Lumpy Cams Help !!!!!!!!

poormansporsche

alright peeps

had my 2.4 manifold and some cams fitted yesterday - the cams are the dbilas ones but are pretty much the same spec as the piper regrinds.

I expected a lumpy tickover but it really is terrible - you have to rev up to at least 1500 rpm before you lift the clutch at all or else you kangaroo

Its ok when you are moving but in stop start traffic it was all over the show

would a remap help the tickover at all - on a remap is it possible to raise the tickover to say 1250 rpm or anything?

Or do i have to go down the head adjusting route

My car has a sports cat, milltek, air box mods ??

any thoughts would be appreciated

thanks

Brett

JohnnyN

Not really heard of it being that bad before but i'm sure Vocky can advise. I don't know of anyone else running dbilas cams but they may require additional headwork and a remap?? The extra intake of air from the 2.4 inlet may be causing the issue now seeing as you haven't had a map done?

dunno..

baldie87

i think lightening coupe had the same problem as you mate with lumpy idle after his mods not sure what he did to cure it though

alanoo

You should check the timings marks notsure.gif

Yello

I had the same problem after I fitted the 2.4 inlet, I had an air leak around the oil breather gasket.
If you have the same problem, dont drive too much before you repair it, because its running very lean at high revs, my exhaust were glowing red dunno..

Lightning_Coupe

Yea, you have a hardwear problem somewhere, you shouldnt need a remap to make the car run smoothly and it wont solve the problem. Easyest test you need to do first is a compression test. I'm not sure of the exact figure, Im sure somebody else can help but you need around 190psi per cylinder. I had the same problem you have, it was an absolute dog at idle and low revs and would just die if stuck in traffic. I was down to about 170-160 psi and it was down to the new hydraulic liffters i got off autosprint. They where manufactured wrong and didnt have the correct bleed rate so they pumped up holding the valves open slighty. If you havnt fitted new lifters and compressions down a little that might indicate the timings out slightly, which to be honest should the the next thing you tripple check anyway. After that then spray a load of carb cleaner or easy start around the intake manifold whilst its running, if the engine picks up then you have an air leak. The dbilas cams idle a fair bit better than the piper ones, they have a shorter duration and higher lift. My freind has a set and the idel is very smooth so its not inherant of the cams. See how you get on with that and let us know.....

vocky

it's possible the hydraulic lifters need replacing or theres an air leak, the mating surface gets quite corroded and can allow air in :roll:

poormansporsche

blimey - alot to think about !!

anyway i had the chains done at the same time so hopefully the timing should be spot on (!!)

I doubt very much the lifters were changed (as i didnt supply them)

Vocky the mating surface you mention is that on head were the manifold sits or somewhere else?

poormansporsche

also one other thing to mention is that on the way home tonite the longer i sat in traffic the worse it was getting ?????

vocky

mating surface is inlet manifold to head

it could be the cam timing is wrong, that will cause a lumpy tickover with standard cams notsure.gif

Daz

Here ya go....heres wot mine was like when i removed my manifold...

poormansporsche

well i bloody well hope they cleaned mine up !!!

anyway when you fit uprated cams do you need to change the cam timing ?

also I may just change the lifters in any event just for peace of mind - do you need to buy uprated lifters or can i just buy standard replacements from vauxhall ?

also could it be anything to do with the servo pipe bodge as one of the pipes popped off the one way valve and the garage just told me to super glue it back on !!!

thanks for everyones help by the way !

Lightning_Coupe

Mine did the exact same thing. The longer I sat in traffic the worse it got to the point where i had to rev the tits off it to pull away. Youve got the exact same symptoms as I had. As I said. Check the compression, and if youve not changed the lifters then it might be the timing thats out.........I put the old lifters back in once I found the new ones I bought were no good, and apart from the tapping from a couple of the lazzy ones it runs perfectly, I dont think replacing your originals will solve the problem. As I said, its a quick and easy test, just get the garage to whip the plugs out and plug in a compression tester, see whats going on.

poormansporsche

cheers mate, the garage aint open till monday but will bash em over the head first thing and get em to do that

thanks

poormansporsche

seen the mechanic today and hes adament that the timing is fine and there are no air leaks as he checked. he thinks that the stroke of the cams is throwing out the lamda sensor making the engine run too rich. if thats true would fitting the O2 cheater make any difference as ive got one sitting in my garage ????????

alanoo

none

Lightning_Coupe

Did he do a compression test or did he fob you off? Might be time to find a new mechanic......

poormansporsche

he couldnt look at it today but going in tomorrow for a complete checkup - will make sure he does the compression test !

Anyway now fitted my ported throttle body and the idle is a bit better !!

BUT what should i be expecting from uprated cams as ive never had them on a car before, basically with the cams on its idling up and down between say around 600 and 650 rpm (the gauge is permantly moving but it is a relatively smooth movement) whilst before it used to idle at dead on 800, its only whilst sitting in traffic that it starts going a bit mental. The mechanic wasnt bothered at all about the standing idle only the loss of power in traffic ????

Lightning_Coupe

From what your describing It sounds like the ECU is strugeling to trim the idel fuel mixture, and so the longer you sit at idel, the more wrong the trim gets trying to compensate. By the time you try to pull away and drive normally the short term trim is so far out it drives like a pig. The only thing that I can see causing it to do that is a mechanical problem with the valve train. Either its not timed in correctly or you have a hydraulic lifter stuck open which is a little like what happened to me. As I keep saying, a good way of checking things quickly would be a compression test on each cylinder I think. It was way low when my lifters where pumping up.

astraandy

my idle was good on cold startup or with the aircon on it improved but once warm it was terrible. They are fast road cams so not really made for idle if you get what im saying.

I now have standard cams back on and i prefer these as you have more power down the bottom (where its needed most).

I had a courteny map on mine and pre cat removed.

mine idled at about 500ish