Time for new motor?

[BlowHo]

My OMC 460 would not start, I tore off the exhaust manifolds and risers. Gaskets were obviously leaking. Tore off the valve covers, everything looks OK. Tore off the intake and this is a picture of the one of the intake on the left head. This is the worst but ALL of them have rust.

I have two head bolt that are rusted in place, after trying to get them out for an hour, I decided to take this picture and see if I should even bother or just start looking for a new motor.

What do you guys think??

 

[Coors]

Re: Time for new motor?

If any port looking like that had a valve open, the cylinder will look like that too.

 

[BlowHo]

Re: Time for new motor?

rebuildable or is it an engine replacement??

 

[Coors]

Re: Time for new motor?

Depends, you need to pull the heads and look.

 

[BlowHo]

Re: Time for new motor?

Any good tricks to get stubborn head bolts out?

 

[Coors]

Re: Time for new motor?

soak overnight with pb blaster, etc.
Propane torch.

 

[BlowHo]

Re: Time for new motor?

That's what I was thinking, but I have today off, not tomorrow.

I tried my impact wrench and the bolt heads are so rusty that the socket just slipped. Oh well, I'll get to soaking.

 

[Robj]

Re: Time for new motor?

You can always drill the bolt head, remove the head and then use a pipe wrench to try and remove the remainder of the bolt.

Good Luck,

Rob.

 

[BlowHo]

Re: Time for new motor?

Got one of the bolts out, one to go.

I have found a replacement 460 on craigs list just in case. It is out of a 1977 pickup, my boat has an 89 460. If I need to replace, will this work or will I have major compatibility issues?

 

[HT32BSX115]

Re: Time for new motor?

I would be willing to bet that even with a pickup cam it would probably run alright. You need to determine if the engine is externally or internally balanced. I can't remember what mine was. I think it might have been externally balanced.

Getting a pickup engine is perfect if you're going to have it rebuilt though.
The marine type engine kits come with the correct cam and soft plugs.

Got one of the bolts out, one to go.

I have found a replacement 460 on craigs list just in case. It is out of a 1977 pickup, my boat has an 89 460. If I need to replace, will this work or will I have major compatibility issues?

 

[BlowHo]

Re: Time for new motor?

I got one of the heads off and it wasn't that bad. There was light rust on the bottoms of the valves, however it cleaned off easy and now appears to be good.

The tops of the pistons and cylinder walls also look good, I soaked a rag in oil and wiped them down. The top of the cylinders have a ring of rust about 1/4 of an inch down and then the walls look smooth and polished.

All of the gaskets tore apart when I removed head, intake and exhaust. I can't see anything that is obvious for a blown gasket on the wear marks in the metal.

I tried to turn the crank by hand and the darn thing will not budge. Am I missing something? I would think it would turn pretty easy with everything off/open. The starter was turning it early yesterday morning, it was slow, but turning.

I will post pics of the head & cylinders later, my daughter took the camera to a party.


Any ideas why the crank won't turn now when it was turning yesterday??

 

[BlowHo]

Re: Time for new motor?

Anybody have any ideas as to why I can't turn the crank by hand?

I assure you it is not a lack of superhuman strength, does the boat need to be in neutral? Or in gear?

Thanks.

 

[Reel Poor]

Re: Time for new motor?

In neutral.

Do you literally mean by hand, or are you using a socket and ratchet on the center bolt in the front of the crankshaft?

If your using a wrench and it's really hard to turn it could be a drive problem.

 

[Coors]

Re: Time for new motor?

yep, Reel is on it.
light rust points to drive froze

 

[BlowHo]

Re: Time for new motor?

HAHA - socket and wrench, not me bare hands.

If it is a stuck outdrive, why did the motor crank with the starter? It was cranking really slow, which is what started me down the path of the motor needing rebuilt.

Could this whole crap somehow been a seized outdrive?! HELP!

 

[Reel Poor]

Re: Time for new motor?

Only real way to know for sure is to pull the drive and see how the engine turns with the drive off. You might get an indication of drive condition by draining the drive lube.

 

[BlowHo]

Re: Time for new motor?

I already drained drive oil when I got the boat. It was chocolate chunk. My servie manual says I need a 500lb. hoist to get the outdrive off, does it really weigh that much? I also don't have a stand to put it on.

Crap this sucks.

 

[Reel Poor]

Re: Time for new motor?

Removing you King Cobra drive can be done by two men. The problem is it's heavy (around 100lbs) and awkward. You can make a simple drive stand. They have been picture here many times before. Use the search function and search for "out drive stands".

 

[HT32BSX115]

Re: Time for new motor?

2 people can easily remove it.

Give me a call this week and I'll drop over and help you pull it off.

I used a neighbors engine hoist to pull mine. I have an eyebolt that will screw into the dipstick hole too.




Cheers,

Rick

 

[BlowHo]

Re: Time for new motor?

Reel poor - Super easy, I'm building one tonight.

Rick - I don't have time to mess with it until the weekend and I know you're busy with graduation festivities. I don't want to bother you until you have more free time.


I still don't see how the starter could turn the motor over and I can't with a wrench and socket. Wouldn't a frozen outdrive prevent anything from turning it??