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

[Don S]

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

Like I said before, you posted your point of view, others should be allowed to post theirs as well without having to answer to you each time.

If you want to pursue the issue, start a new thread.

 

[Bondo]

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

As i said previously i have replaced countless flat tappet cams with worn or completely flat lobes in engines that gave many miles or hours of service afterward.

Ayuh,... That ounce or so of ground cast iron's gotta go somewhere, 'n the filter is After the oil pump....
sorta right up there with assemblin' a long block motor, in a sand storm...

The hour spent poppin' the motor out, is Saved by not climbin' in, 'n outa the boat 200 times....

 

[joewithaboat]

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

Ayuh,... That ounce or so of ground cast iron's gotta go somewhere, 'n the filter is After the oil pump....
sorta right up there with assemblin' a long block motor, in a sand storm...

The hour spent poppin' the motor out, is Saved by not climbin' in, 'n outa the boat 200 times....

A Chevy oil pump couldn't care less about the almost immeasurably amount of metal dust going through it, give me a break!

So an hours labor is all you charge to pull an engine....

Last time i swapped a cam, in the boat, i bet i dint get in and out maybe 12 times. Done in prob 4 hours bs'in, drinking a couple cold ones with a friend. Even stopped to eat a sandwich. Much easier than pulling the engine.

 

[Don S]

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

STOP the hijack Joe
if you want to argue the case start your own thread and stop hijacking this one.

 

[joewithaboat]

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

STOP the hijack Joe
if you want to argue the case start your own thread and stop hijacking this one.

PM sent !

 

[joewithaboat]

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

Ok guys so work has picked up and I dont have time to do everything myself. Took the boat to a reputable shop today to have them verify the problem so I can go from there. If it is the cam what else do you guys recomend me to replace while the motor is pulled apart. I will update you guys again tomorrow when the shop calls me. To be honest I want to make sure that while everything is apart I do as much as possible to make sure its good to go for this summer. Not sure if the motor will need to come out yet or not seat looks like it can be removed and if it can be the pan can be dropped with it sitting in there or so it would seem (lots of room underneath the motor).

Did they say what they charge to pull the engine and put it back?

 

[riptorn]

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

STOP the hijack Joe
if you want to argue the case start your own thread and stop hijacking this one.

I don't think joewithaboat is high jacking this thread. I think that coopin87 has the right to read other peoples opinions about '1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help' .
Remember! The results are not in yet.

 

[Don S]

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

I don't think joewithaboat is high jacking this thread. I think that coopin87 has the right to read other peoples opinions about '1996 mercruiser 5.7 with thunderbolt ignition ... Top End knock Please Help' .
Remember! The results are not in yet.

Yes, he does have the right to other peoples opinions, that's why I posted this to Joe in post #142

Like I said before, you posted your point of view, others should be allowed to post theirs as well without having to answer to you each time.

If you want to pursue the issue, start a new thread.

 

[coopin87]

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

Guys great advice from all. Like I said before I really dont have the time in the next few weeks to work on anything let alone my boat. I took it to the shop because I dont want to have much down time without the boat this summer (reason we all have boats ). Even though you guys have posted your views on pulling or leaving the motor in Im sure the shop will lead me in the right way. They will more than likely pull it out (Mechanic is quite anal). Either way how ever they do it I really dont care as long as it will get me back on the water. My question was never answered ... If it does turn out to be a flat cam loab what else should I make sure they replace while they are in there? Just want to make sure I have the basis covered.

 

[Pete104]

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

If in fact it turns out to be a " flat lobe", you/they must replace both cam & lifters! Also, you must use engine oil blended for flat tappets!

While it's out, maybe they find out exactly what engine it is! You may a few other issues in that regard. Who knows what! 5.0 vs 5.7 perhaps!

 

[joewithaboat]

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

Guys great advice from all. Like I said before I really dont have the time in the next few weeks to work on anything let alone my boat. I took it to the shop because I dont want to have much down time without the boat this summer (reason we all have boats ). Even though you guys have posted your views on pulling or leaving the motor in Im sure the shop will lead me in the right way. They will more than likely pull it out (Mechanic is quite anal). Either way how ever they do it I really dont care as long as it will get me back on the water. My question was never answered ... If it does turn out to be a flat cam loab what else should I make sure they replace while they are in there? Just want to make sure I have the basis covered.

Well if you were going to follow the advice of some people around here, or your "anal" mechanic and pull the engine to inspect a camshaft.... You should check everything. Heck why not just buy a new crate motor with a warranty. Make sure you replace the starter to... if bond-o was working on it he will charge you to pull the engine for that if it goes bad. Lol

In all seriousness, if your mechanic doesn't offer to take the carb & intake off of it while it is in the boat to get a better look at it you should find a different mechanic. The oil filter set up on that type engine is very good, the oil pumps are near bullet proof and failures are nearly non existent. So these guys saying you are pumping metal through your engine is, baloney.

Flat cams in small block Chevy's are VERY common, ask any cam company. Most common in high mileage vehicles with poor oil change history. Hundreds of thousands of camshafts have been changed on engines that don't get torn down. It would be fine if that's all that is wrong with it. Based on the cleanliness of your heads i would bet that your cam went flat because the valves were set too tight when the heads were changed. I have on two occasions seen a spun cam bearing because of increased load by the over tight lifters and heavy springs. You would be wise to check that.

Make sure to get work agreement in writing that has specific dollar amount's on it and dont ever sign a generic looking work order that says something like "approval to fix engine". If they want a deposit and you want to really protect yourself, pay with a credit card that you use often.
Sorry if you already knew this part. I dont mean to make you sound like an idiot or anything.

Best of luck, keep us posted

 

[coopin87]

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

Well if you were going to follow the advice of some people around here, or your "anal" mechanic and pull the engine to inspect a camshaft.... You should check everything. Heck why not just buy a new crate motor with a warranty. Make sure you replace the starter to... if bond-o was working on it he will charge you to pull the engine for that if it goes bad. Lol

In all seriousness, if your mechanic doesn't offer to take the carb & intake off of it while it is in the boat to get a better look at it you should find a different mechanic. The oil filter set up on that type engine is very good, the oil pumps are near bullet proof and failures are nearly non existent. So these guys saying you are pumping metal through your engine is, baloney.

Flat cams in small block Chevy's are VERY common, ask any cam company. Most common in high mileage vehicles with poor oil change history. Hundreds of thousands of camshafts have been changed on engines that don't get torn down. It would be fine if that's all that is wrong with it. Based on the cleanliness of your heads i would bet that your cam went flat because the valves were set too tight when the heads were changed. I have on two occasions seen a spun cam bearing because of increased load by the over tight lifters and heavy springs. You would be wise to check that. It could also be a reason you are seeing poor oil delivery to the top end.

Make sure to get work agreement in writing that has specific dollar amount's on it and dont ever sign a generic looking work order that says something like "approval to fix engine". If they want a deposit and you want to really protect yourself, pay with a credit card that you use often.
Sorry if you already knew this part. I dont mean to make you sound like an idiot or anything.

Best of luck, keep us posted

Lol Joe. Thanks for the advice. Yes they are pulling intake manifold tomorrow to verify the issue before going any further. I dont have much to worry about with the shop in general considering I know most of the guys personally and are all quite honest people who I dont think would try to pull a fast one on me. The basic gist of what im trying to figure out here is if there is anything else I should go ahead and change while they have all the stuff pulled apart. Recomendations would be great. Im not about to drop a new motor in it deffinately dont have the funds for that right now. crate 383 is running around 7k around here. Just dont want to be blind sighted by anything extra if you know what I mean. I get that it is basically a truck motor with a different cam and freeze plugs and intake manifold. Just want to cover the basis. I will let you guys know what they say tomorrow.

 

[Don S]

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

Well if you were going to follow the advice of some people around here, or your "anal" mechanic and pull the engine to inspect a camshaft.... You should check everything. Heck why not just buy a new crate motor with a warranty. Make sure you replace the starter to... if bond-o was working on it he will charge you to pull the engine for that if it goes bad. Lol

Since you have obviously not been reading the replies, you might want to re-read from about reply 125 to now. No one said to pull the engine to check the cam, there have been a few of us that say if the cam has a dead lobe, then it's time to pull the engine and the pan, and check other things.

 

[joewithaboat]

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

Lol Joe. Thanks for the advice. Yes they are pulling intake manifold tomorrow to verify the issue before going any further. I dont have much to worry about with the shop in general considering I know most of the guys personally and are all quite honest people who I dont think would try to pull a fast one on me. The basic gist of what im trying to figure out here is if there is anything else I should go ahead and change while they have all the stuff pulled apart. Recomendations would be great. Im not about to drop a new motor in it deffinately dont have the funds for that right now. crate 383 is running around 7k around here. Just dont want to be blind sighted by anything extra if you know what I mean. I get that it is basically a truck motor with a different cam and freeze plugs and intake manifold. Just want to cover the basis. I will let you guys know what they say tomorrow.

Well based on the obvious fact that the engine has been worked on and had the heads upgraded you never know what you might find. Like i have been saying it could have just a flat lobe or two and be perfectly fine otherwise. If that were the case you might get away with only a cam and lifter change. Take some pics once they open it up and lets have a look.

As far as other simple things... I would change the timing chain to a true double roller, front seal at the harmonic balancer, give the balancer a good look where the rubber bonds the inner and outer hub. Maybe a speedy sleeve on the balancer. If it were me in my younger years, not that Im old now, i would put an inexpensive two piece front cover on it. I'm the type that would be apt to change the cam just to try a different one and that makes it much easier. Check distributor gear for wear, maybe upgrade the oil pump shaft to one with a steel collar not plastic or at least a new plastic sleeve. Give the rockers a good look and roll the push rods on a flat surface to check them for being bent. These last two especially because we suspect the valves were set too tight. Im sure ill think of something else.

If you are considering letting them pull the engine i would run a compression test to check overall health maybe even a leak-down.
If the engine winds up upside down on the stand like some have suggested id be looking at the bearing conditions, check clearances. Not just inspecting the oil pan for metal. In other wards, If it comes al the way out to change a cam, which is loony, i would be getting my moneys worth and check everything i could easily get at. Oil pumps and pick ups are cheap once your in that far. I'm making some assumptions that the mechanic is qualified to do all of this, a lot are not. I lived, ate a breathed race cars/engines for a solid ten years, i have a lot of mechanic friends...I wouldn't let them open up my engine Lol

 

[joewithaboat]

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

if the cam has a dead lobe, then it's time to pull the engine and the pan, and check other things.

Like what for instance?
What as consumers should we expect to pay to pull an engine and change a cam/lifters And "check other things" if we find ourselves in the same position as the O/P.
Thanks in advance.

 

[coopin87]

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

Like what for instance?
What as consumers should we expect to pay to pull an engine and change a cam/lifters And "check other things" if we find ourselves in the same position as the O/P.
Thanks in advance.

Yeah if you guys could give me some round about estimates on how much I should be looking at spending on a high side and a low side that would be great. Just to have it pulled cam and lifters replaced inspect everything else and reinstall and have it running well again?

 

[81 Checkmate]

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

Wow!!!!!!

Coopin - I see you took it to a mechanic for a look see. After all that had been said regurding your situation it is most likley gona be a bad cam.
With it beeing a bad cam - Pull motor or not too?????

1. Pulling motor to inspect and clean and replace whatever it needs, being top end and or bottom end parts, Cam, lifters ,rod bearings, main bearings, oil pump, gaskets, ect and so on. Could be up to $1500 or so. Most boat mechanics charge anywere from $65 to $100
per hr.
2. Not pull the motor and DIY - Replace Cam, lifters, gasket set and a few oil changes. I would say around $300 to 400 maybe cheaper if you shopped around. Now would this work and be right? Who knows, Could last 10 years or 3 min that would be the $1000 question. Like Joe has said it has been done a million times over with the small block chevy. To me i would have wayed how long am i keeping the boat and or run it till she dies and then look into a replacment. If you are useing the boat on a lake were someone could get you back to the dock with ease then i would take the time and do it myself and chance it. But that is just me. Now out on the ocean... no way would i chance it!

When Bondo and Don do things they have all the tools and equipment and knowlage to do it the right way and not look back, so pulling the motor would be the right thing to do in order to make the motor last and costomer happy!

I had to throw this into the mix of things!!!!!! Good luck and let us know what they find

 

[coopin87]

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

Wow!!!!!!

Coopin - I see you took it to a mechanic for a look see. After all that had been said regurding your situation it is most likley gona be a bad cam.
With it beeing a bad cam - Pull motor or not too?????

1. Pulling motor to inspect and clean and replace whatever it needs, being top end and or bottom end parts, Cam, lifters ,rod bearings, main bearings, oil pump, gaskets, ect and so on. Could be up to $1500 or so. Most boat mechanics charge anywere from $65 to $100
per hr.
2. Not pull the motor and DIY - Replace Cam, lifters, gasket set and a few oil changes. I would say around $300 to 400 maybe cheaper if you shopped around. Now would this work and be right? Who knows, Could last 10 years or 3 min that would be the $1000 question. Like Joe has said it has been done a million times over with the small block chevy. To me i would have wayed how long am i keeping the boat and or run it till she dies and then look into a replacment. If you are useing the boat on a lake were someone could get you back to the dock with ease then i would take the time and do it myself and chance it. But that is just me. Now out on the ocean... no way would i chance it!

When Bondo and Don do things they have all the tools and equipment and knowlage to do it the right way and not look back, so pulling the motor would be the right thing to do in order to make the motor last and costomer happy!

I had to throw this into the mix of things!!!!!! Good luck and let us know what they find

Ok well just got off the phone with the shop they have not had a chance to take a look see yet. But just to let everyone know these guy are personal friends and I normally buy all my parts from them for any of my vehicles because they sell them to me at cost. As far as the labor being an hourly rate every time in the past they have charged me roughly 25-30 per actual hour not book hour. I plan on keeping the boat for about 2-3 more years and never take it to the ocean. Most of my boating is on the potomac river where there is quite a bit of boat traffic and most of my friends own boats and normally when we go out it is a group outing aside from the occasional fishing trips. Most people around here are great with helping out when someone needs a tow ect. Personally I helped 4 or 5 guys last year get back to the dock. As far as chancing the boat breaking down on me I would rather not. Take my young kids out with me quite a bit and wife is always with me aside from the very occasional guys outings. All that said would rather not give my wife another reason as to why I should get rid of one of my toys as im sure most of you have to deal with from time to time. I dont mind spending the money but want to make sure I get the most bang for my buck. I do agree that I could probally do it myself alot cheaper and chance it but I just dont have the time right now :facepalm: and when I do get to the point to where I would have time I would much rather be out enjoying the water than turning wrenches.

 

[joewithaboat]

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

Crickets.......

Funny that we have 2 mechanics that constantly brag about being able to remove and have the engine on the stand in an hour but refuse to post what they charge for that hour or to take the engine in and out.

 

[Bondo]

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

Crickets.......

Funny that we have 2 mechanics that constantly brag about being able to remove and have the engine on the stand in an hour but refuse to post what they charge for that hour or to take the engine in and out.

Ayuh,... Sorry joe, I'm an in-house Mechanic,... I draw my salary whether I'm wrenchin' on a dumptruck, or a boat....