292 tune up

rvtransport · 05-05-2008, 01:11 PM

Just wanted to let you 292 owners the up grades I am doing to my 06 292. I have installed revalotion marine polished exhaust and removed factory mufflers with captians call. I also installed 1.6 ratio roller rockers for more lift and duration. I also ordered a set of mallory marine high flow spark arresters. I will be testing hopefully this week with a set of labbed 28's and labbed 30's. Hoping for a few more MPH!!

4mulafastech · 05-05-2008, 01:36 PM

Great to hear! Please keep us updated. Are you planning on testing one at a time, or doing it all at once? I was looking at those Mallory high flow spark arresters. When changing to the 1.6 ratio roller rockers, were there any issues with valve geometry, like did you have to have to go with a slightly different pushrod length to keep the roller centered on the valve stem tip? Was there enough clearance with the stock spring retainer/seal/valve guide set-up?

Sorry for all the questions, but I imagine you understand why!

Oh, and I see this is your first post. Welcome to OSO! It's a great place to learn and also share information!

rvtransport · 05-05-2008, 02:47 PM

I did not feel there would be a problem with coil bind being a very mild cam from factory, I have used same springs and heads with .480 lift cams with 1.5 ratio arms. I did check tips and seem to be right in line with valve head through complete rotation of engine. I did have the exhaust on the boat since new. The boat would run 70 mph most conditions with labed 28's one cool day I did see 72 mph at 5200rpm with exhaust. I then swapped to 30's and boat ran 68 to 70 and lost it out of the hole. I am hoping with rockers and arresters I can pull 30's or trade back to 28's and bounce rev limiter!!

4mulafastech · 05-05-2008, 10:23 PM

Thanks for the info. What brand rockers did you go with and did the stock valve covers clear them okay?

My 2006 292 came with the Quick-&-Quite corsa Y-pipe (non-switchable) and corsa tips/mufflers. When you changed to the Revolution manifolds did you eliminate the Y-pipe all together? In other words, is your exhaust thru-transom only, or still thru-transom and thru-prop? That exhaust must give you some good bottom/mid range torque to pull 30's to get on plane okay.

Right now my 6.2's are completely stock. Debating on what to do, or to just run them as-is for a while. I do have Latham steering and had K-planes installed, so I'm pretty much ready for anything down the road...

rvtransport · 05-06-2008, 10:59 AM

I bought jegs 1.6 self alining narrow body rockers part # 555-20154. Yes I do have corsa captians call and it did all fit with revalution marine exhaust. The roller rockers are supposed to fit under stock covers I did install a set on my buddys 97 vortech pick up truck a year ago and all is well. I did change my covers to polished alum short center bolt covers from jegs also. I wish I would have ordered k-planes and hydralic steering but I am looking at larger stainless add on tabs. I also had factory cable helm replaced under warenty from formula and it was a big improvement.

fastboatbob · 05-07-2008, 10:35 AM

Jesse,
could you tell us more about adding ss tabs. Would they be add-ons to the Bennetts?
The reason why I am asking is there could be a 45 mph speed limit on lake Winnipesaukee someday, so having the 292 stay on plane at slower speeds will help.

4mulafastech · 05-07-2008, 02:16 PM

Quote:

Originally Posted by Jesse Matthias

I bought jegs 1.6 self alining narrow body rockers part # 555-20154. Yes I do have corsa captians call and it did all fit with revalution marine exhaust. The roller rockers are supposed to fit under stock covers I did install a set on my buddys 97 vortech pick up truck a year ago and all is well. I did change my covers to polished alum short center bolt covers from jegs also. I wish I would have ordered k-planes and hydralic steering but I am looking at larger stainless add on tabs. I also had factory cable helm replaced under warenty from formula and it was a big improvement.

I don't know for sure, but I read that the cam that is in the 6.2 is a Crane 104224 (see link for specs). I have been playing around with my Desk Top Dyno and changed the rocker arm ratio from 1.5 to 1.6. I made the change in valve lift and I figured an increase of around 6% in cam duration. The attached picture shows the calculated torque and horsepower curves comparing stock and using 1.6 ratio rocker arms (curves without dots). While the change shows an increase of 10-15 HP and a shift in peak HP up a couple hundred rpm, it was at the expense of low-mid range torque.

http://www.cranecams.com/?show=brows...24&lvl=2&prt=5

Not sure how accurate these simluators are, but if you find the time to plane increase or mid-range performance suffering, this may possibly explain it. Please let us know how the real world numbers work out. Good luck!

fastboatbob · 05-07-2008, 04:09 PM

Could you tell us about the ss trim tabs. Are you going to extend the Bennetts?
I am looking for a reasonably price fix to get on plane quicker and maintaining plane in the 25 mph to 35 mph range since where I boat(lake Winnipesaukee) could have a 45 mph speed limit someday.

rvtransport · 05-08-2008, 10:40 AM

Fastboatbob a place out of AZ advertising in back of powerboat magazine I will post web address later when I find it. They are replacements made of stainless that uses factory bennetts rams and mounting you just add there new bottems. They look pretty nice for 400$ 4mulafastech I got on the water last night and they upgrades worked very well! I was running some barrowed 28 lab's with one with a ding in leading edge I had 3 guys in the boat and half tank of fuel. It was cold and ruff on lake michigan 2' to 3' seas. I needed to drag a little tab and trim about neutral to keep boat flying even. In those conditions I was running 72 mph at 5200rpm!! What realy impressed me was how the boat jumped on plane it felt like I gained alot of low end torgue. I am sure the 28,s helped compared to the 30's I ran last summer. I did not get my spark aresters yet so I think I will need alittle more prop because I bumped port side rev limiter once but that was the side that was running damaged prop. I think 29' s would be perfect.

C_Spray · 05-08-2008, 03:51 PM

I'd start saving for thay hydraulic steering about now....

Congratulations - Nice gain.