Thanks Bruce for posting up the pictures, your help and knowledge is very much appreciated. One great thing about this forum is being able to get answers to things. Being novices both of us want to know the 'why' and 'how' things happen or moreover to be educated about everything even though its frustrating along the way. You go in being naive and not knowing and you take what is given to you as being 'correct' and its not, or is it.. then you start to look at everything else thinking its the problem.... or is it.
We made it back around to trying to get things sorted out. We think the issue is with fuel psi during startup at the Hilborn BV which leads to lack of fuel psi at the hat distribution block and thus not staying started. The motor has always fired instantly, its just getting it to stay started is the whole issue still. I put a fuel pressure sensor before the BV and i have one at the distribution block in the back. We tried to start it Saturday and still have issues but its getting narrowed down to couple things. One is spring pressure on the main and second might be the poppet psi settings for main and maybe idle?
Backing up a bit and again to the intro of this post, we thought there was an issue with the rebuilt 110. Enderle checked it out and said it was fine. Nevertheless, I got a new Waterman with equivalent pump PSI to the 110 and thats what is on there now. Two things that were changed are first, the loop is deleted and now returned to the tank and second, the main return was moved from the pump up to before the BV so there is fuel in the line to that point at least.
Nevertheless, one question we have is as main jet size increases how much change/increase does the spring pressure need to be increased by? The main is set at 5psi and never has been changed. The 110 was worn out when first setup at i think 11.2lbs psi. when rebuilt, it was i think 13.2lbs so the main jet needs to be increased. it was a 140 i think at 11.2lb pump and it was set at 165 to be safe with the rebuilt 13.2lb pump. When we made the pass in July with the 165, the EGT's were right in the ball park with the 165 main.
Reason for asking about spring psi increase on main with jet increase is with the 140 jet and old 11.2 gpm pump setup we really didnt have any issue with the motor starting and stay running. when we put the rebuilt 13.2gpm 110 on, the spring wasnt increased in the main so there was no fuel pressure for fuel to pass through the BV is our thinking. What clued us into thinking about this is, with the Hilborn BV the leak is a lot lower then for Enderle BV and the butterfly's are closed a lot more. ie; 38% and like 5k on the hat. only way we could get it to run was to increase (about 65% and 8k @ hat) the BV leak a TON allowing more fuel to 'dribble' by and that is not correct as the EGT's were WAY fat. So back to the question about main jet spring pressure increase versus jet size increase. Premise is to increase fuel line psi to force fuel passed the BV at idle.
Looking at one of the first logs with 11.2gpm psi pump setup, we had about .8x psi at idle at the hat distribution block. I didnt have a sensor setup before the BV so i dont know what that was. Yesterday i added a sensor before the BV, we had an average of about 9psi and only about .2x psi at the hat distribution block. As mentioned, with 11.2 psi pump setup we had .8x psi roughly. that leads back to spring psi vs jet increase in main jet???
Everyone runs the Enderle setups, with this hat we cant without major mods (i think). Looking at the front of the hat, this hat has provisions on the left side only for a BV. Looking at the hat, All Enderle stuff is on the right side of the hat. Really dont want (and wont) mod the hat so stuck with the Hilborn BV and this hat for now. Its a bitch'n hat and would really like to use it.
So, I have a few questions.
- is there a ratio or percentage to increase main poppet spring psi as main jet increases/decreases?
- should the idle poppet psi be less then the main psi on a Hilborn BV setup. Main is BEFORE the BV, not after. Main is at 5psi, Idle is at 12psi. To me the main should be higher then the idle, otherwise why have an idle bypass.
- for those with the Hilborn BV setup and main before the BV, what is the main spring psi set at. are you blown or injected?
- For those that run hat and port nozzles, at what PSI do you have your port nozzles flowing fuel? 1psi, 50psi, or and why
- for those that have logged fuel psi at the distribution block, what idle fuel psi are you getting.
- for those that log fuel psi at the BV, what PSI are you showing before the BV at idle & RPM? is the fuel psi sensor before the main or after the main poppet. eg; is your main at the BV or off the pump. if main is at the BV then is fuel sensor before or after the main but before the BV.
To me, I think there isnt enough psi at the BV to force fuel past the BV at start/idle. Further, with the main before the BV and the idle off the BV why have a low main psi (lower then idle psi). that doesn't make sense. I would think hypothetically if idle was 5psi and main was say 7 or greater would make more sense. to me, the main is in play and dumping fuel before it even gets to the BV, or at least reducing the psi at BV to get fuel back to the distribution block. if im understanding things correctly, the idle poppet is out of play after about 30-40 degrees of BV rotation. Idle should be main fuel bypass i would think .... at idle, not the main.
Thank you
Dean
