92 351 has major knock |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Posted: April-30-2017 at 10:51pm |
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When I took my 92 SNOB 351 out of storage last week it had a loud knock/tick coming from the driver's side of the engine. The boat shop looked at it and then I took it to an old time mechanic shop that knows engines. In 2014 I had the original block replaced with a Jasper block due to a crack in the block. 3 seasons and 110 hours later now I have a really bad knock. The machine shop repair place upon my approval took a chance and I had all the lifters replaced. It didn't resolve the knock. Short of pulling the motor and dropping the pan it appears that we will end up running it this Summer until it dies. The oil pressure is great 60+ lbs and the compression is good all around except for the #2 cylinder which is a littler lower but not a big issue.
The boat is stored in the underground caves here in KC where it doesn't get below 60 degrees all winter. It's got me totally baffled as to the cause, the knock wasn't there at the end of the season when we put it on the trailer. The boat shop is suggesting I just replace the whole motor with a new PCM crate motor - 5.7l with EFI etc. Any suggestions? Anyone know about someone who has put a new GM/PCM engine in a 92 Nautique OB? |
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Shep72
Newbie Joined: January-15-2017 Location: New Braunfels Status: Offline Points: 20 |
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Pull the valve covers and press on all the rocker arms. Could be a stuck lifter or you might have a collapsed lifter. If it is collapsed you could have a wiped lobe. Best case, new cam solves it. Depends if it's a tapping or a knock. But if it ran good last year don't think it would start knocking from sitting over the winter.
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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Since it had no problems when you put it in storage and now it has, leads me to believe that there is an outside chance that carbon has broke loose in one or more cylinders.
Run engine at very fast idle and trickle water down the carb. If it is carbon it may steam itself out. Beats taking it apart. Have seen that fix done before. Duane |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10667 |
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Having no idea what your knock/tick sounds like, I'll ask the silly question, is there any chance it's external to the engine? A loud knock and a tick wouldn't exactly sound alike. A short video would be real helpful to people. Your raw water pump is on the right side and if it has a bad bearing you can get some funny noises from that. You could remove the belt and start the engine long enough to see if the sound is still there. Could be a long shot but won't take long to find out if it's the pump |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Several knowledgeable people besides myself have listened to the engine. It's not the raw water pump. Thanks for the suggestions, I am open to any ideas at this point in time.
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Duane,
Thanks for the suggestion. I will likely give that a try. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10667 |
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Video |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Have you checked for cracks or leaks where your exhaust manifolds bolt to the block? They can produce a sound just like a lifter tick/knock.
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Shep72
Newbie Joined: January-15-2017 Location: New Braunfels Status: Offline Points: 20 |
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What's your idle speed. Flex plate in trans rattling? Does the noise increase or go away with higher rpms? Can you stick your ear to a long screwdriver and narrow down where the noise is coming from?
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Pouring some marvel mystery oil down running carb can knock carbon loose too.
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75 Tique
Grand Poobah Joined: August-12-2004 Location: Seven Lakes, NC Status: Offline Points: 6100 |
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Yeah, find a new shop. You need a new engine is a pretty drastic "parts swapping" for a tick. I think there are other things to check before dropping in a new motor. |
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tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
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Ibiz we need a video with you moving around the engine.
stuck or collapsed hydraulic lifter sounds rational. Did u run it on the hose before taking it out this season? Remote chance you turned off the engine before shutting off the fake a lake? Could possibly have hydrolocked a cylinder and bent a connecting rod. Maybe drop pan (ugh) and look for main or rod bearing material. I'm sorry I'm. It much help without audio. You can learn a lot from Sound (where from, 1/2 crank speed or crank speed). Get us all a video so we can guessculate. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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I agree with Larry that you do not need a new engine but rather a new shop/mechanic. |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3594 |
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With your engine running ( and Knocking ) remove one spark plug wire at a time on the noisy bank. If this makes no change in your noise it is in the overhead, Cam, Lifters and valves. If the noise gets quieter with the guilty plug wire pulled off you can isolate to that cylinder. It will be related to the Piston, Connecting rod or Main bearing under that cylinder. Carbon deposits can make a piston rock hard in a cylinder and create a sound similar to a lifter tap. A rod knock is lower in the block and louder, same for a main bearing.
I have heard of Fuel Pumps causing loud knocks when they go out also so rule that out. For $15.00 you can buy a mechanics stethoscope at the local parts store and isolate your noise location. If water got in that cylinder it could bend a rod and cause the piston to make noise. Jasper Engines is a very reputable house. You can call them tell them all details and they will help diagnose also. They may even stand behind the engine or at least partially stand behind it since it is most likely out of warranty. They do good work and use good parts so you chose a good engine. |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Yes I have.
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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I will take a look at the troubleshooting tips you suggested.
But both the Boat shop that bought the engine from Jasper and installed it and the automotive shop that does a lot of work with Jasper got no where with the Marine rep. They were told it's a two year warranty period! They wouldn't budge and provider any reimbursement for parts or labor. |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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I will get a video/audio of the noise and post it here. Unfortunately, due to business travel it's going to be another week before I can post back here.
The engine was run on the trailer to pull in 3 gallons of anti freeze at the end of the season. Engine was shut off as soon as it got to the bottom of the antifreeze in the bucket. absolutely no knocking at that time when it was run on the trailer.. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Did you drain ALL the water out of the system first? |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10667 |
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I hardly think it matters in the grand scheme of things considering the above |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Yes. all the water was drained out of the engine first and then it was run with the antifreeze.
But also note here in Kansas we have underground caves in the area so it was stored in a constant 65 degree environment all winter - no chance of freezing. |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Okay guys, I have created two videos and uploaded them to onedrive for anyone that wants to listen. There is one with the engine cover up and it's recording the knock from a cold start. The other is with the cover down after the engine is warmed up.
https://1drv.ms/v/s!AqJGILMQ7vgygeAzZjsMNGzQocsgUQ Your thoughts Jerry |
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Smithfamily
Platinum Member Joined: December-26-2007 Location: Orlando, Fl Status: Offline Points: 1602 |
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Sorry you are having problems Jerry! While I am no expert, and you got some excellent advice here, I will say that I have spun a few bearings before and that noise does NOT sound like a knock/noise from that. Not as loud or consistent.
Good luck with it. Please keep us posted. |
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Js
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Here's a direct link to Jerry's video
Jerry, Did you?
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Yes we have checked for leaks.
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Shep72
Newbie Joined: January-15-2017 Location: New Braunfels Status: Offline Points: 20 |
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I never found the cold start video. Did you pull one plug wire at a time to find out if it was specific to one cylinder?
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10667 |
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Jerry
Here's a video from last year in the linked thread just for reference You can compare noises ticking noise Edit seem to have to click a couple of times on the start symbol to get sound. |
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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When you shot the videos, how did the water/steam trick do????
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Keep it as original as YOU want it
1978 Mustang (modified) |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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I didn't try the water/steam trick yet. I wanted to upload the video/audio and get more feedback before I tried that.
Do you think the water/steam approach is the same as pouring some marvel mystery oil down the carbs? It seems to be similar from what i have read online? |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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I am going to go out next weekend and try some of the suggestions. There are no leaks where the exhaust manifold connects to the blocks.
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