I claim no credit for this advice - the following notes were copied & pasted from a post on this very Forum a few years ago; but it worked for me, so I thought that I\'d copy and paste them back again:
It\'s fairly easy to do. First you take a scribe or pointed sharp object and scratch the pump and engine well to mark where the pump is now. Since left and right are easily confused depending on how you look at the engine and when discussing rotation I use a simpler explanation.
The first 3-4 MD6A I set I used all the correct timing procedure, marks,> rotation and counter rotation check again bla bla bla and followed the book. This is a long and lengthy process and expensive to have done because of the time consumed. When they were finished I looked at the results and played with them. I determined there was a fairly large "comfort zone" in timing that the MD6A\'s were happy with, performed well and smoked little to none.
If your timing got a bit behind you suddenly get mass smoke(black) when working hard, slight smoke (grey/white) when cold and sometimes even when warm at idle. If you get a bit ahead you get "kick back" when trying to start and a very loud and obnoxious diesel knock that would make an old Yanmar YSB-12 jealous. Anyplace in the middle is fine, maybe not perfect but the Volvo will be happy and so will you.
To advance the timing simply loosen the nuts that hold the pump enough that you can use a large set of channel locks or a rubber or plastic hammer, or crowbar (whatever works) and twist or tap it the opposite direction of your raw water pump rotation. Just pull the cover on the raw water pump and look at the impeller to determine which way it is turning (it never hurts to look at it anyway) and to advance the timing move the pump the OPPOSITE direction.
Only slightly move the pump enough to tell you moved it. Now snug the nuts back to almost full torque and give it a work right there at the
dock. Did the smoke clear up some? Better power? Slightly more pronounced diesel knock? If so repeat the process until you reach the point where you can have full throttle and advance the combi enough to pull the engine down a bit before you see any signs of black smoke.
Normally I\'ll start mine up, allow it to warm up then advance the combi to full speed of the engine. At this point I advance the combi
slowly until I hear the engine working hard and check the exhaust. There should be no smoke or only the slightest hint of smoke but not objectionable. At that time I will advance the combi until I actually pull the engine down 100-200 rpm from full speed and then you should see some smoke even with a new MD6A or 6B.
Remember your engine is working alot harder tied to the dock at full prop pitch than it would be underway so underway there will be less
smoke.
I talked a fellow through this on his mobile/cell phone about 3 months ago. It took him more time to find his tools etc than it did to set his timing.
On his first advance almost all the smoke was gone and it started
better. He quit right there and was happy even before more tweaking. His mechanic had told him days before he needed injectors, injection pump work and gave him a $2100 USD estimate. In the end it cost him 2 hours of his time and a 40 minute long distance call to me. This guy is a realtor and his mechanical experience prior to this was 3 lawn ower spark plugs and an automotive oil change.
Just remember you CAN’T screw this up. If it gets to be too much, you get cold feet, you decide to let the mechanic do it or whatever just twist the pump back to your marks you made and tighten it back down, no harm done.
The only problems I\'ve had with helping people through email or the phone were they forgot to tighten the pump back down before trying to start it or never loosened it enough to move easily and had a hard time adjusting it.
For all of you with different brands of diesels it is also this easy.
Even if you don’t know which way to spin the pump for advance it\'s easily determined. Mark it, Move it slightly and start it. If you advanced it the diesel knock will always be more pronounced and the engine more peppy (but don’t do it unless you have the smoke described above) if you retarded it the start may be harder and the smoke will definitely show up or increase. Again if you think it\'s not right put it back to your marks and tighten it down,no harm done.
Lastly with this in hand, and your knowledge you can ask your mechanic to do it. Since you know now what he has to do, and how he has to do it, he\'ll have a hard time riding the clock or "pumping up" the problem or the work. It should NEVER take more than 2 hours of his time.
Claude
I hope it proves as helpful to you as it was to me,
Bob.
________________________________
From: Bruce <bruceandruby@...>
To:
AlbinVega@yahoogroups.com
Sent: Friday, 6 January 2012, 6:04
Subject: [AlbinVega] Re: Fuel pump timing this weekend...
Volvo MD6A fuel injection pump flywheel timing marks. Here is a photo of the #10 mark on the flywheel, and the alignment mark on the block:
View the full album on Photobucket.
s1095.photobucket.com
