Dirthead

Hot boat,
You said to test the water pressure before the thermostat. If I am thinking correctly (and I very well may be wrong) but I tested the pressure on a plug on the side of the block and on the intake manifold. When I tested on the side of the block would that not be considered before the thermostat? Thanks for the help.

Hot Boat

I do not run a crossover with a bypass. That is why I cant run a thermostat . As long as the by pass is not restricted you should be fine

Testing the pressure on the side of the block is fine. I would not look for pressure above 28 PSI @ WTO

Do you run a oil thermostat ????????

If so oil would only go through the oil cooler when it gets above 230 degrees. If the cooler had a leak in it, then it would only leak when the oil temp is hot.

Did you pressure test your oil cooler????? even if you did, It still might leak. Working on water systems for aliving . I have seen things leak only when they are hot or only when they are cold, Under positive pressure or only under negitive pressure. Heat and pressure play a big role on metal and how it expands.

It sounds to me like you have changed the gaskets and pulled the motor apart enough to find the problem. As long as you dont have reversion and the water pressure is fine I would then check or change the oil cooler . if that dont do it I would pull it all apart and have everything magnifluxed (sp?) also check all the mating surfaces to de sure they are true and flat.

I had a engine builder use the Wong head bolts . When they tightened them up the shank of the bolt went into the deck of the block. It cracked the block on about 6 head bolt holes. you could see the damage when the heads were off and the block deck was clean. There was small cracks around the holes. I only ran the motor for 2 hours and the oil was a milk shake. and the block was junk.

Your situation really sucks. I dont know what else to say. Good luck.

Paul

Dirthead

Here is the update! I went out Saturday and Sunday and did not have any milkshake. Here is what I found. I did not run the exhaust with it going out the rear, having the exhaust only go out through the prop. For some weird reason, the reversion does not happen when the exhaust is going through the prop. Can anyone explain this??? The guys at Lighting, CP, and Comp cams can't.

I installed a water pressure gage on the top side of my intake manifold and it reads 3 PSI at idle and 20 PSI most of the time at WOT with one reading at 23 PSI. I am running a crossover with a bypass and a thermostat with a hole in it and I have half of my water from the thermostat housing going to both exhaust headers and the other half dumping out the side. Would I still need to put a pressure relief valve in? Isn't the side dump from the thermostat housing acting in the same manner? My water temp was 140 all day and oil temp around 180. If I do install the pressure relief valve, should I install it in the 1 1/4 line between the oil cooler and the crossover?

rich allen

Just some info for you to add to your troubleshooting. I have same motor as you and same crossover setup, with third port acting as a dump, to relieve pressure when t-stat is closed and keep water flowing in pipes. I have a guage permanently attached to intake,( done so I can quickly look at guage to make sure ears havent fallen off while working on running motor.) Anyways, I get same psi readings as you. My t-stat is not drilled, my cam is similar to yours, I have emi headers, with silent choice still attached, and I get NO water reversion problems. I know many are saying crossover is the problem, but just letting you know in my case, it works fine.

Hot Boat

What about eliminating the Y pipe and run just the through hull exhaust only. This way you could use a longer exhaust riser. Problem solved.

Also , 180 degree oil temp is not hot enough to burn out any moisture in the oil. you need it to be at least 220 degrees. I would keep your eyes open for an oil thermostat.

Glad to hear you found the problem.

Dirthead

Hot Boat,

That is what I have done. I ordered a different header system, this time eliminating the y pipe and switchable exhaust. Therefor the new header will be longer, plus I am having the water exit out the exhaust through a hose then I can control how much water gets injected back into the exhaust via gate valve.

The problem I am having on the oil thermostat is that every one I find is set up for #12 hose fittings. I still have the stock oil lines and the size of these lines and the type of connections that they use are both quite different from these aftermarket oil thermostats. I realize that I can get adapters to make them fit, however it has turned out to be more of a problem than I expected. I guess now that I have the reversion problem fixed, getting my oil to 212 degrees is not as big of an issue. Is this not correct? Does anyone know is Mercury or anyone else makes a oil thermostat that will work with my stock oil hose setup? Thanks.

Hot Boat

I am running HP500 oil thermostat. The oil filter adapts right to it. I used all aeroquip (sp?) fittings and hoses to the cooler and the block but I am running a aftermarket cooler. There are other companies that make oil thermostats.

articfriends

iTrader: (1)

Been following your thread,hope the exhaust fixes your problem. I have run a 228/236 at .050 cam w/lightning headers w/silent choice in same hull w/out reversion but i also run a procharger and some say the air being forced to throttle blades helps deter reversion so i'm not sure you can compare the 2. I have also been plagued w/similar setbacks (boating season is burning up quickly and boat still isn't running),my exhaust does revert now w/my new cam and i am waiting on tailpipes for my new exhaust(i ordered the hi tq 3 stainless marine after hearing about chec454's problems w/cmi wet tails). Good luck,Smitty

Leathl_WS6

I'm feeling your pain I have the same problem. On a twin setup but only one motor is getting reversion. Both motors are identical and fresh. I'm running a gil dry riser that dumps at the end of the pipe. I truely don't understand it. I thought I had it beat until I put the flappers back on and now I have a milkshake again.

blue thunder

When the engines were freshen up leathl were the cam degreed in? I had 2 engine set up similarly last yr yet one got milkshake and one did not. Over the winter I recammed both engines but before doing that I degreed the old cams in to see where they were. The one reverting was retarded causing the exhaust valve to be open longer on the downward stroke of the piston on the intake cycle. Just a thought for you.

BT