Overheat on 5.0 with SX outdrive

[Scott06]

I guess it did not hydro lock only because it cranks? My understanding of hydro lock is not solid. Can you help me understand it better? any advice is appreciated.

As lou said water doesn’t compress so when you get water in a cylinder vs air and fuel, when the piston comes up on compression stroke there may not be enough room in the combustion chamber to accommodate The water volume. The compression ratio of 9 or so to one if you have a cylinder half full of water via exhaust valve when piston is down, when that piston comes up there is no where for it to go, rod will bend or piston break.

i really think for what ever reason boat heavier swim paltform you just need taller riser elbows. Then this will go away. The sea ray i have if you got it with a V8 vs a V6 that 100 extra pounds on the transom they added a 3” riser….

 

[QBhoy]

It likely wouldn’t crank if there was water taken into it, I’d think. If you’ve found water in it for reasons other than coming back up through the exhausts…and given what you’ve said about overheating…my money would be on the cylinder heads being warped or best case, gaskets gone…hence the loss of compression for it to fire up. Defo needs a compression test. The heads being toast would explain why it could turn over at all, with water in there. That would mean the water has somewhere to go (as opposed to water making it lock up). All makes sense if that’s the case. Hope that helps

 

[QBhoy]

As lou said water doesn’t compress so when you get water in a cylinder vs air and fuel, when the piston comes up on compression stroke there may not be enough room in the combustion chamber to accommodate The water volume. The compression ratio of 9 or so to one if you have a cylinder half full of water via exhaust valve when piston is down, when that piston comes up there is no where for it to go, rod will bend or piston break.

i really think for what ever reason boat heavier swim paltform you just need taller riser elbows. Then this will go away. The sea ray i have if you got it with a V8 vs a V6 that 100 extra pounds on the transom they added a 3” riser….

Unless the head has lost the compression and allowing the water to be forced out the cylinder. Just my thoughts

 

[PaulinSWFL]

Update: The boat has been with local mechanic who worked at a Volvo Penta dealership for many years. He retired and now has a nice shop of his own. He found water in all cylinders and at this point he was able to flush the water out (salt water) and is soaking everything with a chemical I cannot recall the name of. It will be put back together for a compression test but he's pretty sure it will need what he called a top end rebuild. He's had the boat for a month but he was sick for a week and half. Plus, it's snowbird season here and he is slammed like every other shop. I will find out more this week.
I know y'all do your own work but I would still appreciate any input you care to post. Thanks!

 

[Lou C]

Top end overhaul is not tough on those old school engines I’d say it’s within the ability of an experienced do it yourselfer. I would be concerned about the condition of the cyls; how long was salt water in the cyls? I had a similar problem salt water in 2 cyls from blown HGs but not enough to hydro lock it. I did get the water out right away & fogged the cyls & changed oil 3/4 times to get the water out of the oil. Total cost of top end overhaul parts wise was about $800 or so. I also had to upgrade my old one piece exhaust to the later style used by both OMC & Volvo; that added $1200 to the cost. So, $2000 for a top end overhaul & new exhaust. Still running well 4 years later…

 

[PaulinSWFL]

Thanks for the picture Lou. Unfortunately the water was in the engine for at least a week while he was out of commission.
The mechanic is saying at this point he can salvage everything that has salt water damage/corrosion.
2k doing it by yourself is a big chunk so I imagine by the time I am done, add another 35-40 % to that and that's if all the parts can be obtained at reasonable cost. Not much is reasonable in the current environment we find ourselves in.

 

[Lou C]

Remember you have a Ford 5 liter (302 cu in) V8, parts aren’t as common as for GM V8s but they are out there. Those engines were used for decades in FoMoCo cars abs trucks. When I bought the cyl heads for my 4.3 V6 they were $275 each, gasket set was about 120 and new cyl head bolts were about 100. When I removed the heads the bolts were REALLY in there tight I used a 1/2” Dewalt impact gun to get them out. I cleaned up the block really well and used a thread chaser to clean out the threads in the block. The cleaning and prep work was what took the longest. If the cyls are rusted you may have to pull the block and get the cyls bored oversize and install oversized pistons. You can still find reman marine versions of the Ford 5.0. That might wind up being the best plan. If you do that I’d also install a half closed cooling system….

 

[Lou C]

Just to give you an idea what this involves....and this is just a simple cyl head replacement. Like I said the cleaning and prep takes most of the time....

 

[PaulinSWFL]

Remember you have a Ford 5 liter (302 cu in) V8, parts aren’t as common as for GM V8s but they are out there. Those engines were used for decades in FoMoCo cars abs trucks. When I bought the cyl heads for my 4.3 V6 they were $275 each, gasket set was about 120 and new cyl head bolts were about 100. When I removed the heads the bolts were REALLY in there tight I used a 1/2” Dewalt impact gun to get them out. I cleaned up the block really well and used a thread chaser to clean out the threads in the block. The cleaning and prep work was what took the longest. If the cyls are rusted you may have to pull the block and get the cyls bored oversize and install oversized pistons. You can still find reman marine versions of the Ford 5.0. That might wind up being the best plan. If you do that I’d also install a half closed cooling system….

There is no question that the parts are harder to get for the Ford engine. The mechanic that has it thinks everything can be saved and reused at this point. It's in the process of being put back together for a compression test and then we'll go from there.
The cylinders had some rust but they soaked in a chemical I couldn't recall the name of and should be ok. It's still apart because this is almost a side job for the guy because most of his bussiness is mobile. Driveway/dockside/boatlift. I am ok with that because it's crazy crowed here now, more than the usual snowbirds are here. I have never seen it this crowded, even in March! My beneifit of waiting is reduced price to get it back in the water. He likes the boat and enjoys working on the Fords and I have no exuses for not taking care of everything around the house on off days.
As I was seeking out a mechanic familiar with this Volvo Penta setup, many said they wouldn't be interested because of the Ford engine. Like you, they said parts aren't easy to come by and not worth the hassle of chasing them down.
If it comes down to dropping a different engine in it, I agree with the cooling system change. I will keep this updated as it progresses.
Thanks for pictures Lou. Your finished product looks brand new. God has blessed you with some serious skills!

 

[PaulinSWFL]

A update on this boat. It's finally fixed and runs like it's brand new. The end result is it required a top end rebuild. New heads and all that goes with that plus the things that you would assume melted/warped in the overheat. Biggest problem was getting parts that were required but not major expenses. The other problem is it was being fixed by a mobile mechanic during the height of snowbird season in this part of Florida. Crazy crowded and normally very windy. The timing of getting it backs is perfect.
It was a expensive screw up on my part not putting on the engine?raw water flush cap tight enough but I guarantee you it will never happen again. I appreciate everyone's input and Capt Lou was spot on for all of it. Thanks!

 

[Lou C]

Great to hear that it’s fixed and you’re back on the water! Old school American engines are easy to take apart, easy to put back together and parts are reasonably priced. Great for old school DIY guys…