Aligning Fuel Injection Pump Perkins 4-108

[CTRDVM]

Group,

This is my first post, but I have enjoyed reading many forums on here. Very informative!

Question: I have removed my fuel injection pump and had it rebuilt ready to reinstall after finding diesel fuel leaking from the top/(stop/throttle controls) on a recent cruise. Although a very difficult job to remove, it appears the spline can only go back in one way. However, the manual talks about aligning timing marks on the fuel pump flange to ensure the timing is correct on re-installation. I did not see these when I removed it so I drew one with a sharpie. Unfortunately, the rebuild company painted the pump and thus eliminated my handy alignment mark...

Bottom line: It seems hard to believe that I will not have this pump within millimeters of perfect even without this alignment as the three bolts holding it on only allow so much rotational play anyway (and only rotational play from what I can tell...) once the spline is engaged within the engine. I assume the spline or motor will not be damaged if I am off a millimeter or two one way or the other?

Any words of wisdom before I blindly go bolting this thing back on?

Thanks in Advance!

[Stillraining]

Been there.....Scibe into the metal next time...There should be a factory scribed line on both the pump flange and the timing case cover though...if not its not totally the end of the world but there are several degrees of play as you noted and this will affect performance. You will have to "ear" it much like rotating the distributor in your car to advance or retard the timing...Try a couple places in all load and RPM ranges an see where she preforms the best.

Whatever you do don't rotate the engine without the pump back in place! and you may get lucky..

If it won't start it will need re-timed by a mechanic as its all about NO# cylinder being in top dead center and your pump internally and externally timed to fire the same time..so its actually best to set the engine up first before mounting the pump so your not just taking a chance on it...Not that you cant do that yourself but you will need a manual and basic understanding on how it all functions...Do not try to internally time your pump yourself though.

[MaizieDerrick]

aloha.. if you have a slot on the spline you should be able to stick it in the hole and go.. sometimes there is room to move it for fine adjustment like in a car engine and that you can only play with.. you cannot hurt anything either way so dont be afraid of it..derrick

[CTRDVM]

"Stillraining" thanks for the prompt reply! I did set the flywheel timing mark to top dead center before removing pump so that if it got bumped for any reason I should be able to reposition it. Barring for any unforseen mistakes it sounds like I am in good shape to experiment a bit with the pump without fear of major catastrophic part failure/damage. Frankly, I took a bunch of pics of the flange, bolt positions, etc before removal so I have a pretty good chance of being VERY close. "MaizieDerrick" also gives me confidence I can bolt on and go from what I have done to replace within a close tolerance.

Thanks guys! I was dreading an 11 hr drive (one way) to the boat over the holidays only to find it was unable to start or worse yet, I really screwed things up!

Hopefully this will mean a week of cruising the lower Keys thanks to your advice!

[fareweather]

Not sure about your injection pump specifically but there might be a place where you can insert a dial gauge and set the static timing to a certain spec. Pretty easy to do if you can borrow a dial gauge (maybe need an adapter as well) and find the specs/directions.

[Sailmonkey]

You have to be careful with this. Not only does the pump need to be corectly positioned (shaft rotation) but it must be positioned in correct sync with the engine. ie if the engine begins wants to begin fuel delivery 10deg before TDC, you need to set #1 cyl up on TDC and make sure #1 pump/plunger combo has begun fuel delivery on the pump.........once this is done you should be able to bolt the two together.

[Stillraining]

Ya..I said the same thing you just explained it better...You must have went to collage..

[CTRDVM]

Group<
Just wanted to post a follow up to this question. As I had left my engine in a known position in its flywheel rotation when I removed the pump and the spline on the pump is keyed so it only goes back in one way I was only left with matching the body of the pump to the engine housing (timing mark - original question) to worry about. I managed to get this very, very close due to all of the photos and marks I made prior to removal. Bottom line: She started up just as quickly as when I change filters & bleed engine regularly... So all is well! Thanks to all that posted info. I really appreciated the words of advice and encouragement!

[Chief Engineer]

Doesn't it just give you a warm fuzzy when that happens?

I am serious......

Well....maybe not a warm fuzzy but a sense of accomplishement on a job well done.

Good Show, my friend

[CTRDVM]

Accomplishment. Absolutely! There are days when sailboat ownership is no fun, but it only takes one GREAT day to make me know why I love cruising! This was one of them. Although most others are turning OFF the engine and sailing along merrily in good weather!

[Stillraining]

Good Job Captain

[dancamp009]

This might sound stupid, but I'm still wondering which direction (besides opposite of the flywheel ration) should I turn the injector pump to advance the timing on a Perkins 4-108 with a left handed prop? Remember, the injector pump fits in facing the same direction as the engine.
Question #2: I have a left handed prop. Is prop direction determined by the transmission or the engine? If it is dertermined by the engine, then I guess I would have to go the opposite direction to right handed prop users.

[doog]

No replies to this question as to way to turn the pump in order to advance the timing? I see this is an outdated conversation but I'm double-checking this because I'm about to adjust the timing myself since I first built my engine 20 years ago. Just look at the water pump rotation and this will give you your injector pump rotation as well because they're both driven by the same gear. So that should tell you which way you need to turn the pump to advance the timing and it's counter-clockwise. In my case I want to just retard the timing a bit to make the engine run quieter and smoother. Too far Advanced and it clatters horribly, retarded too much and it smokes. But it will sound very smooth almost like a gasoline engine. I recall doing it originally and it wasn't hard.