Engine ticking

[Doral90]

Hello all! Hope everyone is enjoying the warmer weather. Boating season is here in Ontario Canada!

Quick one for you guys. I have a 90 OMC cobra 4.3. It has a ticking noise going on that I would like to know more about. Increases with speed and I believe it’s probably a valve issue/ lubrication. Done a compression test and all is good there. Just tuned up and rebuilt carb. Boats running good but tick tick tick

thanks

 

[alldodge]

My first guess with limited info would be you have a lifter or two starting collapse, or part of the rocker arm is moving (loosening). What is your oil pressure

 

[Doral90]

Oil pressure is good. Just had it into the mechanic, said good oil pressure.

 

[alldodge]

Just had it into the mechanic,

Sorry and no offence, but if we took a mechanics word with just about anything we would have never found the problem here on iboats. The term "Mechanic" is best thought of as a verb, he/she did something, but not certain if it was correct or done at all. Only thing we know for sure is they told the person asking the question something

 

[Doral90]

Understood. How would I go about checking up on this or to diagnose the problem any help is greatly appreciated. Oil pressure gauge on dash reads about 3/4 to full when running. Also I had my oil changed in this engine and they seem to have put 15-40 I’ve always used SAE30. Thoughts?

 

[alldodge]

Only way I know of correctly testing liquid pressures (oil, water, hydraulic) is with a calibrated mechanical gauge. The 40 psi is good for running (rule of thumb is 10 psi for each 1000 rpm) and the only issue I'm reading is at idle. If oil was to low that first thing noticed would be hearing the valve lifters ticking, and you don't have that.

I actually don't think you have an issue, but see no problem digging in further.

Straight 30 is OK and so is 15W40, many use it. I don't get in a boat if I need a sweater, so straight 40W for me.

 

[Doral90]

The ticking is there at all different engine speeds. I could hear it last year as well but it was more noticeable yesterday when I was out on it. I will take a video of it this weekend and try to post on here. Appreciate the replies!

 

[alldodge]

If you have 40 psi and still hear ticking its almost always lifters collapsing. This happens from age, the seals get weak. Only fix is replace or rebuild the lifters.

The only other possibility is the rocker nuts are loosing a tad