lumpy and erratic idle with cam

[mad-driver]

Now before you all say it, i know a car will idle lumpy with a performance cam in it lol.

Anyway, i have just had a 1300 head and ultimate road cam, by piper, put on. It doesnt seem to want to idle correctly, i mean its lumpy but the revs are not stable and fluctuate all the time. Would this be because the cam is best used with 40s, and that my 32/34 isnt setup for the cam? Obviously if this is so i could get the carb re-jetted, but with the 40s going on in a few weeks am i just best to leave it and see how it goes?

Sam

[Stuart]

ultimate road cam, by piper

WTF is that one? the BP300 ?
it will be a little rough if its not setup but as you say since your getting 40's soon then there is a simple "live with it" mentality..

[johnny27]

I had a 295 kent cam running with both 40s and then later a webber 32/34. I found the engine would idle alot better with the 32/34 rather than the webber twins. You know yourself, with a 300 deg cam no matter what you do it will never ever idle even half decent, altough i love the sound of a nova idleling with a lumpy cam, it grows very quick on you, just think of the power just waiting to be reved out in 2nd gear lol

[Adam]

IIRC.
Sam told me the cam was a 285 duration one, shouldn't be too lumpy.

[Stuart]

seeing as the 300deg cammed 1.6 we all know and love idles fine... the old wives tale of "it wont idle right" is down to bad setup

[mad-driver]

the ultimate road one is a 285, for use with Twin 40s as stated by piper, though i've turned the fuel mixture up and it idles at around 1k, it still runs rough, fine once you get into power band though. Must be that it needs the carbs on, and a RR setup, next month...

F***ing sound wicked though init! lol:D

[mad-driver]

IIRC.
Sam told me the cam was a 285 duration one, shouldn't be too lumpy.

LOL i am actually wondering whether they sent me the right one Ad, coz for a 285 it sure is lumpy lol

[Adam]

Lol.
It should have the part number stamped on the cam ;)

[mad-driver]

cant see part number coz got cam in now lol

[Adam]

Take the dizzy off.
Should be stamped in the end plate.
Tis on most anyway.

[BigStan]

I had a cam in my last GTE, it idled terrible and even though i tried to sort it out by turning the fuel mixture up or turning the dizzy round slightly it never would work !! F**k me the car flew though lol , and yes i did get used to it and sort of started to like it !
Cant you buy a cam wheel that tunes it into the engine ??

[johnny27]

if it is a 300 deg cam i could'nt see it ever tick'n over even near normal. I have used 285 on carbs before and it is'nt too bad, but you still know its there, i think a 300 is abit extreme for your engine spec.

[Adam]

300deg is fine with T40s.
If the 40s etc are setup correctly.

[Dan]

the ultimate road one is a 285, for use with Twin 40s as stated by piper

Dont believe the hype. It is a good cam yes and delivers good results, but by no means the ultimate lol.

And johnny, please dont talk nonsense, i personally run the ast2 kent cam (295) and that idles near as damn it perfect, almost as smooth as standard. Coupled to the fact jim has the piper bp300 cam which also idles well, so again i'm afraid dont believe the hype and old wives tales.

A poor idle due to cam is either from extreme cams or a not so good tune up imo

[johnny27]

Also had the kent ast2 295 in my old 1.2 nova. In My case, i ran it with 40s which were setup and then a webber 32/34 which was also setup. Was'nt terribly erratic but by no means was it normal running. Ran a 285 for a while and i found that there was a suprising difference in 10deg for idiling.

[johnny27]

wether the capicty of the 1.2 engine was not suitable for a 295 i don't know, but was setup each time with the different carbs

[Stuart]

we shall see how a 1.2 likes a 306 deg cam then lol

[johnny27]

As a matter of intrest, what is the highest deg cam you can use, b4 having to convert the lifters,rockers and cams to the flat nose roller rocker system?

[Stuart]

mines a flat nose solid setup.. but you can "have" to convert at 10degrees if the lift profile is harsh enough...

[womble sri]

mine dosent idle well at all and never has done it could be a stiff cable or , in my case, the idle screw likes to rattle a bit loose when you are reving it so high. mine is not down to poor set up just old bits! you need to relly build the whole thing from scratch, like jim, if you want it to idle, run well and last for more than 5 minutes

[mad-driver]

Right, trying to diagnose the problem properly now, as it has become clear that the car isnt running right. Above 2500 rpm its fine, but then again the cam has already reached its powerband so it may be because of that. However the car will not idle at all, it always fluctuates between around 500 revs and 1200 revs and sounds as though its running on 3, and no matter how much you change the timing or carb setup it wont make a difference.

Anyone have any ideas or similar experiences? I am going to be putting the twin 40s on in about 2 weeks though i doubt that will solve the problem. I dont know whether its the carb that cant handle it or what, maybe it would need rejetting to suit the cam, but im not going to waste my time if it is that because the 40s are going on soon.

Just dont know what it is, though it has definately got some power above 2500rpm so there cant be that much wrong?

Just a thought aswell, the 1300 head i put on had to be skimmed more than normal because it was warped slightly, and if the valves werent lapped in correctly would that affect it?

Sam

[womble sri]

mine is set up perfect and it irraticly idles between 600 and 1200 i dosent idle when cold it does when hot for about 2 minutes and eventually dies. mine has no power before 3500 if you put your foot down it just jolts and splutters you literally hyave to cover the throttle. this will give me problems at the pod because the only way too get away fast is by lighting up the tyres. shame your not local id take you for a spin

[Adam]

/\
If its coughing and spluttering then the fueling isn't right.
The power band of a 300deg cam tho starts at about 3000rpm, so not much will happen to it reaches the band.

[Stuart]

it should still drive nicely...

jims was a little like womble says till he got it "resetup" at nothampton motorsport and now even only as a passneger i can tell its got much better pulling abilities from lower down the rev range...

[Geth]

I'm running the Kent AST2 290deg cam with 32/34 carb and Janspeed 4 branch manifold. It will idle perfectly at about 1200 rpm which it holds for about a minute after clearing it's throat. after that it sinks to 900 and is very lumpy, but it does stay there.

It used to just cut out after falling below 1000rpm but I canged the primary idle jet for a larger one and now it hasn't dies on me since.

Booking it into Mosley's RR for a proper set soon, it's the only way to get the best out of your engine really.

[mad-driver]

Exactly...I dont expect it to idle like it did before, it WILL be lumpy, but as bassboy stated, it should idle in one place, though it wont, im sure its the fuelling so maybe the jets in the carb cannot handle the new setup?

[womble sri]

mines good once its warm