Hey guys, here's what I've been up to lately.

(sorry for the crap pics and video -- I've lost my camera so I'm using a cell phone)



I've always been bothered by the idea that in most cars you really don't have a way of knowing how clogged any of your filters are. So I decided to do something about it.

I've been working on creating a differential pressure sensor setup so that I can measure the pressure drop across my fuel filters. Its based on a motorolla differential pressure sensor:



I soldered up a little board consisting of a power supply and an op-amp in order to boost the output of the pressure sensor so that it can drive a gauge:





to plumb this sensor into my fuel system, I assembled two brass 'tee' fittings. I used 5/16" barbed fittings for the fuel line fittings, and used an 1/8"
barb for the pressure sensor line. thus, I'm 'tapping' the fuel lines before and after the fuel pre-filter, so that I can I measure the pressure drop across it.

The fuel line I'm using is 1/4" tygon F-4040-A from mcmaster-carr. Tygon is a transparent tubing which is resistant to fuels (its the only clear fuel line I know of). The 1/4" tubing stretches to fit over the 5/16" barbed fittings as well as the mercedes fittings and makes a good seal without the need for hose clamps (I'm not using any hose clamps on my entire fuel system).



I housed the electronics in a disposable tupperware container.





here's a crappy cellphone video of the setup with the engine running (note: the sound in these videos is completely corrupted):

http://www.youtube.com/watch?v=ZEmNuHfVL18

here's a video of the gauge:

http://www.youtube.com/watch?v=Ksm4L9hBoPs

the needle really bounces around like crazy. the fuel pressure must be varying wildly as the lift pump goes through its pumping cycle each revolution.

I haven't printed up a custom gauge backplate, so I translate the voltage readout on the gauge (averaging about 1.5 volts) into a pressure using the datasheet. The output is linear, and a full 5 volt output would translate to 1.5 psi, so 1.5 volts translates to about 0.45 psi.

I'll try swapping out a fresh fuel filter and see if that makes any difference on the pressure drop.

after that I'll plumb in a second sensor to measure the drop across the main fuel filter, as well as a third absolute (rather than differential) sensor past the main fuel filter to measure the total pressure drop of the fuel system.

Oh, I forgot to mention -- I went down to the tax assessors / collectors office the other day to have my title and registration updated to reflect the fact that my truck is now a diesel. This turned out to be a piece of cake.

When I explained to the clerk that I replaced my gasoline motor with a diesel, she had to go ask her manager what to do. Clearly, she doesn't deal with screwballs like me very often

It turns out all they do is check a little box labeled 'diesel' in their software, and then give me a new registration. I'm not sure they even updated the title record at all.

However, the only place this change is indicated is on the invoice sheet on which my registration sticker is printed. So I'll probably hang on to that and take it with me when I get the truck inspected, just in case they give me any grief about having the "wrong kind of engine" .

This was really a sigh of relief for me, as I had half entertained the idea that they would simply tell me "you can't do that", and then I'd be stuck (I had called them up before I began this project, but I'm not sure the clerk I spoke with really understood what I was talking about). So it appears this is legal and kosher as far as Texas is concerned, but I'm pretty sure it isn't legal as far as the EPA is concerned. I remember seeing a policy document from them online a few years ago which stated the requirements for legal engine swaps. The requirements were:

1) engine can't be older than the vehicle (ie, you can't put a 454 into a modern car)
2) the engine had to be available as an option from the manufacturer for that model year.

Its #2 that would trip my swap up. The way I interpreted this was that you can swap, ie, any honda civic motor into any other honda civic car as long as that motor was an option for the model year in question. But in my case, not only am I swapping an engine from a different manufacturer, but there was no diesel option at all for the 1967 c10 pickup.

However, the wildcard here is that my truck is a '67, and I'm pretty sure the first clean air act wasn't passed until 1969, so I'm not sure the EPA has any jurisdiction over my vehicle anyway. At the very least, at the time of manufacture there were no emissions equipment or requirements for my truck nor my mercedes engine.

So as long as I don't get pulled over by some sort of EPA official I guess I'm in the clear (at least as far as the state of texas is concerned).

I don't think it will really matter with respect to the EPA, because if Federal Law exists, state law can't contradict it (unless it's got a clause that allows for it.) and Diesel swaps, afaik, are legal just about everywhere (except probably California... damn CARB.) or at least have a "proper channel" that can be followed to make them legal, if nothing more than state inspection.

EDIT: Ok, apparently, the EPA doesn't approve, and Texas doesn't "get involved" with the actual inspection process that outlaws it. So, you're safe until you get pulled over by the NHTSA or EPA

I finally got around to installing an exhaust gas temperature (EGT) probe. (pics: http://jason.pepas.com/photos/pyrometer/)

Initially I had great difficulty drilling into my manifold. It seemed the cast iron was very hard.

So I attempted to anneal it. I heated the spot I wanted to drill with a MAPP gas torch until glowing red, and then let it "cool" in a wood fire overnight.



That, combined with some brand new cobalt drill bits made the drilling much, much easier.

Here's the result:

Cell,
Next time you need to drill some hard metal, get a masonry bit. Sharpen the carbide tip on the same angle as you would a high speed steel bit, a stone wheel in an angle grinder will do it. The bit will drill through most metals, even tool steel. I have watched them drill through a file. Its handy when drilling a broken high tensile stud out. You could most probably drill a hole through a cobalt bit if you really wanted.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Howdy from just a few miles up the road!

This thread involves two of my favorite things: Diesel engines and free software!

I am a big GIMP fan and run Linux on all my computers at home and at work. It was cool to see Gnumeric used to display a spreadsheet...

I would like to swap a high-output OM603 six-cylinder engine into a sleeper car and enjoy the torque, mileage a cool factor! I wish I had time to play with this idea.

Keep up the work and keep us posted!

Kevin

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Is this beast going to be eligible for the mileage badge from Mercedes ? Great job and a blast to follow.

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92 500E Silver 66k
82 Porsche 911SC 84K
68 Cadillac ( Gone Now )
03 Suburban Z71 200K
85 300SD 217k From Original Owner ( Dad )

SO how is this coming, it's been awhile since an update!

Hey Cell, where ya at, Im undecided wether ill use the 292 with duel fuel or a a spare 617 in my old GMC.

Time changes situations sometimes, the 250 and 292 kept being developed south of the equator after they went to v6's here.
Lotus redesigned the internals some and they got crossflow heads and mpfi.
im talking to a connect in Brasil about getting a head and manifolds for this 292 that was yanked from this ole blue pickup.

This is a really cool project.

I really love 60s/70s American pickups, so this combines two of my favorite things. I like it almost as much as SBC Jaguars.

[QUOTE=Grey;2881201]This is a really cool project.

turns out the new south american derivitive of the old chevy 250 is not crossflow

Google Translate

http://www.youtube.com/watch?v=SDncupbn50c

Im gettin a WoodIe,

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On your EGT sensor, on my semi, and on most of them, the sensors are placed in the down tube past the turbo, exhaust pipe is definitely easier to fabricate a spot than the manifold.
I am curious to see what exhaust temps you come up with! I run a 0 backpressure muffler on my semi, and that has lowered the temps quite a bit; food for thought!

Great project!