Built this motor recently. It is a brand new L31 chevy short block with Edelbrock e-tec 170 heads, comp cams xm270HR cam, 1.52 comp cams roller rockers, 8 qt Canton oil pan, Davis unified ignition, carter electric fuel pump, edelbrock performer intake manifold, Edelbrock 600CFM marine carb, all marine gaskets and Stainless Marine exhaust.

Initial timing is set to 10 degrees BTDC, plug gap is set to .055 (per the DUI ignition manual) and fuel pressure is about 6 psi.

Just recently got it started and not being too much of an engine guy wanted to get opinions here on how it sounds. I went through the initial setup in the Edelbrock carb manual, but nothing else has been done. I cannot pin point it, but I have listened to a bunch of motors with this cam and mine doesn't sound the same. I could be being OCD about it.



Here is another video showing the small amount of movement from my crank mounted water pump. Is there too much movement in the pump?


Here is a picture of the engine and my rigging. Not as nice as most boats on here, but fits my budget.




Heres a picture of the boat

I heard nothing too crazy to be concerned with from that short clip. I think one of the internal exhaust flappers may be nosier than the other but I'm not losing sleep over it. You will find out a lot more when you get drive installed and a load on the motor.

As to the water pump, I've seen that kind of pump, but I've never seen them in action so I can't comment on whether it's moving around too much.

[QUOTE=Trash;4721611]I heard nothing too crazy to be concerned with from that short clip. I think one of the internal exhaust flappers may be nosier than the other but I'm not losing sleep over it. You will find out a lot more when you get drive installed and a load on the motor.

There are no flappers installed in my exhaust system. I was planning to put them on the tips. I hear what I think you are referring to and that is what bothered me.

Thanks for the response.

I have no answers to your original question, but almost everyone that I know of who set the DUI recommended .055 had issues and went back to something more reasonable with good results.

Is that a custom water pump mount? I remember ones on my dad’s 454s that the bracket went to both sides of the crank pulley, and they weren’t triangulated at all like yours is. So the bracket could flex side to side.

ok, good information. I felt like .055 was a bit big. I'l set them to .045.

Thanks

I modified the one that came with the pump because it felt flimsy and I also wanted to mount my electric fuel pump on it. If you look to the left of the water pump, my fuel pump is mounted on the same bracket.

I suspect you’ll be happier with that. The issue seemed to be a loss of top end or it wouldn’t rev out as expected.

I believe they are designed to be flimsy so the pump can move back and forth. Hence they are called shaker pumps.

Sounds like its idling at 1000rpms or more.