Merc 5.7L 260 Problems. Now What? Advice Please
 

:( Just got a compression check done on my Merc 260 5.7L engine. Although the engine is original (1987) it only has 340 hours on it.

OK, now with my problems. At the end of last season I was noticing a low oil pressure and some white smoke. Not excessive smoke but some noticable smoke.

Anyway, did the compression check yesterday and got these numbers:

Cylinder 1 165
Cylinder 2 160
Cylinder 3 162
Cylinder 4 155
Cylilnder 5 65
Cylinder 6 90
Cylinder 7 160
Cylinder 8 165

So you can see my problem is with opposing cylinders 5 and 6.

What options? Do I spend the money on a valve/ring job and hope that there is no more damage, do I try to live with one more season, or do I replace the engine which blows my maintenance budget for this year. If I could get one more season out of the boat I would be work for next year but at this point it looks like the engine is on borrowed time.

So my thinking is new engine. I would prefer to get a turn key drop in engine but my mechanic is telling me to get a Merc Cruise longblock (around $3,000-$4,000), Intake Manifold ($250-$300), Carb ($800-$1000) and Exhaust Manifolds ($1000-$1500). So basically I'm looking at $5,000-$7,000 for a new engine.

What are my opions here for a new engine? Any websites, site sponsors, etc where I could come up with a good deal? Please let me know.

Thanks in advance for the help.

Re: Merc 5.7L 260 Problems. Now What? Advice Please
 

I got a long block vortec 350 from michiganmotorz.com last year delivered for $2200. Put it in the boat an all seems to be great. If you are in fresh water get the edelbrock rpm air gap manifold for $200 ish and ebasicpower.com has aluminum exhaust manifolds for $500 ish a set.

If you don't wan't to mess with all the parts get a complete new motor from michiganmotorz.com:
5.7L Vortec Marine Engine-GOLD Package
$4599 + shipping
Ken

Re: Merc 5.7L 260 Problems. Now What? Advice Please
 

You also need to do a leak down test on the motor and that will diagnose what kind of problem you are having....rings, valves, etc....

Re: Merc 5.7L 260 Problems. Now What? Advice Please
 

Small block heads are known to rot thru depending on use and
storage. You may want to check them first


Daddio

Re: Merc 5.7L 260 Problems. Now What? Advice Please
 

The only way to be sure of what is going on is to do a leak down test and to be able to tell where you problem is.....

Re: Merc 5.7L 260 Problems. Now What? Advice Please
 

Salt or no salt is the key.............

Re: Merc 5.7L 260 Problems. Now What? Advice Please
 

Salt water of course......

19 year old engine and parts.....even though only 340 hours......I think it's time to buck up and put in a new one. Going to totally blow my budget but at least it won't be anything to worry about for a couple of years.

I'm going to start a new thread on to where to find an drop in, turn key engine. Thanks for your help on this one.

Re: Merc 5.7L 260 Problems. Now What? Advice Please
 

I had a '87 260 Merc that rotted out in an exhaust port (after I did a valve job). I know you don't want to hear it but I wouldn't use those heads again.