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Originally Posted by jeff1000man
(Post 3033863)
STEAM POCKETS are usually the wrong head gasket, not intake gasket. No other symptoms in the engine? Really strange.
There are thousands of engines out there that don't channel the water from the back of the engine. Maybe check your exhaust for a hairline crack? Crank the air pressue up pretty high as the problem might only show up once the engine reaches temp. Same thing with a possible hairline crack in the head?? Just thinking out loud? Try dumping the water first, but if that doesn't help, you might want to start looking somewhere else. |
Originally Posted by JohnSchiavarelli
(Post 3033328)
BUT.. kept going off.. temp sender would read @130 or so.. switched them.. temp says 170 (cycles due to crossover) and buzzer is never heard from.. Why the difference in water temp from side to side??
thanks John I did some testing on the hose with an infrared pyrometer. Cylinder heads around #1 #2 and #7 were running around 190*F and cylinder #8 was around 300*F. :eek: I took the heads off to look for obstructions in the block and I found none, I drilled more water ports on the head surface of the head and still no help. I then drilled out the back of my manifold and added dumps. This seems to have fixed it. I have 4 Merlin heads and same head gaskets on my twin engines. These heads were on other engines with no problems and I had GM 088's prior with no problems. I can't explain why I had this problem but the drilled out rear intake manifold solved it. |
Originally Posted by Rookie
(Post 3033962)
All summer I was fighting a problem with #8 cylinder sticking exhaust valves. I took out I think 3valves this summer, hit the piston on all occasions and bent the valves pretty bad. Luckily they did not take out the piston, Good Ferrea inconel valves.
I did some testing on the hose with an infrared pyrometer. Cylinder heads around #1 #2 and #7 were running around 190*F and cylinder #8 was around 300*F. :eek: I took the heads off to look for obstructions in the block and I found none, I drilled more water ports on the head surface of the head and still no help. I then drilled out the back of my manifold and added dumps. This seems to have fixed it. I have 4 Merlin heads and same head gaskets on my twin engines. These heads were on other engines with no problems and I had GM 088's prior with no problems. I can't explain why I had this problem but the drilled out rear intake manifold solved it. |
Originally Posted by Panther
(Post 3033539)
yup, 1/2" male npt to the intake, other two ends are female. Install the sensor in one and connect the hose to the other.
On mine I have 1/2" male NPT, to two female 1/2" npts. Then a 1/2" npt sensor in one hole and a male 1/2" npt to -6 fitting in the other. Stainless looks better but you can also get it in brass, whatever your fancy is! :coolcowboy: Any ideas where I can find stainless? |
Originally Posted by JohnSchiavarelli
(Post 3034213)
Panther
Any ideas where I can find stainless? http://www.mcmaster.com/#stainless-s...ttings/=5l2u9y http://www.mcmaster.com/#stainless-s...ttings/=5l2uw1 |
Originally Posted by Panther
(Post 3033452)
Put a "t" in when you're rigging the manifold and you should be fine. I can't post a pic of mine cause I dump overboard but for my overboard dump, I ran "2" #6's lines into a tri-y fitting and a single #6 overboard.
I wouldn't go as large as #8's, I'd use #4 or #6 hose. You're relieving air pockets, not changing flow pattern. My .02 in what I learned with mine... Can I just run a 90degree fitting on one side to a "T" and a 90 degree fitting from the other side to the "T" then from the "T" out the back? I am assuming we never touch the front 2 holes in the intake.. Just the rear 2? What fitting did you use from Eddie??? |
Originally Posted by JohnSchiavarelli
(Post 3033933)
Nice.. that is what I am looking to do.. but instead of 90 degree right angles I need to run a “T” and put my sensor and pressure senders in.
I have heard that a steam pocket can be “developed??” due to no circ pump and a crossover. Not sure how true that is.. |
Originally Posted by ROTAX454
(Post 3034684)
One of the most popular and trusted marine performance motor uses a recirculating pump-----Merc HP525. I will be using a recir pump and thermostat setup. I just like the fact that the motor is in control of the water and the consistency of temps within the motor itself.
but my setup is done and I don't want to add belts, therm. housing redo all the plumbing ect.. many people here make a crossover work and they work well when setup properly.. Spoke to Hardin marine today in great length.. They think (and perhaps rightfully so) that my crossover is at fault. the bypass is a small 8an line.. only 7/16 thick. so.. when the thermostat opens a ton of water rushes through the block.. cooling down quickly.. then, the thermostat closes.. temps rise.. and the process starts again.. they said I need a cross over with a bigger bypass and that will help a ton.. also going to try their thermostat spacer.. run the rear lines from the manifold to the spacer.. and if that don't work circ pump here we come.. |
Originally Posted by JohnSchiavarelli
(Post 3034711)
Yup.. I have heard it from my builder many times.. Big Merc fan.. works on them all.. from 496 up to the new 1075..
but my setup is done and I don't want to add belts, therm. housing redo all the plumbing ect.. many people here make a crossover work and they work well when setup properly.. Spoke to Hardin marine today in great length.. They think (and perhaps rightfully so) that my crossover is at fault. the bypass is a small 8an line.. only 7/16 thick. so.. when the thermostat opens a ton of water rushes through the block.. cooling down quickly.. then, the thermostat closes.. temps rise.. and the process starts again.. they said I need a cross over with a bigger bypass and that will help a ton.. also going to try their thermostat spacer.. run the rear lines from the manifold to the spacer.. and if that don't work circ pump here we come.. This keeps the drastic ups and downs from occuring, and the engine stays at a more consistant temp. |
Originally Posted by jeff1000man
(Post 3034781)
After you mentioned that. There is the old trick where you take off the bypass, and drill a couple small holes in the thermostat base. This lets a little water bypass through to keep the exhaust from overheating and still allows the thermostat to work properly.
This keeps the drastic ups and downs from occuring, and the engine stays at a more consistant temp. |
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