Hello Dennis,I run this cam in my 230FT with big valve head and the idle is very rough.
I am not sure if this is only caused by the cam. The block was skimmed 0,4mm and the head 0,2mm which makes about 2,4? retarded cam timing. Am i in need for a adjustable camgear or is that just fine?!
Valve clearance is set to 0,35mm on all Valves.
Otherwise i can confirm the characteristics you stated above.
Regards,
Dennis
It is likely a combination of things. I would raise the idle speed to at least 800(or 900) when warm by adjusting the throttle plate if LH2.4 or idle adjustment screw if LH2.2(block off the idle motor when adjusting). I would then adjust the valve clearance to 0.4mm or just over to give you a little bit more seat time for the valves and re-check.
I don't know what KG suggests setting the valve lash at, but 0.35mm is low enough to contribute to a rougher idle over something that's closer to 0.4mm or 0.45mm which is normal factory spec.. Yes, I know this isn't a factory camshaft, but I still suggest going looser if you want a better idle.
On my H cam in my street car I have the clearances mostly set to 0.5mm/0.020" to help improve the idle quality and torque off idle. It's much more friendly down there at that setting than it is around 0.35mm/0.014" that I use for more performance when I don't care about idle quality and emissions. I also set my idle around 900-1000rpm.
If, after loosening the valve clearances and raising the idle speed you are still unhappy, you could look into getting an adjustable cam gear and playing with the timing. It may or may not have the results you desire, but you can at least better fine tune how the powerband fits your desires.
Before getting the adjustable camshaft gear, it would be good to verify the engine has good and even compression in each cylinder when warm. I would check it after adjusting the valve clearances looser.
As mentioned above, I would block off the idle motor and instead of setting the base throttle/idle setting to 500rpm as per Volvo originally stated, set it to at least 800rpm so the engine doesn't rely on the idle motor as much to maintain an idle.I haven't adjusted anything as of right now ECU stock 91 940T with a chip. No compression check has been done.
I see that on that KLR T2 camshaft KLRacing does recommend setting the valve lash at 0.35mm which as mentioned above is on the tighter side and will create a more rough idle in general. They also say that it has a decent idle, though. Raise your idle speed, maybe try slightly more valve clearance or at least re-check it now that the engine has been run a bit as things may have seated more if it was a fresh build, and check compression to be sure all is well after that.
-Kyle