Silvertip
Supreme Mariner
- Joined
- Sep 22, 2003
- Messages
- 28,771
Re: i need to know if anyone out there knows what the cross reference is for the 3.0
Agreed on the displacement numbers but for quick conversions, there are 61 cubic inches per liter. I also agree that the 3.0 is a different engine than the 2.5 but not as much as you would think and I'll get into that later. As for the timing gear set, GM is not one to re-invent the wheel when it?s not necessary to do so and therefore they use existing designs wherever possible. If the 3.0 uses a cam gear that's pressed onto the cam I still feel there is a fair chance it?s the same gearset as the 2.5 used in cars. I suppose most wrenches would assume I'm talking about the front drive 2.5 (and although I don't dismiss that engine either) I am speaking about the longitudinally mounted 2.5 that was born in 1961 and found its way into the then new Chevy II and in later years the Olds Starfire, Pontiac Astre, and Buicks equivalent. That block was changed to accept the front drive train so bellhousings don't match. The original 2.5 has the original small block V8 bell housing pattern. Granted, the engine has been marinized and industrialized in various forms and obviously modernized over the years including the changes you indicated and depending on application all versions cannot be interchanged. . All I suggested is that he try a direct comparison of the gear sets. It costs nothing to possibly get lucky. Using the term Marine or Industrial engine while technically correct, does not mean that engine did not start its life back in 1961 or that it didn?t have an automotive heritage. Let?s look at some pictures. The first is the timing gear setup on the pre-front wheel drive 2.5 (and it really is no different on the front drivers). Does it bear a resemblance to the 3.0?
Here is a picture of the current 3.0 right from the GM Marine web site. Pay attention to the lifter galley covers, the distributor location, oil filter location, fuel pump location and motor mount bosses and the valve cover.
And here is a picture of the pre-front drive 2.5. All of the items referenced above are in the exact same location on this engine. Does that mean the engines are identical? Of course not but it bears witness that these two engines share a common origin. Just as the original 265 V8 does not resemble the last 5.7?s in every respect, the blocks indeed shared a common origin. And just like the 3.0 those small blocks were ?Industrialized? and ?Marinized?.
Once again, we are picking at quite minor points but to call the 3.0 an Industrial or Marine engine is a stretch as the only thing that earns it that reputation is its displacement. The same applied to the 2.5 marine engine. It still started life as a car engine. There are very obvious part differences in these engines, but for certain items there very well may auto equivalents. Items like cam bearings, push rods, rocker arms, core plugs, perhaps oil pumps depending on oil pan useage, and even some gaskets are the same (perhaps not by part number) but by use. Composition makes a part number different. It does not always mean two different part numbers can?t interchange. As for the pictures -- circa 1977. I can also provide the same pictures back to 1963 and there will be little if any difference.
Agreed on the displacement numbers but for quick conversions, there are 61 cubic inches per liter. I also agree that the 3.0 is a different engine than the 2.5 but not as much as you would think and I'll get into that later. As for the timing gear set, GM is not one to re-invent the wheel when it?s not necessary to do so and therefore they use existing designs wherever possible. If the 3.0 uses a cam gear that's pressed onto the cam I still feel there is a fair chance it?s the same gearset as the 2.5 used in cars. I suppose most wrenches would assume I'm talking about the front drive 2.5 (and although I don't dismiss that engine either) I am speaking about the longitudinally mounted 2.5 that was born in 1961 and found its way into the then new Chevy II and in later years the Olds Starfire, Pontiac Astre, and Buicks equivalent. That block was changed to accept the front drive train so bellhousings don't match. The original 2.5 has the original small block V8 bell housing pattern. Granted, the engine has been marinized and industrialized in various forms and obviously modernized over the years including the changes you indicated and depending on application all versions cannot be interchanged. . All I suggested is that he try a direct comparison of the gear sets. It costs nothing to possibly get lucky. Using the term Marine or Industrial engine while technically correct, does not mean that engine did not start its life back in 1961 or that it didn?t have an automotive heritage. Let?s look at some pictures. The first is the timing gear setup on the pre-front wheel drive 2.5 (and it really is no different on the front drivers). Does it bear a resemblance to the 3.0?
Here is a picture of the current 3.0 right from the GM Marine web site. Pay attention to the lifter galley covers, the distributor location, oil filter location, fuel pump location and motor mount bosses and the valve cover.
And here is a picture of the pre-front drive 2.5. All of the items referenced above are in the exact same location on this engine. Does that mean the engines are identical? Of course not but it bears witness that these two engines share a common origin. Just as the original 265 V8 does not resemble the last 5.7?s in every respect, the blocks indeed shared a common origin. And just like the 3.0 those small blocks were ?Industrialized? and ?Marinized?.
Once again, we are picking at quite minor points but to call the 3.0 an Industrial or Marine engine is a stretch as the only thing that earns it that reputation is its displacement. The same applied to the 2.5 marine engine. It still started life as a car engine. There are very obvious part differences in these engines, but for certain items there very well may auto equivalents. Items like cam bearings, push rods, rocker arms, core plugs, perhaps oil pumps depending on oil pan useage, and even some gaskets are the same (perhaps not by part number) but by use. Composition makes a part number different. It does not always mean two different part numbers can?t interchange. As for the pictures -- circa 1977. I can also provide the same pictures back to 1963 and there will be little if any difference.
