Crossflow vs looper for saltwater use?

[reelfishin]

I have been looking at several mid 80's and up V-4's, I was told that since I run mostly in saltwater, I should be looking for a crossflow? Does this make any sense? Why?
What is the difference between the two designs and were the V4 motors availble in both styles at the same time? or Where there only certain HP motors that were either one of the other?

I am concerned with fuel economy as well as longevity. It will be on a fairly light boat, not over 3000 lbs, and will be run premix only. I am looking at several 120 thru 140 hp motors, how do I tell which is a looper and which is a crossflow?
Is there any real performance difference? I am not after speed, just an efficient package that won't cost me a weeks pay everytime I take it out.

 

[WillyBWright]

Re: Crossflow vs looper for saltwater use?

120+ are loopers. 115 and lower are crossflow.

Some loopers use V-6 gearcases, all crossflows use triple/V-4 gearcases.

Loopers have extra porting on the cylinders and piston walls to force more air/gas charge resulting in more power. Kinda like the difference between naturally aspirated and turbocharged.

Loopers use more fuel.

Loopers use fuel more efficiently, but it's not a great difference.

Crossflows are a little less picky about gas quality.

I'd have no preference regarding saltwater. I don't see that as a factor at all.

Typically crossflows have better longevity. But they're easier to work to death in a marginal powering situation. A stronger motor might not to be worked so hard.

 

[reelfishin]

Re: Crossflow vs looper for saltwater use?

Are things like compression ratios the same?
How much more fuel will a looper use vs. a crossflow? I am looking at the 110, 115, 120, and a 140, all are priced the same and use the same lower unit and mid section. All are in A1 shape and priced about the same. All are freshwater motors and have low hours. All are either without or have had their VRO units disabled or removed.
I was originally under the impression that all of the V4's were the same with only minor carb, exaust, and cylinder head differences, but I came across an old magazine that listed the weights of each motor, the 140 was listed as 365 lbs, and the 115 was listed as 289 lbs. I suppose that difference may be the V6 gear case?
I had several older shops tell me that the crossflow motors hold up better in salt water, but they couldn't say why, I launch in freshwater and haven't had any past problems with salt corrosion, but was just curious. When I first heard it I just figured it was one guys opinion, but I've heard it now a few times from a few different shops.
In my looking around for a used motor, I seem to find more 115's than anything else, after that its the 88, and 90 hp models. I found a clean 140 that I am considering, but my concern is still fuel consumption. I don't doubt that the 140 will have an easier time and work a lot less but I am afraid that it'll be a gas guzzler. I talked to a guy the other day with a similar boat with a 115, he's about 450 pounds lighter and says he can go all day on 20 gallons of gas, but I have no idea how he runs his boat and whether or not he's anchored up fishing all day. I will prop this for more torque than speed to keep the motor load low, I am not too concerned with speed.
My normal run is about 30 or so miles a day, and will have a 40 gallon tank on a 19' boat that weighs in dry at 1150 lbs dry, plus tw passengers, fuel, bait, coolers, and tackle. I had boats in the past with smaller motors that couldn't make the day on a tank of fuel but gas was cheaper then. At $3.25+/gal on the water, sometimes more, I don't want to have to fuel up on the water too often and I prefer to mix at home anyhow to keep the ration correct in the tank.

I am leaning toward the 140 since I like to have extra power, everybody I talk to says this boat is overweight and will need all the motor I can hang on it. The last owner had a 90 on it, but said it was lame, but the motor obviously wasn't healthy and blew up after only a few months, so I can't use that as a reference. The boat can take a 150, but I think I'd get better service from the V4 vs a V6 150 hp? Especially considering the weight difference. I think the added power would be offset by the added motor weight and greater fuel usage?

 

[jimmbo]

Re: Crossflow vs looper for saltwater use?

As of the mid 1990s a looper 90hp and 115hp are also in the mix. They have slightly more displacement( 106 cubic in) than the crossflow motors(99.6). The looper 120, 130, 135, and 140s came in two different displacements; 110 cubic in.(1.8 litre) and 121 cubic in(2 litre). Either of these were substancialy larger than the 99.6 cubic inches(1.63 litre) of the crossflows. The 140/late 115 or 110 crossflow is a good engine on light fast boats, but on larger heavier boats the early 115 and all the 90 crossflows are usually better choices. This might sound odd but... Comparisions of engines that have the same displacement but difference hp ratings usually ends with the lower hp models pulling harder in the lower rpms onto plane than the higher hp versions. At higher rpms the story will change and the higher rated engines will come onto their own.
IMHO the 60 degree looper 90hp is a engine with great bottom end and more top end than the crossflows. The looper 115s have great top end but seemed a bit soggy on the bottem end, we had a heck of a time getting it to pull hard without proping it so low it reved past 6000.

In the 90s the V4 looper weighed 10 pounds less the looper 150 V6 which was 158 cubic in.(2.59 litre)

If you want low end torque a looper 150 is the way to go. The V6 should be able to be slightly more fuel efficient at midrange speeds than the V4s. Reason being it is easier to tune the exhaust over a large rpm band on a 3 cylinder than on a 2, or 4 cylinder engine. The exhaust system on 6 cylinder engine can be splint into 2 systems of 3 cylinders each. With 3 cylinder engines exhaust tuning can be quite easily accomplished without a lot of fancy design. Longevity might be longer due to running at lower rpms than the smaller engines

 

[kenmyfam]

Re: Crossflow vs looper for saltwater use?

I run a mid eighties 140hp looper on our 17ft fibreglass Doral. Lots of torque at the low end. Plenty of rpm at the top end with the right prop and good top speed. Fuel consumption is not too bad. No idea what it is but we can pull a full days combination of tubing, ski-ing and fishing on about 20 gallons. The difference in fuel consumption from a 120 is probably marginal. A friend of mine has a 90hp on his similar size boat and constantly wishes he had gone larger.

 

[Solittle]

Re: Crossflow vs looper for saltwater use?

Were it me I would go with the one in the best condition with a competitive price. Yea there are a bunch of differences between the loopers & crossflows but not as significant as condition.

By the way I run a pair of 1987 1.6L 110 hp crossflows pushing a heavy 23' CC in salt water.

 

[reelfishin]

Re: Crossflow vs looper for saltwater use?

Is there a such thing as a crossflow 140? Or is the seller confused?

I agree that condition is the most important, but these are all pretty clean.
All are super clean and have near new compression specs. I have been only looking at freshwater motors, I don't care to deal with saltwater corrosion.
I have a good 70 HP 3 cylinder that came off a 13" Whaler and it flew on that boat even fully loaded, I was going to try it on my 19' open hull Renken but got talked out of it. I agree that that would be underpowered, but I'm not after speed. My last boat was a 31' displacement hull that topped out at 21 mph or so. Anything over that will seem fast. I just don't want to be in a bad situation and be underpowered.

I just couldn't figure why I keep getting told that the crossflow engines hold up better in saltwater. But of course that was coming from a shop that doesn't see saltwater at all.
This boat is rated for 150 HP max, I wasn't looking for a 150 for fuel usage reasons, I actually passed up a few in nice shape. They were way heavier and much larger than the V4 side by side. Me and two buddies lifted his V4's off for a repair by hand, I wouldn't have tried it with a 150 V6. I have helped install on of those and both the size and weight was far more than I wanted to chance by hand. I lift mine with a hoist but that time one wasn't available.

The boat is pretty solid, but I don't want to max the motor weight on an older boat. I also considered two smaller motors on this, maybe two 50's or even two 70's. But I just figured that would be even more fuel and twice the maintenance.

 

[jimmbo]

Re: Crossflow vs looper for saltwater use?

From 1977 thru till 1985 there was a crossflow 140hp(crankshaft rating) it later became the 110/112/115 hp prop rated engine.
As I stated earlier, the looper 120/130/135/140 V4s are only 10 pounds lighter than a 150 V6 looper. The crossflows were much lighter, also much smaller.
The late 1990s looper V4s(90 and 115 hp) are smaller than the crossflows