Optimax Motor Opinons requested

[GPappy]

I am looking to repower my older 25' Grady White. It is rated for 400 HP and being older, was not designed to take the heavier motors. I have found a set of 2003 Optimax motors that are priced lower than most of the other motors I have been seeing and are reported to be in good running condition but they have 1600 hours on them and I am not sure if I am buying into more trouble than they are worth.

The compression numbers are as follows:

100, 95, 100, 105, 90, 98 Leak down 30%, 20%, 25%, 20%, 34%, 29%

100, 95, 95,100, 95, 95 Leak down 15%, 20%, 20%, 22%, 30%, 20%


Should I be worried about the hours? Do the compression numbers look acceptable or are there warning signs I should be worried about?

Thanks in advance for any insight.

GP

[Capt.Insane-o]

The leak downs are horrible, and I wouldn't touch an opti with that many hours on them with your wiener. Unless you can get both for 500 a piece and rebuild them, I wouldn't even put yourself through the misery. They will absolutely empty out your wallet with a compressor failure or a carbon induced burn down.

[XstreamVking]

Thats a lot of hours. And the leak down is high. Ready for re-build.

[Motv18]

Agree. To much leak down. Also need to leak down the dfi compressors, see if they are due for rebuild or replace, and if they are the one bearing or two bearing (upgrade). Also hook up the laptop and see if it's getting 15+ psi on the fuel. And pull the dfi air filter (typically they are never changed. Check the shiny part on the compressor gear to flywheel if it's uneven it could indicate compressor bearing excessive play.

[vnemous]

I dont believe the new compressors are rebuildable JMO

[GPappy]

Thank you all for the confirmation of what I had already suspected. If it sounds too good to be true, it probably is. The hunt continues.

[GPappy]

Again, thanks for all your help. For future reference, what should I expect to see in the way of compression and leakdown on a Optimax motor? Does the altitude the test is conducted at make a difference? I did see one motor that had compressions in the 80's but the owner said that was due to the fact that he lives at 7000' elevation. Just don't want to buy something that is a lemon right off the bat, too many chances of quick failure with used stuff as it is without having it bad from the get go.

[Capt.Insane-o]

Leak downs should be 5% or less, compression should be 100-110 @ sea level ish.

[quicklt1]

I thought compression on optis can be false bad if air-pump is bad it may not be cylinder's?

[Motv18]

True if the " I forget the part name" is leaking but that normally blows the injector apart and scorches the cowling. Blow by on the air injector selonoids. The injector gaskets can leak. Not enough pressure during a compression test to affect it on the high side though. But it does have it's own piston and bore to check.

High altitude yes psi will be lower by some ratio 15 psi at sea = say 130psi cylinder then 13 at 7000 = x or something like that. Not positive on this we just have a it's ok chart.

[Capt.Insane-o]

I thought compression on optis can be false bad if air-pump is bad it may not be cylinder's?

All the compressor does is supply a fart of air, in no way does it effect anything to do with cylinder pressure.