92 351 has major knock |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3600 |
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Has the engine been overheated? Almost sounds like piston scuff or a loose lifter/rocker arm.
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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no it hasn't been overheated.
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Update.
1. Tried Marvel Mystery Oil in the carb - no change. 2. Tried MMO in gas tank - no change 3. Tried MMO added to oil - no change yet but wasn't able to put in 20% 4. Tried removing one sparkplug wire at a time. No change in knock. Jasper won't cover it, its out of warranty. :) |
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tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
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Sounds like a collapsed lifter to me. Pull the valve covers just to take a peek while it's running. If so it's a quick fix.
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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The lifters have already been replaced.
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tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
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We're the lifters replaced since the noise erupted? Any contaminants (like carbon or dirt or metal chips) that wind up in the oil can wind up in a lifter and can block oil flow into a hydraulic lifter stopping it from expanding to zero the gap at the rocker. From my earbuds the tick sounds like a lifter or exhaust leak and you've said there's no exhaust leaking.
One little thought is that the distributor rotor might be striking the inside of the cap if it's not locked down properly. |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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the lifters were replaced after the noise started. The oil was drained, flushed, lifters replaced and then new oil was put in.
I will double check for exhaust leaking and the rotor. FYI to all. My skiing buddy that was with me when ran the boat the last day of the season and then ran it on the trailer to suck in the antifreeze agrees with me. The noise was not there last season. This is something that some how happened between when it got turned off in October and when it was started up in May. |
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throttle out
Senior Member Joined: May-11-2015 Location: Chelsea, MI Status: Offline Points: 153 |
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It certainly sounds like valve-train or exhaust leak.
My old silverado sounded identical to that when cold noise would be gone in 2 minutes, manifold gaskets took care of it. I know you cant find an exhaust leak so we will rule it out for now. I did an ls swap on my 87 chevy shortbed 4x4. It is an LS1 out of a donor car. I drove the car before buying and the engine ran great. It however sat for sometime before I could perform the swap and the oil was like sludge when I changed it before fire up. The engine sounded awesome but after about 200 miles it would randomly start a nasty lifter knock, sounded just like your boat does. I did some quick oil changes and got the crud out, but more to the point, pull your valve covers and have a look !!! Could be a loose rocker arm, slightly wrenched push-rod you wont know until you look. Maybe upon first fireup this year it backfired? I've seen a good back fire tweak a push-rod. Good luck!! |
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1989 Ski Nautique 2001 351 PCM w/ 1-1.23
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10703 |
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It sounds like you haven't found your tick yet, so if you've ruled out everything that's been mentioned maybe it's time to think about the cam itself having a bad lobe unless your mechanic verified the lobe lift or valve lift to be the same on all 16 lobes/valves.
Did he verify that all the pushrods were straight and all the rocker arms good? Shep 72 hinted at this early on along with throttle out A cam lobe going bad usually starts as a tick.from the valve train as clearances open up (and gets progressively worse) What kind of oil are you using and how was the new engine/cam broken in initially? Not telling you it's your problem but giving you things to think about as possibilities since you're stumped right now. |
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scootdogydog
Senior Member Joined: November-03-2013 Location: Central MA Status: Offline Points: 404 |
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How do you know there are no leaks? based on the noise, as others are suggesting, it sounds like a lifter/exhaust noise. I'd recommend buying a stethoscope and move that around while you can hear the tick. This would help identify where the tick is coming from...and lead you in the right direction
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10703 |
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The stethoscope came up 18 days ago, he's done the plug wire routine with no noise change |
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scootdogydog
Senior Member Joined: November-03-2013 Location: Central MA Status: Offline Points: 404 |
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The idea came up...I missed that. Did I also miss the result? If not, hopefully they get posted soon |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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I haven't done the stethoscope yet. will do it this weekend. The local auto parts store was out of them.
FYI, the exhaust risers have been on and off as part of the replacement of the risers as on the 351 ford you can't get to a bolt for the valve covers without removing the risers. So there has been some 'repair' of the risers gasket seating during the troubleshooting process. |
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Shep72
Newbie Joined: January-15-2017 Location: New Braunfels Status: Offline Points: 20 |
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On my 94' I removed my Valve covers with a 1/4" drive ratchet long extension and universal joint over the socket.. This may help if you tear back into the Valve covers.
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5771 |
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they're not talking about the riser gaskets, they're talking about the manifold to head gasket. when they leak there it can sound like a knock. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10703 |
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I'm thinking he means the manifold to head gaskets and that his mechanic took the manifolds off way back when, so he could get to the valve cover center bolts so they could do the lifter replacement.
Not everybody does the 1/4 inch ratchet/extension/universal joint routine.as it's still a bit of a PITA. If that's the case he had the noise before and after the manifold gaskets were replaced. Just me thinkin'. |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3600 |
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Years ago I had a little coolant get into one cylinder, Head gasket was failing and I did not know it. It dripped enough on that cylinder to form a slight Hydro Lock, The engine started just fine but knocked like a loud lifter tap. Turned out the hydro lock had bent the connecting rod just slightly, enough to make one side of the piston touch the head on every rotation. Engine ran just fine but had that noise. I ran it a couple months and it never got louder and never got better. This boat had 1,200 hours on it so I planned to do the heads, it was starting to foul spark plugs. On tear down I could see the spot on the head and on the piston where they had been touching slightly.
New heads, one new rod and it ran like a top till I sold it 300 hours later. In a boat with a constant supply of fresh cooling water a leaking head gasket can go undetected at first. |
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Smithfamily
Platinum Member Joined: December-26-2007 Location: Orlando, Fl Status: Offline Points: 1602 |
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Whats the post weekend update Jerry? Hope its good news?
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Js
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10703 |
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It's been about a month.................wonder if it's still tickin?
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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It is still ticking, although a little more noticeable than before. We have about 4 hours of skiing and running on it. I plan on changing the oil in 5 hours to see what it looks like - ie any signs of metallic in it.
The plan/hope now is to hope it holds out for this summer, then pull the engine over the winter, do a repair and re install. Thanks for checking in. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10703 |
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Glad you're skiing and having some fun with it.
Hope you get thru the season OK What oil are you using now? Whatever you give for an answer will probably start another oil discussion but that's OK |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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valvoline 20w - 50 racing oil
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4945 |
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Before you do any kind of major repair or engine pull, definitely rule out your exhaust manifolds and exhaust manifold gaskets.
I had a similar tick for a while and my brother and I fixed it two weekends ago. When I first saw the old gasket, it looked like it was in pretty ok shape to me. I didn't have high hopes that replacing the gasket would fix it, but sure enough it did. My brother also cleaned up the mating surfaces really well, using a flat file on the manifold and brash brush and gasket scraper on the head. These are pics of the gasket, if you look close you can see where it was blown thru just a little. My boat only made the noise under load (in gear) and I could never feel the leak externally, which was weird. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10703 |
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Ok no oil discussions needed maybe I should capitalize that, NO OIL DISCUSSIONS NEEDED
Bri they've been thru the gasket issue already |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4945 |
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Well, the riser gaskets... but a tick is more likely to come from the manifold (to head) gasket. |
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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Since you still have the tic and are set on running the boat, I would order an oil testing kit for oaitest.com. The company name is Oil Analyzers Inc. you can send then in oil sample and they will tell you if any particulates are in your oil. If the oil test is good keep running the engine for the summer and try the gaskets on the exhaust manifolds. Maybe this added information will keep any terminal damage from being done. Good luck.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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ibiz
Groupie Joined: June-18-2012 Location: Kansas Status: Offline Points: 50 |
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Just to recap also regarding the gasket leak theory vs internal engine issue. I don't think there is any doubt that its an issue internal to the engine. I have had some qualified mechanics look at it and we have verified it.
However, if it is just a leaking gasket then I presume that there is no error damage occurring and it will run 'forever'. |
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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If gaskets fix it an the sound goes away, Good to go. I would just hate to sling a rod and ruin a repairable engine by running it till failure.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10703 |
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Since taking a riser off the manifold really does nothing for your ability to get the valve covers off, I figure what Jerry meant here was that the manifolds had been off the heads and put back on. I think he's calling the whole assembly a riser I guess Jerry can verify whether it's had new manifold to head gaskets on it. |
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