SB

Not really that #. The #’s before…starting at about 5200. Also remember, most engines produce peak hp 1200-1400rpm over peak torque…few exceptions of course (tuned long runner efi intake as one example)

What springs ? What height installed ?
What lifter ? What cam # ?

ICDEDPPL

You threw on those heads out of the box? No changes for marine use? (larger clearances?)

DRAG

Dramatic fluctuation in power above 5000 and those variances increasing more and more as it approaches 5700. Most of the time this is valvetrain related.

PAC has many different grades of springs but I'd think that is enough for this RPM range. You'll know more if the other engine does the same thing. Keep an eye on the servo valve on the dyno when it gets up there 4800-5700 on today's pulls and see if its fluctuating a lot. They can give you a printout of that servo control also. If the water brake setup is not dialed in for this power range it can have trouble controlling the engine. I change quite a bit going from a 300hp engine to a 1000hp engine to a 1500hp engine...it's a lot of setup.

AllDodge

No AFR readings?

PQ290Enticer

Just got back from running the second engine and there is absolutely nothing wrong with either engine. They are both smooth from start to finish with no signs or sounds of valvetrain distress or any distress at all. He said he has run engines that do have "valve float" and you can easily hear it when it happens. Could be an anomaly with the dyno unit itself but nothing with the engines. I do appreciate your concerns but all is well. Really looking forward to this upcoming season. AFR was no higher than low 13's and it should go a little fatter with my wet exhaust.

DRAG

I don't think anyone was meaning to put you into a state of concern, just some guys that look at a lot of dynos and have been around them awhile. I live on the dyno and have never really heard valve float. If its that bad its past that...if I'm in the room with the engine all I hear are my 3 brain cells hitting the metal plates in my head and if I'm sitting out at the dyno stand door closed I am drinking a beer so all noises heard are ignored LOL! Could have been water brake control or other things as well.

Did the second engine look similar? Would be cool to see the graphs laid over.

PQ290Enticer

DRAG, Thanks for your input. I was in a state of "relief" after running the 2nd engine. Didn't intend on sounding defiant or whatever. Just relieved to hear the 2nd one run and to go over with the dyno guy the questions I had and some from this post. Yes, this engine is very close to the first one. I neglected to grab the sheet but will be picking them up next week with all of the paperwork and I did ask for an "Overlay" of both so I could see the differences. I'll be sure to post them.
For ICDEDPPL, yes. They were installed right out of the box. AFR recommended that for marine use, that I should order them with Inconel exhaust valves and to have the heads hard anodized. Which I did. I feel as though if there was something else they would have mentioned it.
I also misspoke about my dyno guy, he only ran to the 5600 because they stopped making power so what would be the point and again, he never thought that either engine was having a problem.
He has a wide band 02 sensor in each side to watch but nothing prints out. He said he goes by the BSFC numbers? DRAG, do you use BSFC too or a combination? Anyway, I was watching those AFR gages during the runs and they were in the high 12's and low 13's. Should fatten up a little with the wet exhaust. Hoping it's not so fat that I get soot on the transom.
And again, I am really looking forward to this upcoming season.

PQ290Enticer

Got the engines back and the paperwork. He was not able to "overlay" the 2 engine graphs. They are pretty close to each other or at least as close as you would expect? I do like the look of the curves he printed out however you can see the actual data points so maybe just a decent curve? My understanding is the higher hp numbers at the end of the run are not actual. Something to do with the dyno. Inertia? Anyway, very happy with the combined 1002.3 hp.

BBYSTWY

I wish I would have saw this sooner like before you went there...I'm not going to get into bashing anyone on the internet but I will say I would be VERY cautious of any advise that place gives you....especially regarding dyno numbers or valvetrain advice....looks like you got a couple solid 500 hp runners! glad it's all working out!

PQ290Enticer

BBYSTWY, Thanks for taking a look. The dyno guy just verified that the tune and carb were good and then did the pulls. He didn't assemble anything. When I was there during the session, we didn't hear anything that gave us pause. The other shop who put them together for me didn't spec anything out, just did the block work and assembled what I brought them. I am going to prop as close to 5300 rpm as I can. I am interested in your opinion on what you see especially if it is something I can correct before they get installed and or I go for my first run and set off a grenade. If it's the appearance of the valvetrain distress in the upper numbers, I'm not convinced there is a problem at least nothing we heard. Someone else commented that it could be the way the dyno is set up? Anyway, feel free to let me know your actual thoughts.