Ram Van with a 400ci and glowing manifolds

Propane, Butane, LPG, GPL, C3H8, C4H10
351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Ram Van with a 400ci and glowing manifolds

Post by 351m »

Hey all, its been awhile since I was here last, been busy with school and such, now kind of wound up with a new problem, but also a recurring one from a few years ago.

I couple of months ago a friend of mine sold me a '91 Dodge B250 van, on propane from new, ex Kamloops RCMP unit.

All I know about it is it has 228,000km on it, it was originally equipped with a 318Tbi/A904 combo with 3.21 rear gears.
LPG system was a Model E, VFF40 and a 300A mixer (50&70), dualcurve box etc.

Now my problem... The van was way over geared for the higyway, and couldn't get out of its own way so i pulled the 318 and swapped in the 400 big block from my pickup.

It runs a 425 mixer and the truck's electronic ignition (from 1977), the problem the truck had was that after a highway run the exhaust manifolds would glow red... I kind of forgot about this and I'm sure most of us can see how it can be a problem in a van. Since the swap, it bogs bad if I smash the throttle from a dead stop but on the highway it has no end to the power it produces, but along with the power comes a massive engine temp increase, to the point where it won't cool down once it heats up if left to idle. Should add that under normal city/highway driving this engine stays much cooler then the 318, of course until I get to hills or have to pass.

From what I have read here, I should probably be running the lean gas valve in the mixer vs thestandard one currently installed.

I am noticing a few things that bother me and are pointing me to a problem though.

First: With the truck, it needed to be primed on a cold start, but warm it always fired with just a touch of the key, since being installed in the van it starts as usual when cold but also needs to be primed on a hot start after say 5 minutes of sitting

The second thing: When doing the timing we usually power time it(as with the rest of the Dodges including the 318) but the engine seems very unresponsive to changes.

Part is me is screaming vacuum leak causing a lean condition since the intake had to be pulled to put it in the van, but another part of me says the timing chain may be off a tooth causing the timing issues. Last time I set this engine with a light it would kind of run, but the timing was way WAY out. If its nice out tomorrow I will check for vac leaks and see where the timing is at currently

Thanks for taking the time to read this, I'm kind of hoping there is someone on here that can shed some light on this problem.

351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Re: Ram Van with a 400ci and glowing manifolds

Post by 351m »

Well, I have a bit of an update, much earlier then planned... I was out on the highway a 1am playing and notice 2 things the engine is doing that leads me to suspect an excessive lean condition...

1: at a steady speed I can feel the engine surging constantly, it seems to go away if I either get into the throttle or back off.
2: I was pulling a hill and had it pulling as hard as possible with the secondaries open (not in passing gear) and as I let off and the secondaries closed I felt the van surge forward. If it makes a difference, the 425 is mounted to a Quadrajet base.

Steptoe
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Location: JAFA , New Zealand

Re: Ram Van with a 400ci and glowing manifolds

Post by Steptoe »

Check the VFF activation needle for wear....I chassed a similar issue for quite some time.....
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351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Re: Ram Van with a 400ci and glowing manifolds

Post by 351m »

Thanks for the reply. :) I was just going to add a bit more info, I have a couple more tests I want to run but...

I just had a vacuum gauge hooked to the engine, it pulls 15" at idle, if I hammer the throttle wide open the vacuum reading drops to 0 and the VFF seems like it clamps shut until the revs drop some. I think its time to see what the gauges says under load.

Edit: I'm an idiot... I didn't look at the fuel gauge on the tank, and managed to burn through the last 1/4 of an 80L tank. in 2(yes 2) 3km tuning runs earlier today. :oops:

Since I have opened the full tank it does feel like its getting better, at least the engine isn't heating up as quickly anyway.

Steptoe
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Re: Ram Van with a 400ci and glowing manifolds

Post by Steptoe »

Im dedicated..in 30yrs run out of ?LPG once and coasted into the gas pump once and ran out at the gas pump once.
Non of those times did I have running hot and only had miss fire in the last few seconds

When I had the issue with the worn VFF ...which took a couple monthsa to find, again never running hot.

Personally I think u have several issues going on here...
Running hot...
If on thr highway....generally blocked cores, or bottom hose reenforcing spring has corrided away, soft rubber and it sucks partly closed ....or thermostat sucked a kumura (stuffed)
..or radiator cap stuffed
Run hot at idle, low speed....a lot of cores blocked, themostat stuffed radiator cap stuffed
I know on a chevy, if u do not have the raditor fan shroud on , it will run hot....the air splills off the ends of the blades...which is why competer fans are so small and efficient.
it pulls 15" at idle, if I hammer the throttle wide open the vacuum reading drops to 0 and the VFF seems like it clamps shut until the revs drop some.
The engine at WOT will not 'pull' zero vac....its normally 1 to 1.5 "....you will always have restriction in the manifold, carb etc.....I cant rem what the VFF actuates at , regardless, it is real low and if thengine is running there WILL be enough to pull the diapham and open the valve....but may not open fully, because of as mentioned before the actator pin behind the diapham is worn....and most proberlty the housingf it sits in....

Note: when opening up ther VFF, when u pull the pin out, there is a O ring that goes round it...it drops out of sight into the LPG ports.....by turning the VFF u can roll it back so u can see it, hoo into postion and then poke the pin thru.

Other stuff to look at:
Converter:
If the converter is on it back it tends to collect ctap..oil gundfge....remove front cover, peel diapahm back very very carefully, patence, and wash out with kerosene.
Check holes in diapham agains a good light in the background...sun is good ...
Check the spring is the orange one
Check the lever is 5/32 above the case body....be very arccrate.
NOTE: wipe a little engine oil on the gasket parts of the diapams and gaskets...this tops them sticking , and makes disassembly, reammbly easy.
Mixer:
make sure the top spring is the green one
Check diapham as above
The cycliner...check machined surfaves are round ....+/- 0.5/1000" ... no burrs....
Check the vlave at the bottom has not worn....indicated by seating surfaces have sort of compressed and spread out, and the seat it sits on inside.
Check the diapham behind the idle mixture side plate, and give the port in there a bit of a blow out with air...

Checking pressures in the converter....
instructions in older posts....
NOTE: these are measured in inches of WATER NOT inches of mercury as per you run of the mill vac gauge.
I a couple old posts I have posted a pic of a home made water vac meter made out of a bit of oid board and some clear plast tube with water coloured with a bit of food dye......apparantly its meant to be set at a 45 deg angle (see an old post) on mine it didnt make any difference......this home made unit is as accurate as any expensive uint u may buy.

I repeat, I do strongly suspect u have more than 1 issue going on here.
Cheers
Steps
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351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Re: Ram Van with a 400ci and glowing manifolds

Post by 351m »

The zero vacuum I saw was the engine quitting at WOT due to lack of fuel, once I opened the aux tank it ran and I'm seeing 1.5" at WOT

As for the heating up, I have been playing all day and it has gotten better, all things considered it actually runs cooler then the 318 did in this van but once I hit a hill it will heat up some, just doesn't seem to get to the point of causing the manifolds to glow anymore.

On the mixer, I had the gas valve out, and looked at the seat and other areas prone to wear, other then some slight scuffing it looked good, far better then my Ford's 225 did last winter when it was having problems. I will pull the idle mixture plate tomorrow and report back on that as soon as I can, as well as what I find with the converter.

as for other issues, there have been a few people who are getting the feeling that a previous owner has messed with the cam timing at some point causing the difficulty dialing the timing in with the specs provided by the conversion sticker on the truck.

Steptoe
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Re: Ram Van with a 400ci and glowing manifolds

Post by Steptoe »

Fire it up from a cold stand over night.....
Run your habnd over the radiator.....it will warm slightly, but not enough to feel any cold spots, when the thermost starts/opens....and the rpms aroud 1000/1100, the radiator should warm evenly all over....cold spots indicate blocked or partly blocked cores.
Check that bottom hose...the only time these get replaced is when the spring has corroded away...and where do the peices go? and what 'filteres ' them? the cores.
Pull the bottom stop cock (or fan temp sensor) a bit of mig wire with a hook, see whay is jambed in there...if a lot of crap, so will the cores be in bad condition.
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351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Re: Ram Van with a 400ci and glowing manifolds

Post by 351m »

Radiator hoses checked out good, the were replaced by the P.O less then a year ago, and the lower's spring feels good. As for the radiator, I will check that when I can here but right now the engine is hot and there is no room to get at it with the grille and grille guard in front.

So far today I have pulled the vaporizer apart and it was nearly spotless inside, the spring is silver so I'm at a loss on how to tell what it is, the lever was 5/32" above the case and no tears in any diaphragms.

As for the mixer, I tore that apart as well, it has the green spring, no wear on the gas valve or seat at a after I cleaned it out with Kerosene. It did however make the engine a royal pain in the A** to start and keep running when cold, things are much more sensitive since the cleaning. (no vac leaks though)

I'm headed outside again to build a manometer and check the pressures on the vaporizer, any specific number of inches it should be built to?

ttxpc
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Location: Australia

Re: Ram Van with a 400ci and glowing manifolds

Post by ttxpc »

Glowing manifolds, first thing check ign timing, verify TDC and the timing marks correspond. Blocked exhaust is the next thing, melted catalytic substrate, dislodged baffles, kinked tailpipe, seen a lot of weird and wonderfull things over the years, but lean and lpg/propane usually drops the exhaust temp.
LPG turbo V8 tray truck
Twin turbo '66 363 falcon hardtop e85
Turbo diesel 60 series landcruiser

Steptoe
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Re: Ram Van with a 400ci and glowing manifolds

Post by Steptoe »

Cool so u now see how simple the Impco...
All that in good nic and eliminated
The silver converter spring..no faint sign of a bit of orange or 'red' on it?
The manometer..If u look at the picuture, the marks are in inches, go off that.
dualcurve box etc.
I have not played with one of those for near 40yrs and that was on a CNG install...and ended up dumping it.
Txpc post above was going to be my next suggestion....
Find TDC....take #1 plug out, put your finger over, turn engine over jumping starter and when feel presure ..that the compression stroke....now turn engine by hand, a bit of mig wire in the hole, u will feel the piston coming up...and it will stop, then starts to move down...1/2 way on the timing mark , between piont where it stops coming up and where starts going down is damn near enough to TDC.

I dont have experiance with late model dizzy curves ( early model uses manifold vac and are very different in nature between the cent and VA ccaractorisics
Nor do I have experiance with catalylic converters...near all my stuff is 1912 to early 1970s.
The other guys will have to step in here...
But in ther meant time...
Disconnect VA...
what is intial advamce?
what is 1500 rpms, 2000, 2500 and at what rpms is the curve all in at what advance
Repeat with VA connected.

and clean the PVC valve in the rocker cover..wash in kero.
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351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Re: Ram Van with a 400ci and glowing manifolds

Post by 351m »

Pay no attention to the year of the van for this, the engine trans and ignition system are all 1977 Dodge D100 pickup spec, the van's computer is still in and used for the speedometer only.

I will stop and see if my parts guy has any timing tape in stock, the damper has turned and I can't even find the marks with the light.

With the VA hooked up to ported vac the engine misses and surges on the highway, but now it is hooked up to the distributor port on the Q-Jet base(I think... Lower corner of the carb closest to the right bank of the engine) and it seems to run fine there almost like it runs with no VA at all.

Exhaust: True dual 2.5" with glasspacks, no cats, and the tail pipes turn out in front of the rear tires.

As for the converter spring, there is no signs at all of paint, I pulled the lever and spring right out to look. All of my converters have a part number that has "EB" in it though if that helps.

351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Re: Ram Van with a 400ci and glowing manifolds

Post by 351m »

The EB answered my question, its a blue spring in all of my vapourizers, one is an unknown that I will look at further. I have yet to make any further progress on anything though.

Steptoe
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Location: JAFA , New Zealand

Re: Ram Van with a 400ci and glowing manifolds

Post by Steptoe »

the damper has turned .

Pull #1 spark plug, put your finger over the hole and bump the engine over on the atarter till fell pressure
Turn by hand and with a bit of mig wire feel the cyclinder come up
u will feel a piont where it stops moving,
lightly mark the balancer
u with feel another point where u feel ity going down...TDC is near enough to 1/2 way between these pionts
I will stop and see if my parts guy has any timing tape in stock
I know chevs have diferent circumferamce balancers...make sure u get the correct tape for your balancer
OR
Grab the missus taylors tape and put around the balancer
Divide by 36 and mark...these are your 10 deg marks...lay ON/around the balancer and mark off to about 45 degs
number each mark off, do not simply mark froma given distance....the balance is round and using dividers or similar method does take into accout the surface curve of the balancer
make all marks in white so easy to read with the timing light.
I have mine marked then used the edge of a cold chisel to mark position, and numbered punches to number each mark, then painted with white paint, rubbing the excess off leaving what is in the indented punched marks....I also have puntched dots for the 5 deg marks in between

If the balancer has sliped it pays to replace it any way
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351m
Posts: 26
Joined: Thu Jan 06, 2011 3:06 am

Re: Ram Van with a 400ci and glowing manifolds

Post by 351m »

Got a question that may seem stupid relating to this engine... I talked to an installer that has done a few(dozen) 440 powered Dodge Van chassis motor homes. He looked it over, told me to put the power valve all the way in, then back it out 4 turns, and put the stock air cleaner back on instead of the open element one and see what happens. The reason behind the air cleaner was something to do with how the mixer operates. :?: Kind of sounds like something that would apply more to a venturi type system like Vialle to me.

The other thing was that with the tight engine compartment, he said the are may not be flowing through well enough causing less to go through the radiator. Seems he used hood scoops to fix that problem.

Steptoe
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Location: JAFA , New Zealand

Re: Ram Van with a 400ci and glowing manifolds

Post by Steptoe »

He looked it over, told me to put the power valve all the way in, then back it out 4 turns, and put the stock air cleaner back on instead of the open element one and see what happens.
No.
Run a forum search, there is somewhere by C3H8 (member) a post as to the distance from the top of the nut to body...which 9 times out of 10, if havnt a CO anylser or dyno will be pretty close
The power valve only works at WOT...other than that it does nothing in the tuning.
Tuning the powervalve by anything but a dyno is pretty well hopless to get right, but it is possible to get sorta ok road testing
again ..forum search button...or may come across how to in the 1st search...
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