Considering dyno-testing / procedures for marine engine?
 

I am toying around with spending the money and having my engine put on a dyno at the local shop before dropping it in the boat. The main reason for this is to hopefully hone in on my fuel and timing curves. I don't think he really has provisions for me to run my wet exhaust, since he uses a closed cooling system. Also, I'm not sure how I would run it with the Merc wiring harness and T-Bolt IV ignition system.

Has anyone else run their engines with the Merc ignition on a dyno? Did you just run a hot wire and ground to the appropriate pins on the harness? What about fuel pumps? I'm running an electric pump right now.

Any other things I need to consider?

If you want a baseline of what HP you engine is - do it.

If you arent running wet exhaust you are wasting your time tuning it... You might even be wasting your time tuning it on the dyno no matter what.

Yeah, thought about how the wet exhaust versus dry exhaust might affect carb settings. I am running Lightnings, which should get me more in the ballpark of what the dyno header produces in regards to back pressure. Maybe I need to just build a startup cart and spend the money for the dyno testing on a set of EGT gauges or something.

budman,the dyno will get you in the ballpark,but the best way to tune it in the boat is with a wideband 02 meter,i like the one FAST sells with dual sensors,one for each bank.they dont like any water on the sensor so they dont work with a wet exhaust.

Dyno'ing is nice to see what kind of HP your making, and also a good tool to give you a idea of what kind of ignition lead the engine likes. But, also tuning in the boat is really my first choice like Mike Tkach said. With a AFR meter.

The fuel curve can be quite different in the boat. ON the dyno, with good air, big dry dyno headers, you can tune for say 12.0 if that's your number. But once its in the boat and its 90*, with wet exhaust, flame arrestor, enclosed engine compartment, you may find the AFR's now in the low 11's or even 10's. So the dyno tune is no longer valid. Normally you wont blow it up, because rarely does the engine need more fuel in the boat then the dyno.

The AFR will not only tell you jetting and what not, it will also alert you to fuel supply issues if the fuel system cant keep up....or show that lean spot at part throttle you may not have seen on the dyno pulls.

So what kind of money are you talking about for one of those setups? I suppose the headers would have to have some type of bungs installed through the water jackets where the collector starts to get a reading. Might not be very conducive to my setup, since I will be running collectors that have silent choice built into them.

getting it to run should be nothing more than buying a harness pigtail and wiring it up appropriatly... about 20 bucks from any number of places. i think the dyno idea is a great one and should be SOP for any number of reasons , the tuning aspect not withstanding. you get to break it in and set it up properly the first time. you get to run it long enough to find out if there are any issues or leaks or wierdness and when you are done you get to change the oil and cut up the filter and confirm everything you need to confirm. if someone built the motor for you you get to sort any warrantee issues right off without any question of liability and when you are all said and done you get to put it in the boat and know what to expect when you turn the key and if you DON'T get what you expect, you know its an installation issue as opposed to something else. doing the dyno program is the best money you will ever spend.

On thunderbolt IV ignition all you need is the battery cables hooked and a jumper from + battery to + coil. Electric pump should be running through an oil pressure switch and relay so applying power to + coil will get the pump running also as soon as there is any oil pressure

We dyno tune everything for the reasons given above. Finding the engines potential power and matching twin engine packages is another plus.

Well, the twin engine thing is out the window for me since this is a single, but see where you're coming from. From the sound of things, I probably will have to do most of my tuning on the water anyway, so that normal benefit might not apply. I'm wondering if I might do better just to build myself a startup cart to run the engine before it gets dropped in. That would give me a lot of the benefits of the dyno, and I could use it for future builds. The warranty issue does not apply because I am building this thing myself.

I have one of those roll-around engine cradles available. I'm wondering if I could modify one of those to strengthen and stabilize it, and add a gauge panel and fuel delivery system to it.

mike tkach is the man
 

Mike makes it look real easy, before I knew it the motor was running and we were looking for my oil leak..

http://33outlaw.zenfolio.com//img/s2...GVDj91nHpII9o=

Whos that guy working the flashlight? :)

He also has a legit run stand. But to de-rig the trans, coolers, and all the other stuff, it just made sense to start it and let it run as it sat. Oil leak found, fixed, and ready to drop back in in short time....Nice.

Running it on a stand followed by 02 tune in boat is a proven method but it does not give you the load and data you get from a dyno. The dyno makes it easy to make changes to the engine with real world results. Breaking in a engine using a load and not free wheeling the engine is also a plus.

Budman II, I have to agree, with others.
Insuring the engine is properly broken in, and not damaged, due to haste. If something is incorrect; it will be easier to detect and correct, versus installing it in the boat and running it in a uncontrolled situation. You need a baseline to start with, adjusting A/F ratios in the boat after installation will surely, be minor.
I would be 100% clear with whoever is doing this for you, that they break it in, and let things cool back down, double check everything and not just throw it up there, run the hell out of it and say: here you go. They have no invested interest in it, so you need to be clear of what you expect and what your end goals are.

Mark, the builder who has the dyno (second guy I went to who straightened out my mains) said that they usually break the engine in on the dyno, let it cool down, then retorque head bolts if necessary, etc., before any additional pulls are done. He also said they commonly run racing fuel on the dyno, mainly because he does not trust the quality of the regular pump gas available in the area with all the ethanol that they now put in it. That alone might throw my timing and fuel curves out the window.

What additional goals might I want to state that I am after, aside from determining the optimal timing and jetting for the engine? Obviously I want to reveal any problems up front before it is installed.

Is $500 about the going rate for this?

Correct if I am wrong, Getting from the "dyno pulls", the motor power level data is helpful in prop selection too?

You definitely don't want to dyno it on race fuel and then run it on pump gas in the boat. That pretty much defeats the purpose. If you are running crappy ethanol based fuel in the boat, then run it on the dyno. That's what we do. If the customer can only get 89 octane with ethanol, then that's what it gets on the dyno.

Several (Steve, Brian, Mark) have mentioned the top reasons to dyno the engine. Nothing leaves my shop without hitting the dyno. The actual power number isn't the biggest reason for doing it. It breaks the engine in under a load in a controlled environment with WAY more data available then if you were bouncing down the lake. There are enough things to worry about the first time out with a new setup. You don't want to worry about the tune being totally in left field, oil leaks, etc.

As for the dry headers, it not that big of a deal. Unfortunately, I can't run wet headers on the dyno either. We tune it a little lean on the dyno. How much depends on the boat's exhaust. If you are going to run silent choice or restrictive mufflers, expect the tune to richen 1 full point or more in the boat. With your Lightnings straight out the transom, expect about 1/2 point of AFR change. Once it's in the boat and running, it may be a little on the rich side. That's a quick and easy fix. At least you will know everything else is good. It will be money well spent.
Good luck.
Eddie

its not hard to do at all. i did that here for my 502's. for water supply i just use a 55 gallon trash barrel that i put a fitting in the bottom of and filled it and just let a hose run into it while the motor was running. took no time at all to put together. as for the tuning... i would have to ask/suggest that unless your new combination is someting really really different, there are good baseline settings well established for both timing and likely jetting for you based on what you have.

As Eddie, said; running on race fuel defeats the purpose. The specific gravity, energy level, and fuel burn will be way off. I could see if you had 12:1 or higher c.r. or running some high boost.
If this guy is set on running that fuel, I would keep looking for someone else. Actually; running as lower c.r. would allow you to speed-up the burn and make more power. I am trying to understand how an experienced builder, operating his own dyno would always run race fuel, unless it's 96-97 octane unleaded. Even being so, if tuned to race fuel, leaving set-up and going into boat with pump gas, would most likely burn the engine up.
What would he do; break it in rich and make all the pulls rich and wash the cylinders down and dilute the oil with fuel? I would be more comfortable, running the engine on the dyno on the lean side than in the boat, due to the fact the load can be controlled to engine speed.

I'll have to ask him again to make sure I did not misunderstand him. He does mostly drag engines, so I would assume that is the majority of what goes on the dyno. He did a blown 502 for a friend of mine's boat, but that engine was not run on the dyno. It had a B&M 250 on it IIRRC, and Nickerson did the cam and carb for that one. Ran without issues for several years.

Right now, if it turns out that I won't be able to dyno it on pump gas, I will probably pass on the dyno and just look into maybe setting up a startup cart for it.

Rich,
Yes its helpful in getting you closer to a prop to start testing with but every hull/set-up reacts differently.... to many variables.

Are you splashing this year?

Me.... maybe.

Spring run theme is " If is not a cat...it must be a dog"

Brian , If you have t-shirts made with that saying on them I've just got to have one . Let me know where to send the $$ . :evilb: Cat killerz my azz . :lolhit:

Crocket dynoed ours and it was an all day affair. We ran it on the same fuel from a gas station as you run every day. Broke it in on the dyno. Tuned it on the dyno with all my pumps regulators pulleys belts and CMI exhaust.
After it was in the boat we took it to him and with me driving he retunned in the water to a full boat with 3 people on board and 3/4 tank of fuel.

Some tool bag:evilb:

I couldn`t post the vid from my tablet for some reason, here it is:

http://33outlaw.zenfolio.com/img/s2/...972750-210.mp4

What I was referring to is the precise Torque and HP peaks. Say for example that a given motor has a peak HP of 550 at 5400rpm. Starting a 5500 and beyond, that HP curve starts dropping like a fat girl off her bar stool.

Yes given the fact as you stated reference hull/set-ups react differently, but you now know NOT to exceed 5400 (better put kept it precisely at 5400) rpms when under WOT.

Same with the torque peak. If the boat falls flat on it's back (reference made to the fat girl-------difference is she bounces a few times while the boat just stays flat) and has a very hard time gathering forward motion (speed) at the torque peak, then further prop tweaks are necessary.

In conclusion, put her on a diet. No, not the girl-----the boat.
Ok, both.

That was the plan. Wrote a large contract that starts up in mid-May. Hey, gotta follow the money. Will get to the boat build after the contract is finished (mid-July). Hopefully get some late summer boating and the fall run.

You going to have the cat in the water? Several more cats in Leopa. Should be interesting. Do like the saying.

To stay on the Thread Content folks. Brian does know what he is talking about. He owns/operates a prestine high end dyno cell at his shop.

Rich,
What we use when selecting props is 1000 RPM's past max TQ to unload the drives. For the most part the aspirated engines we build Max TQ in between 4700-4900 RPM's and HP starts falling off at 5700-5900 RPM's. So yes we set our props up at the point HP falls off on these engines.

Chasing cash has been the hold on getting the OE done for the last 2 years but enough is enough this old man needs to have some fun.

As far as the theme for the spring run goes, I was kidding about that but it is the new shop saying.

Well, as luck would have it, I'm not having much luck finding anyone in my area who can dyno this thing at all, much less with pump gas. You would think a city the size of Louisville would have more shops with a dyno. If anyone knows of one within an hour or so, let me know. I might have to talk to Eddie to see how much he gets for a dyno session, but that will probably have to wait until after the summer with the way everyone is booked up right now.

It's real tempting to just wing it and drop the thing in the boat with a conservative tune on it and ease it through the summer, then pull it out in the fall and dyno / tune it. Either that or go the O2 wideband route. In the mean time, I might even just find another engine to drop in it for the rest of the summer. I could keep that engine to drop back in it if I ever sell the boat.