Unlimited jd

iTrader: (5)

Had a few last summer that the guides were not checked and leaked water. Cool water dripping on the seats that were old I believe caused them to fall out.

Racerngr1

My boat is 95% fresh water.

JimV

iTrader: (1)

If your on a budget I would question if new pistons were needed. 450 hours is not that much time on the rotating for a stock 502 unless it has exessive leakage or other damage and the extra cubic inches wont justify the hp gain vs. cost. If your consern is the heads change the seats have some bowl work done in the exhaust ports. Or soon to be available, a replacment head that has the stock ex port positon with all the bolt holes in the stock positions including the extra bolts in between the intakes. The heads will have better quality ex seats and improved airflow on both ports. Better head cheaper than Darts or Merlins I think they will be priced low 800.00 per set. All your parts will interchange to the new castings. My guess is with some port work on those heads will make a lot more power than the extra cubes. my 02

Strip Poker 388

iTrader: (6)

Also have them magnaflux the heads around the seats,Like Jim said I would just ck the pistons skirts,size, and bore see how it it is. If its good plate hone and ring it,I would pull the oil pump and look inside,make sure no weird wear,the the opt of having the work done to the head vs buying new heads, most of the time if gets closer to just buy new, machine shop labor adds up quick!!

Really just depends on your budget.

here some stuff I did
http://www.offshoreonly.com/forums/g...-build-up.html


I rebuilt a buddys 29Scarab once that had around 500 hours onit, it was a 415 mpi motor ,not the same engine, but a example,but he ran the hell out of it, wide open all the time!!!, never lift coming out of the water etc. It looked like brand new on the inside, it really didn't need rebuilding, but I made him replace valves,springs and rings and bearings and he never looked back, I think he had around 2k in the rebuild,


rob

Racerngr1

Awesome write up Rob, thank you.

Strip Poker 388

iTrader: (6)

Thanks

make sure your cmi's are not leaking, the water will get to the valves,

I had a exhaust seat fall out in 2010, no reason i could find, rebuilt it and been running fine since, also remember im running a whipple and turning the motor over 5500 for short burst,

Ive got anougher buddy with a 2001 38 formula,almost 600 hours 500efi, he also runs it wfo all the time,hard!!!, he just had valve spring prob this year, and they were still sealed ,never been touched. so they are tuff.

the comp valve spring are pretty cheap,i would reuse the retainers if no wear, change keepers, seals,

im jumping around, sorry

Hey good luck with it

Rob