325 Monsoon performance mods

[OhTwoBu]

Starting to put this together, what do you think?

Forged Eagle rotating assembly running 16cc dishes and a compression of 9.8-1. Too much compression? I think it would be fine on 91 octane

http://www.jegs.com/i/Eagle/356/B13051L03053/10002/-1?parentProductId=2867852

Crane HR-206 cam, pretty mild, torque where we need it. Still need to look at valve springs and make the vortecs work.

http://www.cranecams.com/product/cart.php?m=product_detail&p=24210

Are the forged pieces overkill, could cut cost in half by going cast. Cast ok up to 500hp and this engine shouldn't be touching that?

[WheelerWake]

Will the injectors spray properly at higher pressure? Is it better to just get higher flow injectors to make sure the spray pattern is good? MEFITuning.com also has a reference page for those, ranging from 30 to 96 lbs/hr. Oops, I just read the rest of the page, and it looks like a 33% increase in pressure (to 58 PSI) gets a 15% increase in flow (to 57.7 lbs/hr) on a 50 lb/hr injector. I guess it depends on just how much flow you need.

I'm no injector specialist, this is my 1st injected build, but adjusting pressure is common. I did try increasing the pressure to see where the injectors couldn't control it any more, that was >70psi.

I could have bought larger flow injectors, but that cost money, and I still would want the adjustable regulator to tune it.

Since this fuel injection system has no MAS or O2, it's kink of running open loop the whole time. I think Indmar/GM just tunes them a little rich so they work at all altitudes/temps. I plan on dialing mine in for my "typical" conditions.

Starting to put this together, what do you think?

Forged Eagle rotating assembly running 16cc dishes and a compression of 9.8-1. Too much compression? I think it would be fine on 91 octane

http://www.jegs.com/i/Eagle/356/B13051L03053/10002/-1?parentProductId=2867852

Crane HR-206 cam, pretty mild, torque where we need it. Still need to look at valve springs and make the vortecs work.

http://www.cranecams.com/product/cart.php?m=product_detail&p=24210

Are the forged pieces overkill, could cut cost in half by going cast. Cast ok up to 500hp and this engine shouldn't be touching that?

I had the same forged/cast dilemma, went cast because of the low RPM intended use, Eagle says they are good up to 500hp (I wonder if Indmar use Eagle parts since they are both in Memphis):

http://www.summitracing.com/parts/esp-13054l030/overview/

That Crane cam looks pretty good, lobe center not too tight.

Edited December 31, 2013 by WheelerWake

[2014Skier]

I would go with forged components, (pistons at the very least if $ is an issue) for reliability and piece of mind. Most of the power ratings are coming from an automotive view point, street cars, race cars or otherwise are not running at say 85% or 100% or max rpm for an extended period of time. A drag car only needs to run at WOT for a few seconds at a time, not minutes, road racing is harder on engines as the rpm is higher for a longer period of time. Marine use, is arguably the harshest environment to operate in. Also the rings you use are important, due to the heat build up, look into a kit with a steel top ring. Don't skimp on rod bolts either, get some good ARP ones.

Just my 2 cents.

[OhTwoBu]

Wheeler,

That kit looks good as well with the forged I-beams. 18cc for a little less compression, which is another number I'm trying to nail down. Want to get as much as I can running 91 octane.

Can someone speak to what type of balance (external/internal) I should be looking for. I think the proper configuration is a fully balanced internal with no flywheel weight and neutral harmonic balancer? What is the factory Indmar??

[WheelerWake]

Wheeler,

That kit looks good as well with the forged I-beams. 18cc for a little less compression, which is another number I'm trying to nail down. Want to get as much as I can running 91 octane.

Can someone speak to what type of balance (external/internal) I should be looking for. I think the proper configuration is a fully balanced internal with no flywheel weight and neutral harmonic balancer? What is the factory Indmar??

The factory Indmar balance is front internal/ rear(flywheel) external. GM did this when they went to the 1-piece rear seal because they used to use the flange on the crank that the flywheel bolts to as part of the balance (look at a 2-piece crank). They changed the bolt pattern when they went 1-piece also. You could by an internal balance 1-piece flywheel and build a all internal engine. Or by an external harmonic damper and build an all external engine. Or do what I did and balance it like Indmar/GM did, front internal/ rear external. I went this way because it was less $.

All internal is the strongest though, it stresses the crank the least. I considered having my flywheel converted to a neutral(internal) balance when I had my engine balanced.

By the way, I am jealous of you, you have a cool project going on. I am just working on trailer brakes.

[hethj7]

This won't help much on your rebuild, but here is post I made when I first picked up my boat, with part numbers included for many of the general maintenance items.

• Changed the spark plugs and wires. I used NGK plugs, part number 2238 and gapped them myself to 0.045". Very easy to change the plugs once the engine side panels are out of the way. The wires were a different story. I bought the wires a few weeks ago and didn't have much info on me at the time, so I just asked for wires for a 2000 era Chevy 350. Apparently the truck motors and boat motors changed at different years, so the first set of wires didn't work. I ended up with Omnispak wires, part number 9050. The only issue with these is the coil wire is too short, so I'm still running the old one. If anyone knows of a better part number that would have a longer coil wire, please chime in.
• Changed cap and rotor. No issues. Used Accel part number 8132.

http://www.themalibucrew.com/forums/index.php?/topic/31289-new-boat-first-time-maintenance/

[WheelerWake]

This won't help much on your rebuild, but here is post I made when I first picked up my boat, with part numbers included for many of the general maintenance items.

• Changed the spark plugs and wires. I used NGK plugs, part number 2238 and gapped them myself to 0.045". Very easy to change the plugs once the engine side panels are out of the way. The wires were a different story. I bought the wires a few weeks ago and didn't have much info on me at the time, so I just asked for wires for a 2000 era Chevy 350. Apparently the truck motors and boat motors changed at different years, so the first set of wires didn't work. I ended up with Omnispak wires, part number 9050. The only issue with these is the coil wire is too short, so I'm still running the old one. If anyone knows of a better part number that would have a longer coil wire, please chime in.
• Changed cap and rotor. No issues. Used Accel part number 8132.

http://www.themalibucrew.com/forums/index.php?/topic/31289-new-boat-first-time-maintenance/

I used that Accel cap and rotor also. It has brass terminals, much better that the originals aluminum. The inside of my cap looked like it had barnacles on all the terminals. I did an internet search and that was an issue with Chevy trucks of this era too. Why would they ever use that in a marine application?

[OhTwoBu]

Hethj7, thanks a lot I needed that. Here's what I've have come up with so far. Thoughts?

Rotating Assembly

http://www.summitracing.com/parts/esp-13054l030/overview/

Heads- Been thinking about this one, and I'm of the opinion at this point of if I'm going to do this, then do it all the way. So fast burns make sense (factory on HH i believe), the vortecs will need work for the lift I'd like to run, and would still be valuable to sell

http://www.summitracing.com/parts/nal-12464298

Cam

http://www.summitracing.com/search/?keyword=Crane%20Cams%20109851

Exhaust- This one is optional, not sure if this is worth it, or if there is a better option for less out there… but if it's good enough for the HH...

http://www.bakesonline.com/detail.aspx?ID=2394

Comparing this to factory HH, it seems like its almost the same thing? Now to do some research on injectors and tunes. The folks over at MEFI burn say they have the stock Hammerhead tune available, this could be a good starting point?

[formulaben]

I have the same boat. Do a basic tune up and compression check to verify engine health and then get a new prop before you dump any money into the motor. I went with the 1235 but I would now opt for the 2315 instead.

[OhTwoBu]

formulaben,

I know that's what I SHOULD do When I get back in the states in a couple weeks and get back to reality that's what it may come to, but I really think I can do this. Question for you, your experience with the 1235 in holeshot and top end? I understand the 2315 gives substantially better low end grunt while only sacrificing little top end?

[formulaben]

That's what I was sold on with the 1235: good low end grunt but enough prop to pull a skier. But it turns out I still had a bit more at the top end than I wanted, plenty to pull some hotshot water skier wanted to run the course at 36mph. I wanted to get the prop right to that point where it is just short of the rev limiter at 36-38mph*, providing good low end grunt in the process. What I have now with the 1235 works pretty well, but I want a little bit lower gearing for surfing, so if you're planing on doing any surfing then definitely go with the 2315, IMHO. I wish I could rebuild my engine now (and probably will in the future), but at ~$700 for a new prop, it is a safe and inexpensive place to start your quest. It might save you money, or at least buy you time before your engine project.

Having said that, what little I know about boat motors, I was glad to see you addressing the quench issue in your proposed rebuild. Whatever you do, please document it for the rest of us!

*On a side note, another reason for getting my top end speed down was that insurance asked what the top speed was. I asked why that would matter and top speed ends up being one of the major indicators of premium, and 40mph or greater is one of the tiers. As long as I prop it down to <40mph the rate goes down a fair amount. I couldn't care less about going over 40mph anyhow, and wanted a surfing prop anyway so it saves me some money.

[WheelerWake]

Hethj7, thanks a lot I needed that. Here's what I've have come up with so far. Thoughts?

Rotating Assembly

http://www.summitracing.com/parts/esp-13054l030/overview/

Heads- Been thinking about this one, and I'm of the opinion at this point of if I'm going to do this, then do it all the way. So fast burns make sense (factory on HH i believe), the vortecs will need work for the lift I'd like to run, and would still be valuable to sell

http://www.summitracing.com/parts/nal-12464298

Cam

http://www.summitracing.com/search/?keyword=Crane%20Cams%20109851

Exhaust- This one is optional, not sure if this is worth it, or if there is a better option for less out there… but if it's good enough for the HH...

http://www.bakesonline.com/detail.aspx?ID=2394

Comparing this to factory HH, it seems like its almost the same thing? Now to do some research on injectors and tunes. The folks over at MEFI burn say they have the stock Hammerhead tune available, this could be a good starting point?

I don't know much about those heads, but it looks like you might have to do some grinding on your exhaust manifold to get the to match those d-ports.

I thought about those hammerhead exhaust manifolds also, was going to run them unpainted, raw aluminum look. You could do the same with those heads if you go that way.

I guess MEFI burn has the tune for the version of MEFI controller you have.

[100PercentFooter]

First sign of a rookie boat owner: Thinks auto parts store is a good place to find boat engine parts.

[Bozboat]

First sign of a rookie boat owner: Thinks auto parts store is a good place to find boat engine parts.

Ouch, going out of your way to be friendly on this thread now?

[Woodski]

@OhTwoBu: what is your operating range? Are you looking for good performance at lower boarding/surfing speeds or ski/footing speeds? Looking at your choices I will provide some thoughts based on my build: fast burn heads are great specifically for the slalom/footing speed range, might not be worth the cost for slower speeds. I would consider a cam with a little more intake/exhaust lift split, a bit more on the exhaust side (I use a ZZ4 and it is great for my application although I would probably not change from the marine cam if I was only boarding/surfing), it really works well for footing and higher speeds, it pretty much is a wash to 2000 rpm, then it lights up a lot. An easier and cheaper route might be marine cam w/ 1.6 (roller) rockers. The GM marine cam is an excellent cam for the small block. The ports do make you take care on assembly and gasket choice to ensure proper matching. If you go to aluminum heads, etc. and specifically the fast burns, you will end up doing gasket maintenance every few years, material growth and less contact area work them harder. As for compression ratio, I am at 10:1 and no issues running 34 deg max advance. Remember, you are running the engine at less that 180 degrees and have a huge radiator under the boat, just make sure she gets that water (good impeller). Your choices of components will certainly liven up you mill and give you a strong runner, have fun it is a very rewarding project.