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Denon Osterman

  • Karma: +0/-0
New build complete + weird noises?
« on: August 28, 2021, 04:24:12 pm »
Hi all,

Long time lurker and immensely thankful to all the help I've gotten from you folks, even though I'm all the way up in sunny Ontario, Canada! I finally, *finally* got my boat finished and in the water and my god am I in love. Full details below for those that are curious on the engine / hull / pump. I cruise at ~15% throttle or 3k RPM to hit ~35, and so far my highest speed is 60 mph (on GPS) at less than half throttle, low 4000s RPM. Wooo!!! There's only two things stopping me from really pushing it. The first is I stupidly left the ride plate off my pump...and it definitely wants / needs it for stability. The trim / place diverter is so incredibly sensitive right now it's almost laughable...the nozzle is 3' back from the transom and there's nothing for the boat to ride on to balance it. The other thing that's worrying me are a few noises I'm not a huge fan of, that I'm hoping you guys can help me with! Engine is fresh off the dyno (~30 min break in to seat the rings plus a few pulls), pump is "brand new" after sitting for about 6 years, freshly greased with Valvoline front and rear.

Noises:
  • Noise #1 - Clunking at idle. I've read both on here, and in the American Turbine manual, that this is common at idle when the pump hasn't had a chance to load the impeller. My bowl only sits ~3/4 into the water so I'm hoping this is the case? But if someone can confirm, that would settle my nerves.
  • Noise #2 - an incessant whine. Once on plane and at cruise speeds or higher, there's a whine. It's directly tied to engine / pump speed. It's not aggressive, or angry, or even that loud...but man it gets on your nerves after a while. It sort of sounds like a blower, but quieter, and more muted...and my build is N/A. Any ideas on what this could be, or how to stop it?
  • Noise #3 - a more metallic sound that only comes on higher up in the RPM range, when accelerating. If I give some throttle, say to get from 3700-4000, you hear it. Then if I let off just the slightest touch to drop to 3950...it's gone. No idea what it could be, and a bit concerned given the metallic nature of it. It's not a grinding or a scraping...sort of hard to describe...but definitely more metallic than the whine.
;
Any help would be MUCH appreciated...and I've done my best to include pics. Video coming soon, hopefully :)

Thanks!!!

Hull:
Modified Glen-L rampage that's longer, wider, and taller than stock. Built with a combination of mahagony and white ash / sitka spruce / white cedar. Hull weight without engine, rigging, etc is ~900 lbs. I estimate ~2000 "wet" and ready to go. The deck is a deeply stained mahagony as well, even though it looks sort of black in the photos.

Pump
American Turbine SD-309, AA impeller, performance intake (shoe, ride plate that's not yet installed), and the newest version of their trim system. I also added a custom trim gauge that I made using 3D printing and a bike brake cable...it works really well, and I'm happy to share details / files if members are curious.

Engine
492 chevy (40 over instead of 30), Scat forged crank and rods, icon forged flat top pistons, AFR 265 heads, a custom hardin / comp cam (226 / .591 intake, 234 / .601 exhaust, 112 LSA, installed 4 degrees retarded), Vic Jr intake, and a Sniper EFI system which I am *LOVING* and also happy to share all of my details on. Exhaust is a Hardin seaward system, water jacketed with the mix point occurring ~2 ft after the manifolds. Thermostatic water (10 AN lines, 4 port thermostat @ 160 degrees) and thermostatic oil (2x16" tube cooler, remote filter, 10 AN lines...running 20W-50 break in but will likely switch to straight 40 or a 5/10/15W-40 as pressures are a titch high with the 20W-50).

If I forgot any pertinent details, don't hesitate to ask!

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mash on it

  • Karma: +29/-0
Re: New build complete + weird noises?
« Reply #1 on: August 29, 2021, 06:59:58 am »
#1- Is it a stainless steel impeller? Stainless steel impellers are known for clunking at idle. What's your idle at? You can bump up the idle to 1000 rpm or so and it usually goes away. Any slop in the u-joints would be evident at idle too.

#2- I'd try to isolate it... Look or listen while underway at the pump seal, rear main seal and balancer seal. Easier said than done.

#3- just a wild ass guess- valvetrain.
Inspect closely the push rods, rockers and valve springs.

Dan'l
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CJ/RR 212...under construction  "Pistol Annie"

mobboss

  • Karma: +15/-0
Re: New build complete + weird noises?
« Reply #2 on: August 29, 2021, 12:45:54 pm »
# 1 agree with ( mash on it)

# 2 this is going to sound funny but could actually be intake and carb setup try changing to a different air cleaner.

#3 change the oil and run a magnet thur the used oil . new valve trains are really touchy on break-in and can go away quickly if something went wrong.  also when i was first taught to build engines , the first and foremost thing was CLEAN second was break - in oil should always be straight weight oil.


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Denon Osterman

  • Karma: +0/-0
Re: New build complete + weird noises?
« Reply #3 on: August 30, 2021, 07:18:14 am »
Hey guys, thanks for the quick answers!

#1 It's an aluminium impeller, idle is ~800 right now. I only really notice it when pulling away after the first start of the day when the engine is still steadying into its groove, so I'm pretty sure you guys are right...just kind of weird that there's enough slop to do that on a brand new everything.

# 2 Easier said than done for sure - don't know if it would be possible to look at the rear main or pump seal while underway. I have gone to hold my hand on the thrust housing of the pump immediately after a longer, harder run, and it was cool to the touch. My front main leaks a couple of drops while running but I've replaced it twice already so I've left it for now. Very interesting point on the air intake - I actually thought it might be that too. Due to the *stupid* coast guard regulations, I've got a tiny spark arrestor hidden inside my air cleaner...and there's no gasket between them, or between the cleaner and the throttle body, so I'm thinking that might be it.

# 3 I'll give the valvetrain a close look. I was incredibly paranoid / meticulous about cleaning everything when I built the valve train, and it's a full roller setup running a good break-in oil...but worth checking for sure. I did notice when I put the boat away for the week yesterday that my china-special timing pointer has rubbed on my ATI balancer...so I'm hoping that's what this is. Fingers crossed!
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Denon Osterman

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Re: New build complete + weird noises?
« Reply #4 on: September 18, 2021, 03:35:33 pm »
Mostly solved the noises. The annoying drone is still there but mostly gone, I think it's an air filter thing because when I removed the spark arrestor and used just the air filter it got way better.

Angry metalic-esque noise turned out to be some whistling from the EFI system that's apparently a known problem - a 4 hole spacer completely fixed it. Yay!

Running pretty darn good now :D


 


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