for the mercruiser 470 guys

[hadaveha]

I was reading a hotrodding blog, and there was a discussion about the mercruiser 470 a lot of guys using them as racing engines, To make a long story short these guys have tried many many things on these motors one thing they all said the really helped with the over all operating heat was to use dish top pistons, the guys said that it really makes the engine run cooler, anyone thing this would be a good option used in a marine application.

 

[achris]

Re: for the mercruiser 470 guys

As long as it doesn't change the compression ratio, and those pistons are capable of run long periods of time at high throttle settings. A racing engine and a boat engine are at opposite ends of the spectrum as far as application goes. Race engine has short runs, then is shut down. A boat engine must run, sometimes for hours on end, at mid to high throttle...

Chris.....

 

[Bamaman1]

Re: for the mercruiser 470 guys

I had a 470 in a 17' bow rider, and it ran great. But it didn't run long. The engines were closer to a tractor engine than a boat engine, and they were junk.

And there are not as many good used 470 engines out there as 140 hp motors due to durability problems. The 4.3 was a great change. unfortunately you cannot take any other engine and mount it up to the 470 transom assembly and outdrive.

 

[achris]

Re: for the mercruiser 470 guys

I had a 470 in a 17' bow rider, and it ran great. But it didn't run long. The engines were closer to a tractor engine than a boat engine, and they were junk.

No, they are not. They are good for what they are. Their power to weight ratio is excellent and they are great on fuel, really economical. Properly maintained and with the 2 or 3 main issues sorted out these engines will run as long as any Gm of Ford engine. You just need to understand how they are different.

And there are not as many good used 470 engines out there as 140 hp motors due to durability problems. The 4.3 was a great change. unfortunately you cannot take any other engine and mount it up to the 470 transom assembly and outdrive.

The 470 transom assembly and drive are exactly the same as any for the GM engines of the era use. If the 470 is an MC-1, any GM engine with its own MC-1 flywheel housing will fit. The only change for the drive (apart from ratio) is the input yoke length (if changing to a V engine and not an in-line).

If the 470 is an 'R' or later, then any GM engine with its flywheel housing will fit straight up to it. If the engine is a V6, then not even the ratio needs to be changed.

Chris........
BTW, the best engine in a boat IS a tractor engine!

 

[hadaveha]

Re: for the mercruiser 470 guys

well from what I was reading some of the guys use them is pure race cars and some of them are daily drivers. Its a really neat read if I can find it again Ill post a link. The guy that was explaning the dish top pistons was a 30yr mercruiser tech that had saved every old 470 he could get his hands on.

 

[Scott Danforth]

Re: for the mercruiser 470 guys

the 470 is used occasionaly in old rails for a "different" motor vs an SBC, especially if trying to keep a vintage 4-pot look. since it is basically half a Ford 460 with a GM bellhousing area, its easy to use for the application. However the use in a vehicle and the use in a boat are two different things as Chris has pointed out.

 

[stonyloam]

Re: for the mercruiser 470 guys

The best thing you can do for your 470 is keep it cool, but not too cool, that is run it in it in it's design temperature range, about 160-175 F. Best way to do that is to make sure you have maximum raw water flow through the exchanger by changing the impeller every other year (at least) and making sure you have unrestricted flow out of the exchanger through the exhaust elbow. A good indicator that the thermostat and exchanger are working properly is that the temperature holds steady at ALL throttle settings, idle to WOT. Good luck.