engines guys chine in please
 

trying to figure out were to spin these motors, previous owner was very conservative and never went above 5K except for occasion shot for fun, I need to figure a safe sustainable rpm range so any input is appreciated.

Engines are merlin block 572 4.5 x 4.5, splayed caps, Hank the Crank forged steel cranks, balanced, complete jesel solid roller pro series valve train and belt drive, Dart 320 aluminum heads 120 cc chambers, , 2.3 intake and 1,9 exhaust, 720 lift solid roller cam, 262 intake and 272 exhaust duration, kinsler mechanical injections, stelling big tube full headers, motors are 9 to 1 compression, designed and assemble at Keith Eickert Power Products and recently completely rebuilt.10 quart pans with external pumps, two stage water pumps, they have all the best parts and would appear to be capable of turning in the high 6K range no problem but, someone who really knows might shed some lights for me.

Cheers

Moxy

Out of my league by far, and without crunching numbers, I'd say 6400rpm max power. We'll see what others say. You could call KE himself and hope he answers your question. Maybe he'd have a dyno chart too.

Sounds like a great engine full of great parts. Cool !

Here's his shop info. Yes, this is him. http://www.kustomboltons.com/contact-us.html

ya spoke to KE, they haven't built motors for a few years now according to the tech on the phone,

thanks for your input thought somebody will have an idea

Very similar build to my 598 and my design RPM is 6400.

any dyno numbers?

NOPE - never been interested in putting an engine on the dyno. I know how to dial an engine in without. I never had an engine problem that the dyno would have found. Should create better than 800 HP

Mine has the Merlin BIG M block, Crower crank, Oliver rods, JE 8.6 comp flat top blower pistons, AFR 357 CNC'd aluminum heads, Jessel PRO shaft rockers and belt drive, 14 QT oil pans ( not dry sump) My cam has more lift than yours (.75 inch), Holley EFI sequential port fuel injection and MSD 6 ignition ( timing done by EFI ) I built this engine to some day add a M4 Procharger. ( 1400 HP ) This same engine dynoed at 1425 HP

The heads are pretty small. But the intake and cam should carry them pretty high. Depending on where the cam is installed they could potentially make power close to 7000 rpm

How do you know where the engine makes peak HP, and Peak tq, and what the powerband is shaped like, without a dyno? How do you know what kind of ignition lead an engine likes? I've seen where 10* of timing in the midrange, made a small , very small, change in torque output, something you wouldn't see in a boat. Like 5ft lbs of torque loss with 10 * more timing. In the boat that wouldnt be noticeable, but on the dyno, it was clear what the engine liked.

My assumption with that combo, is somewhere in the 5900-6300 range for peak power. I don't think thats enough cam, for 7,000 in a 572 incher in N/A form.

Might want to check valve spring pressure before winding it to high, just a thought.

I am told motors made 830@5900 as best the original owner could remember lol which I am happy with but he wasn't really sure on his numbers and it appear the motors had more rpm available

5,900 sounds a lot less scary than 6,500. I just have a 525 but I run it close to the rev limiter which is 5,400.

Sounds like a nice setup congrats and thanks for sharing!

Where are you getting your specs and info? Previous owners memory or actual build sheets. Have they ever been apart since? Hours? Would be nice to be confident about what's in there, it's not abnormal to open them up and find something different.

I would be scared to spin a 525 also considering the have no valve spring pressure. 140 on the seat 4xx open.

Build sheet from Keith Eikert, recent rebuild, maybe 20 hours on them

BIG difference between a stock Merc engine and a custom built engine.

I am told that some of these parts are the best that money can buy

dart makes the big m block,i did not know merlin called their block big m.

How do you get 8.6:1 with a flat top piston, 4.5 stroke x 4.5 bore ?

Might be in the hole compression height like a 1075 merc.

Shouldn't have said flat top. There is a slight dish. I am used to pistons with a big hump. 4.5 X 4.6 bore