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Fuel pump timing on MD6A this weekend

groundhog

Member
"I am going to try to do the f

"I am going to try to do the fuel injector timing this weekend on my MD6A. Can anyone tell me where the marks are on the flywheel and block? I have looked for these marks and can not find them.

Also, It says I need to see the valves rock, so I need to remove the valve cover?

Thanks,
groundhog
ps. below is copied from the shop manual and mentions the marks I am referring to.


75. Adjusting the BOSCH injection pump
a. Turn over the engine until the valves in cylinder
No. 2 “rock’. Continue to turn over the engine in
the normal direction of rotation until marking 10
on flywheel coincides with the marking on the
block.
b. Remove the pump inspection cover and check
that the marking (1) coincides exactly with the
pointer (2). Adjustments are made by slackening
the pump securing nuts and turning the pump.
c. Tighten the nuts.
d. Check the setting by turning over the engine 1/4
turn in the opposite direction of rotation, then
back again to the “10,’ marking on the flywheel.
Check that the marking (1) and the pointer (2)
still coincide.
e. Fit the inspection cover with the rubber gasket."
 
"The tdc mark should be at top

"The tdc mark should be at top of the flywheel when the rocker arms change. You may have to take a fine sand or wet paper to get the paint off to see it, the same for the '10' mark if none, make some. Get the engine at TDC (rocker changes), make a mark at the flywheel and block. Measure the flywheel, divide by 36 and make the '10' mark."
 
"Well,
I did something like


"Well,
I did something like a "/ C" and then about 3-4 cm from that I saw something like a "9" and "B" maybe?

I looked really hard at that / C and tried to make it into a 1 0, but I'm pretty sure it's not.

I saw no marks on the engine block.

So, If I understand you. I will remove the valve cover (which is the cover with the oil cap), move the flywheel (which is the wheel with the belts on it) just until the rocker #2 is just perfectly in the middle of it's position. Then I will either find or make a mark at the top of the flywheel which will be .. Zero degrees?

Then, I measure the radius and calculate the circumference of the flywheel, divide by 36. Move the flywheel this distance in it's normal direction (or backwards?) and make another mark for 10 degrees.

I guess this is where the fuel for #2 is supposed to start squirting.

I do the gear and pump adjustment (I guess I'll figure this out when I am actually doing it?) to this flywheel setting.

Which is cylinder #2?

Will it be obvious where the middle point in the valve rock is? Is the middle point the right point or just when it opens or just when it closes?

WHen they talk about adjusting the pump, you just move the whole pump a bit? You don't play with the gears at all do you?

Will I need to replace gaskets? Will the standard automotive cut-your-own gasket material be ok?

Thanks so much for your help.
groundhog"
 
"And one more thing that is on

"And one more thing that is on my mind.
My compression test showed 400 psi which I belive is high. Think 330-350 is supposed to be normal?

Anyway, how do you get high compression? THe only way I can think of is that you start with a motor that has good rings and stuff, then you add LOTS of carbon to the point that you reduce the volume of space in the cylinder.

If this is the case, and I try to do a fuel timing procedure, will I be doing it accurately? Will I even find the sweet spot for the timing if I use the knocking sound as a monitor to key off of.

I already suspect that I am firing only on one side anyway (previously changed all filters, elect fuel pump, rebuilt injectors).

gh"
 
"When cyl 2 (rear) cha

"When cyl 2 (rear) change, cyl 1(forward) is in TDC. You will see one valve comming up, and immedeately the other one starts going down. Take down the cover on the pump and do a rough check. It is safer to borrow Your wifes tape measurer from her sewing box and measure around the flywheel than trying to measure the dia and calculate! (Diameter x 3,14) Note that the '10' mark should be before TDC. Loosen (not take off) the nuts holding the pump and just twist it in the right direction. Make a mark at the pump and block before You start so You may get back again. You may 'test' the pump and injectors by taking out the injectors, loosen the injector line and put the injectors back on the lines so You may see them spray, then cranck the engine and watch the spray. (This test may be a bit messy with iesel spill around.) I doubt Your engine is running only on 1 cyl, it would die when put into gear. Do a test by starting the engine and just loosen one of the fuel lines to the injectors at a time and notice the rpm drop.
As for the comp test reading, be happy with the 400 reading, they normally give the min required comp reading. The more You advance the timing, the more of the typical diesel knock You will get, there is no 'sweet' spot on this engine!"
 
"Well, this is what happened..

"Well, this is what happened...

I found the "10" mark. So I lined it up with the mark on the block.

Then I removed the inspection cover on the fuel pump to see the mark. It seems to me that it was lined up fine.

Somebody mentioned that you can be 180 degrees off and still have the marks line up? Does that make sense and if so, is it possible my MD6A has this problem?

THe other thing I was wondering, is it possible that the marks can be lined up and because of gear wear or something, the timing is still be off?

Then, I read this other simplified procedure for adjusting the timing, where you just loosten and twist the fuel pump and listen for the engine sound and inspect the exhaust smoke. Well, when looking at the mounting bolts for the fuel pump, it seems to be twisted clockwise (looking from flywheel side) as far as possible already.

So basically, nothing was done to the engine. It still smokes light smoke all the time, and black smoke if you ask for more than 1/2 thottle. Not much power.

On the fuel pump adjustment. You know it really doesn't seem to give you much adjustablity. It looks like you can only move the fuel pump like 1/4 inch. The left hand bolt is slotted, and the right side (the engine side) seems to be not slotted. So that tiny bit of adjustment can make that much difference?

Thanks for any observations..
gh"
 
"First of all, You have a Volv

"First of all, You have a Volvo Penta and they smoke black under load. Whenever You see a boat with a 1/2ft rubber hose sticking out from the exhaust outlet, You know he/she has a Volvo Penta onboard. If Timing is correct according to the book, the only thing You may concentrate on is to get the engine temp up.
You seem to have compression, I do not know if You have tested the injectors attached to the pump as I mentioned earlier, but if they are OK, the missing part is temp.
Lifting the head and cleaning the cooling channels is not much of a job, a bit messy perhaps. The only cost wouls be a head gasket and valve cover gasket."
 
"Yes, they were pulled and reb

"Yes, they were pulled and rebuilt so all the internals and nozzel are new on the injectors.

Do you still think I should pull them and observe the spray? Could the pump not be able to generate the pressure required to turn on the injectors fully?

I measured my engine with a digital thermometer about 6 weeks ago and it was running about 77C on the outside of the block. The temperature gauge read a little above 80C. I'm not sure if this is normal or not. It was also done before any work was done on the engine.

I think I need to get a mechanic that is very familiar with these engines and have him look at it and tell me if the thing is now working as it should. I have no previous experience with diesels of any type, let alone a penta marine engine.

I still feel something is wrong however, just by watching all of the other sailboats go wizzing by when under power.

And I did meet a marine diesel mechanic briefly in the marina where my boat is. He came over to my boat and had me turn it on. Within a few seconds after the engine was on, he said without any hesitation, that the engine didn't sound right for a two cylinder. He said it sounded like it was running mostly on one. Then he put his fingers overtop of the cylinder and one was cooler than the other. I have since, used my digital thermometer and the forward (#1?) cylinder lags the aft cylinder by 10-15 degrees F when the engine is warming up.

So how do I go about getting the engine temperature up?

Thanks,
gh"
 
It is probably not the forward

It is probably not the forward cylinder that 'lags' but the rear has a partly blocked circulation which make it run hotter.
 
"Morten, and Sidney, I had a s

"Morten, and Sidney, I had a similar problem a few years back. ( well, a lot of years) I am working from memory as I have no manual, so Morten please check and correct. went through same troubleshooting steps as You without success. finally pulled head to find injector spray hitting end of sleeve. result was drip instead of spray. in my case, sleeve was streched when installing injector. seems I read in earlier post mechanic gave washers to put under injectors. does this engine use washers? could injector be raised out of position? this really sounds like an injector problem to me. if You are going to pull head,(sounds like You should) look closely at this."
 
Scott:
You may be right as th


Scott:
You may be right as the use of copper sleeves normally excludes the use of sealing washers.
 
"Thats a great idea. I think I

"Thats a great idea. I think I'll try that.

If I pull the injectors again, I can answer several new questions...

-I will try them without the washers to see if that is any different.

-I noticed that the spray holes are not symetrically located on the nozzle tip. I guess cause the injector enters the cylinder at an angle. WHat is the chance the rebuild guy put the spray holes in facing the wrong way? Anyway, I'll check that.

-If I let the injector spray outside the engine, I will see if the pump has enough pressure to open the injector properly. Is it possible that the little pump "piston" or whatever can loose compression also?

Thanks
sydney

ps.. To run the injectors outside of the cylinders, don't I have to bend those small fuel pipes quite a bit? Will they crack?"
 
Do NOT try to bend the fuel pr

Do NOT try to bend the fuel pressure lines to the injectors! Just loosen at the pump and direct them so You have the injector free of the head.
It is possible for the pump to loose pressure.
 
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