Hello everybody,
Two years ago i bought a new gm350 base marine engine.I 'm replacing the head gaskets due to overheating.In fact this engine has never worked at WOT properly without cooling problems although i replaced almost every part of the cooling system (raw water).The whole setup is that of MCM228 1978 with SE106 outdrive in the place of pre-alpha and the new 350 block in the place of 305.The characteristics of the new block are:
{This engine block is used in 1986-99 Gen I heavy-duty applications. It has 4.00" diameter cylinder bores and four-bolt main bearing caps. This block is machined for a one-piece rear crankshaft seal. Technical Notes: Cylinder wall thickness is the same as current production engines. The lifter valley is machined for hydraulic roller and flat tappets. Crankshafts with two-piece seals can be installed with adapter P/N 10051118. (Block casting P/N 10243880 or 14093638.)
This block came with the 64cc 275/300hp heads 14096217 (not VORTEC for 12 bolts intake,the center bolts at 72')
a)Do you believe that the reason of overheating at WOT maybe that the volume of water the A1 provides together with old style manifolds with the elbows at the back is inadequate for this motor and maybe i need to add a through hull cirqulating pump or the newer center riser manifolds ? (difficult experiment-all these things cost a lot)
b)The head gaskets the block had on i think is the steel shim style with a grey coating on the top side and a black coating on the back and measures 0.028" thick. I can recognise these gaskets at the catalogues from the characteristic triangle passage where the oil passes to the lifter valley as the 27-8791943491 oem head gasket for very little models such as 350(4bbl) Gen + Crate Engine and Scorpion 350 whereas the majotity of mercruiser 350s puts on the 27 75611.The man who resurfaced my cylinder heads told me that these are very good gaskets (the word MARINE is printed on them) whereas the Merc dealer told me that the first ones are for automotive use and that the merc 75611 with the hole instead of the triangle passage for oil are better for marine use .Which is my best choice?
Thanks in advance
Two years ago i bought a new gm350 base marine engine.I 'm replacing the head gaskets due to overheating.In fact this engine has never worked at WOT properly without cooling problems although i replaced almost every part of the cooling system (raw water).The whole setup is that of MCM228 1978 with SE106 outdrive in the place of pre-alpha and the new 350 block in the place of 305.The characteristics of the new block are:
{This engine block is used in 1986-99 Gen I heavy-duty applications. It has 4.00" diameter cylinder bores and four-bolt main bearing caps. This block is machined for a one-piece rear crankshaft seal. Technical Notes: Cylinder wall thickness is the same as current production engines. The lifter valley is machined for hydraulic roller and flat tappets. Crankshafts with two-piece seals can be installed with adapter P/N 10051118. (Block casting P/N 10243880 or 14093638.)
This block came with the 64cc 275/300hp heads 14096217 (not VORTEC for 12 bolts intake,the center bolts at 72')
a)Do you believe that the reason of overheating at WOT maybe that the volume of water the A1 provides together with old style manifolds with the elbows at the back is inadequate for this motor and maybe i need to add a through hull cirqulating pump or the newer center riser manifolds ? (difficult experiment-all these things cost a lot)
b)The head gaskets the block had on i think is the steel shim style with a grey coating on the top side and a black coating on the back and measures 0.028" thick. I can recognise these gaskets at the catalogues from the characteristic triangle passage where the oil passes to the lifter valley as the 27-8791943491 oem head gasket for very little models such as 350(4bbl) Gen + Crate Engine and Scorpion 350 whereas the majotity of mercruiser 350s puts on the 27 75611.The man who resurfaced my cylinder heads told me that these are very good gaskets (the word MARINE is printed on them) whereas the Merc dealer told me that the first ones are for automotive use and that the merc 75611 with the hole instead of the triangle passage for oil are better for marine use .Which is my best choice?
Thanks in advance
