Crack found in the block

[Karl1972la]

Ok engine folks, here is one for you. I prepped my boat to take out last weekend and found water in the oil. After many YouTube videos and forums I decided to take off parts. This is a 2002 GM 4.3 Vortec Mercruiser. Here are some photos. Can this be welded / brazed / JB Welded? At least to get me through another summer without ultimately replacing the motor. There are many videos on YouTube that are about block repair using the methods but all are on the outside. This is on the inside.
I actually found the confidence to pull parts off because of this forum. Thanks in advance.

 

[flashback]

I'm afraid that motor is finished. It froze up..

 

[matt167]

Time for a new block.

 

[Scott06]

Ok engine folks, here is one for you. I prepped my boat to take out last weekend and found water in the oil. After many YouTube videos and forums I decided to take off parts. This is a 2002 GM 4.3 Vortec Mercruiser. Here are some photos. Can this be welded / brazed / JB Welded? At least to get me through another summer without ultimately replacing the motor. There are many videos on YouTube that are about block repair using the methods but all are on the outside. This is on the inside.
I actually found the confidence to pull parts off because of this forum. Thanks in advance.

No get a new long block. if it were on the outside yes you can JB it, not on the inside.

First how did you winterize?

second you need a new base engine or reman long block

look at places like michigan motorz. Really low buck get a used 4.3 vortec truck engine from wrecking yard. Strip it down, swap in marine head gaskets, brass or ss freeze plugs, put all your marine accessories of this engine on it.

Likely your exhaust manifolds are roached as well they will crack on outside just above the spark plugs. Could not see in the thermostat opening but that may be cracked as well.

 

[flashback]

My guess is it wasn't winterized at all, cracks in the top of the block to me means it was full of water, I bet you find more cracks.in the valley as well...

 

[Lou C]

Not only that, but other parts that can be damaged by freeze up:
intake manifold
exhaust manifolds & elbows
power steering cooler

 

[Scott Danforth]

Should have read the manual on winterizing

 

[tank1949]

Ok engine folks, here is one for you. I prepped my boat to take out last weekend and found water in the oil. After many YouTube videos and forums I decided to take off parts. This is a 2002 GM 4.3 Vortec Mercruiser. Here are some photos. Can this be welded / brazed / JB Welded? At least to get me through another summer without ultimately replacing the motor. There are many videos on YouTube that are about block repair using the methods but all are on the outside. This is on the inside.
I actually found the confidence to pull parts off because of this forum. Thanks in advance.

pitch it for parts and look for one in a junk yard to make Marine.

 

[jimmbo]

Just don't grab a Car/Truck engine and drop it in, there are plenty of Differences between the two

 

[nola mike]

Just don't grab a Car/Truck engine and drop it in, there are plenty of Differences between the two

Not really

 

[jimmbo]

They are not the Same. Close only counts with Horseshoes, Grenades, and Nuclear Weapons

 

[tank1949]

Not really

Having built 1/2 dozen SB Chevys, u are correct.

 

[Scott Danforth]

both truck motors and boat motors came from the tonawanda ny engine plant

both truck motors and boat motors were built with the same block, heads, cranks, rods, pistons, valves, etc.

boat motors get brass or stainless core plugs
boat motors get a marine cam (no overlap)
boat motors get a marine water pump with a brass impeller
boat motors sometimes get a different oil pan

Boat motors are then shipped to the marinizer that adds the marine induction system, front engine accessories, rotating electrics, ignition, and exhaust

 

[Lou C]

My old 4.3 was definitely from the Tonawanda NY plant because the engine serial # starts with T. Some 4.3s were made in Tonawanda NY, some were made in Romulus Mi., those engines have a serial starting with R. I don’t know if all the marine engines came from Tonawanda but I recall reading here that the internal rotating components are different comparing Tonawanda to Romulus even though they are nominally the same engine. The marine cam is important you don’t want exhaust reversion ruining your engine. The Vortec 4.3s were more prone to this and OMC/Volvo had to modify the aluminum 90* down pipes to keep exhaust water from getting pulled up the exhaust by vacuum developed in the exhaust. They also added one way check valves in the exhaust elbows to allow air in (but don’t allow exhaust out) to break the vacuum formed in the exhaust. Not sure if Merc did the same thing but it’s a good thing to keep in mind.

 

[Bondo]

Can this be welded / brazed / JB Welded?

Ayuh,.... That motor is junk,..... You need a new long block, at a minimum,.....

 

[Karl1972la]

Great…5 grand to 10 grand and I paid 6500 6 years ago for the whole thing

 

[matt167]

If you know your way around an engine, you can get a truck 4.3 dirt cheap and convert it. You could save thousands

 

[Scott06]

Great…5 grand to 10 grand and I paid 6500 6 years ago for the whole thing

You mean that engine was already a replacement engine?
need to work out how it was winterized so it doesnt happen again

 

[Karl1972la]

I live in Louisiana with usually mild winters and have never winterized the boat
In hind sight especially after taking all the parts off I didn’t realize how much water was still captive. It of course is my fault

 

[Karl1972la]

You mean that engine was already a replacement engine?
need to work out how it was winterized so it doesnt happen again

No it was the original engine. Looked on google and all replacement engines cost that much to replace. Paid 6500 for the whole boat back 6 years ago. The motor replacement is more than the complete boat