1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Nothing abnormal in the oil just really black and my hand pump didn't seem to pull much oil out 3-4to quarts maybe but the dipstick showed acceptable level when checked before hand. Just left the local marine shop and picked up plugs wires cap rotor fuel watter separator exhaust manifold gaskets

 

[Don S]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

I am having a horibble time trying to figure out what is going on with my motor. The top end is knocking some kind of bad. The wierdest part is it sounds to be coming from both sides.

If you had an exhaust leak, you could track it down by simply following the sound by ear. If you can't tell any difference from one side to the other, then it probably isn't a valve or single lifter either, for the simple fact that you could still tell by the sound from which side the noise came from.
If you can listen to the engine from both sides and the top and it all sounds the same no matter where it's coming from, then it's probably coming from the center of the engine.

Get in there and listen carefully, use a mechanics stethoscope or even a long screw driver with your ear on the handle and move it over the engine.

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Ok guys I went ahead and finished the oil change (had to use some serious elbow grease to get the oil filter off) put new plugs in it (old ones were pretty bad old auto lights. anyway i figured what the heck i will start her up again ... same noise but sounded to be more prevalent from left side front so i shut it down and pulled the valve cover and here is what i found

http://www.youtube.com/watch?v=uNWh...DvjVQa1PpcFP_th3NDXbUv2BafKG1uAx8L3eutfV_jhE=

 

[Pete104]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Why do you have an automotive distributor on your boat motor?

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Why do you have an automotive distributor on your boat motor?

Honestly I have no idea was like this when i bought the boat at the end of last year. I just started another thread about that issue.

 

[Bt Doctur]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

auto dist is a no-no. possable causes:
collapsed lifters, try to push the pushrod down
bent push rods, remove and check for straightness
rocker studs pulling out, remove all rockers, put a straightedge across the studs

 

[Pete104]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

As long as someone atleast pointed it out to you! Would think the dealer that winterized it would have said something.
That just leads to a bunch of other questions.
You were changing the oil & filter, how much oil did you get out? Atleast 4qts is OK. Anything less, either it wasn't at the full mark or you didn't get it all out! New filter how much oil went back in to get at the full mark?

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

I guess I got about 4 quarts out because thats how much it took me to fill it back up and yes it was full when i took it out. I will talk to the shop that winterized my boat in the morning and ask why they didnt say anything about the distributor.

 

[Pete104]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

WOW!
I'm just quessing by the vid, you are at least looking at flattened cam lobes. 1 for sure. The rocker stud wouldn't pull out standing still.
Is there a serial number tag down by the starter? You need a telescopic mirror to look along with 3rd elbow, I know! I'm thinking that the motor you have was put in just make it go away. Sorry, but it happens.

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

WOW!
I'm just quessing by the vid, you are at least looking at flattened cam lobes. 1 for sure. The rocker stud wouldn't pull out standing still.
Is there a serial number tag down by the starter? You need a telescopic mirror to look along with 3rd elbow, I know! I'm thinking that the motor you have was put in just make it go away. Sorry, but it happens.

Are you saying I should just rip the motor out and put in a new one? That seems a little drastic to me considering the thing runs great and pushes the boat great. Other than the tap there has never been an issue ... I just dont see why I would putt the motor without at least attempting to fix the current issue. I dont know about the rest of you but I would much rather spend a couple hundred dollars and fix what I have instead of replacing and putting a new crate in $8k (for what i would want). You basically just completely confused me.

 

[Pete104]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

I'm just sayin' you need to fiqure out what you have!
!st you just bought it last fall, now you've owned it forever!
Whatever, it ain't right!

 

[tpenfield]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Definitely look for the serial number for the engine. It is usually located on a metal plate that is on the block in the area above the starter motor. Then you can track down the distributor issue, (which is probably going to have you buying a marine distributor, then the new cap will fit )

That loose rocker arm is on #2 intake ??? . . so the high probability items would be lifter, push rod, valve spring. If you do not have the online manual for the engine, you will want one. Maybe do a valve adjustment while the covers are off.

Good luck with it . . .

 

[81 Checkmate]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Coopin - What did the oil in filter look like? Any metal particals?

On the brite side of things, atleast you you have found a problem and are not still looking!

Like others have said get the serial number so you know what year you have. In all reality you are going to have to pull the intake to get to the lifters.

I would start by removeing the dist cap and bring it up on No1. cyclinder TDC compresion stroke and note were your dist rotor is pointing. This will give you a starting point when you put the new marine dist back in.

Next take losta pics - the wires, hoses, linkage, Ect.

Then if you have never pulled a motor apart - Start reading, get a manual!

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

I'm just sayin' you need to fiqure out what you have!
!st you just bought it last fall, now you've owned it forever!
Whatever, it ain't right!

I understand I need to figure out what I have ... never stated I have owned it forever sorry if it sounded that way was just trying to state I never had an issue with it before. (Was not tapping when winterized/stored for winter/tapping on first start up) Just seemed odd to me. I will try to get the s/n off the block this evening

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Definitely look for the serial number for the engine. It is usually located on a metal plate that is on the block in the area above the starter motor. Then you can track down the distributor issue, (which is probably going to have you buying a marine distributor, then the new cap will fit )

Talked to the shop that winterized the boat told them I have an automotive distributor He said it wasnt an issue. Im very confused now

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

That loose rocker arm is on #2 intake ??? . . so the high probability items would be lifter, push rod, valve spring. If you do not have the online manual for the engine, you will want one. Maybe do a valve adjustment while the covers are off.

Good luck with it . . .

Yes the loose rocker is on the #2 intake ... first rocker toward the front ... going to turn motor over by hand tonight and see if there is any movement (if none im guessing bad cam) if movment then will check other stuff as you stated.

 

[TilliamWe]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Talked to the shop that winterized the boat told them I have an automotive distributor He said it wasnt an issue. Im very confused now

'

No need to be confused. That shop is NOT qualified to work on marine engines.

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Coopin - What did the oil in filter look like? Any metal particals?

On the brite side of things, atleast you you have found a problem and are not still looking!

Like others have said get the serial number so you know what year you have. In all reality you are going to have to pull the intake to get to the lifters.

I would start by removeing the dist cap and bring it up on No1. cyclinder TDC compresion stroke and note were your dist rotor is pointing. This will give you a starting point when you put the new marine dist back in.

Next take losta pics - the wires, hoses, linkage, Ect.

Then if you have never pulled a motor apart - Start reading, get a manual!

Yes I agree at least i know what is making the horrible noise The oil filter was a fram ph 30 and no metal particals in it at all was quite black but other than than looked ok to me. I will pull serial number this evening. I dont mind pulling the intake but i do need to buy a manual (any recomendations?) I have taken motors apart before but only really pulled and replaced entire heads or complete assemblies. I am fairly mechanically inclined and follow directions quite well (most of the time wife would dissagree lol).

On another note the distributor issue what "could" happen if I leave the current one (apparently automotive) in there? motor risks, safety risks, probability, any other considerations?

 

[coopin87]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

'

No need to be confused. That shop is NOT qualified to work on marine engines.

Ok please explain to me why automotive distributors are bad on boats. I know it has something to do with them not being spark proof or something but im trying to not only get everything right but understand the "why".

 

[81 Checkmate]

Re: 1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help

Coopin if you bought the boat from the so called shop, Thats why he is telling you it's no big deal. Please do not call the so called shop anymore. Thease guys on this site are xperts and will not steer you wrong in any way!

An auto dist will work in a boat as you are already awear off, but the thing is it needs to elect safe for being in a inclosed engine compartment. A marine dist is made with safety componets that will not spark out side of the unit.

With that being said, if you have a gas leak and fumes build up in your inclosed engine compartment and your auto dist arcs, well you know what happens!!!!!!

Have you ever tore into an engine before?