Changing lifters on a Mercruiser 3.0LX engine

[MikeDobbs]

Hey everyone-

I finally got around to changing the lifters on my Merc 3.0LX and I figured I'd post a little video of the job. I wasn't able to find ANY videos, or instructions online about how to proceed with this job, soI figured a little video might help someone else out if they are looking to tackle this job.

I'm not saying I did everything right- just that you can get a glimpse of what to expect from this video.

I still have a clicking/tapping noise in the engine (you can hear it in the last 20 seconds of the video), and I'm thinking it may be the mechanical fuel pump. I've read that these can make noise if the return spring wears out/down. I'd much appreciate anyone with experience giving me their opinion on the engine noise at the end of the video : )

 

[Silvertip]

You can use a piece of rubber hose, a broom handle, a wooden dowel, steel rod or anything like that placed against the fuel pump to determine if that is the issue. I am reasonably certain however that the noise is not the fuel pump. Are you certain you adjusted the lifters properly? You can use the same technique on the valve train that you used on the fuel pump. Does the engine display proper oil pressure? Does the noise go away or reduce as rpm increases? If so, this may be an oil pressure issue. If the engine was not any quieter with the new lifters than it was with the old, chances are this was not a lifter problem at all. Worn (sloppy) timing gears makes a noise but it is usually more solid noise than the clattery valve train noise. I think you need to start with a proper valve lash adjustment. This can be found on various web sites or in any service manual for a 2.5 four cylinder GM push rod engine. You can find such a manual at most libraries.

 

[MikeDobbs]

Whoops- realized I uploaded those videos in SD- here's the HD version : )

 

[MikeDobbs]

You can use a piece of rubber hose, a broom handle, a wooden dowel, steel rod or anything like that placed against the fuel pump to determine if that is the issue. I am reasonably certain however that the noise is not the fuel pump. Are you certain you adjusted the lifters properly? You can use the same technique on the valve train that you used on the fuel pump. Does the engine display proper oil pressure? Does the noise go away or reduce as rpm increases? If so, this may be an oil pressure issue. If the engine was not any quieter with the new lifters than it was with the old, chances are this was not a lifter problem at all. Worn (sloppy) timing gears makes a noise but it is usually more solid noise than the clattery valve train noise. I think you need to start with a proper valve lash adjustment. This can be found on various web sites or in any service manual for a 2.5 four cylinder GM push rod engine. You can find such a manual at most libraries.

Thanks for the reply silvertip- I'll go over it with a rubber hose this afternoon. I adjusted the valves as per the manual's instructions- so I'm reasonably sure that's not the issue- esp since I just put in the new lifters. The noise does seem better to me after replacing the lifters; I can still hear some valve train noise (I think), but it's softer what it used to be. I'm not even sure this is the same noise as before (wondering if it was covered up by the previous noise). The oil pressure is good- 40PSI at idle, so I don't think there's an issue there.

Here's another video of me revving the engine a bit- you can hear the noise much more distinctly at higher RPM.

 

[Bondo]

Ayuh,..... Disconnect each spark plug wire, one at a time, 'n see if the rap goes away,......

I'm thinkin' rod knock, piston slap,....

 

[MikeDobbs]

Ayuh,..... Disconnect each spark plug wire, one at a time, 'n see if the rap goes away,......

I'm thinkin' rod knock, piston slap,....

Do I need to get a spark plug pliers for that? Or is it safe to just pull them by hand?

 

[Bondo]

Do I need to get a spark plug pliers for that? Or is it safe to just pull them by hand?

Ayuh,..... I donno, I don't own any spark plug pliers,.... Bazillions of many kinds of pliers, but no spark plug pliers,....

I guess it depends on yer understandin' of electricity, yer ingenuity, 'n yer tolerance of pain if ya don't get it right,.....

In other words,.... I pre-loosen 'em at the dist-cap, 'n just lift each off with rubber handled insulated pliers,...