KN

I need some opinions on this, I've been reading previous posts. I'm looking at a 28' boat with a single HP500EFI engine it has 270 hours on it and has been well taken care of. It looks like I should have the valve spring replaced with either Isky or Comp Cams how much should this cost? Is there any other thing I should have done. Does this need to be done every couple hundred hours of longer now that the factory springs are replaced with stronger ones. I'm nervous about buying a boat with this engine and thinking I should look for a boat with a 496Mag HO. My previouse boat had 7 seasons on it with the 496 and never had any troubles.

Thanfs

Smitty

Depends on what model year you are talking about. Early 500EFI motors had bad springs, but the later ones are O.K.

Give us more info. I would also see if you can do a leakdown test to get the true health of the rings and valves.

rrentsch

It is my understanding also that the problem was with the early HP 500efi's and the carbed HP500's. I have 330 hours on a pair of 2000 efi's and they run great.

Bryan Rose

Go blue.... worth every penny. I have one and have had nothing but good things to say about it , I did however pull the heads and do new head gaskets and top end build but only because I was going with a supercharger....every thing was good upon inspection. Great platform for adding power. Much better and stouter than a 496. Don't be nervous about going blue.


Bryan

PatriYacht

Valve springs and lifters should be considered wear items and replaced every 250-300 hours on all HP 500's and HP 525's. The cam profiles on these engines are much harder on parts than the 496's. But that's why they put out so much more horsepower.

jkelly

what is the cost to do the valve springs and lifters

JaayTeee

The last one's I did cost about $ 1500 to do 2 engines,
( springs, lifters, seals, retainers, keepers, gaskets)
but that didn't include my labor.....and that was a couple of
years ago.

Linster

As posted above, Springs (Comp 929) Lifters (Crane), Cometic Head gaskets, I would also do the rings. Merc uses the GM low tension that burn some oil. Hone with a 400 grit and use Speed Pro metric standart tension rings, file fit. I have rebuilt about 6 of these in the last year or so. The rings crumble when you take them out. I also replace the timing chain with a true roller. Parts & machine work are at $2K. If you cant do all the work you will probally pay a reputable marine shop $4-5K to do the work. It definately a better motor than the 496.

Raylar

I will argue a bit here about whether HP500's EFI or Carbed are better than a Merc 496.
The Mercury Racing HP engines are fine motors and they cost a lot more up front for the added features and upgrades. The analogy is kinda like comparing apples and oranges on a cost of similar features basis.
If you have to rebuild or upgrade a lot of parts on the Mercury Racing HP engines the parts costs and rebuild expenses will not be inexpensive.
The biggest reason the 496 is comparable or even sometimes in my opinion is the closed cooling that the HP500's don't come with. If you boat in salt or brackish or high alkaline fresh waters this advantage will be a huge advantage over the life of the engine.

I can say without question that the 496's will go 500 hours plus and in many cases over 1000hrs without spring replacement or rebuilds and re-freshen and they certainly don't disassemble wit piston rings in pieces. They are also equipped standard with true double roller timing sets nad standard 10 quart oil pan systems.
If you want to compare our HO525 and HO600 Raylar reworked 496's, they definitely step up the level of stock 496 Merc engine
horsepower and torque and provide hundreds of hours of high performance use without valve spring replacements or low hour rework.
Guess I am obviously biased here, however when you compare the 496 engine family with the HP 500 family of engines on a "apples to apples" basis the Merc 496 engine family will hold its place just fine and at a usual lesser cost basis both initial and maintained basis.
In any event its a buyers market in performance boats right now and either choice with the services of a good mechanical survey or inspections should get you a nice boat with a good engine package with either of these choices!

Best Regards,
Ray @ Raylar

bigboat28

How much is your HO525 and HO600 kits?