87 omc 350, no power, Help!

[Bt Doctur]

Re: 87 omc 350, no power, Help!

If 1 cyl. was affected then have the head checked for a crack or a corroded hole. Fill the block with water and check for a cracked cyl. wall.
Kinda wondering where that chunk went to.

 

[subcrx]

Re: 87 omc 350, no power, Help!

Have the head checked? the cylinder was full of water up to the lip when i pulled the head off. Is it worth having the head checked? I need my boat working in no less than two weeks.

 

[JCF350]

Re: 87 omc 350, no power, Help!

With that time frame, replace engine and manifolds and be done with it.

 

[subcrx]

Re: 87 omc 350, no power, Help!

ok, i was at united engine earlier and found a couple options for long blocks, rebuilt standard 350 engine for autos for $750, or marine upgrade for $1100. Is the difference that big?

 

[oops!]

Re: 87 omc 350, no power, Help!

it sounds to me like a cracked manifold started the whole problem.....

pressure test it before re installing......

i had a very simmelar problem....it was a pita to track down.....once the mainifold was replaced...easy boating

 

[oops!]

Re: 87 omc 350, no power, Help!

ok, i was at united engine earlier and found a couple options for long blocks, rebuilt standard 350 engine for autos for $750, or marine upgrade for $1100. Is the difference that big?

cam....

but anything marine co$$ts more

 

[subcrx]

Re: 87 omc 350, no power, Help!

Just scored a 350 from a friend of mine in the car business, It came out of a van and is in the right year range. Now what should I do to prep this for marine use. I do plan on going full closed cooling system. so what on the motor would i need to change

 

[RCSConstruction]

Re: 87 omc 350, no power, Help!

Just scored a 350 from a friend of mine in the car business, It came out of a van and is in the right year range. Now what should I do to prep this for marine use. I do plan on going full closed cooling system. so what on the motor would i need to change

Nothing, just transfer over your parts.
Better get new exhaust manifolds or you'll be on to engine number 3.

 

[subcrx]

Re: 87 omc 350, no power, Help!

yes i already knew that part. I plan on replacing all oil related gaskets. And does the cam absolutely have to be changed? Ive only done head work on these chevy motors in the past. never changed a cam

 

[zvolv]

Re: 87 omc 350, no power, Help!

Off the top of my head the differences in a boat motor are:

dual valve springs, marine gaskets, brass freeze plugs, dual timing chain, water pump, brass coolant passage in intake mani, marine cam, marine starter and alternator (no exposed sparks), and whatever else I forgot.

My 86 4.3L sucked in water somehow and blew the engine. Never figured out why...

 

[RCSConstruction]

Re: 87 omc 350, no power, Help!

yes i already knew that part. I plan on replacing all oil related gaskets. And does the cam absolutely have to be changed? Ive only done head work on these chevy motors in the past. never changed a cam

No need to change the cam...
The difference between a marine cam and a truck cam is not noticeable (some say they are the same) and swapping cams will not make a difference at all.
Boats do not have double valve springs, no double roller...
Just strip your new motor down to longblock form and start bolting your marine parts on.

 

[subcrx]

Re: 87 omc 350, no power, Help!

I know the one i have in there has 2 springs per valve, one little one inside a larger one

 

[RCSConstruction]

Re: 87 omc 350, no power, Help!

I know the one i have in there has 2 springs per valve, one little one inside a larger one

Sure it's not a dampener inside the spring your seeing??

 

[subcrx]

Re: 87 omc 350, no power, Help!

sure looks like a spring to me. you can see bt doctur talking about them earlier in the thread, turned out not to be that problem

 

[RCSConstruction]

Re: 87 omc 350, no power, Help!

Look like this? These are single springs with dampener.

 

[subcrx]

Re: 87 omc 350, no power, Help!

you are right, they look exactly like that. looks like a flat looking spring inside. gotcha

 

[subcrx]

Re: 87 omc 350, no power, Help!

Ok guys I got that new motor over to my house and I noticed its a little different. this one is off of a 1990. and the valve cover bolts are on the top instead of the sides. Will this motor still work? will my manifolds bolt up?

 

[RCSConstruction]

Re: 87 omc 350, no power, Help!

No problem, just revised for better sealing.

 

[subcrx]

Re: 87 omc 350, no power, Help!

Just did some examining of the engine today, the casting on it is 14093638. It also has a brand new edlebrook performer intake manifold on it. I wonder if its usable

 

[Dakota47]

Re: 87 omc 350, no power, Help!

you arnt done yet?? boating season is here.. slap that motor in there.