Fuel supply pressure

[Paychk]

Appreciate the update on the new P/N!



BTW welcome to the forum; drag up a chair, make yourself at home & the drinks are kept in the frig

 

[MontyDyer]

Thanks for the welcome Paychk.

 

[bgilbert]

Monty, is that the pump you have on your truck? Great looking truck btw.

Pump Stand Measured Flow: (LPH) 108. 1 - 230. 9

The LPH flow measuremets for the P pumps transfer pump shows to be 187. 4 - 304. 2

Sounds like this LP might give a little low FP at low rpm, 108. 1 vs. 187. 4 for a p-pumped motor. Which would make it sound more like an upgrade for our VE pumped motor, which was stated back earlier in this thread? Anyone agree? Also if someone can tell me what those LPH #'s are compared to VE powered diapraghm LP LPH#'s. Thanks.

 

[Greenleaf]

Hi guys,



This is the pump I'm installing onto my 1st gen. (# 3936320) I have the Cummins manual for the "B" engine and it lists all the info previously mentioned such as part nos and flow rates. I had to call Cummins Bridgeway for the updated part# though.



The book lists specs on the various lift pumps such as the diaphragm and the three styles of piston pumps. One of the piston pumps is listed as a replacement for the diaphragm model lift pump.



Bill, the specs you are asking for are found in the Cummins manual. I have been studying these things for days, but can't say for sure what the flow rates are.



Good job guys... . now you "ALL" know my secret... ... .



GL

 

[bgilbert]

1-3933256 pump

1-3914753 tube

2 3931348 Gaskets

1- 3914284 spacer

2- 3918191 seals

The 'tube' in this list, I'm wondering if its the hard metal fuel line that runs between the lift pump and the fuel filter housing? Scott we were talking about fittings and such for a different style LP, ya think this is the line we need, or can someone else find out or already know what it is? That would be awesome a complete bolt up job, no need to find fittings and such... .

 

[Greenleaf]

Bill.



That is the fuel line. The pump (from Cummins) is 147. 00 and fuel line is $27. 00

the part no for the little seals (banjo bolt) have changed to 3963983 they are . 89 cents



The piston pumps use a 5mm spacer between the pump mounting flange and the engine block. Hense you have to use two (2) mounting gaskets



The Bosch spec for fuel inlet psi toi the VE is 10. This is stated as maximum, however some people go farther, say 12psi ... ... .....



Hope this helps out. No, I have not installed mine yet. Bill, maybe we need to do this to your truck too??????



-S

 

[bgilbert]

Yes sir. I will be going to my local diesel shop this week and ordering these items. They get a discount from Cummins, I might be able to get it slightly cheaper. Thanks, GL, Jim Leonard- originally posted those pn's, for the help, I will post FP #'s after the install.

 

[bgilbert]

Update: Well I may have a problem. Got the LP 3936320, and I can't get it to bolt up to my 89 motor. The top outlet fitting on the LP keeps hitting the ?tappet? cover right where the blowby tube comes out, preventing me from bolting it up. I can't even get it close enough to compress the LP plunger to push it against the block and bolt it up. Jim, Sean, GL, any ideas? Did Cummins change the shape of that tappet cover on the 91. 5-93 IC'd motors? Can I take a hammer to it to make room? Can a shorter fitting be put on the LP outlet? Course then I bet the new fuel line I bought won't reach . Or does it have oil or coolant running through it? I hope this isn't another darn nonIC'd motor difference, they the select few of us early guys run into!!???

 

[Greenleaf]

Bill,,

I just looked at two model year engines. They are the same. 1989 and 1996



The tappet cover is flat except near the back. There is a buldge with the vent hose attatched to the buldge. The LP on the 89 is diaphragm and not even close to this buldge in the cover. The 96 model has the piston pump. The outlet fitting on the pump is very close to this buldge.



To my knowledge the automotive engines use a sound deadening cover over top this tappet cover. You'll have to remove this insulation. the Industrial engines do not have this insulation.



On the lift pump... ... ... . does it have the primer button (piston) on top of the pump (when mounted) or is it to the bottom. There is a difference in pump housings. This could result in the outlet port hitting something, like the cover.



Go now and check it out!!



-S

 

[bgilbert]

Check'd out, primer button-big black rubber thing right, when LP is properly installed its on the bottom. Theres no way I could see how this LP could have the primer on top. Comparing the old LP to this one, if I had the primer to the top the bolt pattern wouldnt match up and cover the hole.

 

[Dman]

Bgilbert - I ran into clearance problem, when installing piston type fuel pump, with tappet cover insulation. Problem is with insulation only. I cut a hole about 6" square with my dremel tool and the pump and fuel line will fit. My primer button points toward drivers side and slightly up.

 

[bgilbert]

Dave thanks for the reply. I had a talk with Greenleaf about this and he said the same thing. Got the dremel out too and cut about the same size hole in the tappet cover insulation. Fit just fine afterwords. Direct bolt up with all the parts listed earlier. With only an around the block test drive, I got 13psi of fuel pressure at idle and with wet roads I couldn't really give it a bonsai run, but near WOT it held 10psi. This piston type LP is a direct replacement for our diapraghm LP, only thing is it was made for the 'industrial' B series Cummins not the Dodge app. Industrial Cummins don't have the tappet cover insulation, so fitment is not a problem with them, we with tappet cover insulation on Dodge B series apps, have to grind off some of it or remove it entirely for this upgraded piston LP to work. Very simple, must have for us 1st genners IMO. I will post more after I've run with it for awhile.

 

[michigandon]

Would I stand to benefit from this upgrade? My lift pump has to suck through a MUCH longer straw than the rest of you guys', so I figure the stronger/healthier it is, the better. Oh yeah, I still wanna install a fuel PSI guage too, for the simple reason that I need something to replace the defunct Isspro tach in my custom built dash.



Bill and Scott, you guys are gonna help me install this stuff at the next cookout, right?

 

[bgilbert]

Ah heck Don, you should have this installed before the next cookout in October. Like I said I haven't run with it yet for awhile. But based on the specs, and seeing good fuel pressure on my gauge after the install, I would say this is a great upgrade for us and especially the 1st gen house. I'm still working on pics of my fuel pressure gauge install for you Don, plus I'll get pics of this lift pump and modified VE install. I will be driving over to Scotts house soon and over there I will take plenty of pics while Scott is getting his hands dirty changing VE's.

 

[Greenleaf]

WOW , there must not be much interest in upgrading the old diaphragm lift pump on these first generation trucks... .....



Must not be many people runing with a fuel pressure gauge as you'd know you have negative fuel pressure @ WOT with a tuned VE.



I'll post the specs on lift pump psi with this experimental VE (if) this pump works. Bill had 6 psi @ WOT with the formerly tuned VE. We'll see what the high output VE does to this new piston lift pump.



You guys ain't asleep out there are you!! ?? Happy with 250-300hp eh??



GL

 

[michigandon]

You guys ain't asleep out there are you!! ?? Happy with 250-300hp eh??

I'm game for any and all pointers to help get my 12,000-lb rig over the road. But I wanna start out with the easy (cheap!) stuff first.



Don

 

[DPetrey]

Here are some #'s for you guys Maximum allowable Restriction to fuel Lift Pump -mm Hg (IN hg) 95 (3. 75) Maximum Allowable Fuel Return Line Restriction MM Hg (in Hg) 518 (20. 4) these #'s are from the cummins technical Manual hopefully they Work for you guys

 

[swankmetal]

got 'er done. just wanted to thank those responsible for r&d'ing this one. can't wait to get everything back together and drive a little easier knowing that one more issue got cancelled.



dave

 

[BushWakr - RIP]

"... ... You guys ain't asleep out there are you!! ?? Happy with 250-300hp eh??..... "



Ok now... . you need to have some dyno sheets here you "closet tuner" you... .

I found a sump pump that I think will work for us now that you mention it... ... . only problem is the shaft is 3' long and the motor is WAYYYY to big... ... . hmmmmm, can we use an inverter to change 12vdc to 120VAC... .



pb... .

 

[Greenleaf]

That otta do the trick.



Let us know how it goes.



Dyno Sheet:

I hope that Bill will dyno his '89 while in St. L I don';t think the lift pump alone will make any more power, or maybe so... . I dunno. One would have to test run with a OEM unit and then once again with much higher fuel supply. Could make a difference I suppose if the pump needs more fuel.



Bill, you going to dyno here soon bud?? Think your clutch will hold the ponnies?





GL