Timing a Perkins 4.108

[Mike Sibley]

I have a Perking 4.108 in my Pearson 365. Recently, the high pressure fuel pump had to be rebuilt due to a leak. A mechanic removed the pump, had it rebuilt and reinstalled it. Following all this, 1) the engine is noticeably harder to start, although it is acceptable, 2) the pinging noise of the engine seems noticeable harder/louder, and 3) there is a puff of white smoke when the engine starts, which I did not notice previously.

I'm not a mechanic and am not sure I have a problem, but it occurs to me that the timinng may be related to these changes. Even if it is, I don't know whether the timing was off before the work or if it is off now. Any suggestions or help from the mechanically inclined would be greatly appreciated. I sure would like to quiet the engine a little and have it a little easier to start.

[Maddog]

Make sure the timing mark on the pump bracket matches up with the one on the block. It should be near the upper left bolt as you view it from the rear of the engine. Mine looks like a file mark across the bracket and were it attaches. Search the for the shop manual here on this site. It will tell you all about it.

[Stillraining]

I agree....But..... play with the timing buy rotating the pump a tad until it sounds and or preforms like it use to....rather the marks realign or not.

The pumps internal timing may have gotten changed just a tad and its not going to be the same external line up if that's the case.

[Maddog]

Good point. I was reluctant to suggest rotating the pump while the engine was running. I've never done that on the perkins. I imagine it is the same as rotating the distributor on a chevy 350 small block. Take it slow and easy -- or -- roate while the engine is off till you find the right adjustment. If it is off, it will not take much to adjust it. Measure in hairs.

[beneteau-500]

question did the mechanic remove and refit pump if so why didn't he check it and and make sure it was all working correctly

[Maddog]

Good Question, my shop accepts the old pump as a core exchnage and has rebuilts on the shelf that have been adjusted and bench tested.

[avazquez]

Forget about the old marks! When they rebuilt your pump they changed the timing because they probably didn't have the Perkins special tool. Now, just rotate your pump a little bit and run the engine. In my case I had the same symptoms and if looking at the front of the engine I had to rotate the pump counterclockwise about 1/16 of an inch at a time about three times until the white start up smoke went away and the engine ran smoother.

[Mike Sibley]

Thanks for adjustment suggestions. I'll try adjusting the timing in small increments and see what happens.

[Mike Sibley]

Well, the plan of rotating the pump didn't go too well. The pump is secured by three bolts. I can reach two of them, but the one on top next to the engine is totally hidden by the heat exchanger, high-pressure fuel lines, etc. It appears that removal of the heat exchanger would provide access to the bolt, but removing the heat exchanger is no small task, and besides, it seems to me that the heat exchanger needs to be in place when running the engine. I am not a mechanic, so I recognize I may be missing something. Any suggestions on how to loosen that third bolt so that I can rotate the pump and adjust the timing?

[Minggat]

There are different configurations for the 4-108 but I don't think the heat exchanger would be different. Point is, yes-that one bolt is tough to get to, but doable. If you're just loosening it, get the smallest socket you have on it with the correct extension(s). A little wiggle (like you'd get from using 2 extensions instead of one) might actually be helpful.

If you're removing the pump altogether, some people replace that one bolt with an allen head bolt to make it easier. I've been able to do it with sockets/extensions.

Hope that helps.

[Maddog]

If its like mine, that one is the Allen Head. I bought some long (6") Allen/Hex drives for my socket drive. Using these and a number of drive extenders I was able to get at that SOB. I think I was able to do it around the high pressure lines.

Good luck.

[Stillraining]

Perkins re-engineered their heads on other models in their line to exhaust to the opposite side of the engine, for the obvious reasons your finding out.

[goldbeard]

You are going to want to buy both of these puppies! Trust me.
Get the appropriate size for your set up.
You may need to be creative and buy specific sizes of driver extensions.
You may need to take things apart, hose, fitting, something....start with the easiest, then move on the the harder.
Put on some chill music, have a sports drink and water handy, and try to stay calm.
Many of us have been there before.

Also, what does you mechanic say about how the engine runs?

And, go on someone else's boat who has a Perkins and is happy with it, listen to it, decide from there.

[Jesse]

Yep I know it sounds silly but they do exist and I'm told they work just fine. I'm not certain what triggers the light or how it is sensed but they are available online and would realy simplify a 'pain in the ass' operation that can become far too involved.