Merc 454 alignment

[MahtyMaht]

I've finally got the freaking engine in this tub! It's a Mark IV 454 with a fat cam and some other fun stuff, in front of a Bravo 1, ser # OB8whatever. My problem is that I've never aligned one of these things before, and I don't like what I'm seeing. I grease up the end of the alignment tool and slide it in, and it goes till it hits an obvious shoulder, but it's a little stiff pulling back out. The coupler spline tracks in the 2-4-C are more apparent on top of the alignment tool than on bottom. I dropped the front motor mounts a full turn, but I'm not seeing any change in the spline track pattern. I've seen it said on this forum by the heavy hitters more than once, that the tool ought to slide out with 2 fingers, or you ain't there yet. The motor mount brackets are sitting on the lower nuts. What am I missing here, girls and boys??

 

[Anchor Management 1]

Re: Merc 454 alignment

I would guess you do have the fiber washer and spring under the rear motor mounts?

 

[Alpheus]

Re: Merc 454 alignment

Make sure your gimbal bearing is not cocked to one side or another. I take the alignment tool and slide it into the gimbal bearing. Smack it around until its perfectly aligned. You can move the engine up and down all day and it wont change anything if your gimbal isn't lined up...

 

[Bifflefan]

Re: Merc 454 alignment

You are going the wrong way. Grease on the top and none on the bottom means you need to raise the front mount.

 

[MahtyMaht]

Re: Merc 454 alignment

Oh, yes indeedy, I do have the fiber washers all glued in, and the double wound lockwashers in place. I'll try a little smackage on the alignment tool, too, but It sounds like in trying to figure out which way the front mounts needed to be moved, I mis-thought my way into the dumper. I'll try dropping those buggars. Thanks for the replies, gentlemen.

 

[Bondo]

Re: Merc 454 alignment

but It sounds like in trying to figure out which way the front mounts needed to be moved, I mis-thought my way into the dumper. I'll try dropping those buggars.

Nope,.... Raise the front...

 

[Alpheus]

Re: Merc 454 alignment

Here we go again...

f the spline marks in the grease of your alignment bar show heavier on the TOP OF THE BAR, you need to LOWER the front of the engine.
That shouldn't be that hard to figure out.

^^^^^This is a direct quote from Don S^^^^^

from this post.

http://forums.iboats.com/showthread.php?t=421602

I have researched the he!! out of this subject when I was installing my new engine this spring and it seems everone has different opinions on which way to move the front of the engine in accordance with the spline marks.

No one can agree. This should be made a sticky once and for all and put to bed...

http://forums.iboats.com/showthread.php?t=420900



I am going with Don on this one. I listened to the wrong people and kept raising the front of my motor when the heavy marks were on top with no results. When I LOWERED my engine it aligned perfect...

 

[MahtyMaht]

Re: Merc 454 alignment

Took another crack at that alignment today. I looked at the big mount studs, and starboard had an inch of thread above the mount bracket, port had a half inch. "BILGE", I say - I remember what they looked like when I took the dead engine out, so I thought I'd start over there. That meant jackin' up the starboard to match port. BAM! The bar went in easily enough to warm the cockels of my heart. So I torqued the rear bolts and front nuts, and promptly lost it. When I rechecked with the bar in the bung, it was that queasy not quite good enough feeling. My hands now know what it's supposed to feel like, though, so I figure I'll jack'em up a little, and check it again. Bottom line - up was the answer. I figure it was cocked, but it still came up when I matched'em.

 

[Alpheus]

Re: Merc 454 alignment

So I torqued the rear bolts and front nuts, and promptly lost it.

Are you talking about the rear motor mount bolts?

They should have been torqued already so the spring washer is compressed...