replace head on a mercruiser 350 engine
 

Hi, I need to replace the head gasket of the engine in my boat and I
need some help from you experience folks. I have done it on a truck
engine (same chevy 350 engine) and it was painless. I took the heads
out and bring them to the engine shop to resurface the head. They
said the head was cracked and I pay a little extra to exchange for a
good one. I install the exchanged heads and everything went pretty
smooth.

I have no experience with marine engine. I know I need to use marine
stainless head gasket. Other than that, are they the same? If I have
to exchange the head, will an automotive one work the same? Should I
insist a "marine" head if they must exchange them? Is there such
thing as "marine" head?

While I'm at it, is there anything else I should replace?

Thanks in advance,

replace head on a mercruiser 350 engine
 

The special head gasket is the only difference if you are just replacing
the head gasket. The exhaust manifold gaskets have slots instead of holes
where the bolts go but that is just to make them easier to install, regular
exhaust manifold gaskets work fine.

A lot of the marine 350 head's have the sodium filled exhaust valves. You
can tell by removing an exhaust valve, the sodium filled ones have thicker
stems that taper down where the valve spring keepers go on. You might check
your local boat shops for a used one if you need one as they replace a lot
of engines that the owner forgot to winterize.

"Han" wrote in message
om...
Hi, I need to replace the head gasket of the engine in my boat and I
need some help from you experience folks. I have done it on a truck
engine (same chevy 350 engine) and it was painless. I took the heads
out and bring them to the engine shop to resurface the head. They
said the head was cracked and I pay a little extra to exchange for a
good one. I install the exchanged heads and everything went pretty
smooth.

I have no experience with marine engine. I know I need to use marine
stainless head gasket. Other than that, are they the same? If I have
to exchange the head, will an automotive one work the same? Should I
insist a "marine" head if they must exchange them? Is there such
thing as "marine" head?

While I'm at it, is there anything else I should replace?

Thanks in advance,

replace head on a mercruiser 350 engine
 

(Han) wrote
Hi, I need to replace the head gasket of the engine in my boat and I
need some help from you experience folks. I have done it on a truck
engine (same chevy 350 engine) and it was painless. I took the heads
out and bring them to the engine shop to resurface the head. They
said the head was cracked and I pay a little extra to exchange for a
good one. I install the exchanged heads and everything went pretty
smooth.

I have no experience with marine engine. I know I need to use marine
stainless head gasket. Other than that, are they the same? If I have
to exchange the head, will an automotive one work the same? Should I
insist a "marine" head if they must exchange them? Is there such
thing as "marine" head?

While I'm at it, is there anything else I should replace?

Thanks in advance,


Use a marine head gasket like the Felpro 17030. (you can contact
Felpro to verify the part number. Avail by order from most auto
suppliers.)
the head is the "Truck" head. Using the larger diameter shaft on the
exhaust valve. personally I havn't seen any aftermarket heads for the
marine/truck engines. So you are probably stuck with either a rebuilt
head or a aftermarket performance head.

The truck head can pull more heat away from the exhaust valve seat
area, which is the source of your problem. but has a unknown amount of
wear already. A aftermarket head may have better valve seat materials
which can address the heat issue as well. Your choice depends on how
you want to use the boat.

Myself I put a pair of aftermarket Cast Iron Heads (World Cast.
Sporter) with hardened steel valve seats and stainless valves.
(Caution the waranty on these is voided by putting them on a marine
engine.) You may want to consider using a slightly smaller runner
volume than my 215cc, I think I went a little too high in this area.
Also FelPro fas a intake manifold gasket with a screen mesh to boost
low end torque. I would/will give it a try the next time I am in that
far.

Good Luck

BBJ

replace head on a mercruiser 350 engine
 

Thanks for the info. The previous owner had the engine and outdrive
completely rebuilt (I was told but don't know for sure). It's a 1979
Mercruiser 260. The head gasket blown with water in the oil after
less than 20 hrs of use. I wonder what could have cause that. The
engine block and manifold does look pretty new and clean for a 1979
engine. I want to do it right and don't mind spend a little extra to
replace the head and related components and hope it will be more
reliable. Can you recommend a set of head/valve/gasket/ect I can buy
outright to replace the existing potentially damaged heads. Should I
go to a Mercruiser dealer and pay full list price or get it from a
discount auto part store? Can you recommend a brand name. I really
appreciate your help.

Thanks again.

replace head on a mercruiser 350 engine
 

If that has the orignal heads then they are probably regular chevy small
block heads. They were not using the sodium filled exhaust valves back
then. Get the casting no off the head and you can match up a similar one
pretty easily in the used market. I hope it is a gasket and not a cracked
block. The guy did winterize it last year?

I went with edlebrock performer rpm, aluminum heads but I'm on a fresh water
lake. Aluminum heads, aluminum intake, and aluminum exhaust manifolds will
take 2-300 lbs off the tail end of your boat :-)

"Han" wrote in message
om...
Thanks for the info. The previous owner had the engine and outdrive
completely rebuilt (I was told but don't know for sure). It's a 1979
Mercruiser 260. The head gasket blown with water in the oil after
less than 20 hrs of use. I wonder what could have cause that. The
engine block and manifold does look pretty new and clean for a 1979
engine. I want to do it right and don't mind spend a little extra to
replace the head and related components and hope it will be more
reliable. Can you recommend a set of head/valve/gasket/ect I can buy
outright to replace the existing potentially damaged heads. Should I
go to a Mercruiser dealer and pay full list price or get it from a
discount auto part store? Can you recommend a brand name. I really
appreciate your help.

Thanks again.

replace head on a mercruiser 350 engine
 

On Wednesday 16 June 2004 7:36 pm in rec.boats Han wrote:

Thanks for the info. The previous owner had the engine and outdrive
completely rebuilt (I was told but don't know for sure). It's a 1979
Mercruiser 260. The head gasket blown with water in the oil after
less than 20 hrs of use. I wonder what could have cause that.

Either the head or the block (or both) may be warped.
Get the head and the block planed.
Be VERY carefull how you torque down the head bolts, you MUST tighten
them in the correct sequence to the correct torque settings. Read
the manufacturer's instructions and do it right.

Warping is usually caused by overheating or incorrect assembly.

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