Boat motor. I have a 305 chev in boardmotorsaltwater cooled just had heads crack tested and planed after about 3hrs runninghave

muffycaz, Jan 14, 8:52pm
i have a 305 chev in boardmotorsaltwater cooled just had heads crack tested and planed after about 3hrs runninghave water getting in to both rockers any sugestions
donz01, Jan 14, 9:06pm
did you use any form of sealer around the head bolt threads as the water can water can come up through the threads from the water jacket. Talking from experience many years ago.
pfemstn, Jan 14, 11:49pm
donz01 has hit the nail on the head must use a good quality sealer on all the head bolts!
muffycaz, Jan 15, 2:03am
have found that the block is cracked
owene, Jan 15, 4:53am
Where abouts is it cracked out of interest!
intrade, Jan 15, 7:24am
did you use a straight hairline edge to mesure the straightness of the actuarl engine block also!
lookoutas, Jan 15, 7:58am
Probably corroded away inside.
Should really run a heat exchangerin salt.
muffycaz, Jan 17, 1:40am
behind push rods on no 6 cylinderengineer is going to try and weld
petermcg, Jan 17, 8:38am
I dont know what would cause the block to crack,, but welding is a good option,, it will work well if the casting is not too thin,, I have done it before,, weld in very small sections at a time,, cooling the block down with the air gun between welds,, tap the welds,, as there cooling down,, with a sharp chipping hammer,, if when everything is back at room temperature, you see a new crack in the weld, repeat the process with a mild steel Rod.
muffycaz, Jan 18, 6:24am
thanks for your input welding not succefful.kept on cracking . newblock is between $5000 to $6.500fish are going to be expensive.
kingfisher21, Jan 18, 6:33am
!What! says who! It's only a common as mud 305, you should be able to pick up a whole complete good running engine for under a $1000.
muffycaz, Jan 18, 7:10am
Is it a marine engine you are talking about cos that is what I am on about.
ralphdog1, Jan 18, 7:13am
I think you will find it is all the peripheral bits like the cam and headers etc that make it a marine engine, I doubt the block is anything other than a common ole 305 Chev block
muffycaz, Jan 18, 7:14am
Only a boatie would know
owene, Jan 18, 8:51am
Same block as 350, all small blocks are same casting. Just acquire another runner and swap everything over. You can't fix cracked Chevs.
jmma, Jan 18, 9:09am
Well, maybe you should ask in craft & hobbies, seems you use this craft for your hobby, you might even like the answers you get from there.
kingfisher21, Jan 18, 9:23am
No different to a car engine AT ALL, it's only the exhaust manifolds and a few other things that are different, mercruisers are the same, only a common ol Chev, I can get you a perfectly good running 305 tomorrow for under a grand. If you want to pay someone 5-6 grand for a new block, feel free, because you are getting shafted.
owene, Jan 18, 8:20pm
For a man of your word, you have plenty of them!
lordv81, Jan 18, 9:39pm
WOW5k to $6500! Do the mercruisers come gold plated!At least the OP has a new boat anchor now!