Young Performance

I'll throw my findings out there. ,We used to build a ton of turn key, 100% complete, new engines when new boat sales were much higher. Because of that, we did a bunch of very similar engines. One really common build was a 598 with a 3.3L Whipple. We called it a 925 efi, but they made anywhere from 970-1030 hp.They varied slightly in parts selections, which accounts for the hp range. We tailored them to the customer and the boat, so we changed the cam and head selection from one to the other. On average, we set the rebuild interval at 250 hours. There was nothing more than routine maintenance until then.We recently freshened a pair that had 318 and 322 hours on them. Now, they didn't get run WOT a bunch because even though the boat was 38' long, it couldn't handle the power that well. On top of that, the boat ran over 90 mph at 4000 rpm, so there wasn't much need to run around WOT. The lake it was on is pretty long at over 60 miles. It regularly got run at 4000+ rpm the entire length on the lake and back again. Though it didn't get a ton of WOT, it got a bunch of sustained running over 4000 rpm. Where we have seen that most boats have about half of their hours at idle, this one had very little idling. There are very few and small idle zones, so it spent most of its time on plane. I'm sure that more WOT would have shortened its life span, but how much? I don't know that answer. I do know that the inside looked incredible. We were able to hone it and go right back together, with some upgrades to make over 1200 hp.

We have done most of them at 250 hours or so, and they all looked the same. Hone them and reassemble. In a few cases, we coated the skirts of the new pistons to make them .001-.002 larger to snug them up in the bore. On the flip side, with our 1200-1300 hp engine, we typically go through them around 125-150 hours. I have done a few at just less than 100 hours, and didn't really see a difference in them versus one that had 125+.

I find it much easier when you have done a particular engine combo many times because you know exactly what to expect. You know what the wink links are and correct them with each successive engine.That is big advantage over a one time build.
Eddie

Panther

Good info, thanks Eddie!

I'm curious to see how my new setup (965hp) will fair over the years. I tried something very different and I'm not running an intercooler (6-7psi boost) at this power level. Instead, I'm running a twin nozzle water/methanol injection system. Right now it's a 50/50 mix but next year I might run 60/40 mix and see what it does. "Without" methanol it ran 94.5 mph and "with" Methanol it ran 95.4mph and the equivalent of 1/4 tank of fuel in weight. It also didn't trim it to the moon on those passes because we were reading A/F numbers so there may be another 1-2mph in it yet. It's the fastest my ole Apache has ever run. :-)

Young Performance

I've always been hesitant to run a meth injection for fear that the customer will let it run out, not realize it's not on, etc. etc. and burn the engine down. If it was my own, then no problem. I have some customers that can't check the oil correctly, so I try to make everything as simple as possible. For lack of a better term, I have to make it dummy proof. lol

However, meth injection is a very viable way to get the job done. As well as cooling the intake charge, it has the added advantage over an intercooler by raising the octane a bit. It definitely works when set up properly.

Sounds like you are getting it dialed in. Good luck with it.
Eddie

MILD THUNDER

Thats some fantastic hours of service, for that kind of power. 300 hours from 900-1000HP engines? I like it!

315duramax

the boat i picked up are making 850hp 557ci. only 20 hrs on them now. but builder says they are good for 250-300hrs if i beat them and if a dont beat them he says they could last quite a while longer

MILD THUNDER

Unfortunately, what they say, and what they do, are two totally different things.

Rambocj7

I have a pair of vortec blown and intercooled 540s with just under 800 hp each. Pulls 5lbs of boost at 5000 rpm. I have 300 hrs on them now and doing top ends. After a leakdown, a lot of valves were leaking. Nothing leaked through the rings though. Still have the nice cross hatch on the cylinders. They have callies cranks, Carillo rods and je pistons. I have prelubers so never a dry start. I also have KE oil thermostats and don't go over 3000 rpms until oil temps are good. I cruise at 45 mph at 2500 rpms. They don't pull boost until 60 mph at 3500. I end up cruising mostly since none of my buddies can run with me. It's boring being first to the beach and nobody to party with. Lol

MER Performance

Running methanol through a fuel system is one thing of flushing system to prevent corrosion after the fact, injecting methanol into the intake charge has a cooling effect of the air charge... I guess the question is are you changing the the A/F ratio to correct for fuel and addition of methanol at those points excessive methanol creates moisture within the air charge due to the absorption of moisture, this will cause milking of oil and contamination of oil from UN-burnt methanol....If all these factors are addressed, it's a great power multiplier.

MER Performance

Getting back to this Thread;
Power verses maintenance and cycles times of components.. Rebuild; times really start at the beginning of the build sheet of the engines, power, usage, maintenance, quality of parts and tuning....cylinder wear is going to be directly proportional to, piston design, bore finish, ring pack, lubrication and proper fuel curve....Valve train components, and there life and service points are going to be determined on rpm, cam design and cycles... that falls true for rocker arms, also... Lifter rebuilds, as far as wheels and bearings, starts at the part its self.... springs should be checked as certain hours in service, the spring is still making the same cycle along with the lifter.. wheel oiled lifters over non oiled wheeled lifters.... idling on a non oiled wheel, is going to have a wear effect at low rpm s, verses a higher idle...
To a certain point, running a hydraulic lifter verses a solid lifter on a bigger lobe can possibly mask valve train instabilities, due to the lash changes are being taken up by the hydraulic to a certain point..... Running a solid lifter, say a tight lash..... will show instabilities in the valve train, due to lash changes. either tightening lash from valve seat erosion or any issues with valve face or increases from lifter wheel bearings or lobe wear/ damage..... Valve springs, should be checked annually, either in a bench Rimac or Logan Smith, that attaches to the rocker arm and you can read the PSIs from a oil dampened gauge.... This is all based on the individual engine builds and specs of components..

Coating piston skirts a common practice, standard coatings come in about .0014" over that not recommended by Calico Coatings, they will not guarantee, thick coatings... Other questions; would include ring lang areas in pistons, worn grooves are a issue, that will "piss off " a ring sealing causing ring flutter and blow-by....All being said; if the valve train is stable all lashes will remain constant...... cycle times are important before failure could occur....

Owner, operation, maintenance, along with the parts being used all determine service life... you can put 500 hours on a 525 EFI and have the parts not fail but be far beyond service life and spec. You, could have a engine that starts to destroy it's self on the dyno or 10 hours in the boat.. only due to improper part selection and machining / assembly...You can have a engine on the dyno, that looses ring seal due from incorrect honing or fuel wash taking the rings out...... all is going to shorten engine life......
It all comes down to proven knowledge, and success of engine builds with parts selection, and machining practices....

kvogt

thanks for your input Eddie