BBC Crossover Temperatures
05-09-2018 | 07:33 PM
#11
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Joined: Jul 2014
Posts: 670
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From: Denton, MD
I am determined to make this work. This system had no issues on my previous boat, not sure why crossovers have such a varied outcome from engine to engine. For now, she is parked next to the house and covered while I regain my motivation to tear it back down. It was great having it on Friday for those two hours after this extended winter that Maryland has experienced. Nothing like hitting the water with good people and enjoying the noise, speed, and beers.
05-09-2018 | 07:37 PM
#12
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Joined: Jul 2014
Posts: 670
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From: Denton, MD
My first Formula with a clone blue engine was set up this way. Ran 110 in the dead of summer. No issues with water or condensation.
05-09-2018 | 07:47 PM
#13
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Joined: Mar 2001
Posts: 2,517
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From: Pompano Beach FL, USA
It is just not possible to properly maintain temp with a crossover setup. You always have cold water at one end and hot water at the other. The only way to gain temp is by having less water flow through the block. There is no way to have even temps.
The circ system is always moving water (and a lot of it) at basically the same temp through the block/heads. As the T stat opens hot water is let out allowing cold water to enter the loop. So the loop is pretty much a constant temp.
By some combination of restrictors & holes you might manage to get something that looks normal on the temp gauge but that does not tell you what is really going on in the block, center and rear of the heads. Try putting a temp sender in the hole next to the exhaust in the middle of the head. To be honest I don't know if that hole is even there any more on the newer stuff. On aluminium heads we used to drill & tap it ourselves. It is common to see 140-160 in the intake manifold and peg the gauge on the middle sender (which is next to an exhaust port) meaning there was a steam pocket there.
The circ system is always moving water (and a lot of it) at basically the same temp through the block/heads. As the T stat opens hot water is let out allowing cold water to enter the loop. So the loop is pretty much a constant temp.
By some combination of restrictors & holes you might manage to get something that looks normal on the temp gauge but that does not tell you what is really going on in the block, center and rear of the heads. Try putting a temp sender in the hole next to the exhaust in the middle of the head. To be honest I don't know if that hole is even there any more on the newer stuff. On aluminium heads we used to drill & tap it ourselves. It is common to see 140-160 in the intake manifold and peg the gauge on the middle sender (which is next to an exhaust port) meaning there was a steam pocket there.
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Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
05-09-2018 | 08:09 PM
#14
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Joined: Oct 2005
Posts: 11,691
Likes: 217
From: Olmsted Falls,Ohio Marblehead,Oh
It is just not possible to properly maintain temp with a crossover setup. You always have cold water at one end and hot water at the other. The only way to gain temp is by having less water flow through the block. There is no way to have even temps.
The circ system is always moving water (and a lot of it) at basically the same temp through the block/heads. As the T stat opens hot water is let out allowing cold water to enter the loop. So the loop is pretty much a constant temp.
By some combination of restrictors & holes you might manage to get something that looks normal on the temp gauge but that does not tell you what is really going on in the block, center and rear of the heads. Try putting a temp sender in the hole next to the exhaust in the middle of the head. To be honest I don't know if that hole is even there any more on the newer stuff. On aluminium heads we used to drill & tap it ourselves. It is common to see 140-160 in the intake manifold and peg the gauge on the middle sender (which is next to an exhaust port) meaning there was a steam pocket there.
The circ system is always moving water (and a lot of it) at basically the same temp through the block/heads. As the T stat opens hot water is let out allowing cold water to enter the loop. So the loop is pretty much a constant temp.
By some combination of restrictors & holes you might manage to get something that looks normal on the temp gauge but that does not tell you what is really going on in the block, center and rear of the heads. Try putting a temp sender in the hole next to the exhaust in the middle of the head. To be honest I don't know if that hole is even there any more on the newer stuff. On aluminium heads we used to drill & tap it ourselves. It is common to see 140-160 in the intake manifold and peg the gauge on the middle sender (which is next to an exhaust port) meaning there was a steam pocket there.
05-17-2018 | 11:23 PM
#15
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Joined: Mar 2008
Posts: 892
Likes: 83
From: Maine
I agree with that, just seems to be fine for my setups over the years as long as clearancing is good, The Hawk Gun I am leaving as it has been for 31 years, the Mistress I played with all kinds of options and ended up same, no bypass, no stat, 110 ish temps, oil temps always been more important to me to get right.
