SoCal Jet Boats
Tech Talk => I/O's => Topic started by: holorinhal on August 26, 2012, 09:33:23 PM
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I have a 81 Spectra 20 With a 260 Mercruiser. I am going to convert the exhaust, from the log style to center rise and thru hull exhaust. I will be getting rid of the Y pipe and installing a block off plate.
Do I have to buy a different Tstat housing, or can I use my existing housing?
Is there any thing else that won't work with the conversion, like accessory brackets and such? thanks........Hal
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I have a 81 Spectra 20 With a 260 Mercruiser. I am going to convert the exhaust, from the log style to center rise and thru hull exhaust. I will be getting rid of the Y pipe and installing a block off plate.
Do I have to buy a different Tstat housing, or can I use my existing housing?
Is there any thing else that won't work with the conversion, like accessory brackets and such? thanks........Hal
Sounds like you are going to go through hull...This is a great mod. You should be OK on this swap because everything on your current set up (providing it is stock) bolts to the intake manifold and transom bracket. If you have Thunderbolt ignition you may need to make a bracket for the module.
If you are pulling the engine anyways, make sure to align the engine with a pilot tool (a lot like a large clutch pilot tool).
When I do the though transom set ups I always like to use pipe from the outlets of the manifolds to the through hulls, not only does it sound better, it will allow you to use regular exhaust hose instead of the wire reinforced stuff. Copper is what I use, works great and lasts forever, if you powder coat it they will be really awesome looking for a long time.
Good luck, should work out great.
GT
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Well i scored a set of EMI Thunders for the 260. Got a really good deal on them and they were barely used.
While the engine was out I gave it a litle facelift also.
I baught a new T-stat housing that will work better with this exhaust. The only problem is that the raw water inlet hose conection is on the right side where the originalcame down the left side and straight up under the Tstat housing. Now I have to find a hose that will come from the water inlet at the transom plate and conect to the right side.
I did have to change the alternator mounting, but i am not sure if it is going to work out. i may have to buy the expensive mercruiser combo power steering/ alternator bracket. We will see when I drop the engine back in this week.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.performanceboats.com%2Fattachment.php%3Fattachmentid%3D188182%26amp%3Bd%3D1357015777%26amp%3Bthumb%3D1&hash=4986ab456cbdfb80f01eec20f3f8d4ded2136e32)
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I got the engine back in the boat and I have isues and questions. Where it sits the risers come in.in a position that will not work. The riser and powersteering unit are interfearing with each other.
What I need to do is have the tips come thru below the power steering unit and in order to do that i will have to use an S pipe and hose, and inorder to do that the risers need to be shorter. My question, is there any reason that I could not cut the risers shorter? I really hate to cut them, but its what I have and I dont want to spend the money to just buy shorter ones.
Also I had to switch T-stat housings and the original water inlet hose came in on the starboard side, but the new housing has the inlet on the port side. I need to rout the hose from the tramsomplate on the starboard to the port side. Can I route the hose and cross under the oilpan to the port and use the molded hose for the port side conection?
Here are a couple pics of the issues.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.performanceboats.com%2Fattachment.php%3Fattachmentid%3D226706%26amp%3Bd%3D1361766800%26amp%3Bthumb%3D1&hash=7d3bdd645789afeaba3dfb8432705329e5c195d7)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.performanceboats.com%2Fattachment.php%3Fattachmentid%3D226714%26amp%3Bd%3D1361766846%26amp%3Bthumb%3D1&hash=0155e068f221b2507949a4cd84c1e969b21e3a35)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.performanceboats.com%2Fattachment.php%3Fattachmentid%3D226722%26amp%3Bd%3D1361766882%26amp%3Bthumb%3D1&hash=7682e114bf88778b976304c938d341d19a8eb140)
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i cut my risers to get them to fit. dont cut them too short, or you could get a reversion problem. also when you cut them, there is a part where the inner tube is welded to the outside tube with spots cut out to restrict water flow. if you cut that off, you MUST recreate that cavity restirction or else all of your water will go to the bottom and straight out and the tops will be hotter than hell.
make sense? keep posting progress. also if you happen to find a source on some decent 4" mandrel bends that dont cost a fortune.
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Time to go hydro external steering.... Got another $5000 you don't need? :sly:
In all seriousness, you can cut them down. try to leave as much length as you can and check into elbows meant for what you are trying to do.
Good luck. Looks bitchen
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Yea no doubt, If I had another 5 grand there is alot i could do.
Here is what I need. If i had this riser, It would solve all My problems, Of coure Its $1400 for a pair, unless I could find a trade or a used set.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fbseperformance.com%2FproductImages%2F13-EMI-451.jpg&hash=a9b8a0ef20e0eef354cd2379b150ad275474c56a)
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try posting a WTB ad on rd, powerboats, and offshoreonly... offshore seems to have a LOT of center rise stuff floating around.
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So I am trying to decide where to exit the exhaust, above or below the swim step?
I am ready to cut the holes and just cant decide above or below?
How are you guys running your setups?
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Looks awesome I want to do the same thing so I don't have to pull the exhaust just to change the oil.
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