.060 over v6 looper

[tjbco]

I am rebuilding the powerhead on a 1996 Johnson 150 Ocean Runner v6 looper. I found a high performance kit that punches it out .060" over. I am told that this will give me between 200 to 225 hp.Has anyone done this, and what were the results? Thank you in advance, Tom

 

[Dhadley]

Re: .060 over v6 looper

Hard to believe, isn't it?

 

[CFronzek]

Re: .060 over v6 looper

If you bore it to .060 oversize that may be limit for overbores. If it is, then a damaged cylinder would require a sleeve job, which is complex and can cost a lot.

 

[tjbco]

Re: .060 over v6 looper

Originally posted by CuyahogaChuck:<br /> If you bore it to .060 oversize that may be limit for overbores. If it is, then a damaged cylinder would require a sleeve job, which is complex and can cost a lot.

 

[tjbco]

Re: .060 over v6 looper

Good point. I have seen a kit at .064 over.do you think that .004" would leave enough room for a future repair/hone? Maybe i should stick to .030 over to be safe. It's a tough decision because i could use all the horses i can get.

 

[tjbco]

Re: .060 over v6 looper

Originally posted by CuyahogaChuck:<br /> If you bore it to .060 oversize that may be limit for overbores. If it is, then a damaged cylinder would require a sleeve job, which is complex and can cost a lot.

 

[jimmbo]

Re: .060 over v6 looper

buy a used 200 or 225 then

 

[tjbco]

Re: .060 over v6 looper

jimmbo, that would be the easy way out, but... in the past year i have dumped some cash into this motor. power pack - regulator/rectifyer - charge coil - starter - and lower unit. everything electrical is tip top. a rebuilt powerhead would basically give me a new motor.

 

[Dhadley]

Re: .060 over v6 looper

There isn't a .064 over piston for that motor. <br /><br />

It's a tough decision because i could use all the horses i can get.

I'd be willing to bet you're not getting all the motor has to offer now.<br /><br />What else is in this kit besides pistons?

 

[tjbco]

Re: .060 over v6 looper

I think you are correct. i checked again and .064 is for a cross flow. The kit includes pretty much everything you can think of(forged pistons, rings, connecting rods, main bearings, rod bearings,gaskets and seals, the whole 9 yards.) it even includes carb kits for all 6.

 

[red boat]

Re: .060 over v6 looper

tjbco, If you purchase a rebuilt powerhead it does not come with the electronics so you would have to switch all your electrical components to the new block. If I were you I would bore to .030 over and then you have the possibility of then going to .060 if you need a rebuild in the future. I am on my second rebuild and currently bored @.060 (1990 XP-200)and I did not notice and big change or increase from the bigger displacement. I find it hard to belive going to .060 bore would get you to 200 to 225 hp. In order to gain 50 to 75 hp you would need some porting work. That would also decrease engine life.

 

[steamboatwilly]

Re: .060 over v6 looper

What about this?????? 150HP 1978-91.....<br />175HP 1977-83<br />185HP 1984-85<br />200HP 1976-83<br />235HP 1978-79 Crossflow,150 CID.3 1/2in bore<br />STD.,+.020,.030,.044,.064.

 

[tjbco]

Re: .060 over v6 looper

red boat, i am having my existing block bored,so electronics stay with it anyway. I appreciate your input. i am surprised that you did not notice a big change in power, but if you own it, you know. thanks

 

[jimmbo]

Re: .060 over v6 looper

No, a rebuilt powerhead is not like a new motor. It is a combination of some new parts, some reused parts(hopefully still good), and a block with thinner cylinder walls. All reassembled hopefully by someone who knows what they are doing and can recognize parts that should not be reused. I have never had a rebuilt/remanufactured engine ever last as long as a new engine wheather it was for a boat or a car. <br /><br />BTW a 0.060 overbore isn't going to increase the displacement enough to rate a power increase. Even if it did it would only increase in the low and mid rpm range cause the existing carbs and induction system(reeds and crankcase) would be still be sized for the smaller displacement.

 

[Dhadley]

Re: .060 over v6 looper

Who makes a forged .060 piston for that motor?

 

[red boat]

Re: .060 over v6 looper

probably Wiseco??

 

[Dhadley]

Re: .060 over v6 looper

Nope, .040 is the biggest shelf stock they make. I hope the block isn't being bored for something that doesn't exist.