Newly assembled small block chevy
 

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.


https://cimg6.ibsrv.net/gimg/www.off...1230e8b7f8.jpg

Heres a picture of the boat

https://cimg4.ibsrv.net/gimg/www.off...02a33475df.jpg

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.

Did you install roller rockers?

The ops engine doesn't sound raspy like the others I've heard. Maybe it's the recording?? The exhaust drops down pretty low on the transom making for a couple of sharp bends. Not sure how much of an effect that would have on sound. Valve timing been verified? Compression ratio also plays a part. Didn't see it mentioned.

L31 with 64cc chambers is advertised at 9.3:1.
That should be pretty happy with the cam choice.
If you haven't done so, please do these things:
1) borrow a piston stop, a degree wheel, and a 1" travel dial indicator.
2) use the piston stop to find TDC on #1. Adjust the stop so that it allows the piston to get within 20 degrees of TDC. Mark in CW direction. Mark in CCW direction. Remove stop. Split the difference, and you will be at TDC. Verify the timing marks on the timing cover and damper match up. Then match up the temporary marker for the degree wheel.
3) use the dial indicator on the intake rocker to find the intake centerline so you can verify that your cam is degreed properly.
Now you never have to worry whether the cam is mistimed or whether your timing marks are erroneous for setting g your ignition timing.

I haven't listened to the clip

I listened to the brief video. I cant tell squat regarding the sound. Too brief, too much echo.
The water pump is not too bad, but the less wobble, the better as far as bearing life.
I have one on a Westerbeke, and I used a dial indicator to tap it around to get it to run on center before tightening the snout bolts. It started with .060" max/min deviation, and I ended up with .014" max/min and it was visibly much happier. As far as your bracket, all the bracket needs to do is keep the pump from rotating. I don't even run a bracket on my Westerbeke. The hoses are stiff and well anchored very close to the pump.

good deal, thanks. I started another thread over in the 'General Q & A' section regarding this boat because I found that I have reversion and am getting lots of water back in. Oil is milky as well.

I'll double check the cam timing like suggestion here. I have the tools to do that.

Yes, I have comp cams 1.52 pro magnum roller rockers installed.

im worried his pump isn’t aligned and he overconstrained it with a stiffer bracket, which would kill its bearing life

thanks, I had a couple people mention like this. I'll get it centered on there with a dial indicator before I call this project finished.

This is a popular conversion from the hideous merc. Brass sea pump. Need to have the pulley that goes with that pump and it's aluminum centering button between the pump and the gm balancer pulley and try reindexing the 3 Allens that attach to the pulley and balancer , should be wobble free .

good information. I'll call Hardin to see if they have it. Do you know of a source for these parts?

R

My Innovations were built with a bracket that went around the post on the side of the pump, which would have a nylon bushing mounted to it. Limited movement/rotation, but allowed for play. Never any issues

When I switched from the stock slider rocker arms to the rollers there was a definite increase in noise, enough to ask about it here as it was worrisome.

I would add that with some of the ramp rates and lift we see on hyd roller cams will cause the valves to seat fairly fast and hard. This hammering affect can be heard upstream through the induction system almost like a rod knock. Different intakes/induction systems will either amplify or mute this noise.

idle sounds high.I have same cam as that i idle mine at 650-700rmp

comment to the crank driven water pumps,,
i just added crank driven water pumps and i had concern on mounting them and how would they be centered to crank,,,,
so i had dynamic speed take my lower pulley and machine in a .030 recess for pump
https://cimg9.ibsrv.net/gimg/www.off...558d92335d.jpg

i would doing something similar for mounting pump