MEP-002A Valve Adjustment Procedure

[LuckyDog]

So, played with my MEP 002A last weekend. Went up to N1OTY's and compared my and his. (His is nicer )

Decided that I want to re-adjust the valve clearance again before pulling the injectors. I will then send them out for test/cleaning/rebuilding.

Is the TM valve adjustment procedure correct??? TM 5-6115-584-12 pg 4-52 (Change #11 installed)

The parts manual shows the crankshaft as even-fire. Both pistons move togther. (i.e. both are TDC at the same time). If I line up A with the pointer, the piston is just starting to go down on the power stroke. BUT when I line up B Cylinder #2 would just be starting the compression stroke, the intake valve would have just closed or be finish closing. Wouldn't it be more correct to adjust cylinder #2 at the A mark? (Turn one full turn after adjusting #1?)

I read the TM procedure for the MEP-003A and looked at the crankshaft illustration. The 002 TM looks like a cut and paste from the 003 manual. Looking at crankshafts, IP operation, Firing orders, I have conviced my-self that it should be one full turn (360°) on the 002 not one-half (180°) like the manual says.

Anyone who knows me, knows I think too much. (and DO too little ) I plan on trying to adjust the clearance by using the A mark for both cylinders tonight and see how she runs.

I did adjust the valves once per the manual. It still ran poorly. I then was able to test compression. #2 is very low, like 175psi vs ~350-400 like #1. When up at N1OTY's, we decided that I AM firing on both cylinders. Lots of white and a little bluish smoke. It will run for about 10 minutes before stalling. Just enough time to get everything warmed up to operating temp. When it stalls - it blows a LOT of black smoke. The IP has moved into the WOT (wide open throttle) position and the selenoid finally de-energizes after it stalls.

Gee, maybe this should have been two thread?

 

[Isaac-1]

For a different take on the same basic procedure, here is a link to the Onan manual for the civilian version of the same engine:

http://www.cumminsonan.com/www/pdf/manuals/967-0751.pdf

Ike

 

[LuckyDog]

Ok, That makes sense with what I was saying. (See page 56 second column in Ike's link)

It should be "A" both times on the 002A.

(The 003A procedure is on page 57 and matches the TM)

 

[n1oty]

So, played with my MEP 002A last weekend. Went up to N1OTY's and compared my and his. (His is nicer )

Decided that I want to re-adjust the valve clearance again before pulling the injectors. I will then send them out for test/cleaning/rebuilding.

Is the TM valve adjustment procedure correct??? TM 5-6115-584-12 pg 4-52 (Change #11 installed)

The parts manual shows the crankshaft as even-fire. Both pistons move togther. (i.e. both are TDC at the same time). If I line up A with the pointer, the piston is just starting to go down on the power stroke. BUT when I line up B Cylinder #2 would just be starting the compression stroke, the intake valve would have just closed or be finish closing. Wouldn't it be more correct to adjust cylinder #2 at the A mark? (Turn one full turn after adjusting #1?)

I read the TM procedure for the MEP-003A and looked at the crankshaft illustration. The 002 TM looks like a cut and paste from the 003 manual. Looking at crankshafts, IP operation, Firing orders, I have conviced my-self that it should be one full turn (360°) on the 002 not one-half (180°) like the manual says.

Anyone who knows me, knows I think too much. (and DO too little ) I plan on trying to adjust the clearance by using the A mark for both cylinders tonight and see how she runs.

I did adjust the valves once per the manual. It still ran poorly. I then was able to test compression. #2 is very low, like 175psi vs ~350-400 like #1. When up at N1OTY's, we decided that I AM firing on both cylinders. Lots of white and a little bluish smoke. It will run for about 10 minutes before stalling. Just enough time to get everything warmed up to operating temp. When it stalls - it blows a LOT of black smoke. The IP has moved into the WOT (wide open throttle) position and the selenoid finally de-energizes after it stalls.

Gee, maybe this should have been two thread?

And it seems to be throwing a LOT of oil up into the air intake at the moment it stalls.

John

 

[n1oty]

Paul,

Have you had a chance to re-adjust the valves??

John

 

[LuckyDog]

I did readjust the valves.

Made a difference using the "A" mark both times. The number 2 cylinder was off quite a bit.

Ran with less smoke on start up.

Still had poor pressure and a but load of blow by. More info on post #16 @ http://www.steelsoldiers.com/auxiliary-equipment/83566-compression-testing-mep-002a-003a-2.html

 

[storeman]

Lucky,
I think you may be on to something. I managed to turn the 002a which is my current project, from white/blue smoke to all black and back to white/blue today fooling with valve adjustments, but using a and b. will try a only. It can't get much worse.
Jerry

 

[storeman]

Lucky,
Tried the valves on A. Got black versus white/blue smoke. Pulled head and checked all out. readjusted valves per tm, back to white smoke. tm has worked for my other 002A's.
Jerry

 

[heritageequipment]

So, has it been determined which one is the correct procedure? I read and reread the TM then performed the procedure and it seems to run worse than before I messed with it. BUT, I just cant imagine how a manual like that can be wrong so I am going to assume I did something wrong. I do agree with LuckyDog, cylinder B is not adjusted during the same part of the stroke as cylinder A when adjusting it 180 deg apart.

 

[LuckyDog]

I still believe it should be A both times. The fact that Jerry's went from white smoke to black smoke leads me to believe this also.

White smoke is unburnt fuel,
Black smoke is partially burnt fuel.

So, I would think higher compression due to adjusting the valve on A vs. B. (White vs. Black)

I wonder if this is why some members have diesels smoking on start up, but clearing up as they warm up? The compression comes up as the engine warms.

A vs B might not be as big a difference on good engines vs marginal engines. Reading Ike's link (page 56) and seeing that the pistons do move together (after removing my head), just convinces me to use A both times. Both pistons will be on the same part of the cycle when adjusted per CUmmins/Onan, and it doesn't matter which cylinder you start with. One of them will always be in the correct position. The other only needs one more full revolution.

That's my story and I'm sticking too it (Unless Tom or Ike tells me different )

 

[storeman]

Lucky,
I wound up replacing the smoking engine. All is now well so I haven't messed with the valves. I did the experiment because I had nothing to lose and was curious. It changed things but would not allow the engine to run continuously. Using the TM procedure did allow the unit to run while producing heavy white/blue smoke.

I must repeat that the TM procedure has worked on all my others. Maybe it accommodates differences in slack between cylinders one and two. Don't know. Have noticed that few are chiming in on this.
Jerry

 

[LuckyDog]

... Have noticed that few are chiming in on this.
Jerry

I think we both agree that doing cylinder two's valve adjustment on A or on B does create a difference. Just neither one of us has done a comparrison test on a known good running motor.

My opinion is an engineering (the·o·ret·i·cal) judgemnet based on the Onan Service manual, the Parts TM, and piston movement observation.

Yours is experiential. At work, I am know as an Experimentalist rather than a Theorist

BEST test would be for someone with a beffy load bank to:
Adjust the valves one way, load test to see what max output is
Adust the valves the other way, load test to see what max output is

The test would take a bit of time though. The valves are to be adjusted at ~72°F (room temp). The load test should be done when the engine is good and warm. So, maybe a two day test??

I'd love to do it but my engine is torn down and I don't have a load bank.

Paul

 

[jbk]

i have adjusted valves as per tm on several 002s and 003s. noticed less vibration and easier starts and have load tested the 002s with 8 kw. the 003s at 12 kw. i think when #1 fires #2s exh. valve is slightly cracked open this will then happen with #1 as b #2 is firing. i will continue to adjust as the manual states as i have had no ill effects from this.

 

[n1oty]

I have a bunch of 1500 watt fan heaters and the CEP distribution box when you are ready to load test.

John

I think we both agree that doing cylinder two's valve adjustment on A or on B does create a difference. Just neither one of us has done a comparrison test on a known good running motor.

My opinion is an engineering (the·o·ret·i·cal) judgemnet based on the Onan Service manual, the Parts TM, and piston movement observation.

Yours is experiential. At work, I am know as an Experimentalist rather than a Theorist

BEST test would be for someone with a beffy load bank to:
Adjust the valves one way, load test to see what max output is
Adust the valves the other way, load test to see what max output is

The test would take a bit of time though. The valves are to be adjusted at ~72°F (room temp). The load test should be done when the engine is good and warm. So, maybe a two day test??

I'd love to do it but my engine is torn down and I don't have a load bank.

Paul