Engine noise

Tiny
REDTAHITI
  • MEMBER
  • 1970 OLDSMOBILE 442
  • 7.5L
  • V8
  • 50,000 MILES
This is a 455 olds in a jet boat. I winterized it last fall removed the tarp I had on it last week to work on a bad place in the floor. I thought I would start before I covered it back up well it fired right off but had an awful rattling noise in the front of the engine. This noise was not there last summer. Only started it twice and run it about thirty seconds each time. When I rev it a little I do not hear the noise until it comes back down to a idle. I am changing the oil and filter and pulling the plugs and turning it over a few time before trying to start it again.
Monday, April 16th, 2018 AT 3:33 AM

18 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good morning.

Inspect the oil when you drain it and see if there is any evidence of water or metal particles.

Is it possible that water may have got into the oil system?

Roy
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Monday, April 16th, 2018 AT 4:18 AM
Tiny
REDTAHITI
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  • 11 POSTS
Thank you very much.
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Monday, April 16th, 2018 AT 5:03 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Wow, does not sound good at all.

Does not sound like valve train. It sounds like lower end.

Roy
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Monday, April 16th, 2018 AT 5:06 AM
Tiny
REDTAHITI
  • MEMBER
  • 11 POSTS
Just do not understand what could of happened to it just setting there.
I have run across a lot of different problems with engines but this one's got me stumped! I will try changing the oil and re-priming the pump.
Will let you know.
Thank you.
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Monday, April 16th, 2018 AT 5:18 AM
Tiny
ASEMASTER6371
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You are welcome.

Keep us updated.
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Monday, April 16th, 2018 AT 5:21 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
To me is looks like that alternator pulley is loose. If you watch the fins they appear to be slowing down when the noise is loudest. You can definitely see the belt flopping.
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Monday, April 16th, 2018 AT 4:12 PM
Tiny
REDTAHITI
  • MEMBER
  • 11 POSTS
I am going to untarp again this weekend and give it a good going over.
I will check the alternator pulley and harmonic balancer.
Thank you very much for your reply.
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Monday, April 16th, 2018 AT 6:51 PM
Tiny
ASEMASTER6371
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Sounds like a plan.

Try removing the belt and run the engine to confirm.

Roy
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Monday, April 16th, 2018 AT 6:58 PM
Tiny
REDTAHITI
  • MEMBER
  • 11 POSTS
Back again.
Checked alternator and harmonic balancer both good.
Pumped out oil, took old filter apart and found no metal shavings, and yes there was some water in oil. I have learned all jet boats get water in the oil sooner or later.
Anyway, I filled a new filter up with oil put it on and filled the crankcase with good 10-40w oil took out the plugs cranked it over about twenty times, put plugs back in hooked it to water hose so I could run it longer I went to the right side of the engine and the noise was louder. I pulled the valve cover tappets were dry turned it over by hand and check for loose tappets none.
It seamed like they were to tight could not wiggle any of them.
Started motor with out valve cover and let run for seconds no oil.
I am thinking lifter or oil pump.
I live in N, E Oklahoma it got into and it got down to 0° a couple of times could that water in the oil have froze and broke lifter or oil pump.
I am going back out and pull the other valve cover, probably have to pull intake and the engine before it over, was hoping to start the summer a better.
Sorry for ramble any advice is appreciated.
Thank you.
Redtahiti
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Thursday, April 19th, 2018 AT 12:45 PM
Tiny
ASEMASTER6371
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Okay, yes, it sounds like you need to start at the oil pump.

What you could do is this; get a primer for the oil and remove the oil pressure switch. Then insert the primer into that port and force feed oil into the system with valve covers off. Then see if you oil to the top end. That will at least tell you if the ports are all open and able to transfer oil into the system.

You can rent a primer or make your own from an empty R134 Freon container. I used this to prime all my motors after I rebuilt them.

Roy
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Thursday, April 19th, 2018 AT 12:51 PM
Tiny
REDTAHITI
  • MEMBER
  • 11 POSTS
Thank you, I will see if I can find one.
Autozone rents tools I will see if they have one.
I pulled the other valve cover and it was super clean inside but no oil.
I will try what you said.
Thank you for your advice.
Will keep you posted.
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Thursday, April 19th, 2018 AT 2:08 PM
Tiny
ASEMASTER6371
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You are welcome.

Keep us updated.

Roy
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Thursday, April 19th, 2018 AT 2:47 PM
Tiny
REDTAHITI
  • MEMBER
  • 11 POSTS
Back again.
Released the pressure on the lifters, took out the push rod blew them out.
Took out oil sending unit and replaced it with a hose, used oil priming tool and good drill it pumped out a quart in about a minute.
Tightened all the lifter back down, run the drill for about fifteen minutes before I seen any oil coming out of push rod.
Put distributor back in hooked engine to water and started it with in a few minutes it was oiling the top end and that awful noise was gone.
Let it run for almost thirty minutes no problems, what the heck!
I have seen engines set for years and start easier than this one did after four months.
Baffled!
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Sunday, April 29th, 2018 AT 3:21 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Good morning.

Sounds like it lost its prime and the system was full of air. Not common but happens.

Run it every day and make sure it does not air bound again. If it does, the oil pump may the issue draining back and losing the prime from a bad check valve.

Roy
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Sunday, April 29th, 2018 AT 6:55 AM
Tiny
REDTAHITI
  • MEMBER
  • 11 POSTS
I will do that. Will let you know what happens.
Thank you much for your advice it is greatly appreciated.
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Sunday, April 29th, 2018 AT 7:41 AM
Tiny
ASEMASTER6371
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No problem. We are glad to help.

Roy
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Sunday, April 29th, 2018 AT 12:19 PM
Tiny
REDTAHITI
  • MEMBER
  • 11 POSTS
That noise was back again. Started it Thursday morning was the first chance I had sense the oil pump priming, anyway sent the boat to Joplin MO. With my brother he is a mechanic up there he got his stethoscope out and found the problem, I feel dumb because all of the fly wheel bolts were loose. I have had flex plates come loose or crack out but never had a regular fly wheel come loose. Anyway, took drive shaft loose and took out each bolt check them out lock tight on and torqued them, put it all together started it the noise is gone.
It is crazy how a noise in the back project its self to the front.
The engine has a three quarter in closed bell housings with two inspections ports it was a challenge getting a torque wrench into.
And it was oiling when I started it.
Thank you guys for your help and listing to me.
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Saturday, May 5th, 2018 AT 4:53 PM
Tiny
ASEMASTER6371
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No problem. Glad you found the issue.

Roy
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Saturday, May 5th, 2018 AT 5:04 PM

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