525 sc's

iamfaster · 10-16-2004, 09:59 AM

I will b doing a total rebuild on my 525's this winter. Any experience on upgrades. DO not want chillers. They currently have 325 hrs and still running strong. Seals never opened. Like to gain mild HP increase,maintain integrity. New heads? Cam?Valve and springs, ETc.. Also want to keep my baby Weinand blowers (177 ). Any info would b appreciated.

iamfaster · 10-16-2004, 01:17 PM

any info would b appreciated

InXS · 10-16-2004, 05:26 PM

iamfaster,
I had a '93 Fountain with 525 SC's. You did not list the year of your engines... You may (or may not) have CMI headers. I refreshed my engines in '96 and changed the Gil Headers to CMI headers. The Gil's had hot spots in them and would crack internally allowing water to get in the engine oil; something Merc did not want to tell anyone about. It was one of the best mods I could have ever done. Allowed spark plug changes without getting all cut up by the tight squeeze between engines. Know the engines breathed easier and looked impresive over the Gil but I did not see any added mph.

Also, when I had the engines out, I installed quick-drain hoses on the bottom of the oil pans so the oil could be pumped out thru the pan rather than dip stick.

Teague offers (probably others to also) smaller blower pully's to get the boost up to about 6-7 lbs which will give you a little better performance should you choose to go that route. JMHO

bpine · 10-16-2004, 06:07 PM

I Rebuilt my SC600 with the advise and help from BOB Teague! They built a set of heads and recommend a cam. I was very please with the results! Just make sure you talk to BOB! I also switched over to CMI, Thanks to CMI for building Custom Tailpipes that fit like a glove! If you have new exhaust built think about having ports added for EGT's And O2 sensor! not much extra cost and will help with tuning in the long run! I was so glad I did this!

Bryan
http://www.offshoreonly.com/forums/a...d=101249&stc=1

iamfaster · 10-16-2004, 08:57 PM

thanks inxs and bpine for the info. My motors r 96' with gills. I started to notice salt starting to work its way through the freeze out plugs on the exhaust. I have not had any problems with water in the oil yet. Boat was run in fresh water except for the last 75 hrs. I hope the exhaust can be repaired? I do not want to spend the $$ for new if i dont have to. I also had drains put into the pans. Will Teague give me a rebuild package even though they will not be doing the work??

iamfaster · 10-17-2004, 08:18 PM

Any more info would be appreciated

mcollinstn · 10-17-2004, 08:21 PM

You are pushing the limits of your 177 blowers. If you are looking for another 50hp, then fine. If you are looking for another 100hp, then plan on larger blowers...