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Last edited by raj; 11-12-2011 at 16:57.
Try a different idle jet, one with the original hard plastic seal in good nick.
Well that is strange. Does the engine rev clean? or does it mis-fire. Is the bakolite spacer between the carb gaskets ok, these can crack sometimes.
thinking outside the box.
if you get the distributor timing slightly out then it can run like a pig, all spluttery, but rev OK.
why not mod the dizzy to manual adjustment so you can get it spot on because even the factory settings are not that close!
1) remove 11mm bolt and 'Y' clamp from base of dizzy
2) spin whole dizzy 180deg
3) re-fit 11mm bolt and 'Y' clamp finger tight, so that the dizzy is now adjustable
4) spin your ht leads around so they are correct again (180deg)
5) fire it up and with gloves or a rag adjust the dizzy left and right to see if you can improve the running. you'll find it'll get rough at the 2 'outer' most settings and it'll have a sweet spot in the middle
6) tighten up the 11mm bolt and leave it be!
note: you use gloves or a rag to try and prevent a shock.
Do you have a timing light? What camshaft do you have fitted etc? Are you sure you fitted your dizi drive gear ok and not off to one side? try taking the clamp of the dizzi unit and slowly rotate both ways and see if the car will idle better or try to...
blah you scoff...lol.... do what he posted, makes alot more sense than mine but same thing...
ha! scuppered you rob, sorry mate
raj, yes sometimes. just depends how it lands and how well timed up your cam is.
normally I get someone to hold the car at 2k while I nudge the dizzy left and right, you hear it start to cough when your on the edge of the 'contact' so to speak. find the center and lock it off. if you try do it at idle (not that you can!) then often the car will just keep stalling when you try to do this.
Pic here of how i have my dizi drive fitted and the way scoff also said just to help you get idea
http://s331.photobucket.com/albums/l...t=DSCF0226.jpg
Is the mixture screw in too far. Maybe wind it out a few turns and see if the car runs. Just an idea.
is the breather system all ok? i noticed you say uve modified it, my car wouldnt idle when i fitted sfs silicone breather hoses, changed them back and hey presto?
did you remove any of the hoses with the restrictors inside? if its not too laborious perhaps try reverting breather system back to oe, as long as you didnt bin anything of course. Ive had countless problems with me messing around with the breather system, all resulted in ythe car not idleing. i dont know enough to describe why it wont run properly, im sure one of the other guys can answer?
You have one hell of a strange fault there raj!! You can rule out a electrical fault i think. sounds fueling issue but what. The only other thing i can think of is a blocked exhaust. does it sputter then die or just like turning the key off die?
So im assuming u have stripped the engine, fitted a cam, rebuilt it and it wont idle?
You may have been asked this before' not read the old thread.
Have you compression tested it?
Are the valve clearances correct?
Did it run ok before the engine was stripped or whatever u have done to it?
which ever mate, ill appreciate both
will any old comp tester do? might buy this ebay special . are they not supposed to have a reset button on them
ive never done a comp test before[/quote]
Yea they are!! it will be on the metal block below the gauge part. Looks good for that price and should do the job nicely.
compression has nothing much to do with compression ratio raj
i would do the compression check,
then start spraying around places with carb cleaner to see if the revs pick up and locate ur leak. id concentrate on the inlet manifold area....
Don't push it mate
I'm not THAT good at calculations...
Try this one yourself:
http://www.csgnetwork.com/compcalc.html
Hope you have all the data this tool requires...
im now thinkin that you have got the cam slightly out and that the engine isnt producing much vacuum at idle, which would mean the carb isnt able to dribble fuel into the engine. a comp check should show this.
also, check your tappets are done to the manufacturers recommendation....
who is to say the cam has been ground accurately? get the dti gauge on the cam...
The cam being 180deg' out won't be helping matters. What's to say there hasn't been any valve to piston contact?
You really need to carry out a comp' test, but before that, I'd take the chain off and swing the cam around.
Don't forget that if the cam is out, the dizzy gear (and hence rotor arm position) will also be out.
At least get a known base to work from before starting the process of elimination...
Hold on, I'm confusing myself
how did you get on with compression testing raj ? maybe your still waiting on the gauge sorry, getting curious.
if the compression is ok then the engine is ok to idle, pretty much. so then the fault will be a lack of fuel or no ignition.
If there's no ignition it'll probably want to pop and bang out the exhaust, I guess it isn't doing that, and I'm assuming that when you say you have a spark that you've checked the for the spark at cranking speeds, not 2k+ rpm.
so, pending a compression test showing something wrong the problem is one of fuel.
by chance you havn't had the head and/or inlet manifold ports smoothed or polished ?
another question, when it starts to run rough sub 2krpm does it sound like it's dropping onto 3 or 2 cylinders or just struggling for fuel ?
If it sounds like it's just leaning off then you could drill out a spare idle jet to 0.5mm (or 0.6mm!), it'll fecking idle then, it might at least let you see that the engine is OK, may even help you find an airleak if its running
I think what Mart was getting at is that even though when you rotate the crankshaft you can align the cam and crank it is still possible to do that if the cam is out by 180.
As i'm sure you aware (not trying to teach you to suck eggs I believe the phrase is) for one rotation of the crank you get two rotations of the camshaft therefore regardless of whether your cam is timed in at TDC or BDC when rotating the crank the timing marks will still line up.
Not sure how accurate the cam marks are on 5's but I remember when I fitted a cam in my mini (which was also chain driven cam) I had to use offset woodruff keys to get spot on timing as adjusting the timing by one tooth on the sprocket was too large a jump.
it's all good, you've done it right
sounds like you've done the cam timing right, to double check use a dial gauge to ensure that tdc is in line between the gogs.. and the no1 valve lift is correct, should be a certain no of deg off tdc dept on your cam.... don't think this is gonna be the problem though.
providing that your ign system is all okay, have you checked fuelling - not the carb as you seem to have checked that ok, but fpr and fuel pump? and or vac. leaks, to me feels like a vac leak on one of the hoses around the carb? should run ok with all big boost hoses (main ones running to ic etc) disconnected - running the cup setup on mine so might not be the same on a standard 5? but still should idle ok with big hose running to ic disconnected. if all okay then have to look at more serious causes, leakdown test/compressions, etc.....
ooookay...
try the big old idle jet though, if you can force it to idle it might help you find the leak, which is still the most likely cause I think.
Your plugs are sooty, so you've not got an apparent fuel problem...Just too much has enetered the chamber. But they're damp?.... Petrol evaporates pretty quickly...
yeah, thats more likely, which as you say shows that there is atleast some fuel there.
raj not usually. 0.4x mm is standard, group A too. try 0.5mm. if the problem gets better than you know its a lack of fuel. if it gets worse then maybe its actually flooding like adam says.