Was wondering if there is a known failure rate higher in the VP 44 SO or HO engines as the VP 44 is different internally for the HO.
Any stats on this or just a crap shoot for both?

Also wondering if many of these failures and or lift pump problems whether the root cause may the overflow valve.

If the overflow stuck closed, this could develop high temp in VP 44 and cook it, or overflow valve actually opening at say 5 psi but lift pump actually okay but not able to provide sufficient pressure. How many overflow valve problems have been overlooked as the real cause.

Sorry long winded, but have been reading the threads for sometime and just wondering what your opinions are.
Okay, I'll shut up, I heard that.

 

you know that is a thought ... when my last vp44 went i noticed just before it blew that i had unusual high lp pressure 35 psi it went up from a normal 18 , pump seized ,put new one in bam! back to 18 psi

 

Just a casual observance tells me that the HOs SEEM to have a lower failure rate than the SOs do. But that's about as unscientific as you will ever see.

Of course, there are fewer HOs on the road, so maybe that's the reason..

Justin

 

Still thinking! The overflow valve is set to open @14psi. It is also supposed to close on shutdown to prevent drain back and therefore longer/harder start crank time.

If the system is designed to return 70% of flow back to the tank to ensure cooling the VP 44, then, how can this be achieved with a lift pump putting out 7 psi at idle. Is this cooking the pumps?

To me it seems nothing less than 14 psi is acceptable at idle or low load, but it could be lower at WOT and still achieve cooling/lubing the VP44 because of amount of fuel going through the pump and being injected.
Should I stop thunking now?