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Author: Subject: Pinto carb problems
caber

posted on 7/6/18 at 07:31 PM Reply With Quote
Pinto carb problems

Hi,

I just put my Locost back on the road after a couple of years and I have some problems that existed a bit before but are now worse. I am running a standard Pinto 1600 with twin Webber 40s. At the moment I am getting a lot of popping from the exhaust and an occasional backfire particularly when the engine is cold. I am also getting spitting back through cylinder 1 barrel. Generally there is no power below 2000 revs resulting in necessarily rather noisy starts from traffic lights, fun but get a lot of dirty looks in town

I have never been happy with the set up of the carbs and have so far failed to make contact with anyone in or around Edinburgh who really knows how to properly jet or set up webbers!

I do have a set of bike carbs and a manifold that I built but again need help in how to set these up properly. Any ideas what I should do or who has the knowledge to help sort this out? I would really like to have the car more drivable so I can get more use from it!

Thanks in advance

Caber

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JeffHs

posted on 7/6/18 at 08:03 PM Reply With Quote
Start with Dave Andrew's Weber setup. Do a Google search , it's easy to find. That should point you in the right direction re choke and jet sizes. As you've got a problem with just one cylinder check compression and valve clearances. Check your carbs are balanced ideally with a flow meter and check that both chokes on each carb pull the same. Check for air leaks and check float levels too.
You might still have to pay for final setup but it's not too difficult to get most of the way there by a bit of research and fettling.

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briarswood57

posted on 8/6/18 at 07:06 AM Reply With Quote
Hi caber,

By no means an expert but I do have the Haynes Weber manual if that's any help. I am over in sunny Lanark so your welcome to come across and crib a look or I can PDF the relevant pages if that's any good?


Cheers. Andrew

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briarswood57

posted on 8/6/18 at 07:50 AM Reply With Quote
Hi caber,

By no means an expert but I do have the Haynes Weber manual if that's any help. I am over in sunny Lanark so your welcome to come across and crib a look or I can PDF the relevant pages if that's any good?


Cheers. Andrew

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caber

posted on 8/6/18 at 08:39 AM Reply With Quote
Jeff & Andrew

Thanks for the suggestions. The Dave Andrews pages are really interesting and I will check the current sizes accordingly. I have the haynes webber book but last time I looked at it I found it a bit complicated to work out how to size jets for my engine.

The spitting back is very annoying I am not sure what would be causing it but worried it could be a sticky valve. Any thoughts on how I can figure this out?

Cheers

Caber

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JeffHs

posted on 8/6/18 at 10:00 AM Reply With Quote
I think a sticking valve would show up on a compression check. I'd expect #1 cylinder to be lower than the others if you've got a valve problem. Borrow a compression checker. Take all 4 plugs out then check compression on each cylinder individual with wide open throttle at cranking speed on the starter. I can't remember what you should be looking for but it's somewhere in the 150 to 180 psi range. Probably the thing to do first is check your valve clearances.
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snapper

posted on 8/6/18 at 11:54 AM Reply With Quote
If itís been sat for a while itís more than likely gummed up jets.
You need to clean the carbs with carb cleaner.





I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)

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briarswood57

posted on 8/6/18 at 12:26 PM Reply With Quote
Snapper makes a good point. When I bought the Westfield and brought that out of hibernation after 18 years the jets etc were really gummed up. A few hours with the Weber book and the carb cleaner had it all working. At the risk of stating the obvious it's worth getting some clean plastic tubs to put all the carb components in - if you look at the Weber book there are little stuffing balls etc which are easy to loose if you are not careful. That's said a methodical approach and you should be fine - i managed no problem - just take your time.

Other thing to check is that you are getting a decent spark - mine was doing the popping and banging thing pulling away from junctions etc. and was generally objectionable to drive. After a while I discovered the spade connectors on the coil were pretty loose - tightening those up cured the popping and banging in my case. The ignition timing was also out. Have a spare coil you can try.

If you think further investigation re valves and compression is in order then let me know - I have an "eBay special" leakdown kit I have used a few times. Happy to let you have a shot if you think that would help.

Also although mine is the 1600 xflow I'll check the carb jets sizes if you think that would
Provide a comparison.

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JeffHs

posted on 8/6/18 at 01:19 PM Reply With Quote
Further to the cleaning jets etc, I removed the lead plugs from my carbs to clean out all of the transfer tubes. Made new plugs from sheet lead cut with a hole punch than hammered them back in. Weber manual shows this I think.
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caber

posted on 8/6/18 at 05:05 PM Reply With Quote
Folks

Thanks for the replies. Would it be easier to go with bike carbs if so is there anyone near Edinburgh who could assist with this?

Thanks
Caber

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Dingz

posted on 8/6/18 at 10:43 PM Reply With Quote
I would be tempted to sort out what you have rather than starting all over with bike carbs and then setting them up. But if it is a standard engine then I'd be tempted to fit an original manifold and twin choke carb, should be little difference in performance, better economy, won't sound as nice and sell off the Webers, or save them until you have done some engine mods.





Phoned the local ramblers club today, but the bloke who answered just
went on and on.

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briarswood57

posted on 9/6/18 at 09:01 AM Reply With Quote
At the risk of making another obvious point - have you checked the basics including the cam timing - just a thought but if the car has never been right is there a possibility the cam timing is out - couple of teeth on the timing belt would cause some of your symptoms. I had a K series which was slightly out and it took forever to figure out. I think the general assumption I had made was that if the engine runs then the cam timing must be fine - it was only after going back to basics it became obvious.

Also for what it's worth I would stick with what you have and get that running rather than add another dimension of uncertainty. Over in Lanark which is not too far away from you? happy to pop over some time - by no means an expert but sometimes another pair of eyes helps.

Good luck

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caber

posted on 10/6/18 at 08:58 PM Reply With Quote
Well, I had a good lockup day today and found out some stuff.

Cylinder 3 is low compression, about 40 PSI with the other 3 at 109 to 112 PSI. What should I do to investigate the cause?

The plugs were sooty apart from the electrodes which were clean and biscuit colour, I am guessing it is rich but I have a strong spark.

I also pulled the jets on the webbers. I found the following:

Venturis 30
Idle jet 40 F9
Air adjuster 175
Emulsion tube F16
Main Jet 120

Apart from the idle jet none of these match the recommendation in Des Hamil's Pinto book nor the Haynes Webber manual. What are other people running on a 1600 pinto? What should I change?

Thanks for your help folks!

Caber

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mcerd1

posted on 11/6/18 at 08:46 AM Reply With Quote
quote:
Originally posted by caber
Cylinder 3 is low compression, about 40 PSI with the other 3 at 109 to 112 PSI. What should I do to investigate the cause?


doesn't sound good - don't suppose you've got access to a leak down tester ?





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caber

posted on 11/6/18 at 11:39 AM Reply With Quote
I don't have a leak down tester but could improvise using compression tester? What am I looking for? I could squirt some oil in then re-do compression test this should tell me if it is rings or valves wouldn't it?

Caber?

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mcerd1

posted on 11/6/18 at 02:24 PM Reply With Quote
if you just want to trace the leak then adapting the compression tester hose to let you connect it strait to the air line and listen for the leak...

like this:
https://www.youtube.com/watch?v=WgrfT0LFMhc





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Dingz

posted on 26/6/18 at 03:11 PM Reply With Quote
Did you check the valve clearances first?





Phoned the local ramblers club today, but the bloke who answered just
went on and on.

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caber

posted on 26/6/18 at 06:33 PM Reply With Quote
I did the valve clearances less than 300 miles ago. I tried some valve cleaner that has not improved things and got a leak down tester off eBay so will try that at the weekend!
Cheers

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