I want to switch to a mechanical LP now that I have my Helix cam in.

So from what I understand the stock P-Pump LP puts out to much pressure.

What is the right pressure? 15 at idle? I know this pump builds more pressure as RPM increases.

Can I take the stock P-Pump LP and either change out springs or cut coils on the existing spring to get the right pressure by trial and error?

 

might want to check out the piston pump that the 1st genners put in, they are the same design as the p-pump but with less pressure. im not sure what that pressure is though...the part numbers are in this thread https://www.dieseltruckresource.com/...n&onlynewfaq=1

so it *seems* the p-pump's LP can be modified for different pressures...you just need to find out how.

 

My understanding is that cam lobe controls the mechanical lift pump but there may be some other considerations. Contact Tim Barber at TRE Diesel (DTR site sponsor..... site name "Timinva"). He did my cam and pump for me and is a F1 dealer.

 

I was pretty sure F1 markets a lp for the 24v also?

 

Yes there is a piston pump that f-1 markets. Timinva installed my pump along with the cam. FP was a bit high: 38 at idle and 50 at cruise, so I installed a simflow regulator like what the walbro guys are using and now see 18 at idle and 22 at cruise

 

Please correct me if I am wrong, but the the bottom line is get a 12V LP or the F1 and regulate it with a simflow style regulator and this should regulate any pressure comming in to an acceptable level at idle and cruise then I will be done.

 

Some run it without the regulator, but yes you should be done with lift pumps for the life of the truck with a mechanical pump and a regulator

 

Ph4tty's is the only one that has a regulator on it done by TRE. He added that himself. From what I understand the cam lobe/pump was designed to run the pump at about 40 psi at idle and not drop below 28-30 at WOT. Theoretically it does not need a fuel pressure regulator. I doesn't seem like a bad idea to run a fpr, however I am not running one. I have contemplated it though.