Engine/Transmission (1998.5 - 2002) FINALLY!!!! Some one puts an end to Carter!!

[PRout]

Polly wanna cracker?

 

[rweis]

Polly wanna cracker? Sure, why not?



Bob Weis

 

[PRout]

Im not too familiar with the rasp, but it seems like the walbro would make a nice backup pump for the rasp, or any primary lift pump for that matter. Im guessing the backup would be the initial priming pump before the rasp gets "spooled up" and takes over.

This brings up a question. . Is there some type of check valve or some way of holding prime for the rasp when the truck sits not running, or is this even an issue? Would not want to be introducing air in the system everytime the truck sits for a while.

Either way, imo there is no argument. We need some kind of backup plan in case of failure in the field. No matter what that backup pump is, if it keeps positive pressure to the VP, at least we're not running dry while we're trying to get back home.

 

[mhenon]

For the price of a RASP you could run two Walbro's or Airtex's in parallel AND keep a spare in the glovebox.

I'm not knocking the RASP but if you want a backup to your backup there's cheaper/easier ways to get there.

Mike

 

[PRout]

For the price of a RASP you could run two Walbro's or Airtex's in parallel AND keep a spare in the glovebox.
I'm not knocking the RASP but if you want a backup to your backup there's cheaper/easier ways to get there.
Mike

Agreed - And this is probably a lesson for some people, although at least the rasp is a mechanical type pump which almost justifies the cost. But it still isn't quite as "simple" as the old cam operated pumps were, or are (if you want to do a cam upgrade - which requires A LOT of work to perform).

But at the time when some of us spent the big bucks for aftermarket pumps, we didnt know then what we have since learned (and are still learning of course). I was also sold (maybe duped) on the fass removing entrained air from the system. . Not so sure that is really any more helpful than fuel magnets or better muffler bearings would be.

Right, had i known, or maybe put more thought in before, I would definitely have gone with a redundant type setup that is easy to access and maintain. The walbro wasn't available (or well known about for our application) at that time. But, until the airtex or some other pump is PROVEN more reliable than the walbro and as easy to work with in the same price range, its still redundant walbros for me the next time around.

Unless there is a NEED to do a cam upgrade, then it would be a simple cam driven mechanical pump (with a walbro primer/pusher/backup) no question.

 

[Gary - K7GLD]

The walbro wasn't available (or well known about for our application) at that time. But, until the airtex or some other pump is PROVEN more reliable than the walbro and as easy to work with in the same price range, its still redundant walbros for me the next time around.

I have steadily maintained that what Airtex is now offering for our application IS basically a version of the now-proven Walbro, possibly slightly modded as to delivered fuel PSI, then provided with their custom bracketry for installation in the OEM LP mount position.



For those who might not have looked at or seen a stock Walbro in-tank pump, here's a cutaway pic of what one looks like:



#ad




And here, for comparison, is what Airtex is selling as their own "solution" to our LP problems, with fittings, mounting bracket and wiring harness attached:



#ad




Anyone else notice the obvious similarity?



Even that rubber isolation sleeve between the Airtex version pump and mounting bracket, and what is supplied by Walbro in some of their installations is the same, as can be seen here in a pic of my own frame mounted Walbro version:



#ad




SO, is the likelihood that Airtex has simply modded a readily available stock Walbro in-tank application pump, designed an adapter mount for our trucks and then branded it as their own, a BAD thing?



ABSOLUTELY NOT, since by now, there are a fair number of the Walbros in use on our trucks, with very FEW reported failures. The ONLY question as far as the Airtex version is concerned, is whether there might still be some issues with their setup, since it, like the OEM pump, is located rather far away from and above the level of the fuel tank - and possibly vulnerable to the same fuel delivery issues as the OEM type.



Only time will tell!

 

[PRout]

Anyone else notice the obvious similarity?

Interesting, and what a coincidence! They are so similar looking! Had not seen those pics before. .

Another thing to consider about having a pump mounted up on the engine is the "hammer" the VP resonates back down the line. I know that hammer has taken out 2 of my isspro EV mechanical gauges since they first start rattling in tune with the VP's pulses. Needed to add a snubber to alleviate that pulsing (I guess some people use a needle valve). Now the gauges are holding up. Can just imagine what that hammer does to a closely mounted pump.

 

[PRout]

I wasn't putting down the airtex, just sort of reinforcing the mounting location thing.

There are 3 reasons right off the bat why it is better to have the pump back by the tank. 1-Less pulling distance. 2-Less engine vibration/heat. 3-Less VP44 hammer back towards the pump.

Can only think of 2 disadvantages and one isn't really a big deal. 1-Subject to the elements (salt air, moisture, rocks/debris). 2-Longer wiring length, which if you use heavy enough gauge wire, the voltage drop is minimal.

The back by the tank mount location seems to have more benefits than drawbacks.

 

[mhenon]

... Another thing to consider about having a pump mounted up on the engine is the "hammer" the VP resonates back down the line. I know that hammer has taken out 2 of my isspro EV mechanical gauges since they first start rattling.....

I've always been suspicious of these pulses sent back from the VP. No way to tell for sure what effect they might have but it can't be good for a mediocre LP that's hard lined just inches from the source.

This is probably one of the unseen benefits of something like Vulcans big line/relocation kit. Getting the pump down by the tank where it belongs is a no-brainer. But running 6' of 1/2" fuel line from LP to filter has got to act as a damper on these pulses. Sort of like having a small accumulator in the fuel system absorbing pressure spikes.

Mike

 

[gtwitch]

Finally no more CArter problems

I have a general question for those who have located a Holley or Walbro down on the frame, is there any longevity comparisons between rotary vane type and a gearotor type and also how much fuel does the VP44 bypass and is an external bypass necessary??



Gary K7GLD, I notice that you still have the Carter in line, have you considered the head loss by leaving it in line? I had a different take on that as a had a couple of trashed Carters around sok I took them apart and took the vanes and rotor out and thru drilled it to 7/16 after taking out the hard rotor cage, cutting the wires off and relocating it in the stock location and cutting into the wires to extend to the Holley on the frame. read my post on voltage to fuel pump last week.



gtwitch in Wyoming K7NOI

 

[Gary - K7GLD]

Gary K7GLD, I notice that you still have the Carter in line, have you considered the head loss by leaving it in line?

Yes, I have - and there undoubtedly IS a measurable loss of flow as compared to what the Walbro is capable of without that restriction. BUT, since the initial Walbro install was an experiment, I chose to leave the Carter (which is the OEM DC LP relocated) in case the Walbro proved to be a mistake.



So far, after about 10K miles, it is working great, and I now have a second identically bypassed one which will eventually replace that Carter - and still also be a bit of restriction. But, like others here on TDR, I am gun-shy of the LP's - ANY LP's, in our systems, and will undoubtedly always have the primary and a spare - just in case - and the added restriction seem insignificant compared to the value of an easily activated spare.

 

[rweis]

IF I could have ANY combination of pumps it would be a engine driven mechanical external gear pump (RASP), and a backup electrical driven mechanical external gear pump (Electric RASP).



The gearotor pumps (Walbro, AirTex (IF proven) are good pumps, but the motors driving them are less than what I would want as the ultimate pump. Why not hook up a gearotor pump to the crankshaft like the RASP (or Fuel Boss)? Why is that not a choice? (yet?)? A engine driven gearotor pump backed up by the Walbro or AirTex (if it proves to have a good longevity) gearotor would be a good combination, not my exact ultimate, but a really good combination.



The RASP and Fuel Boss external gear pumps are engine driven and in my evaluation the ultimate pump driven by the ultimate motor (until you have to prime a system before starting the engine ). We need an external gear pump driven by a substancial electric motor as the engine driven external gear pump backup (and fuel system purging without engine starting). I emphasize a substancial electric motor because the engine driven pump will ??? and you are in the back woods 300 miles from a hard road and are going to run the backup pump system for several full days pulling heavy loads.



A RASP (Fuel Boss) backed up by the Walbro is as good a combination as exist right now (again in my opinion of all I have read about the 3 types of pumps offered (vane, internal gear (gearotor), and external gear (RASP (Fuel Boss)). I base my opinion on what does industry use in heavy day in and day out operation. True there are some industrial gearotor pumps that are really heavy duty. Well, hook one of those industrial gearotor pumps up to a substancial electric motor (or the CTD ie crankshaft drives) and you are back in the ultimate pump category. Then back it up with the Walbro.



Why use the backup as the primary? Research the gearotor pumps available to industry applications, build a mount for it, figuer out the pully ratios (use the RASP or Fuel Boss pulley system?), and install it. Then you have the ultimate primary pump, and back it up with the Walbro.



The pump failures (except vane pumps) are generally motor failures. WELL, we have a GREAT motor to drive a pump with, so use it as the primary.



Last question - WHY did Bill K support the external gear pump and not some other pump? WHY has no one hooked up an industrial gearotor pump (internal gear pump) to the engine?



Bob Weis

 

[Gary - K7GLD]

Well Bob, after all the playing cards lie face-up on the table, it becomes choosing time - and most guys probably will go with what's been proven to work, and is readily available both for the original install, as well as what will likely still be available in case of failure.



You can pay all sorts of prices for the "ready-made" kits - or do some reading, then dig out the tools, use some imagination and ingenuity - and build your own.



My own choice is obvious - and CHEAP! :-laf



There may well be more reliable pumps available to build a setup around - but for now, I'm not aware of any - and the Walbros are abundantly available at low cost - and been around for quite a long time and a wide variety of installations.



What with the obligatory gauges in place, and the Walbro install complete, the first HINT of developing problems can result in a switch-over to the in-place spare, then later, a complete swap-out in about 10 minutes of the failed one, at a pump cost of about $100 (about the same as a tank of diesel!). Shucks, even if that was required every year or 2 - not a real catastrophe, in labor OR $$$! :-laf



That being the case, I don't see much need to continue to agonize any further on what is the "best", or "most durable" LP setup available - the one I have now looks to be the best bang-for-the-buck for this East Oregon Hillbilly! :-laf:-laf

 

[Gary - K7GLD]

At the same time I posted the earlier post with pics further above, I also sent a message to the Airtex technical support:

I'm very interested in the replacement pump setup you market for the Dodge/Cummins application. Do you make your own pumps, or instead modify the pumps from another maker, such as Walbro - there seems to be a more than accidental resemblance to the Walbro in-tank pumps. If those you supply ARE a variation of the Walbro, great - and can you give specs on your adaptation as to the supplied PSI and fuel flow volume as installed on our trucks?



Thanks



Gary Davidson

To date, I have not received even the SLIGHTEST response from them, which pretty well matches the "no-reply" several others have received in regards to their similar questions. Potential customers for the Airtex just MIGHT want to consider that if Airtex is so obviously disinterested or incapable of responding to simple questions, they just MIGHT be equally poor in responding to actual problems and issues with customer support for the pumps themselves...

 

[FLynes]

I'm speaking with a tech support guy, Craig, at Airtex right now. Though he is not an engineer, this was his project. He has confirmed that the pump is indeed a Walbro pump, however Airtex bought this roller vane pump line from Walbro some years back and were using them on Blawknox industrial applications with no problems (different outlets and inlets), and he got the idea to use them on the Dodge/Cummins application, but tuned down. They were running out of the Carters and getting a ton of orders, so they adapted this one to fit. He said the only problem they've had so far is that people don't like the line going into the pump, so he's looking at a 90* elbow to adapt to it. The pump is rated at 18-20 psi and 75gal/hr. He would like to have it mounted to the frame rather than the motor, but he said that vibration isn't an issue; they've run shake tests on them with no problems. They've run them at 1000 hrs in the shop with ULSD and the pumps look new. The pump is now a five roller pump, but they are going to go to a six roller, which will boost volume. Hope that helps some.

 

[Gary - K7GLD]

Thanks for the info Fred - you should have suggested to the guy that it would be a good idea for them (Airtex) to check and occasionally respond to their tech email inbox...



And I really appreciate this admission from an Airtex source:

I'm speaking with a tech support guy, Craig, at Airtex right now. Though he is not an engineer, this was his project. He has confirmed that the pump is indeed a Walbro pump

That's gotta break Mav's heart - after this rant of his:



Mav sez: #ad

And since we're on the subject of walbro and your incorrect insistence that the Airtex is a takeoff of the walbro, let's get this straight; the walbro was not ever in anyway developed and designed for the second gen. 24v Dodge/Cummins.

I wonder what Crow tastes like on a cold winter morning?



:-laf:-laf:-laf



In any case, the use of a Walbro by Airtex would seem to be a good thing, in view of their good reliability track record to this point.

 

[FLynes]

Gary,



I did mention to him that some TDR members emailed him with no response, which surprised him, because he said all tech question emails come straight to him, but he had only ever talked to the folks at Vulcan and someone named Scott Fray (sp?). The number, in case anyone is curious, is 1-800-880-3056. Craig was a really nice person to speak with, maybe because he's not an engineer (no offense to those who are).



What I found amusing (and he did too, by the way) was when I asked him whether they'd had problems with the pump being engine mounted and suffering problems as a puller pump. He told me that there hadn't been one single problem with it mounted on the engine, but in an ideal world this pump would be mounted on the frame and used as a pusher.

 

[rweis]

FYI Observation:



I installed my Walbro 392 backup lp today. I have a RASP primary lp. I also have a AN-6 line from the VP44 fuel inlet with the excess fuel bypass valve back to the tank to set the psi the VP44 sees at the VP44 fuel inlet (virtually very very similar to the pics Gary has posted).



By taking out my Carter frame mount and replacing it with the Walbro 392 I now mimick Gary's Walbro direct feed to the Vp44.



My Walbro is on a seperate switch in the cab.



Super simple to purge air out of the fuel system, just turn on the Walbro, air is purged, nice. Could not do that with the Carter because the Carter could not overcome the set pressure (14#) of the VP44 fuel inlet excess bypass valve setting.



Just for couriosity while the engine was running with the RASP providing the VP44 fuel I ALSO turned on the Walbro 392 to see what would happen to the VP44 inlet excess fuel bypass valve pressure. Would it be overcome with both pumps running? Could the AN-6 line handle both the RASP and Walbro pumps at the same time.



Yes, no problem



I have the excess bypass valve plumbed into the fuel tank vent line. I took off the fuel fill cap to hear the excess fuel stream as it is returned to the tank vent line. Yes there is considerable fuel being returned to the tank vent line with both pumps running. Sort of sounds like a garden hose on medium flow pouring onto a bucket.



Definitely a fuel stream, but not more than the AN-6 line could handle.



I turned the Walbro on & off several times to see if the set psi would change. The set psi did not change.



Thought this little observation might be of some value.



Bob Weis

 

[wlowe]

FYI Observation:



I installed my Walbro 392 backup lp today. I have a RASP primary lp. I also have a AN-6 line from the VP44 fuel inlet with the excess fuel bypass valve back to the tank to set the psi the VP44 sees at the VP44 fuel inlet (virtually very very similar to the pics Gary has posted).



Bob Weis

Bob, are you using the OEM filter canister? If so, does the walbro feed the OEM filter first then the RASP, or does the Walbro feed the RASP first then the OEM filter?



Also, I find it interesting that the pressure didn't increase with both pumps running. Apparently the bypass valve is capable of regulating an increase in pressure without re-adjustment. Good info!

 

[rweis]

My fuel system goes like this:



Vulcan DrawStraw, RACOR 690T (10um filter), Walbro 392 / RASP, Canton Mecca 25-915 (8um filter), excess fuel bypass valve, VP44.



I do not use the OEM fuel filter at all. (I live in Florida and do not need the fuel heater in the OEM fuel filter. My RACOR 690 does water "block" way better than the OEM fuel filter)



Reasons:

Picks up too much engine compartment heat into fuel system (my opinion),

Filter not near large enough (my opinion),

Filter not water seperator as well as filter, much better filter choices available (my opinion),

Removes significant fuel plumbing from engine compartment where often difficult to work on.



The excess fuel bypass valve I am talking about is the AN-6 bypass valve you put into the fuel system just before the VP44 to dump the excess fuel back to the tank. My observation is that an AN-6 (3/8") line (back to the tank) can handle a Walbro 392 AND a RASP at the same time without apparent difficulty.



-- Not the VP44's bypass valve mounted in the body of the VP44 which only takes care of the VP44 -- and has NOTHING to do with replumbing the fuel system (ie adding the Walbro lp). I want to be absolutely clear on that.



Bob Weis