7mm delivery valves rough idle

turninheadz94

turninheadz94

casey ross
Joined
Mar 14, 2011
Messages
128
Well just finished my build and swapped my 181 delivery valves out for 7mm 100cc delivery valves. It cranks fine and all cylinders are firing it is just really rough. Has anyone else ever had this problem? I want something that idles smooth yet still flow well.
 
It ran smooth before with the 181s and did you remove the sealing washers below the DVs if there were any?
 
Silky smooth, and negative there weren't washers under the 181's. Pump had just gotten back from being maxed and balanced. I thought I had a cylinder not firing at first but cracked each line while running and they are all firing just rough, smooths out at about 25-3000rpm.
 
So to be clear... You got the pump back with 181s and it ran smooth. Only swapped in the DVs and now it runs rough?
What is your fuel pressure?
 
38psi right now, timing set at 18* then changed to 22 just to see how the truck ran. Talked with the shop I got them from and they said that they have ran into the problem before and had to swap them around to different holes to smooth it out and to be honest I don't want to do that just to get it to run smoother. Do 024's run pretty smooth or what delivery valve would suffice. My signature is old I threw in a fletcher cam, dual valve springs ported the head, main studs, head studs, arp rod bolts. Fluidampr as well just to smooth it out. 180 pump maxed and balanced along with 7x12 143 degree nozzles. Turbos running 63/68/14 over a ht4b with 28cm exhaust housing.
 
DVs shouldn't cause it to run rough unless they are machined wrong I would think. I had 024s in my truck before and they idled smooth and I swapped them out for a set of 7mm DVs from Weston (Smokem) and had to turn my idle back up because it lowered idle about 200rpm but the 7mm's idle good and don't haze as much as my 024s did but they fuel much harder up top and run cooler too. I would try just swapping a good set back into it and see if that fixes it. If so, I'd get a set of the 7mm's from Weston as I've never had any complaints with any of his products.
 
Where could I get a set of his? I figured I got what I paid for I paid 120 bucks for these straight from the builder so i guess I learned my lesson lol. I can't complain on how they run, I can daily drive mine even without my valet switch on and pretty clean
 
He could also probably tell you why you are having your issue as well. He's very knowledgeable about these fuel systems and engines.
 
Sounds as though you may have a seat not sealing to the barrel or holder, I lap every seat before shipping to prevent this.
 
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