Piston Lift Pump For non i/c 727 auto owners

[pepecat]

I know that these piston lift pumps provide more reliability, however I also know they put out increased pressure as well. I am wondering if it would be bad for us 727 owners at freeway speeds because we like to run 2600 rpm all day long or therabouts to obtain highway speeds, will this cause too much pressure for the VE with the piston lift pump, pumping that fast all the time at cruise speeds? Will our old VE seals be in jeopardy?

 

[Greenleaf]

I "think" it wouldn't be any different than the later models. If you increase the internal pis of any VE you risk a blown seal. You may wish to remove the pump and reseal it and perfrom some minor mods as well.



I do not have a piston lift pump on my 90 yet. I have a high pressure unit here ready to install sometime. It's been removed from a 97 model engine with p-pump. It was pushing 20+ psi when I removed it from the engine. My current pump is lucky to see 6 psi

 

[pepecat]

I don't think the difference would matter between the years either. I was just concerned that the difference in drivetrain / drive style (early non od 727 trucks running generally higher cruising rpm's all the time)

well If and when I replace it, I'll update the stats

 

[Greenleaf]

The only thing you "may" have an issue with is the KSB. Them things are much different between the two models. If you have simply disconnected the wire to gain internal psi/advance you just might overpressurize. I have disabled my KSB in favor of a higher static timing.



The internal pump pressure is also adjustable via the relieve valve. I have not increased that nearly as much as I have the later pumps.



BTW the later model KSB has a built in by-pass valve to prevent overpressurization and thus a blown seal. Supposed to