HP 500's-Most hours?
 

Who has the most hours on HP 500 EFI's? Im @ 430 and they run great, but I hearing refresh soon. Wondering who has run them up and who has refreshed-chose to or had to?

Thanks in advance.


PS- If refreshing, Im thinking of whipples and drive beef up- might as well get some more power while they're out-any feedback on that setup would be cool.

Re: HP 500's-Most hours?
 

The Whipple is the best blower out there and you will be very pleased!!

Re: HP 500's-Most hours?
 

my 500efi is out for rebuild ( bore/stroke) after 447 hrs by choice. I figure at least 1/2 of those hours are at 5000 rpm or better. Solid piece of performance engineering. Now, if only drives would last that way :(

Re: HP 500's-Most hours?
 

I am around 450 hours changed my valve springs around 350, Did a leak down and mech said the pressure was still like new, in great shape. SO I am going to keep her stock and keep going.

WILL

Re: HP 500's-Most hours?
 

No, I don't think so. I'm told that the only difference between the 500's and the 525's are the aluminum heads built for Merc by Edelbrock and the closed loop cooling.

Re: HP 500's-Most hours?
 

500 efi is the "Official Engine" of ORL. Affordable , dependable and there are many out there. If you guy's know where some are for sale let me know! Thanks.

www.offshoreracingleague.com

Re: HP 500's-Most hours?
 

Just springs and no valve job? I was told Valve job needed motors pulled and might as well rebuild?

I think I'll run leak down first and then see if I can milk em for another 400 :cool:

Anyone else got high hours w/ no work done?

Re: HP 500's-Most hours?
 

Not closed cooled and yes have been salty 1/2 dozen times-

Re: HP 500's-Most hours?
 

75% of my hours have been under 4500 rpm, do you mind sharing the total cost for your rebuild, roughly?

Lucky for me drives have been solid for XZ's. One minor repair.

Re: HP 500's-Most hours?
 

what make and model boat are they in ? weight ?

Re: HP 500's-Most hours?
 

470 hours valve springs and lifters at approx 300 hours. the engines burn maybe 1 qt of oil in 20 hours. did a leak down test at around 400 hours and everything was good. i expect a total of 550 to 600 when i freshen them. probably do some upgrades short of blowers

Re: HP 500's-Most hours?
 

I had a HP500 in my 29 Fountain and when I sold it, it had 250 or so hours on it. The guy I sold it to ran it for some more hours and then tore it down to change it over to a blower motor. He told me the engine looked like new inside, everything was in perfect shape, springs, valves, bearing, cam and crank shaft, water cooling passages showed no signs of salt water and this had to be clase to 300hrs and all in salt water.
During my time of ownership I changed over to Mobil 1 synth oil at 20hrs and changed the oil every 30-40hrs which for me was around 4 times a year. I also flushed with Salt-A-Way every time or at least every other time.I changed plugs and distruiber cap and rotor every season.
Enjoy your HP500's, they are great engines!
Mike

Re: HP 500's-Most hours?
 

By the time its a 572, I should be into it for another 12 grand or so I figure.


PS, I pulled the heads at 250 hrs and there were 9 cracks between the valve seats spread between two heads. I swapped them out for the edelbrock marine aluminum heads at that time. New lifters, springs, retasiners, keepers and rocker arms.

Re: HP 500's-Most hours?
 

A buddy of mine has a Checkmate with a hp500- In the owners manual it quoted that the engine was "built to run at or near full throtlle for 500 hours" -pretty cool statement. I think he is at about 400hrs. I know he does not have the power he used to have, and is thinking rebuild as well. I've noticed Mercury has a rebuildd program now. Might be worth considering. I'd bet it is pricey, but can't imagine anyone knowing the motor better. and it may come back to you with a warranty.

Re: HP 500's-Most hours?
 

Bob and Shari Smallwood have over 700 hours on their 37AT with HP500s. (I think they are EFIs.) I know Bob runs the boat REALLY easy, and I don't know if he has had them freshened, but that is a testament in itself. (Mostly salt-water as well.)

http://www.activethunderboats.com/ac...otos/small.jpg

Re: HP 500's-Most hours?
 

they are in a 30 ft Hallett that weighs about 8000 lbs. :eek: