Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha One

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

I've found this thread and it sounds like the same issue than mine. Turned out that the distributor was poiting the 3rd cylinder instead of the first? I'll go check on my distributor if that ain't my problem ...

http://forums.iboats.com/mercruiser...ercruiser-engine-rattle-high-rpms-379767.html

 

[81 Checkmate]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Your right…could be like that thread, or like Bondo said going lean and detonation going on. Check the timing

You have to eliminate the possibility’s one by one….. instead of just guessing.

Ok it’s not that…Good…. move on to next item on list!

Like not taking off valve cover…it’s a 5 min job… then you know for sure it’s not the rockers/bent push rod ect.

Good luck hope you resolve the issue!

 

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Tonight I'll be renting a timing light and removing the valve cover. With those 2 eliminated, I'll feel better after (or worst)

I plan on removing the entire distributor and reinstalling. Could someone help me with this part? (installing the distributor)

Engine Disturbed
1. Locate No. 1 piston in firing position by either of two methods described below.
a. Remove No. 1 spark plug and, with finger on plug hole, crank engine until compression
is felt in No. 1 cylinder. Continue cranking until pointer lines up with timing mark
on crankshaft pulley, or
b. Remove rocker cover and crank engine until No. 1 intake valve closes, continuing
to crank slowly until pointer lines up with timing mark on crankshaft pulley.
2. Position distributor to opening in block in normal installed attitude.
3. Position rotor to point toward front of engine (with distributor housing held in installed
attitude), then turn rotor counterclockwise approximately 1/8-turn more to the left and
push distributor down to engage camshaft. It may be necessary to rotate rotor slightly
until camshaft engagement is felt.
4. While pressing down firmly on distributor housing, engage starter a few times to make
sure oil pump shaft is engaged. Install hold-down clamp and bolt and snug up bolt.
5. Turn distributor body slightly until points just open and tighten distributor clamp bolt.
6. Place distributor cap in position and check that rotor lines up with terminal for No. 1 spark
plug. Install cap.
7. Install cap, distributor primary lead to coil. Check and connect spark plug wires, if they
have been removed. Wires must be installed in their proper location in supports to
prevent cross-firing. Firing order is 1-3-4-2.
8. Install rotor.
9. Replace distributor cap.
10. Time ignition as outlined under “Ignition Timing,” in this section.

I don't quiet understand... There's a special way (except making sure that the rotor lines up with cylinder no.1 AND to be at TDC on cyl no.1) to install it?...

 

[sti1471]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

there is no reason to remove and install the entire distributor from the engine. you are going to be giving yourself way more work than you need to. all you need to do is remove the distributor cap to set everything, not the entire distributor. If your boat is in need of timing, or the firing order if off, then this can be corrected without pulling the distributor out of the engine.

-remove the distributor cap.
-rotate engine so that cylinder #1 is at top dead center on the compression stroke
-look at where the rotor is pointing on the distributor.
-it should be pointing to the cylinder wire #1 spark plug wire (or where cylinder #1 spark plug wire would be if the cap was not removed)
-If the rotor is pointing to any other spark plug wire than #1 when cylinder #1 is at top dead center, then just make sure you install the spark plug wire going to cylinder #1 on the distributor cap post that the rotor was pointing to.
-from the newly defined cylinder #1 spark plug wire, moving clockwise, install the rest of the wires in the correct firing order.
-turn on the engine and time the engine

by doing it this way, you now know that when cylinder #1 is at Top Dead Center, the rotor is pointing to the post that spark plug wire going to cylinder #1 is plugged into, and that is all the really matters.

Check the rotor as described above.
check engine timing to sure it is set correct.
after timing is set test for noise
if the noise is still there, pull the valve cover and inspect the rocker arms and rods for damage. start the engine and watch the rocker arms move while idling. if there is something wrong you will see one of the rockers moving differently than the rest is some way.

If all of these tests pass, then come on back and we will move on to the next thing to check.

 

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Put no.1 piston in firing position with both intake and exhaust valve closed, the distributor rotor was pointing in the 1st cyl. spark plug wire direction

Next thing I checked the rocker arms...

Is it normal that they are a bit loose? (I can move all of them from left to right but not from side to side and I can, with a bit of strenght, spin the rods, except the ones that can't be adjusted in this position).
http://img690.imageshack.us/img690/654/n545.png

Guy in the DYI video tells to turn an aditionnal 3/4 turn, but if I do this, they won't be loose anymore? I'm doubting because they are all loose... (I think the engine has to be warmed up before? It was cold when I checked them)

The other rockers that couldn't be adjusted with no.1 cylinder in firing position were all very tight EXCEPT the last one (exhaust valve of cylinder 4). Is it normal?

I will check timing tomorrow and go for a ride.

 

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

EI IE EI IE

Adjustable rocker on no.1 cyl in firing position : no.1 exhaust and intake, no.2 intake, no.3 exhaust, no.4 intake

The other ones (no.2 exhaust, no.3 intake and no.4 exhaust) should all be tight (valve on their way to open) am I right?

Then, if I do a 360 with the crank: no.2 exhaust, no.3 intake and no.4 exhaust should all be loose (closed valve) and the other ones should be tight (valve on their way to open)

Correct me if I'm wrong.

 

[oldjeep]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Is there a procedure in the manual for adjusting them (Adults Only Section). I still do rocker adjustments the old fashioned way - with the motor warmed up and running while I adjust them.

 

[81 Checkmate]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Yea as oldjeep said......check the manual for proper procedure for your motor.

But the old school way is......motor at operating temp, remove valve cover.......start motor and while it's running back off a rocker nut untill it starts to rattle...then tighten back down untill the rattle stops then add a quarter turn. Then move to the next one and do the same.

Correct me if im wrong!

If ya can take some pics and post them.

 

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Yep... But still I doubt this might be the cause of my issue. Loose valve doesn't to this sound (see video at 1:50).

Sounds more like some pistons hitting the wall... I might have to rebuild the whole engine.

 

[sti1471]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

your rockers should not be loose at all. if you can move any of the rockers with your fingers quickly and you hear tinging, pinging, or any other metal on metal sounds clinging sounds, then it needs to be tightened.

this video should explain it to you and let you compare yours to this. Now that the cover is removed, go through the adjustment procedure as described just in case 1 of the rockers is too loose or too tight, this will be a good time to make sure they are adjust correctly.
http://www.youtube.com/watch?v=QAlCVA5cCQM

 

[sti1471]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

I can move all of them from left to right but not from side to side

What does this mean?

Also after looking at this video, this noise sounds a lot like your noise, but theirs is much louder than yours, but still, same "coins, washers" rattling correct?

Boat Noise 2 - YouTube

 

[81 Checkmate]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

If you think it's the piston's slapping the wall than do a compression test....That will tell ya.

Sure a loose valve/rocker would make that noise...its metal to metal with gap in it! The faster it revs more noise it's gona make

Your video is different than the other one. If you do another video hold your phone longer at the noise ......

 

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

What does this mean?

Also after looking at this video, this noise sounds a lot like your noise, but theirs is much louder than yours, but still, same "coins, washers" rattling correct?

Boat Noise 2 - YouTube

yep... same sound... I did tighten no.4 exhaust valve and it helped a bit, but sound was still noticeable even though it was less noisy (We were 2 on the boat instead of 6 + a wakeboarder like last time we heard the noise) I don't know if there was enough load by being only 2 on the boat)

I don't know if I'm doing it right since EVERY rocker that can be adjusted in no.1 cylinder in firing position are a bit loose... When I do a 360 with the crank, the ones that are loose become tight and the ones that are tight become loose.

They can't be ALL loose?...

Also, it doesn't make the sound at idle even if i rev it, but as soon as there's some load it does it.

I can move them from left to right, but not from up and down... Only like this : http://img690.imageshack.us/img690/654/n545.png

BTW, the engine was COLD when I checked everything so that might explain why all the rockers weren't that tight?

 

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Anyone?

 

[Bondo]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Anyone?

Ayuh,.... Have you downloaded the factory manual for the 3.0l motor yet,..??

I KNOW it covers adjustin' the valves,...

It Appears yer lackin' the most basic knowledge of How our motors work,...

If the valves were All tight at the same time, the motor don't run,...

 

[sti1471]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

In order to make sure they are all tight enough, just make sure you cannot spin the pushrod by hand. If you are able to turn the pushrods with your fingers, as it is shown in that video I posted in Post #70, then it need to be tightened until you cannot spin the pushrod by hand + 3/4-1 full turn of the nut.

Put piston #1 at TDC. Adjust the valves instructed in that video. Rotate the engine 360*. Since you just adjusted those valves it does not matter how loose they get at other points of the rotation. What matters is that when cylinder #1 is at TDC they are adjusted where they should be. after adjusting the first set of pushrods with cylinder #1 at TDC, rotate the engine 360* and adjust the other pushrods just as the video tells you to.

You mentioned that the sound of your engine sounds like the engine I posted in post #71. The engine in Post #71 suffers from loose rockers. If your adjustment(s) made a change but it is still there a little, then I would focus on the rockers. If it was not the rockers, it would not have made any change after you adjusted on them.
I think you are on the right track.

 

[thecca]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

I know that if all valves were tight my motor wouldn't be running. I have a few knowledge on engines but marine ones seems to be a lot different.

Anyways, I borrowed my friend's timing light and will try to solve my issue tonight, may-be it's just off a few degrees. I'll let you know thanks.

 

[oldjeep]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

I know that if all valves were tight my motor wouldn't be running. I have a few knowledge on engines but marine ones seems to be a lot different.

Anyways, I borrowed my friend's timing light and will try to solve my issue tonight, may-be it's just off a few degrees. I'll let you know thanks.

Well, in the case of a 3.0L - in any way that matters, its just a car engine

 

[slag]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

Well, in the case of a 3.0L - in any way that matters, its just a car engine

Which car was the 3.0 mercruiser engine in again?

 

[Scott Danforth]

Re: Strange noise coming from motor under acceleration... Mercruiser 3.0 with Alpha O

The 3.0 liter is a stroked 2.5 that was available in the 1962 Chevrolet compact cars such as the Chevy ii