GM 3,0 L Ignition

[affa]

Hi<br />Ive replaced my 1986 merc 140 with this 2002 mod, I was missing one plug at the EST distributor the engine came with, so I put on my old delco distributor, and timed it to 8 dg BTDC, now I have a knocking noise at the top cover area, I have adjusted the valves with an extra 3/4 turn after the play on the pushrods where gone, can this noise be "pinging" because of incorrect timing, or can it be the valves? <br />I also think the waterhose from the circulation pump is very hot, but the temp gauge is fine.<br />Regards<br />Affa

 

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

Timing on that engine should be 4 degrees if you are running 89 octane or 1 degree if you are running 87. Even at 89 octane and 4 degrees I got slight pinging at WOT after a few minutes, but I reset it to 2 degrees and she purrs like a kitten. 8 degrees will burn those pistons up in no time. Who or what told you 8 degrees was the correct setting?

 

[affa]

Re: GM 3,0 L Ignition

Hi, and thanks Steve!<br />Since I used the old ignition, I timed it after the specs for the merc 140 which was 8 dg, but now Ive been out testing the boat and when I got the ignition at 6 dg after (i couldnt reed the marks, but it was between the to latest marks) it ran fine, but I measured the volt at the coil, and it was 11 at +, and 9 at - , I think there is suposed to be a lower voltage after what Ive read here, was wondering if that could have anything with that late timing to do?<br />thanks again!<br />Regards<br />Affa

 

[affa]

Re: GM 3,0 L Ignition

Hi<br />I forgot to say the voltage was when the negine was running, <br />I was wondering if I should give the valves 1/4 turn more so it became 1 turn total?<br />Can that help for the slight pinging Im hearing?<br />Regards<br />Affa

 

[affa]

Re: GM 3,0 L Ignition

Hi<br />I also forgot to tell that the lowest octane we can get here in Norway is 95 octane, and I ment engine not negine <br />Regards<br />Affa

 

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

Coil voltage should not affect timing. Your voltage sounds about right. <br /><br />If it's actually pinging, it's not the valve train making noise, though it does sound exactly like chattering lifters. Pinging is pre-ignition, meaining that the spark is coming too early and the explosion is occuring while the piston is still approaching TDC. Obviously this is not good because for a split second the combustion is trying to stop the engine or turn it backwards. Causes all kinds of nasty things like bent connecting rods, smashed bearings, and see-through pistons (burn-through on the top). You can try the extra 1/4 turn on the lifters, but if she's still making noise I would set the timing for 3 or 4 degrees and see what happens.

 

[affa]

Re: GM 3,0 L Ignition

OK, and thanks Steve!<br />Ill work with getting the plug Im missing for my delco EST ignition, it cant do any harm running it this way for a while?<br />Regards<br />Affa

 

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

If it's detonation you can definitely blow the engine running it like that. I'd be careful, try to get it quieted down.

 

[deckhand]

Re: GM 3,0 L Ignition

Hi,<br /> If the missing plug is the three connector "timing plug"- has two pins jumpered with a white wire and one long black wire, you are going to have to change the way your shift assist switch is wired. Delco originally supplied this plug to set base timing- when the ENGINE IS RUNNING you supply 12volts (B+) to the Black wire and it put timing in base mode for adjustment. Mercury uses this to take load off the gears for easier shifting- your original shift assist switch was set up to ground the points momemtarily. You will have to get rid of the ground connection to the switch and connect it to a purple wire on the engine and the other side of the switch gets connected to the Black wire from the plug. This way every time you shift B+ gets applied to the Black lead and momemtarily puts it in base mode- allowing easier shifting. Another benefit- to time engine WHEN IT IS RUNNING ONLY- hold down shift assist lever and it will go into base mode set your timing and your done. By the way Mercury is now recommending 1 deg. AFTER TDC as timing for 140's of that year.

 

[affa]

Re: GM 3,0 L Ignition

Hi and thanks!<br />Yes it is the three wired plug Im looking for, I hope I soon be able to get it, I cant get it here in Norway.<br />How can I find out if its detonation? Can I hear some noise from the engine then, it runs fine like this, but Im a little bit worried, hope to change to the EST asap.<br />Thanks again<br />Regards<br />Affa

 

[mickey1]

Re: GM 3,0 L Ignition

hello affa ,i concur with oldhand, the newer 3.0 liters are a higher compression ratio, 9.25:1 so 1 deg atdc is required

 

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

Quick question, say I bought a 2002 base merc long block (3.0) for my OMC powered boat.... Should my timing also be 1 degree ATDC? I was getting pinging at 4 dedgrees BTDC, but I've eliminated it by going down to 2 degrees BTDC.... should I play it safe and go to TDC or even 1 degree ATDC?<br /><br />...Also, OldHand sounds like he's right on the money here. I have a wiring diagram for a merc engine with the EST, and it shows +12V going through the shift interrupt switch and to the black lead on the timing shunt plug....

 

[affa]

Re: GM 3,0 L Ignition

Hi, and thanks!<br />I did a compression test, and it was 180 on all cylinders, so this make sence to me.<br />I was wondering if my 3/4 turn on the valves could have anything to do with a slight bug I got if I accelerate hard from standing still?<br />The engine looked quite new when I replaced the cylinderhead gasket, when I looked at the pistons, and Ive read there should be a full turn on new lifters.<br />The carb is rebuilt, and worked fine, but worked different the later the timing was set.<br />Regards<br />Affa

 

[deckhand]

Re: GM 3,0 L Ignition

Even in Norway you should have a Mercury or Mercruiser dealer anyone can order the plug- hell the engine should have come with one. Maybe like me the techs have a couple in their tool box. But no matter- it is the same plug on 4,6,8 cyls. Even Indmar and PCM engines used this ignition for several years ie: Mastercraft. Call all the dealers around, you are looking for the Timing shunt plug for a Delco EST Inigition.

 

[akriverrat]

Re: GM 3,0 L Ignition

go here http://marinemechanic.com/site/page6.html mercury section and volvo section have imformation on est. kodiakmarine.com will sell you the plug.

 

[affa]

Re: GM 3,0 L Ignition

Hi<br />Thanks alot guys!<br />I will get it, its just a matter of time!<br />Thanks again<br />Regards<br />Affa

 

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

Hi Affa,<br /><br />I found that the OMC shunt is OMC p/n 986662, retails for $6.50. Hope this helps.

 

[affa]

Re: GM 3,0 L Ignition

Yes!<br />Thanks alot Steve!<br />Regards<br />Affa

 

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

No problem! If you have a hard time finding the OMC part, the Mercruiser number is 817374A01. <br /><br />I think my next boat will have a mercury/mercruiser in it simply due to the fact that the mercury parts express web site exists!<br /><br /> https://www.mercurypartsexpress.com/ <br /><br />Put in your engine serial number and it gives diagrams and part listings for everything you could imagine. Gotta love that!

 

[affa]

Re: GM 3,0 L Ignition

Thanks<br />Yes I agree, these sites have been very helpful and good, but Ive not manage to find the plug before now.<br />Thanks again.<br />Regards<br />Affa