2.5 liter OMC with lifter noise

[woody 184]

Anybody have any ideas on this. I have a 2.5 liter OMC that I picked up in the spring. It was running great then all of a sudden engine started ticking.. Neighbor of mine said that it is a lifter and I need to adjust it.. And he also said it would be fine after the adjustment.. I talked with a friend of mine who is a gearhead who said those engines have hydraulic lifters that Cannot be adjusted.... Here is my concern. I do not want to damage the engine further..... Any ideas Hank.....I changed the oil about a month ago and put fresh Castrol 10w30 oil in it and has been a very smooth running engine.... Thanks... Dale

[L&M]

2.5 / 3.0L have fully adjustable individual rocker arms similar to a small block chevy. Pm or give me a call & I'll explain it further.

[woody 184]

Hank I have not pulled the valve cover yet. I guess when I get back into town I will pull the valve cover and adjust the rocker arms that need adjusting.. what is the lash tolerance on the 2.5 liter and I will check this out.. Hank I really appreciate the information and Thanks for the help.... Dale

[KOPPERKLAD]

Woody

Check the maufacturers recomendation for oil. Most recomend straight 30 weight oil. If the noise came shortly after you change the oil the oil may be too light.

[Diversion]

That was my thought as well, oil might be too thin

[L&M]

Ck your pm's Woody

[woody 184]

Ok guys I pulled the valve cover this morning 8 hours earlier than I hoped due to Finders Keepers boat problems (no Fair Haven Challenge) we will get them next year. So I pulled the valve cover and found that I had one rocker arm that was not getting any oil up through the hollow tube so I took the rocker arm off and noticed that the tube was clogged. Cleaned that out put it back in started to get the rocker adjusted nice and notice no oil still on that rocker arm. So I pull the tube again and decide to clean the oil galley for that rocker and put it back together and I finally get oil on top of that rocker and the sound starts to dissipate... Now i notice that the rocker arm that was not getting the oil is not rocking like it should. The other 7 rockers are really moving up and down and the other one is barely moving up and down.. But I was getting good lubrication on top of the rockers..... Took the boat out after these adjustments and the boat ran very nice motoring out to 250 fow.. Trolled nice... But as we were ready to motor back in the engine would not power up good and was really making some loud notices... So I am not sure if the engine has a stuck valve or a collapsed lifter... It definately has engine woes... Anybody have any ideas on how to solve this issue...... Thanks in advance..... Dale

[scott594]

I'm real familiar with that valvetrain, having raced smallblock chevys for many years and the 4cyl uses many interchangable pieces typical of GM. It sounds like the cam lobe is worn on that valve. they usually wear right through the bottom of the lifter when they fail, causing the oil to drain into the crankcase instead of coming up through the pushrod.

A simple way to check it is to remove the rocker from the bad valve, and one from an another cylinder (if the bad one an intake valve, make sure the other one is and vice versa) turn the engine over with a breaker bar and compare travel at the pushrod - a dial indicator in nice, but a machinists rule and good eye will do. If the travel is significantly different, you'll need a cam and lifters. You can confirm that by running a magnet through the used oil, if it picks up metal, you know.

If the travel is ok, check for a bent pushrod, rocker arm locknut tension and bent valve. if the pushrod is bent, find out why. Once in a great while we see the locknut loose tension and back off, you'll feel that right away when you turn it - compare to another. I hope that's it, because it's about the only non-serious cause. A new nut and a valve lash will fix that. Lastly, don't be tempted to just adjust the rocker down as it will just cause more damage and throw metal in the oil.

Hope this helps.

[Splitshot115]

My guess would be the lobe on the cam is worn. I've also seen the rocker arm stud

come loose from the head.

[woody 184]

Gentlemen first off I want to thank you for your assistance with this motor issue.. I spoke with Hank before I went out of town and he said the samething. Camshaft has a worn lobe... I disassembled the motor to find the camshaft had a worn lobe on the #4 cylinder so I got a new camshaft and lifters and new gears for the camshaft and crankshaft.. It took about 8 hrs to teardown and reassemble the motor but it is currently running beautiful and has good power... I have not run the motor that long yet maybe an hour or hour and a half... But the sounds are gone.... Hank I want to thank you for the phone conversation about the motor if it was not for you I would not be able to get out in fish this week.... A huge Thank You to you sir....... Thank you to everyone else that posted on this subject..... Dale

[Handyman]

I had the same sound coming from my 140hp Omc 1980 engine even after setting the valve clearances.so I buttonholed a marine mechanic to listen.....he told me it's a flapper valve in the exaust to stop water from coming in when in reverse....at idle there's not enough exaust pressure to hold it open so it flaps(ticks)...once the rpms increase it holds the flapper open and the ticking stops......................................Handyman