Bit of advice

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Matty
Posts: 199
Joined: 12 Feb 2022 08:27
Location: East Lancs

Bit of advice

Post by Matty » 12 Feb 2022 21:13

Hi all
New member and new owner! I've a late mk2 1098. The engines only about 100 miles run in after a rebuild by the previous owner. It has a 295 spec head, a minisport inlet manifold, pancake air filter and a 3 branch tubular exhaust manifold with a 2" approx exhaust. Otherwise stock (well apart from an alternator conversion and accuspark ignition). The car starts on the button and idles well but on the move it can hesitate and pop back through the carb. Even when it runs well under load it always feels like it's holding its best back.
Fuel starvation I thought. So today I've replaced the SU type electric fuel pump with a Facit solid state fuel pump and installed an inline filter to keep an eye on things. The end result? The bloody same! The car is being run on 99 octane. Next job is to recipe the car along it's length as its on 6mm copper at the minute to just before the carb which seems a bit small to me. So I'll redo it in 8mm. If the same problem persists then I'm at the carb.
What do you think? I'm new to pre 1980 cars and if anyone thinks I'm barking up the wrong tree any guidance would be much appreciated :D
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Last edited by Matty on 16 Feb 2022 16:42, edited 1 time in total.

Matty
Posts: 199
Joined: 12 Feb 2022 08:27
Location: East Lancs

Re: Bit of advice

Post by Matty » 12 Feb 2022 21:17

This is my A40 by the way. My Dad is (was) a mechanical fitter as am I. My uncle is still a mechanic and they brought me up obsessed with old tin. I've never been able to have my own till now. It's bloody brilliant.
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Matty
Posts: 199
Joined: 12 Feb 2022 08:27
Location: East Lancs

Re: Bit of advice

Post by Matty » 12 Feb 2022 21:17

And on it side for some reason :lol:

exlkrs
Posts: 480
Joined: 05 Dec 2020 16:46
Location: Manc

Re: Bit of advice

Post by exlkrs » 12 Feb 2022 21:22

Hesitation and popping back would lead me to check the ignition timing and the vacuum advance/retard first. Its a modded engine so might want slightly different to the spec. Also the plugs - are they correct and not too hot/cold rated?

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Dave the rave
Posts: 1324
Joined: 09 Nov 2019 20:19
Location: Coventry

Re: Bit of advice

Post by Dave the rave » 12 Feb 2022 21:51

Might the carb need a slightly different needle ?
The 12G295 head IS the the way to go on the small bore A Series too. I'd go high-lift rockers as well. ( One other mod is a Midget 10CC block with the stronger crank ).
Car looks lovely, even in an unoriginal colour, but well suited to it, as is BRG too. And for once, I love the Midget ro-style wheels on A40s. ( As a rule, I despise different wheels on classics.....).

Oh, click on pic and it's right way up......don't ask me why that should be so......
If in doubt....kick the Ruskies OUT ❗

Matty
Posts: 199
Joined: 12 Feb 2022 08:27
Location: East Lancs

Re: Bit of advice

Post by Matty » 12 Feb 2022 21:52

Brilliant, thanks for that. I'm going away for the next few days but on Friday me and Uncle are getting it on the timing lamp so I'll check the plugs while I'm at it. Any recommendations on plug types?

Matty
Posts: 199
Joined: 12 Feb 2022 08:27
Location: East Lancs

Re: Bit of advice

Post by Matty » 12 Feb 2022 21:53

Thanks Dave. Uncle did mention that a different needle might need to be tried. We'll get there, bit by bit :)

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Dave the rave
Posts: 1324
Joined: 09 Nov 2019 20:19
Location: Coventry

Re: Bit of advice

Post by Dave the rave » 12 Feb 2022 21:54

Yep, you will. Endless advice here, all free and answered very quickly..... :D
If in doubt....kick the Ruskies OUT ❗

Matty
Posts: 199
Joined: 12 Feb 2022 08:27
Location: East Lancs

Re: Bit of advice

Post by Matty » 12 Feb 2022 22:05

I was just saying that. Owners clubs have always been a brilliant resource of advice and knowledge. I'm not a massive Internet fan, but forums have just moved the game on. You couldn't have got answers to a question like that at 10pm on a Saturday night in the past. Not unless you were on a works night out with a bunch of old school mechanics :lol:

exlkrs
Posts: 480
Joined: 05 Dec 2020 16:46
Location: Manc

Re: Bit of advice

Post by exlkrs » 12 Feb 2022 22:22

Can't provide you with up to date plug ratings I'm afraid, I'm a dinosaur who sticks with Champion N5 9 or 12! Some young buck or racing guys on here are more conversant with NGK's and their ratings

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