Thread: marine 327 to stock

Tweet

Hows it going all...New to the forum. Figure i mize well start out with a good one. I have an opportunity to buy some 1962-65 327's which are marine motors. I was wondering what is the difference between marine and stock. I know they have a steel crank and one runs backward due to the cam and being in the same boat. The rest i am not sure about......Cam,heads,etc. Block #'s 3858174.

the cam is sometimes gear drived the pistons are on the rod need to to be switch back the for cw rotation and the rear seal need to be change to so things that will not work cam starter rear seal warter pump if this used a rope seal the crank will not work.

I have a marinized chev and normal 350's in my cars, the difference between the marinized and the street units are usually as follows, camshafts are different due to the torque being required at 3000rpm fixed, the sumps usually have no drain plugs, welch plugs will be made of stainless steel to stop corrosion, water pump will have stainless impellers, intake valves will be stainless, all the add on bits are usually either cadmium plated or replaced with stainless and then lots of paint, as far as running backwards are you sure, the reasdn I say this is because your stern drive legs that you attach to the engines have a lever which modifys the leg to spin left or right not the engine.
So all up to go from marinised to street just a new camshaft, to go from street to marinised expensive.
Steve

Originally posted by simso
as far as running backwards are you sure, the reasdn I say this is because your stern drive legs that you attach to the engines have a lever which modifys the leg to spin left or right not the engine.

On larger boats with 2 engines, they have one rotate 'backwards' of the other. I assume this is to offset the rotational forces from the engine and drive shafts. These setups usually don't use stern drives but prop shafts through the bottom of the hull.

Thanks fellas this does help. I think i will go ahead and purchase them. For the most part i only paid 550 for the pair and it sounds like i do not have to change much.

Well there you go you learn something new everyday, I would never have imagined that you could run the engines in reverse, but I guess in theory it doesnt really matter which way an engine turns, obviously the timing marks would be different eg marked advance would become retard, the camshaft lobes would have to be ground the opposite way. As far as torque your right you have a trim plate to counteract right hand torque on a single engine unit so you can go straight and on a twin engine unit you counter rotate to reduce directional torque
Steve

I would be carefull about using a marine engine. If the engine had closed cooling it should be fine,but if the engine was raw water cooled and was used in salt water the cooling pasages in the block could have a lot of scale and rust in them. I have heard that the scale and rust will clog up the radiator. Just a thought.

John

My brother just had to have his marine engine rebuilt due to oil leak in main seal. It was a Chrysler engine and was the reverse rotation engine.

Cost him $4,500!!! ouch

Not sure about the Chevys, but some engines (Chrysler primarly) had some very light angled "hash marks" cut into the rear main seal area something like /////////// the theory is they are supposed to help force the oil away from the rear main seal.

I recall seeing a tech advisory from Chrysler (late 60's early 70's ?) where a batch of counter rotating cranks had made it into some passenger cars engines, resulting in severe rear main oil leaks.

If the Chevy has these cut into the crank, chances are it will also have to be changed if you reverse the rotation of the engine.

Originally posted by Mike P
Not sure about the Chevys, but some engines (Chrysler primarly) had some very light angled "hash marks" cut into the rear main seal area something like /////////// the theory is they are supposed to help force the oil away from the rear main seal.

I recall seeing a tech advisory from Chrysler (late 60's early 70's ?) where a batch of counter rotating cranks had made it into some passenger cars engines, resulting in severe rear main oil leaks.

If the Chevy has these cut into the crank, chances are it will also have to be changed if you reverse the rotation of the engine.

yes it will leak that is what i tried to tell him. if it hase a rope seal it will have them hash mark //// or\\\\and if not. the new type viton seal dose and the oil will wick out