The patient: 1996 454 LX MPI (330 hp)

The symptoms: moderate 'ticking' sound that increases with engine speed. No discernable impact on performance. No excessive oil consumption. Compression test is good on all 8 cylinders.

The diagnosis: I'm thinking failed lifter rather than rod knock (I hope).

The question: Not being an engine surgeon, I talked to my regular (and respected) mechanic. He says to change out a bad lifter it would be something like $800 bucks. After I **** my pants, I thought I'd see if this is reasonable or if there is some way to 1) verify that it is a lifter and 2) fix it for less than the monthly gas bill for the boat!

Thanks in advance!

It may be the lifter, in which case you have to remove the intake, valve covers, back off the pushrods and replace the lifter/lifters. Not that big a deal.

However on my buddies BBC the noise turned out to be a badly worn valve guide. Which eventualy dropped the valve and trashed the motor.

I hope it's the lifter.

If you are sure that it is lifter noise.
A set of GM roller lifters is about $250.
I don't know how to find which 1 would be bad.
The gastkets are about $100.
So if you think you can do the job yourself, you'll save some $$...

I would be more inclined to look at the rockers. If you use a long screwdriver to your ear (or stethescope) and touch it at places along the valve cover you should be able to find where it is. Then remove the valve cover (usually have to move or remove the exhaust manifold). You may just have one loose. It can be worse depending on the reason why it was loose but you might get lucky.

Been there @ 5500 RPM when I dropped a valve. I too thought it was a lifter, then thought it was a rocker, then thought it was a exhaust manifold leak, then found out it was a bad valve.
If you can reach it, you can use a magnet retriever and take the lifter out by removing the valve cover if you know which one it is. You will have to fish it out through one of the oil galley holes in the head.
To say the least I would just use the bad lifter as an "Wife excuse" to take the motor out and upgrade performance.
"Well honey, it just has to be done right, and since it is taken apart anyway......."

Unfortunatley, there's not much horsepower to be found in these motors, at least economically. And I don't want to dump money in the other motor - the joys of twins.

To my ear, it sounds like the ticking is coming from the valley under the intake, rather than from under one of the valve covers. Guess I'll take another look at it when spring rolls around (I can't reach the boat right now, it's in rack storage).

Do the screwdriver trick...Works real well. Good luck on it just being a lifter !

I expect they're changing all the lifters.
To pull the intake, change all lifters, put everything back together + parts (hydraulic lifters + gaskets), then adjust them, is almost a full days work. So that price is OK for a marine dealer.
It's a under $200 if you do it yourself.
Gary

That's "under $200" if I don't screw it up!

You won't screw it up...
But I will say that most 1996 BBCs are Gen VI roller motors and a set of roller lifters are more than $200.