Mercruiser Knocking

[Midnight Thunder]

Re: Mercruiser Knocking

My god man... do you live here? lol Within 5 minutes of a post - I get a reply - how could this be any better?? lol I can't tell you my appreciation.

 

[Coors]

Re: Mercruiser Knocking

new crank and rod; take it to a shop that wants the complete short block. you need to have piston clearance and cylinder wear check, while it is apart.

 

[Midnight Thunder]

Re: Mercruiser Knocking

ok - I will insist on it.

 

[Coors]

Re: Mercruiser Knocking

Yes, get the whole story while it is apart, so as to not do it again soon.

 

[Midnight Thunder]

Re: Mercruiser Knocking

Ugh.. ok - got the motor pulled - all accessories off to ready the block for the machine shop.

I pushed on cylinder one and sure enough 'knock' - I pulled the rod end to check the bearing - and it is scored badly!!! I had new bearings in there and the motor ran for maybe a total of an hour.

I checked the other bearings and some are scored as well but not nearly as bad.

When I put her together - I made sure she was well lubed with cam-lube and torqued the rod bolts to 35 as per the manual.

I made sure there was no debris in the bearings.

What would cause them to burn out so fast? Will I be able to get this repaired? A new core? A new crank? Let me know so I know what to prepare for $$ wise.

 

[Midnight Thunder]

Re: Mercruiser Knocking

I got the block to the machine shop - they had a 'quick' look and agree - the rod got pounded out of shape - and just re-burnt the bearings. They are going to check the crank and see if there is enough meat on it to shave and then just match the bearings to it. I'm going to have all the pistons done while I am at it.

Do I need to worry about this at all? Will it affect performance? Or do I need to invest into a new crank? Is there another way to repair a crank?

 

[flashback]

Re: Mercruiser Knocking

machine shops do it all the time. bearings come in standard size increments so they will turn down the journals to fit the next size bearing if the journal is still not round they go to the next size. a lot depends on if it has ever been turned down before.. you can only do it so many times then its time to get a new crank...

 

[Midnight Thunder]

Re: Mercruiser Knocking

Any special instructions for re-installing the harmonic balancer? Looking at the manual, it just taps in?

 

[Don S]

Re: Mercruiser Knocking

You don't hammer it on. There is a special installer tool to use to install it.
If your manual says "Tap" it on, then you need an OEM manual not that clymers or seloc you are reading.