Originally Posted by Raylar

Just my opinion, but any performance marine engines that have been sitting pretty much unused and unserviced for possibly ten years could have some real issues after being put back in service. Sometimes marine engines unused and sitting can be a bigger problem than the same engines with lots of use and hours.
A good compression test coupled with a MUST leakdown test may show cylinder bore rust and ring degradation and valve and seat issues and if so that's going to require refreshing the engines. Valve springs should be changed as a MUST and the valve seals at that time as both can be done on the engine without head removal. There could also be some rust and deterioration on the head gaskets that were being used back then that were not stailess so head removal may be required. As for roller rockers, if the engine was cranked only (not running) to prime the oil system and get some oil onto the rockers they might be ok, but removing valve covers and checking and readjusting valve train is easy and should be done anyway. The other issues that may show up will be gasket and seal issues from drying and cracking and only some use will show that issue.
In all, obviously the boat should have been bought "RIGHT" and there should be money in your budget for eventualities!
Be careful to realize that if your boating season is short and you have issues early in the season you will probably loose your season waiting for repair or replacement.
Hopefully you will expierence limited problems but use the old addage "Plan for the Worst and Hope for the Best!"

Best Regards,
Ray @ Raylar

Originally Posted by pondrunner

Well for one, the achilles heel of these motors is the head gasket. I know, mine went at 200 hours! With the blower and EFI, they go without little fore warning. It ran like a demon until went. I had lost about 100-150 RPM before it happened then died. I was going to replace the gasket at 250 hours at the end of the season, but didn't make it. If yours are later motors (2003 I think) they will have a Cometic gasket which is what you want. The stock GM piece of crap I had on it cost me the motor. Burned one of the heads and block across THREE cylinders.

Also, the blower is known to loose screws and you know where they go...through the motor. Take the time to check everyone of them is tightened. It is a great motor when running, I loved the easy starting, idling and throttle response. But if not carefully watched ( I do mean compression tested weekly which is what I should have done) a problem can hit quickly. Incidently, I know where there are 575 SCi parts locally if you need them:^P

Originally Posted by pondrunner

Well for one, the achilles heel of these motors is the head gasket. I know, mine went at 200 hours! With the blower and EFI, they go without little fore warning. It ran like a demon until went. I had lost about 100-150 RPM before it happened then died. I was going to replace the gasket at 250 hours at the end of the season, but didn't make it. If yours are later motors (2003 I think) they will have a Cometic gasket which is what you want. The stock GM piece of crap I had on it cost me the motor. Burned one of the heads and block across THREE cylinders.

Also, the blower is known to loose screws and you know where they go...through the motor. Take the time to check everyone of them is tightened. It is a great motor when running, I loved the easy starting, idling and throttle response. But if not carefully watched ( I do mean compression tested weekly which is what I should have done) a problem can hit quickly. Incidently, I know where there are 575 SCi parts locally if you need them:^P

Originally Posted by 4bus

Compression test every week on a twin engine boat? I would need to helicoil the spark plug threads by the end of the year lol. I see you are local, want to stop by once a week and perform the test?

Have not heard anything about the screws, heard about bearing problems on the later blowers. What screws that can fall in are you referring to?

Originally Posted by JRider

The screws come from the throttle bodies as the blower does not have any. Not sure how deep you want to get into this, but you might want to consider selling the blower packages (wieand/B&M) as they are worth quite a bit of money...and then replacing them with the Blowershop 250s. You might be close to even on the whole package. The Wieand 250/256 is not a very stout blower. You can even upgrade the packages to 671 or 871 with very little trouble and maybe at a cost less than a BS 250. Keep in mind the 671/871 height increase of a couple inches. If you keep boost near stock levels ecm calibration is not necessary.

If you really want to upgrade you could go full whipple 3300s and innercoolers. No worries about the hatch then and the FI system would be a big upgrade over the throttle bodies.

As mentioned earlier the cams are not over-achievers and the headgaskets are terrible. I would not run the headgaskets over a 200 hrs under stock boost. At 235hrs mine were just starting to leak between the cylinders.

Originally Posted by verbi69

Pull the motors and do a teardown Bus.
Good time of the year to inspect all internal parts and install new gaskets, seals, bearings and drive train.
If the budget allows and it does as mentioned, why gamble with the short boating season we have.
Pay now or pay later I say.
This is cheaper than breaking something later......

Originally Posted by 4bus

I would, but then I would have to send the engines all the way to polesmoker in TX because he is the only engine builder you can trust! hahah .

I get what you are saying verb, but then there is the whole making problems because I am fixing something that aint broke. It will be a judgement call, if I see anything at all that I do not like I will pull them.

BTW I have a retired engine guy that just waits for us, he can usually flip engines in a week....we have taken out and sunday and dropped them back in on friday nights before. I won't be losing a season.