lambda socket fitted to the exhaust so we could get better AFR readings, took a little while to get everything set up and the jets where changed, it was quite a while ago, June last year and haven't had much chance to use it too much.

 

But a month ago went to Cadwell for a track day, car ran fine all day until mid afternoon when it developed a slight misfire, but only noticeable on cool down laps, not with full acceleration, I wasn't sure why, so last weekend I was checking everything out before another track day on Tuesday this week (@ Brands) I decided to have a look at the plugs but I have to remove the carbs to do this!!!! I did check with the Tuner that this would be ok to do and he said yes as I wouldn't be going near the jets or adjusters, all I needed to do was balance them afterwards and now that I have a proper balancer that isn't an issue.

 

So when I took the plugs out they were all black again, so cleaned them all up, put it all back together went for a test drive and all was good.

 

At brands on Tuesday I had the exact same thing as @ Cadwell, mid afternoon developed a bit of a misfire, then last thing when I needed to get it on my trailer has issues starting it again, managed to get it going after quite an effort.

 

So I got back in touch with the Tuner guy to explain and his response was that maybe the plugs are nackered, can't quite understand this? or to go injection, don't like the idea of having to through another load of money at it, looks like that would be about £2k.

 

All in all this has been a very painful and costly experience and really don't know what t do?

 

I'm sure there must be quite a few people out there running very similar setups but are not having my issues!

 

Very frustrated as I can only go by what the tuners are telling me and I don't know if they are telling me the correct things, the evidence would say other wise.

 

I did speak to a guy at the track that was running a very Rare UniPower GT (Mini based Fiberglass GT) who recommended some one else, but do I really need to go to yet another tuner to get it fixed.

 

Anyone got any advise? apart from a can of petrol and a box of matches!

[nicklouse]

have you tried a hotter plug? a 6 rather than a 7 ?

[dotmatrix]

dont know much about 7-port heads or webers, but have been to tuners that did not bother with part throttle or idle mixture as my car was mainly used for racing, but this proved a problem as on the transport routes and while waiting to start it would foule the plugs. eventually found a tuner guy that knows what he is doing and checks everything, so using him from now on.

[69Cooper]

Can't seem to find one in a 10mm size plug, but could be worth a try