Merc V6 History

[FUJIMO]

[rckid74]

I see!! Widened the exh. port a lot requiring bridge to support the rings. Thanx Fujimo.

[FUJIMO]

Jerry, Above is a photo of one of the older 2.4 Bridgeport cylinders... Its simply a bridge design in the exhaust port, that provided ring support, in an exhaust port that was too big to support the rings travel. As you can see in the photo, there was always a bit too much scuffing in that bridge area, and so therefore Bridgeports of that era had shorter lifespans. But, they worked. They produced the power. When they first came out, I went through dozen's of them the first couple months, in the Offshore version. I would say that 3 out of 4 of them tripped rings within the first hour of running. If one didn't break in the first hour, it lasted forever. Weird, but true. Merc Hi-Perf got it together after a 100 or so engines went out & the start-up failures came to a halt.

[FUJIMO]

...1986 2.4 Mod-VP(Carb) Hi-Performance Division Block...

[FUJIMO]

They take your original great design Jerry...and Mod the hell out of it these days......This particular block was highly modified by a fellow named Jim Ruck, who was a retired machinist & engineer from Mercury Marine... He recently fully retired, finally.

[Dave Strong]

Jerry, Above is a photo of one of the older 2.4 Bridgeport cylinders... Its simply a bridge design in the exhaust port, that provided ring support, in an exhaust port that was too big to support the rings travel. As you can see in the photo, there was always a bit too much scuffing in that bridge area, and so therefore Bridgeports of that era had shorter lifespans. But, they worked. They produced the power. When they first came out, I went through dozen's of them the first couple months, in the Offshore version. I would say that 3 out of 4 of them tripped rings within the first hour of running. If one didn't break in the first hour, it lasted forever. Weird, but true. Merc Hi-Perf got it together after a 100 or so engines went out & the start-up failures came to a halt.

Before the skirts were cut to cool the bridge?

Dave

[rckid74]

Jerry, Above is a photo of one of the older 2.4 Bridgeport cylinders... Its simply a bridge design in the exhaust port, that provided ring support, in an exhaust port that was too big to support the rings travel. As you can see in the photo, there was always a bit too much scuffing in that bridge area, and so therefore Bridgeports of that era had shorter lifespans. But, they worked. They produced the power. When they first came out, I went through dozen's of them the first couple months, in the Offshore version. I would say that 3 out of 4 of them tripped rings within the first hour of running. If one didn't break in the first hour, it lasted forever. Weird, but true. Merc Hi-Perf got it together after a 100 or so engines went out & the start-up failures came to a halt.

What did Merc Hi-Perf do to solve the problem?

[rckid74]

They take your original great design Jerry...and Mod the hell out of it these days......This particular block was highly modified by a fellow named Jim Ruck, who was a retired machinist & engineer from Mercury Marine... He recently fully retired, finally.

I remember Jim Ruck! I think he worked at plt.6 back when I did. -- It looks like two more boost ports were added to help the breathing. Getting rid of those thick iron liners gave a lot of extra room for porting and bore increases. In a way it's a good thing I was forced to use those liners in the original engine --- otherwise I might have designed everything a lot closer together and you wouldn't have had the room to do what you're doing today.

[FMP]

I apologize for my ignorance , is Jim Ruck a member? Know of his machine shop in WI .

[Capt.Insane-o]

Funny how the chest cuts mimic what Jerry had done originally.

[powerabout]

Funny how the chest cuts mimic what Jerry had done originally.

I'm guessing that it was too hard to do with dies so it has to be milled and that is way too much work for a production block

[willabee]

...... When they first came out, I went through dozen's of them the first couple months, in the Offshore version. I would say that 3 out of 4 of them tripped rings within the first hour of running. If one didn't break in the first hour, it lasted forever. Weird, but true. Merc Hi-Perf got it together after a 100 or so engines went out & the start-up failures came to a halt.

Fujimo, fill in some blanks for me please ..... when, where and how did you break in (or simply break ) these motors?

[rckid74]

Have the rod bearings and center mains been increased in capacity to keep up with the power increases?

[Capt.Insane-o]

The rod bearings are the same...the center mains changed to a different style. The later race motors use a upper main bearing similar to the lower main.

[rckid74]

The rod bearings are the same...the center mains changed to a different style. The later race motors use a upper main bearing similar to the lower main.

I'm surprised those original rod bearings can hack it with the greater loads and speeds. But I assume for the race engines, at least, they get changed every so often to preclude failure during a race.
By a different style center main do you mean steel cages instead of plastic?
So those race motors have a ball bearing on top now? That's different. Do both bearings float now like the inline engines or is the crank still locked by the bottom main and just the top main floats?