Mercruiser 260 "problem"

[savery]

I just purchased a project boat, which means that I buy cheap boats with difficulties. Anyway, right now I'm faced with a possible situation. I purchased an 85 larson with a Mercruiser 260. The outdrive was stolen off of it and I was supplied with another used one. The people that sold it to me told me that it was winterized prior. However when i checked the Oil, the level was really high. Which coul mean that when it was winterized it was overfilled intentionally to reduce the amount of air and subsequently lessening the chance of condensation, or it wasn't winterized at all and i have a cracked block, head, whatever. Anyway I intend to drain the oil from the bottom to check for water, but until then I'm thinking on the side of a busted block, which leads me to repowering, and even more problems. I do all of the work myself, taking a boat to a shop is obscenely expensive. My time and a few busted knuckles and a few hours in the repair manual/internet are well worth the cost of taking it to a shop that's going to make me buy a brand new motor. However, i have a few questions. The main one which i can not find an answer to, is what are the differences between "mercruiser I" and "alpha one" parts. If i was to do a total repower, I'm not sure if i should go with the old pre alpha stuff, the new alpha one gen II stuff, etc. The other is what parts differences are there between marine and automotive as far as mounting is concerned? I could get an old chevy 350 out of the junkyard, replace the cam and heads to make it ready for the demands of a marine engine, but i need to make sure that it would mount in place without discovering that the mounting hardware could fit. Most all of the arguments against using automotive parts are coming from people that sell marine engines. I understand that getting on plane and running at 4000 RPM for 2 hours is different than running at 2000 RPM for the same time, I just want to know if the stinkin' motor will fit!

 

[DJ]

Re: Mercruiser 260

Re: Mercruiser 260

I'm not an expert on the drives, however, if you are repowering, go as modern as you can.

There is more to a marine engine than the cam. THe heads may in fact be the same.

Typically marine engines use brass or stainless core (freeze) plugs.

The blocks will be the same as long as they are out of rear wheel drive vehicle. The flywheel will be different. You'll need the marine bell housing too.

As far as other parts, there is a big difference between automotive and marine: starters, alternators, distributors, modules, carburetors, fuel pumps and air cleaners. All those parts are specially designed to shield or STOP sparks. The fuel handling parts are designed to not allow any fuel into the bilge. Don't mess around in those areas.

 

[Bondo]

Re: Mercruiser 260

Re: Mercruiser 260

Ayuh,..........

A 350 out of a Truck Will Fit,.........

Vintage is the Main Concern,........

The Farther from the Same Vintages,.......
The More Fitment Issues you'll need to Deal With.........

 

[savery]

Re: Mercruiser 260

Re: Mercruiser 260

Thanks for the replies. I still don't know if my motor is busted or not, i was busy last night, but i'm thinking on the side of getting a truck engine from the same vintage. I just wanted to make sure that the motor was going to mount in the right places, and match to the transom housing. My plan would be to get an engine, strip it down, remove the boat's engine, check the cam for wear and install it in the truck engine along with new lifters. Replace the oil pump, and swap all of the marine parts, overhauling or replacing essential stuff (starter, fuel pump) as i go. I just didn't want to throw down the money for a brand new powerplant all at once, which is going to cost me and really not add that much value to the boat in the end.

 

[Bondo]

Re: Mercruiser 260

Re: Mercruiser 260

Ayuh,.......
That sounds like a Solid Plan,.........

I wouldn't bother Swapping the Cams though,......
The Truck Cam is So Close to the Marine Cam,.....
You'll Never Know the Difference..........

 

[Autotech1]

Re: Mercruiser 260

Re: Mercruiser 260

Dont put new lifters on an old cam!!!!! it WILL go flat. instead put the old lifters on there original lobes in the replacement engine. But as Bond-o stated, replacing the cam is not even necessay.
You could also get a new cam and lifters with the marine specs. Flat-tappet cams have had a problem lately tho with going flat due to inferior metals in both the cams and lifters. This is due to the recent flood of overseas parts coming from manufacturers employing shoddy practices.
I would spend the extra money and go with a high end racing cam company, most will build any grind u like if they dont have it on the shelf. Dont go cheap here as it could me another tear-down and lost time. Comp Cams, Crane Cams, Iskendirian, Chet Herbert are a few.