MEP-003a back to life, I hope (fuel system clean up, re-connection switch fix)

[storeman]

Jason,
$65 with new nozzle is reasonable price. Nice jig. Amazing what people come up with with the right machining tools. NJTOOLNUT had a similar idea and produced a great similar compression testing jig/rig. Gauge is broken off on yours but, in my opinion, is not necessary as it indicates restriction on air flow, which would be man issue in the desert with sand storms, but not at home, so long as you check your air filter every few hundred hours.

Jerry

 

[Triple Jim]

Be careful that no significant volume is in your test rig between the cylinder head and the one way valve to the gauge. I've seen compression gauges that come with adapters for different spark plug thread sizes, with the check valve separated from the head by an adapter, and they give erroneously low readings. The one way valve needs to be at the tip of the part that screws in to the cylinder, especially for measuring a diesel's compression.

 

[Jasonz in MO]

Jim,

Very good point, I thought about it briefly but never really considered it until your post. I bought the gauge assembly which does have the check valve at the gauge. My test fitting is made from 1/8" pipe fittings so not a lot of volume but with the hose, air fittings etc it all adds up. I might try to do the volume calculations to determine how much I have added, I bet a smart math guy could figure out a correction table based on the additional volume.

This could explain the low compression numbers I found. All definitely within 15% of each other but all in the low 300's.

 

[Triple Jim]

There are two valves. One is the check valve to capture the pressure at each compression stroke, and the other is the relief valve so you can zero the gauge and start over. The check valve is the one that needs to be right at the tip of the fitting that screws into the cylinder. If you want to know the dead volume you've added with the fittings, you can use liquid to measure the volume before the check valve, if you can get all the air out.

 

[Jasonz in MO]

I'm finally catching on, I hope. With my gauge check valve is at the connector and the relief valve by the gauge. I was thinking about it today and first thought the location of the check valve didn't matter. The cylinder has to compress the air on both sides, which is true on the first compression stroke; however, the subsequent compression strokes would negate the issue. The pressure is captured after the check valve, additional compression strokes balance out the reading.

As you have advised, the additional volume added before the check valve increases the actual volume of the cylinder and affects the reading.

Am I close?

Can't thank you all enough, I've been learning something with every thread I read.

 

[Triple Jim]

Yes, you're correct about any volume before the check valve getting added to the combustion chamber volume. There are online calculators for figuring combustion chamber volume, compression ratio, and compression pressure. But it would be best to put the check valve at the tip of the fitting that screws into the glow plug or injector hole, and then you can use it in the future without a lot of calculations.

 

[Jasonz in MO]

I'll look for a way to install a valve stem into my jig. Thanks Jim.

 

[Jasonz in MO]

I got the injectors back yesterday all cleaned up and looking good but I did screw up. I took one of the flat gasket/washers alone to see if they had any. I left it with the shop. Turns out they couldn't find them but they were nice enough to bead blast it for me! That gasket is some kind of fiber impregnated wire screen. The screen is nice and shiny now and no fiber on the surface. I did try it and it doesn't seal. I'm considering cleaning it with some laquor thinner and coat it with a thin layer of JB weld.

I just looked and they can be bought online for about $5.50 with shipping. Would I be better off just buy a full set?

Guess I'm just anxious to hear it running like it should!

 

[Jasonz in MO]

I tried the JB Weld idea. I smeared a thin layer on both sides and put into a plastic bag. I let it cure between two flat steel plates. Then peeled the plastic off and touched up both sides with a flat file. Put it all together and seems to be working. Time will tell. The engine runs like it should now, hitting on all 4 and sounds strong! No smoke, oil pressure in the 30-35lb range. Very happy with the results!

Now I will focus on the VR issue. I removed the regulation transistor again, Q3 I believe, it tests good with a forward bias of .5VDC Base to Emitter and .5VDC Base to Collector. As recommended I will order a replacement and see if that doesn't solve the problem.

I will keep you posted on my progress.

 

[Jasonz in MO]

Just to give everyone an update on my progress. I replaced the Q3 2N3584 transistor which cross references to NTE384. NTE384 has some higher max current ratings and will dissipate 45w compared to 35w of the 2N3584.

Anyway, this didn't solve my regulation issue. Same problem, at 60hz it puts out a steady 160VAC on the 120 outlets. I plan to set up the VR calibration circuit and test the board. I will report back when I get that done.

 

[Jasonz in MO]

I think I found the voltage regulation problem or at least one more problem... I checked the control windings on the CVT1 transformer is open. Anyone have one in their back pocket? I will start searching the net. Tomorrow I will start calling the suppliers you folks have recommended in the past.

 

[Jasonz in MO]

Update on the -003A. I found a CVT1 transformer close to home. I considered just replacing the whole AC box but everything else tested ok. After replacing the transformer it regulates perfectly.

I'm trying to come up with a good (read cheap) way to load test the unit. Any suggestions?

 

[Grega]

I use our old stove/oven as the wife wanted an updated model. It doesnt get get my genny to full load but around 50-60%. Gets the mep working though.

 

[Jasonz in MO]

Good idea! We have a good used stove in the basement. Which also reminded me I have an electric furnace in the corner of the shop which isn't wired and needs the dust blown out of it! That's what I needed, a kick in the pants to make me think!

 

[storeman]

I got a used 10kw emergency heat backup unit consisting of two 5kw strip heaters from a HVAC friend, along with the squirrel cage to cool it. (The air handler portion of the indoor unit.) It came from a heat pump replacement job. I disconnect one strip to load test the 002a, and leave both strips wired to test 003a.
Jerry

 

[Ray70]

Hi Jason,
Out of curiosity, do you remember what portion of your CTV1 was open?
I have a MEP-002A that is not putting out any power unless I continuously hold the start switch and manually flash the field. as soon as I release the switch, power goes out.
I found H5-H6 on the CVT1 to be open ( actually 15.8 Mega ohms ) which I assume is causing my problem because I was able to isolate the problem to something in the AC control box, but it sounds like I'm having the exact opposite problem that you're having.
Also, how big of a pain was it to change CVT1? Is it a bear to get to all the connections on the large power wires?
Another member had suggested changing the entire AC box, but I don't know if I can afford that. I bet it will cost me a fortune for a good box.