Need engine advice N A 598 cubic inch rebuild
 

My year came to an end with a bang. I have owned the boat for 3 season. At the end of the first two I did a compression and leak down test numbers were great. Boat ran great all summer. Last Saturday was probably the last time out. It broke an exhaust valve. the number 8 cylinder. Screwed up the head and piston maybe more just not that far in yet.
The engine as I know it N A 598cubic inch Dart Big M block Dart PRO 1 345 heads. Not sure on the crank and rods or pistons yet.
The plan have the block and crank checked first and the head repaired. I have contacted Midwest cylinder head about the damaged head they are sure they can fix the damage.
Any suggestion as to whom would be good to do the work in the Cincinnati area. I'm not opposed to driving if it requires someone further away.

Thanks
Tim

I'd get in touch with Eddie Young. You wont be sorry.

http://youngperformance.com/

Eddie would be a good guy to talk to - he is in Nashville, so probably about 4-5 hours away. You may want to call Bob Madara at Marine Kinetics, since he is in touch with a lot of marine engine builders, just to make sure there is not someone good right in your back yard. I think there are a few pro engine builders who post on these forums up in Michigan and the Chicago area who might even be a little closer. Good thing is that it happened at the end of the season, and you have plenty of time to figure out what happened, fix the damage, and make sure it doesn't happen again. The main thing is to carefully document the tear down with lots of notes and pictures to kind of perform a "post mortem" to help troubleshoot the failure. Try to figure out exactly what exhaust valves were in that engine - there can be many causes for it to drop a valve like that. Look carefully for signs of water from a leaking exhaust manifold. Sometimes it's not a bad idea to figure out who you want to do the rebuild, and then take the whole thing intact to them so that they can tear it down and figure out what happened. If you take them a pile of parts, it gets that much tougher to find the cause.

I had the same problem with my 598ci NA, only it was number 7 and dropped an intake valve. Had a big solid roller cam in, same heads, was a Merlin III block. Found that the valve springs were way light for the application, resulted in valve float and piston/valve contact. Ate two pistons, scored cylinder wall, bent pushrods, damaged one Jesel rocker. Upon rebuild we put a new block on it, Dart big M, changed to hydraulic roller, the heads were repairable. I estimate that we lost about 75hp going hydraulic but I have 100 hours of absolutely trouble free boating on it now.

I have read alot about Eddie on this site and certainly consider him or contact him if needed.

Who repaired the head? As mentioned I contacted Midwest cylinder head and sent them pic's. They said it is repairable. They will weld the damaged area and cnc machine the chamber back to original specs.

I'm definitely taking my time, no need to get in a hurry. I'm looking at all local builders first. It would be nice to be able to stop in and check on the progress if needed.
Two that I'm checking on now.
The Performance Clinic. Dayton Oh.
B E S. Tony Bischoff

BES bischoff
http://www.besracing.com/

or steve barker
Barker Machine & FAB

(513) 724-3288

2822 Jackson Pike, Batavia, OH

Wet or dry exhaust?

Wet C M I