Engine Knock

I have not done an oil analysis recently. Last time I had it done was from a kit at local auto parts store, about $20.00. You take a sample in the supplied container which has its own mailing label and the results will be returned by mail.

If the bearings are trashed, a rebuild or repower is in your future. I would rebuild myself.
 
With metal in the filter I would either overhaul this engine or go buy a crate motor...who knows how long its been making metal? It could have started with the knock, or the knock could be the result of long term bearing wear. Sorry to hear about it...
 
I would like to do the rebuild myself... I think it would be fun but I have never done one before... The engine has to be taken out of the boat correct?

Winston
 
Yes you have to pull the engine, get yourself a Mercruiser repair manual so you have all the proper specs and instructions. Inspect all parts for excess wear and damage, inspect water passages for rust, you do not want to build a block or head that is about to rust through. If you have the tools and are mechanically inclined I see no reason for not doing the work yourself.
 
Winston,

You are in the same place you were a week ago, you suspected something was seriously wrong with the engine. I'll repeat my earlier advice; take the boat to an experience tech who can tell you exactly what is wrong with it. That way you can then make an educated decision on what to do next.

I think your willingness to learn by doing it yourself is great. But also feel a marine engine rebuild might to too much too soon especially since you have never rebuilt an engine before. Perhaps removing your old engine and re-installing an engine rebuilt by someone else might be a more prudent plan.

Henry
 
You can do the rebuild yourself. But I will say this, if saving money is a big factor in that decision, you'll come out cheaper buying a crate motor. Even if your heads are fine and all you get is the short block, you're better off. Also, I would venture to say that having a very experienced engine builder available for unlimited counsil would be a must. Do you have a shop available to do the work in?
 
Guess I should start checking prices for both routes.

Where should I start to look for a crate motor? Should I go back with the 502 or a 454? I have heard that the 454 is more reliable. From my understanding the 454 is the same motor as the 502 but with a different head. If this is the case I could use a lot of the same external parts (ie alternator, water pump, ect) and the motor should bolt right in place. What do you guys think?

Winston
 
With zero experience, I suspect doing the rebuild will end up costing you more than replacing. I would advise you get an estimate from a repair shop and a price on a rebuilt engine, and then decide if you really want to tackle a replacement.
 
winstonwilliams said:
Guess I should start checking prices for both routes.

Where should I start to look for a crate motor? Should I go back with the 502 or a 454? I have heard that the 454 is more reliable. From my understanding the 454 is the same motor as the 502 but with a different head. If this is the case I could use a lot of the same external parts (ie alternator, water pump, ect) and the motor should bolt right in place. What do you guys think?

Winston
Click to expand...
the 502 is a very good engine as well...I'll have to look at some specs later this evening to see it the accessories will work with both the 454 & 502.

If you were closer to Atlanta I'd be more than happy to help you rebuild it...
 
Bummer you found metal in the filter. Is it magnetic? You should decide whether you are comfortable enough to start tearing down the engine to find this problem or if you are better off hiring someone/looking into replacement options.

You have made some good progress up to this point. You have confirmed that the problem is in the engine and eliminated an outdrive/u-joint problem. How much farther you go with this is up to you.
 
kindredspirit said:
Bummer you found metal in the filter. Is it magnetic? You should decide whether you are comfortable enough to start tearing down the engine to find this problem or if you are better off hiring someone/looking into replacement options.

You have made some good progress up to this point. You have confirmed that the problem is in the engine and eliminated an outdrive/u-joint problem. How much farther you go with this is up to you.
Click to expand...
I would go one step further and say that it's probably best for an experienced engine builder to be present during tear down. They will see things that the novice will miss for sure. This could give some valuable insight into what happened and what can be done differently in the new build.
 
If you do go that route as far a rebuild, a remanufactured short/block is never out of the question and is cost efficient. I will recommend these guys for your supplier. I have used many of their short/long blocks and have been VERY happy with their work. Second to none in my opinion, keep in mind that they are remans...

http://www.rapidomarine.com/
 
SR Tech said:
If you do go that route as far a rebuild, a remanufactured short/block is never out of the question and is cost efficient. I will recommend these guys for your supplier. I have used many of their short/long blocks and have been VERY happy with their work. Second to none in my opinion, keep in mind that they are remans...

http://www.rapidomarine.com/
Click to expand...
I know this isn't my thread, but I'm looking into whether to rebuild my engine this winter or not...Those are some good prices! I can build my own engine with machine work for about the same amount, but it looks like that would be a better way to go. Thanks for the link!
 
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