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Old 02-05-2019, 12:22 PM   #1 (permalink)
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12v Minivan, not enough power-4 problems

Hello everyone.

To start off, I would like to begin with a disclaimer:
I have done this all myself, in the dirt next to the garage (too tall, doesn't fit) with a heavy hand on the welder and a "wing it" attitude. As the opener in this form has informed me “There’s always someone here to tell you that you did it wrong” however, I’ve got that bit covered on my own, so please try to keep criticism to the constructive variety.

Throughout the process I have researched across forums for topics and past builds to do things in a safe and responsible manner and to try and answer my questions as best as possible. However, as one might expect, not many applications really are similar enough to gain all the relevant information I need.

I would also like to apologize for how much I write. I tend to do that a lot. But I can promise that if you spare a few minutes at nothing else, you might get a good laugh and I can guarantee that this is going to be one of the strangest builds that you have seen.

***[Head to the bottom of the post if you want to bypass details and just read my problems]

So here goes the details:
1988 Dodge Caravan body
1990 W250 Non-intercooled 12v, and the running gear from said W250 (along with a heavily chopped and modified frame to fit)
GVWR: ~8400lbs with some tools and me the driver

Transmission: NV4500HD with upgraded input shaft, fixed 5th gear, and SBC dual disk clutch with hydraulics (should hold way more power than ill ever make)
Everything beyond this point is homebrew.

New engine build: (sorry if this is more information that desired, just want to put it all out there)
Stock block, bored 20 over.
Stock Non-intercooled cam (slightly longer duration and higher lift than intercooled cam if I am correct) with bronze cam retainer.
Billet oil squirters (instead of those plastic ones).
Stock crank.
Higher output oil pump.
20 over MARINE pistons (a poor choice, more on that later).
20 over cummins head gasket.
2nd gen (oops, more on that later) new (thicker cast) cylinder head, O-ringed.
ARP 2000 head studs.
Hamilton hardened tappets, heavy duty pushrods, 110# valve springs.
Billet freeze plugs all around.
Rear cylinder coolant bypass kit (Homebrew, surprise).

Fuel system:
Injection pump: Bosch VE Rotary Style Injection Pump (Yes, intentionally not a p-pump, though perhaps misguided).
Pump mods: All adjustments fiddled with, max fuel up a bit, BD fuel pin and 3200 GSK.
Injectors: 1990 Non-intercooled stock injector bodies and internals, with tips from Bosch 370 Marine Injectors (more on this later too).
Timing: Gear skipped one tooth (~10deg advance) and pump rotated to head.
Fuel supply: Stock lift pump fed by locally adjacent surge tank primed with Racor P510MAM Multipass fuel polisher drawing from twin 15gal fuel cells

AEM water-methanol injection system with single-port injection right before the intake manifold.

Air system:
BHAF (donaldson filter element)
Emergency Air Shutoff Valve (backwards 102mm Mustang throttlebody)
4" intake piping from filter to atmospheric turbo
Borg Warner S472 Atmospheric Turbo
3" charge piping to Turbonetics 61mm T3 high pressure turbo.
Gigantic Russian made 200psi pressure tested Water-Air intercooler core unit. Uses Meziere inline water pump and stock caravan radiator for heat exchanger
Turbonetics Evolution 38mm wastegate to bypass high pressure turbo
Twin Synchronic Synapse Blow Off Valves hooked to throttle switch + solenoid system (currently disabled for testing/leaks)
D.P.S. 3-piece exhaust manifold
4" exhaust with 36" FTE resonator and 36" MBRP resonator, less than 8' of pipe from turbine to exit

Gauges:
Low pressure boost
High pressure boost
Low pressure turbo drive pressure (exhaust)
High pressure turbo drive pressure (exhaust)
Water temperature
Intake Air Temperature
Oil Pressure
Fuel Pressure
Voltage
Exhaust Gas Temperature

Drivetrain:
NV4500 HD as stated above
NP205 transfer case, twin-sticked with interlock pins removed
Stock front driveshaft
Shortened rear driveshaft
Gearing: 3.07 (I think, supposedly that was on the 1st gen non-intercooled automatic equipped trucks, which is what I cannibalized)
35" (more or less-315/75/R16) Goodyear Duratrac tires
A pair of ARB air lockers (sitting in their boxes on my workbench...nobody has enough time to do everything)
RedHead steering box relocated with modified drag link, sporting dual steering stabilizers.
Factory front brakes, disc conversion on rear axle with k20 front calipers.
Hydroboost braking unit with in-line cooler.
Bonus: Smittybilt X20 17,500lb winch that mounts on front or back of vehicle.

Electrical system is all done by me, and is more complicated than i'd like to share, but everything works spectacularly on the electrical side. There is no room in the engine bay for batteries, so there are 3x Northstar AGM batteries in a sub-floor box behind the rear axle.

Entire vehicle has an altogether too overbuilt structural roll-cage throughout to prevent pop-can-like crushing in any sort of rollover mishap.


Phew. Alright, I think that is everything important. If I have left anything out, or if there is anything you need clarification on, please just ask.
I know this is a very strange thing to build, but I have strange tastes and a rather unfortunate amount of perseverance.

Also, the goal for this vehicle is not BIG POWER. It is more in the mind of the best fuel economy I can get, while still having enough power to zip around, occasionally pull my little car hauler trailer, and do a burnout if the need arises. Though ultimately it is "supposed" to be an adventure vehicle to drive around the country and play in the dirt.

***ON TO THE PROBLEMS. [If you skipped the above, please start reading here:]
While there are numerous little issues that I have run into, this vehicle has been roadworthy and covered around 7,000 miles so far, though none of them in a particularly spectacular fashion.

At 5,000 miles, the head gasket went and I found a cracked cylinder head, which is when the entire engine rebuild happened. So there are a few more than 2,000 miles on the rebuild.

3 Main problems I have:
1. Smoke
2. Power (might be tied to #1)
3. Cooling
4. Transmission

1. SMOKE. Since the rebuild, I have traded black smoke for white smoke (unburnt fuel) and lots of it. On any type of colder start, it billows white smoke that burns the lungs of diesel (not healthy) and does not clear up until I can get to about 170 degrees of engine temp, and even once it is fully up to operating temp, at idle it still smokes white, just not as much.

I have a feeling this is due mostly to my bad choice in marine pistons and oversized head gasket, lowering my compression to somewhere near 15 or so. That being said, the cobbled half and half injectors probably aren't helping, and I may have a tad too much timing.

In addition, though it runs somewhat happily, since the build my fuel economy has dropped A LOT. Prior to the engine rebuild running the same turbos and more stock engine bits, I was getting around 20mpg on the highway. Now, after the build, I am down to 12-13mpg, and that is really unacceptable.

If you have any input on this, I would really appreciate it. Because currently the only thing I can think of is to yank the whole new motor, tear it apart, and put stock pistons and a stock thickness head gasket in it to raise the compression back up and revive fuel economy while reducing unburnt diesel smoke. This is obviously not a desirable option as it takes a bit of time, and despite my build, I am about as poor as it gets currently so new pistons would take some saving up.


2. POWER. As mentioned earlier, I feel that this is likely related somewhat to problem #1. Though I believe I have enough fuel/timing/air and parts, I cannot exceed 25psi of boost at the high pressure side under nearly any conditions. Occasionally in 3rd if I stab it right, I can get 30psi, but only if I am lucky and on a hill. While the engine should be able to hold 80psi, I dont need or want to be anywhere near there, but at least 50psi would be nice, and I think not too much to ask for. I have the wastegate diverting air from the high pressure 61mm turbonetics at around 15ish psi, but even so, I can rarely see more than 8 or 10psi at the low pressure pipe, so I think that my 72mm low pressure turbo is barely if at all even spooling. This one is clearly and obviously a huge disappointment seeing the amount of time in the build, to be not any faster than a stock truck. I am sure the setup is capable of so much more, but I am at my end as to what to tinker with to make it happen.

3. COOLING. A problem that I have, mostly on hills on the highway, though occasionally around town too, is my engine temp. I like to think I have done everything I can to help the engine run cool, but it has different ideas I guess. Ive got twin electric fans on the radiator, the coolant bypass from the back of the engine, the methanol injection, and the gigantic water to air intercooler. The intercooler can drop my intake temps by 80 degrees in almost any conditions, but it is still not enough to keep the coolant under control. Cruising up a steep grade, say a 6% grade on the highway maintaining 70-80mph, my EGT's will get above 1250 if I don't pay attention and slow down, and if it lasts for more than 5-10 minutes, my coolant temp will creep up past 220. I usually slow way down or pull over if it gets above 220 because I am afraid of damaging things. But either way, unloaded cruising at highway speeds with the intercooler and meth, it shouldn't get that hot that quick. Even on forest service roads, in the snow in winter, with the fans on, I cant drive uphill for more than 15 minutes.

The only thing that I can definitively point to for this is my radiator. It is a new and clean aluminum BeCool unit, but it is smaller in terms of surface area than a stock cummins radiator, but i got it because it is the biggest that fit. The car obviously drives, but with temp problems like this, I couldn't even hope to tow my trailer anywhere unloaded, let alone with a car on it, or up a hill. That's a huge bummer for me. The only solution I have for this is to buy a wider radiator, cut it in half to the proper height, and tig it together with my current one merging the end tanks and making it a dual pass to utilize everything, making it a 4/6 core radiator instead of a 2 core. I am extremely limited on space, but that doesn't matter if I can't drive it, so I am willing to cut and re-weld almost anything, though hopefully not the frame.

If you strongly believe that perhaps my cooling could be due to tuning and fueling, please let me know so I don't have to take such drastic measures as fabricating another radiator. That takes time and money that I do not currently have, but will make if needed.


4. TRANSMISSION. This was also a big problem until recently. The clutch pedal requires a left leg squat power of probably at least 100lbs, but I dont really care about that, its just amusing to have other people try to shift gears. The transmission was "supposedly" freshly built when I got it. New stronger 1 3/8 10 spline input shaft, 5th gear fixed, and filled with liquid gold $$$ Amsoil which I have read mixed reviews on, though mostly positive throughout the community. When the car is off, the transmission shifts through the gears like butter. But as soon as the rotating mass is spinning, even with double clutching, it is really hard to shift into any gear. Usually it takes a few hard pushes/smacks to shove into a gear, which is a bit concerning. Also, in 4th gear and only 4th gear, under any load the whole vehicle shakes and growls. I have recently diagnosed this as a bad front bearing on the direct drive shaft, but am not positive.

As I said at the top, this has been a problem until recently. By recently I mean yesterday. While just driving around town at low speeds to go fix a friend's car, 3rd gear spontaneously decided it didn't need all its teeth, and shattered. I was able to limp it the last two or three blocks in 2nd gear with no problems, but any time spent shifting into or driving on 3rd gear sounded very, very bad. So, nothing is fixed, but its definitely broken, so when I get time I guess I will be pulling the tranny and putting in new gears. Yay.

Since the tranny is coming out, I am really thinking of taking the opportunity to pull out the motor I JUST FINISHED BUILDING and tearing it down for new pistons and HG. So if anyone has any ideas about problem #1, and #2, please let me know because I really don't want to tear it apart, but if it's the only way I guess I will just have to suck it up and do it. Also, there’s several feet of snow at my house, and that makes everything "more fun".


Once more, I know this is weird, and probably not everything has been done the best way, but please try to refrain from telling me I am overly stupid or simply did such a bad job it's hopeless. I am already telling myself that so your bit there wouldn't help much.

However, if you have any advice or something constructive, I welcome and appreciate all opinions.
PLEASE HELP ME.
And thank you very much for all of your time.
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Old 02-05-2019, 12:33 PM   #2 (permalink)
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over fueled and no boost sounds like a good recipe for getting hot. Check your timing, do you have an injector stuck, pull the injectors and have them tested. It will fog like that with a stuck injector. You layed out few issues that need to be hammered out before any other diagnosis can be done.
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Old 02-05-2019, 12:46 PM   #3 (permalink)
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A failing lift pump can cause some strange issues. Bad/leaking AFC or badly clocked fuel pin might cause some problems.

Those marine injectors and pistons may be hurting performance as well.

Last edited by Back Woods; 02-05-2019 at 12:51 PM.
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Old 02-05-2019, 01:16 PM   #4 (permalink)
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Pictures

Just in case anyone needed a photo or two to clarify what this all looks like.
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Actually, I do not have a high enough post count (currently 1) to add photos, but when the time comes I will be sure to add a few for educational and entertainment purposes.
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Old 02-05-2019, 01:19 PM   #5 (permalink)
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Thanks for the quick reply, I will get the injectors tested this week if I can. The timing should be around 25 degrees or so advanced, but I might pull the pump away from the head to retard it a bit and see if that helps.
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Old 02-05-2019, 01:21 PM   #6 (permalink)
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Quote:
Originally Posted by Back Woods View Post
A failing lift pump can cause some strange issues. Bad/leaking AFC or badly clocked fuel pin might cause some problems.

Those marine injectors and pistons may be hurting performance as well.
The lift pump is brand new as of a month or two ago, but I could inspect that too just to be sure. I will check the clock on the fuel pin, but I believe as it only has a single cut face it would be fairly hard to put in misaligned.

And the pistons and injectors are what I am worried about, as replacing them both will require a bit more funding than I currently have, and another engine teardown that I am hoping to avoid (with my resolve getting weaker on that by the day).
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Old 02-05-2019, 01:53 PM   #7 (permalink)
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Subbed for pics, we're the injectors used or rebuilt with those marine nozzles?

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Old 02-05-2019, 04:12 PM   #8 (permalink)
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I need to see pics.

Link to a facebook or something.
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Old 02-05-2019, 04:42 PM   #9 (permalink)
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You had me at 12v minivan! I am looking forward to this thread. I also like that you kept it all 80’s period correct Mopar!
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Old 02-05-2019, 04:54 PM   #10 (permalink)
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put a real lift pump on it

https://www.amazon.com/gp/product/B01KGQ4BNO

rebuild the injection pump

put the timing back a tooth to stock(will reduce temps), but leave it rotated towards the intake

get new injectors

Last edited by rockyota83; 02-05-2019 at 04:57 PM.
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Old 02-05-2019, 05:31 PM   #11 (permalink)
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Also do you have a pyrometer/egt gauge?


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Old 02-05-2019, 05:37 PM   #12 (permalink)
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Also do you have a pyrometer/egt gauge?


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he has lots of gauges if you read his story

Quote:
Originally Posted by 12v Minivan View Post
Hello everyone.



Gauges:
Low pressure boost
High pressure boost
Low pressure turbo drive pressure (exhaust)
High pressure turbo drive pressure (exhaust)
Water temperature
Intake Air Temperature
Oil Pressure
Fuel Pressure
Voltage
Exhaust Gas Temperature
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Old 02-05-2019, 05:50 PM   #13 (permalink)
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For the photo requests, I made one of those instagram things that are all the rage these days, or something like that. The account name is: theturdwillneverdie

Because the affectionate name of my contraption is "The Turd", and I am so far past committed at this point that there's no way I can ever get rid of it.

To the recent recommendations, thank you very much for your advice, I will be looking into it all some more.

To rockyota: do you think that the high flow lift pump will solve the problems? I mean, I am sure that my setup is fuel limited as far as reaching its full potential is concerned, but I feel as though I am not even hitting stock/slightly modified power levels right now, which I think that the current lift pump should be able to support. If I am not wrong (entirely possible on so many fronts) many 1st gen users seem to just bump timing and max fuel and pull their own weight at a remarkable pace. I struggle with the gap between 3rd and 4th on even mild inclines, which seems to be kinda sad given all the things ive done in an attempt to improve.

Ill retard the timing again as mentioned previously, but maybe tilting the pump first so I don't have to open the case just yet. As you will see in the pictures, there's a fair bit of gear to remove to access anything with more than a parts grabber.

As for injectors, are there any recommendations of types or sizing given my current setup?

And more importantly, this goes out to everyone: if I am looking to regain my fuel economy at nearly all costs (gulp) should I truly consider going to a different compression piston? And if so, albeit at 20 over bore, should I go for stock non i/c piston shape (155 degree/marine spray pattern) or a stock i/c piston with the mushroom? Because if this is something that all of you more experienced tinkerers believe I should do, your answer could result in the need of a different injector, and if I have to do that, there's no way I can afford to do it twice.


Thanks!
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Old 02-05-2019, 05:59 PM   #14 (permalink)
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The questions in the above post are much more important, but I forgot to mention the blasphemy of a few things. While I did try to keep some things mopar era, it does maybe have a few parts that dont belong. Like the 2010 Chevy Silverado headlights, and the Ford Super Duty mirrors.

And the weird door hinge and hood closure mechanism (keeps it from opening at speed, and acts as a low pressure zone generator over the hood louver I made in an attempt to increase airflow through the radiator(s).

Many apologies if this offends any brand loyalists. But at least this way everyone is included!
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Old 02-05-2019, 06:15 PM   #15 (permalink)
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Quote:
Originally Posted by 12v Minivan View Post
For the photo requests, I made one of those instagram things that are all the rage these days, or something like that. The account name is: theturdwillneverdie

Because the affectionate name of my contraption is "The Turd", and I am so far past committed at this point that there's no way I can ever get rid of it.

To the recent recommendations, thank you very much for your advice, I will be looking into it all some more.

To rockyota: do you think that the high flow lift pump will solve the problems? I mean, I am sure that my setup is fuel limited as far as reaching its full potential is concerned, but I feel as though I am not even hitting stock/slightly modified power levels right now, which I think that the current lift pump should be able to support. If I am not wrong (entirely possible on so many fronts) many 1st gen users seem to just bump timing and max fuel and pull their own weight at a remarkable pace. I struggle with the gap between 3rd and 4th on even mild inclines, which seems to be kinda sad given all the things ive done in an attempt to improve.

Ill retard the timing again as mentioned previously, but maybe tilting the pump first so I don't have to open the case just yet. As you will see in the pictures, there's a fair bit of gear to remove to access anything with more than a parts grabber.

As for injectors, are there any recommendations of types or sizing given my current setup?

And more importantly, this goes out to everyone: if I am looking to regain my fuel economy at nearly all costs (gulp) should I truly consider going to a different compression piston? And if so, albeit at 20 over bore, should I go for stock non i/c piston shape (155 degree/marine spray pattern) or a stock i/c piston with the mushroom? Because if this is something that all of you more experienced tinkerers believe I should do, your answer could result in the need of a different injector, and if I have to do that, there's no way I can afford to do it twice.


Thanks!
You already know this:
You need to match the piston and the injector spray angle. It's critical that the fuel hits where the piston is designed to compress it. I don't know if just the tips will work... I know it doesn't for my wife or my GF

So, do your injectors have the right spray angle for the pistons? If not, that's white smoke you will never fix without it.

I'd call Eric at Diesels and pick his brain.

https://www.dieselsfuelinjection.com/

He can help you out.

Last edited by Grendel; 02-05-2019 at 06:16 PM.
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Old 02-05-2019, 06:32 PM   #16 (permalink)
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Originally Posted by 12v Minivan View Post
The questions in the above post are much more important, but I forgot to mention the blasphemy of a few things. While I did try to keep some things mopar era, it does maybe have a few parts that dont belong. Like the 2010 Chevy Silverado headlights, and the Ford Super Duty mirrors.

And the weird door hinge and hood closure mechanism (keeps it from opening at speed, and acts as a low pressure zone generator over the hood louver I made in an attempt to increase airflow through the radiator(s).

Many apologies if this offends any brand loyalists. But at least this way everyone is included!
Not trying to be a dick but i think your going to get the best help by not posting the pictures, i know pirate well enough to know it will be derailed once the pics get posted from your post above

You need to ditch the marine pistons, lower compression ratio like your aware of and think about how a marine engine is used versus something used on the road. A marine engine runs at the top half of the rpm range and at pretty much a constant speed, your pretty much doing the exact opposite.

I dont understand why everyone with a cummins thinks they need to put bigger injectors into it, stock turbo trucks are overfueled with stock injectors after the typical pump mods. I know that youve got different chargers on it but it sounds to me like your way overfueled also. Injectors and pistons must be matched, different bowl sizes and shapes need to match the spray pattern of the injectors. Mismatched is gonna have fuel puddled in the cylinder instead of swirled and atomized.

I agree with resetting the pump gear timing to back where it should be. 25* of timing over stock with as much fuel/boost as your saying sounds like a great way to knock some holes in pistons and window a block.
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Old 02-05-2019, 06:43 PM   #17 (permalink)
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Thanks for all the advice.

Didn't realize that photos would have such an impact, but that's very helpful info in and of itself.

I also don't want bigger injectors and never have, the 370 modification was unfortunately the only option on hand to get my stock bodies in the 7mm head bores, while maintaining the correct spray angle for the pistons inside. I agree that more fuel is not (hopefully) the answer, as many of the miles are on the highway driving across the country, and extra fuel can only make my trips more expensive.

If new/stock compression pistons are the answer, as I have feared they are, as mentioned above would anyone have suggestions as to which style of stock piston I should aim for? Intercooled or non-intercooled (mushroom vs pyramid) as I haven't found any conclusive information as to which would work best, and without making an informed decision I also cannot seek out the proper injectors.
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Old 02-05-2019, 07:15 PM   #18 (permalink)
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To rockyota: do you think that the high flow lift pump will solve the problems? I mean, I am sure that my setup is fuel limited as far as reaching its full potential is concerned, but I feel as though I am not even hitting stock/slightly modified power levels right now, which I think that the current lift pump should be able to support.

with the bd fuel pin, 3200 spring, and bigger injectors the stock lift pump can sometimes hit 0 psi at full load, that can starve the injection pump of fuel and decrease its life and performance. the point of the better lift pump is to elimiate any fuel pressure problems that can develope and just to keep your rebuilt injection pump living a long healthy life, your motor is pushing more fuel than stock.
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Old 02-05-2019, 07:17 PM   #19 (permalink)
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link the pics for us without the instantgrams
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Old 02-06-2019, 12:09 AM   #20 (permalink)
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He has a fuel pressure gauge so I don’t think he wants to put money into that end of things if that’s not a problem right now. I’m in a fairly similar situation in some ways. I built my motor sparing no expense really and went marine pistons because the machine shop recommended them. Mine is a ppump in a Ford but I still feel you on some points here. I put it together with marine 370s and it was stinky for sure. Lots of stink and idle haze. I threw ddp injectors that I had in and that improved the stink a lot but still kinda stinky and hazy. This is all relative to 12v as I’m far from new to old diesels. Power is good but not quite where it should be as well as slightly lower boost and slightly higher egts. I have a huge radiator and big superduty intercooler so that probably cancels those problems you are having. The big problem beyond the stink that I have is really low power at low rpm. Power comes on smooth and nice around 1k rpm but has nothing below that. Is your low power across the whole rpm range or down low? I’m suspecting the marine pistons are what I’m not liking but like you i put a lot of time and money into it and dread pulling it all apart again. I’m running stock timing since my lack of power is mostly down low.
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Old 02-06-2019, 12:23 AM   #21 (permalink)
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Also I don’t think you are gonna want any smaller of a radiator or intercooler than a first gen Cummins has. I’m no stranger to those rigs and they are just adequate with mild turning up. I also have a thing for minivans (Astro vans mostly) so there is a lot about your project that interests me
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Old 02-07-2019, 11:14 AM   #22 (permalink)
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No cummins expert here, but if you ahve no power under 1k, I would bet the marine pistons are part to blame. Boats run at 60-100% of redline, they never (well nearly never) run at low engine speeds. Those pistons are probably designed with 80% of redline in mind
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Old 02-09-2019, 05:41 PM   #23 (permalink)
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Originally Posted by 12v Minivan View Post
***ON TO THE PROBLEMS. [If you I welcome and appreciate all opinions.
PLEASE HELP ME.
Pics bro, pics
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Old 02-11-2019, 01:50 PM   #24 (permalink)
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Originally Posted by klutch View Post
Also I don’t think you are gonna want any smaller of a radiator or intercooler than a first gen Cummins has. I’m no stranger to those rigs and they are just adequate with mild turning up. I also have a thing for minivans (Astro vans mostly) so there is a lot about your project that interests me
Thanks for the helpful input! It certainly takes unique taste to cultivate a bias towards minivans, but they do make for a good time, and lots of smiles from others.

I did get my injectors tested. I wasn't expecting them to be great, but overall the pop pressures only varied from 225 to 250, with one exception being injector #5 at 270 bar, which is definitely too high. However, all things considered that isn't too bad for the variation, and again it did idle and run smoothly, never a hint of a miss or anything like that. So while they might not be the best engineered solution, I think for the most part the injectors are doing their job. I would like to get some that fuel more efficiently than the 370 tips, but that is $ that will have to be put aside later...

I am definitely lacking power throughout the powerband. For example, my buddies completely stock '94 p pump truck pulls much harder. I feel that all in I should at least be able to give him a run for his money. No such luck. But yes, I do have very little power down low. Unless I can keep rpm's up on the highway, the gap between 3rd and 4th (granted, my 3.07 gears don't help the gap size) is almost too much to pull up from on anything other than flat or downhill.

I think that my intercooler system is sufficient. I can read an 80 degree Fahrenheit drop in intake temp between having the pump on or off, so I think that is good for efficiency there. But I do agree that my radiator is quite likely too small. The only problem I have is real-estate. I basically have none. I am willing to re-design my front end to accommodate more radiator, but I still think I will have to tig up a custom unit that trades face surface for depth. Something like cutting a big radiator in half, merging the tanks, and having it 4" thick at half the height. Only way I can see it fitting with the tapered nose of the van.Frame rails are a bit tight too.

Once I get rebuild the new internals for my transmission I will try returning the timing back to stock and seeing what that does for me. However, as mentioned earlier, with the transmission and fuel system removed (three tanks, lots of valves and a transfer pump) now would be the time to do engine work if I have to. Though I still can't see affording the ~2k for new pistons and injectors anytime soon.

Also, I was talking with a few local diesel performance shops, and a bit of advice I saw regularly was to remove my heavy weight valve springs in favor of stockers. Because I have the 110# springs, heavy duty pushrods, and hardened tappets, but only a stock cam, I was told that they will eat up the camshaft and heavily/prematurely wear it down. To me, the spinning design of tappets should negate this type of wear, but I have little experience in this area. Is there any truth to this?

Thanks again.
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Old 02-11-2019, 02:49 PM   #25 (permalink)
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you should probably be posting this on one of the many different cummins specific forums

youve got compound turbos with an o-ringed arp head, you should have all the power you want, have you tried adjusting your low boost fuel levels?

https://www.dieseltruckresource.com/...-wheel-176337/
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