2010 V6 Vortec Crate Engine problem

[WallDiver7]

Installed a new 2010 V6 Mercruiser Vortec last summer. Knew it wasn't producing as much power as the original engine.. it is about 4mph slower at WOT.
Finally got around to checking compression this summer and found that the driver's side cylinders were all 50-55 lbs and the other three on the other side are all 100+ lbs.

How could all 3 cylinders show that much less compression? I've heard of stuck valve before, but never 3 cylinders showing the same problem on the same side. Pull the head and look? Any suggestions? Thanks!

 

[Don S]

Re: 2010 V6 Vortec Crate Engine problem

Water in the cylinder could have all three cylinders rusty, which really doesn't do much for new rings.
Did you have any rust or water showing on the spark plugs when you removed them?

 

[WallDiver7]

Re: 2010 V6 Vortec Crate Engine problem

No water in any cylinders, none. Plugs looked almost like the other side.. only difference was that they looked less "used" than on the side with good compression.

 

[Don S]

Re: 2010 V6 Vortec Crate Engine problem

Not knowing what your procedures were for the compression test, I would follow this service bullen for redoing the test, aand then use the followup measures to determine the problem.

http://www.boatfix.com/merc/Bullet/97/97_25.pdf

 

[Bondo]

Re: 2010 V6 Vortec Crate Engine problem

Finally got around to checking compression this summer and found that the driver's side cylinders were all 50-55 lbs and the other three on the other side are all 100+ lbs.

Ayuh,... Ya should be seein' 150psi + in all 6 holes....

 

[WallDiver7]

Re: 2010 V6 Vortec Crate Engine problem

Not knowing what your procedures were for the compression test, I would follow this service bullen for redoing the test, aand then use the followup measures to determine the problem.

http://www.boatfix.com/merc/Bullet/97/97_25.pdf

Yes, I can go back and do this per these specs, But without a doubt we know there's a problem when one bank measures HALF what the other bank ran. Agreed? My method was very quick and dirty: All I did was pull a plug one at a time and start the engine... running (750 to 850 rpms) on the other 5. So compression won't measure any higher (with the exception of adding oil to the cylinder), no matter what the method, than how I performed this test.

What I didn't know, according to your link, is the diagnostic procedures using that compression gauge .. with oil. Well, looks like I've got some things to try. Thanks.

 

[WallDiver7]

Re: 2010 V6 Vortec Crate Engine problem

Ayuh,... Ya should be seein' 150psi + in all 6 holes....

Hey Bond-o,

150 psi + huh? That means I've got a lot more trouble than just one side of this engine then. Maybe I should just get to it and,... pull the engine. Great.

 

[fossill]

Re: 2010 V6 Vortec Crate Engine problem

With compression that low on 3 cyl your engine would be running really rough, especially at idle

 

[Don S]

Re: 2010 V6 Vortec Crate Engine problem

Compression with a running engine is going to be lower than just cranking the engine with the starter.
Do the tests correctly, and they will mean something.

 

[Evinrude Boater]

Re: 2010 V6 Vortec Crate Engine problem

Is there no warranty on a new crate engine? How was it broken in?

 

[Tonyccs]

Re: 2010 V6 Vortec Crate Engine problem

i know your already flustered, you can also do a cylinder pressure test. (not compression) you put in pressure in through the spark plug hole, you have to make sure that the valves are closed on the hole your testing.

to me sounds like the rocker arms are not adjusted correctly. holding valves open or not opening enough.

im with one of the other posts, it should not have run well at all no matter what.

good luck!

 

[WallDiver7]

Re: 2010 V6 Vortec Crate Engine problem

Compression with a running engine is going to be lower than just cranking the engine with the starter.
Do the tests correctly, and they will mean something.

Ok..... I'll give it another go using the correct procedure.

 

[WallDiver7]

Re: 2010 V6 Vortec Crate Engine problem

With compression that low on 3 cyl your engine would be running really rough, especially at idle

I would have thought at too. I'm going to re-do the compression test, as per a link Don S lead me to.

 

[WallDiver7]

Re: 2010 V6 Vortec Crate Engine problem

i know your already flustered, you can also do a cylinder pressure test. (not compression) you put in pressure in through the spark plug hole, you have to make sure that the valves are closed on the hole your testing.

to me sounds like the rocker arms are not adjusted correctly. holding valves open or not opening enough.

im with one of the other posts, it should not have run well at all no matter what.

good luck!

I am hoping that the way I preformed the compression test lead to erroneous readings. The idle is good. It's just the WOT top end speed that lead me to start checking things.