dixon Posted September 25, 2007 Report Posted September 25, 2007 Hi alll... bit of help required. will try and explain the best i can.... I recently fitted a fr32 cam...i was expecting it to be a slight bit slugish... but it is very bad timed it all up properly .. today i have been playing with the carb... as it wasnt idling properly and checked all the jets.. .with the haynes manual... the jets that are on it are smaller than the ones that are recomended by the haynes manual.. especially the idle jet.. tried slight turning the idle jet when running and idle seems to pick up alot.. so i presume there not big enough,, can anyone shed any light on the issue thanlks... dixon p,s, I think all the jets was around 10 smaller than the one haynes suggestgs.... i have also raised the floats as they was currently very low... and seems to improoved it slightly. .. timing is currntly set to around the 3rd mark from TDC...
Supercharged Nat Posted September 25, 2007 Report Posted September 25, 2007 ok firstly what engine is it on, and what size is that engine? then what size are your idle jets? if turning out the mixture srew helps, then leave it out. (it how your supposed to tune a carb anyways, its called finding lean best idle). you turn the mixture screw until the engine runs its fastest and smoothest. then reduce the speed screw till its idling at the correct speed. note when upgrading cams, you need a slightly higher idle speed too (due to the nature of the cam)
Copey Posted September 25, 2007 Report Posted September 25, 2007 i have a 32/36 webber on my 2.0 pinto, fastroad cam, head skim, and it just wont work well at all, had a go myself, then my dads mate who works for bmw and has been fixin cars since he was 12 and he said "yeah its just not happenin, just not compatible" said he has got it the best he can, but its shit, no real response and it wont idle when its cold, at all, so my solution is a 38DGAS...when it gets delivered
dixon Posted September 26, 2007 Author Report Posted September 26, 2007 cant remmbr what size te jets where but shall look today.... it wast the idle screw it brought back abit it was the idle jet... so i cant leave it out a little bit.............. it is a 2l pinto in capri its starting to run better and idles now it just boggs down alot when quick pull offs... and still revs are jumping up and down at idle....
dixon Posted September 27, 2007 Author Report Posted September 27, 2007 the size of the idle jet was 45..
Conor Posted September 27, 2007 Report Posted September 27, 2007 If the revs are up and down at idle, usually there's play in the throttle spindle where it goes into the carb body and it drags in air... Basically, assuming the carb is OK and the tubes in the middle of the barrels have no play and there's no play in the throttle spindle...AND THAT YOU'VE USED THE PROPER TDC MARK ON THE CRANK PULLEY (there's two types of timing mark and people get it wrong meaning the cam timing is out. It'll run but like shit.)..... The fuel mix is leaning out big style once you get above 2500 RPM. It's something you need to do on a rolling road to get the best result. Mine was down to 0.01% on wide open throttle by the time it reached 5000RPM before I had it rejetted. You want to be aiming for around 4-5%. Anyway, quickest way to jet it is to whip the top off the carb. Remove the jets in the bottom of the float chamber and run a 0.5mm drill bit through them. That'll be virtually spot on (runs slightly rich under wide open throttle) for a Pinto running a FR31/32 with K&N filter. Run on Super Unleaded and start with a base timing of 10 degrees BTDC for the ignition timing.
Supercharged Nat Posted September 27, 2007 Report Posted September 27, 2007 run a 0.5mm drill bit through them dont you mean a 1.5mm bit? std sizes would be 130 & 135 (ie. 1.35 and 1.30mm) revs up and down at idle sounds like a possible air leak, did you remove the carb or inlet manifold when fitting your cam? recheck all pipe connections to the intake side of the engine, all must be tight and good condtion.
dixon Posted September 29, 2007 Author Report Posted September 29, 2007 drilled them out to 1.55 and seems to be running alot better.... just need to drill the pump jet slightly any one have any idea where they are......... as cant find it
Supercharged Nat Posted September 29, 2007 Report Posted September 29, 2007 pump jet is that kind of shooter/ squirter thats between the two barrels. it has a nozzle pointing down each barrel. the holes to drill are the tiny (0.5mm) outlets. its made of alloy and has a brass screw holding it through the center with two copper washers.
Conor Posted September 30, 2007 Report Posted September 30, 2007 run a 0.5mm drill bit through them dont you mean a 1.5mm bit? std sizes would be 130 & 135 (ie. 1.35 and 1.30mm) . LOL, yeah. Glad someone is awake.
Conor Posted September 30, 2007 Report Posted September 30, 2007 drilled them out to 1.55 and seems to be running alot better.... just need to drill the pump jet slightly any one have any idea where they are......... as cant find it You don't need to drill them out. Most of them are just blocked and need a clean out with a fine needle.
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