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lol, right.....
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Discussion Starter #1 (Edited)
Can anybody tell by this pic if the water is plumbed correctly? I did a search & didn't find anything to nail it down & I don't know jack about log exhaust.

Thanks in advance....



This was the description of the plumbing.....

valve on the pump and have it plummed from the pump to the exhaust manifolds, to the front of the block and out of the top of the intake back to the exhaust risers
 

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It looks correct to me. Mine is the same way.
 

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lol, right.....
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Discussion Starter #3 (Edited)
Thanks! Also wanted to add, this is on a Pontiac 400, but the plumbing should be routed the same regardless of brand of engine, correct?
 

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Yes it would be the same.

Nice to see some more poncho power on the boards. Where did you pick up the front support/cover? Any specs on the 400" ? Is that a performer RPM Manifold? Before taking out the cracked olds and thowing in a chevy into my boat I had thought about doing the same. Looks good.
 

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lol, right.....
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Discussion Starter #6
Yep, looks correct.
Cool, appreciate it!

Nice to see some more poncho power on the boards. Where did you pick up the front support/cover? Any specs on the 400" ? Is that a performer RPM Manifold? Before taking out the cracked olds and thowing in a chevy into my boat I had thought about doing the same. Looks good.
Its not mine, had a new guy sign up on THB the other day & he was asking some questions about the plumbing. He put the pic up today to help clarify what he was telling us & nobody has been around to tell him one way or the other so I figured I would throw it up over here & see what I could dig up for him...

I'll pass along you were asking about the Pontiac, he may sign up over here too. Yeah, cool powerplant, different. :) Its in a Sleekcraft....

Thanks again for the info.....
 

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AKA OhOneWS6
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Hey Devilman, Thanks for posting that up over here.

That is my boat. It is a 74 Sleek Craft rebel with a 400 Pontiac. I picked this boat up about 3 years ago. It was a project started by a member of a GM LSX board I posted on. He was tragically killed in a car accident before the project was finished. When I got it the motor was freshly rebuilt and still on an engine stand in the garage. The hull was on the other side of DFW at his GF parents house.

Initially I was going to look for a TA to put the motor in and scrap the hull. When I got the boat home my wife saw it and said "Man that thing is cool" That is all I needed to hear to convince me to finish it. I got the boat just for getting it out of their driveway but let me say right now, There is no such thing as a free boat. LOL.

At this point it is almost complete. It needs a lot to make it pretty but my main goal is just to get it to the lake.

I am concerned about the engine temp. I have run it in the driveway with a water hose hooked up and the pump disconnected. I am having a hard time getting the engine temp up. I have a gate valve installed right out of the pump. I can adjust the gate valve to the point it is almost closed and the temp will com e up to about 130 but there is almost no water coming out the exhaust at that point.

Any suggestions?

TIA,
Matt
 

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AKA OhOneWS6
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2,637 Posts
Nice to see some more poncho power on the boards. Where did you pick up the front support/cover? Any specs on the 400" ? Is that a performer RPM Manifold? Before taking out the cracked olds and thowing in a chevy into my boat I had thought about doing the same. Looks good.
Yes that is a performer RPM. The front support was with the boat when I got it. It is a Glenwood piece. It has been kind of a bitch to get this thing together. The hardest part is the oil lines. Pontiac has an adapter that bolts to the side of the block for the filter. This adapter sticks out too far for the water logs to bolt on. Long story short I had to machine a piece to adapt the oil lines. It was the only thing missing to put the Poncho in the boat. You think Olds parts are hard to find. LOL.

Here is the engine specs.
-Pontiac 400 .030 over, Stock steel crank, Pontiac Super Duty Forged Rods, JE NHRA Forged Pistons
-6X Heads
-800cfm Holly double pumper w/1"spacer
-Crower Cam-297HDP
240/242 @ .050
297/308 advertised
.500/.500 lift
112 l/s
-Comp Roller Rockers
-Comp chromoly pushrods
-Comp Flat tappet lifters
-Comp Double Roller Timing Set
-ARP main studs
-ARP rocker studs
-SFI 12,000 rpm chrome balancer
-Edelbrock Performer RPM intake
-Glyptal paint lifter valley
-Chrome Oil pan w/baffle
-Chrome Valve Covers
-High Torque Mini Starter
 

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I am concerned about the engine temp. I have run it in the driveway with a water hose hooked up and the pump disconnected. I am having a hard time getting the engine temp up. I have a gate valve installed right out of the pump. I can adjust the gate valve to the point it is almost closed and the temp will com e up to about 130 but there is almost no water coming out the exhaust at that point.

Any suggestions?

TIA,
Matt
don't worry about the temp, and keep the valve off the pump a turn open; in the driveway, use the valve feeding the hose to control water flow. it's a single pass cooling system, and the water outlet temp is not indicitive of actual engine temp, like on a car with a closed cooling system. once you're on the water, adjust the valve a little if you like, but don't run it with the valve closed. the engine water outlet is plumbed to the snails and out the exhaust, and there are rubber exhaust hoses which can melt away on you if they get too hot - they need the water to stay in one piece.
also, if you're running it in the driveway, keep the bow of the boat higher than the back like it sits in the water, to prevent any of that water from running backwards up into the heads. if the boat's not level side to side, use a jack to level it.
 

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AKA OhOneWS6
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don't worry about the temp, and keep the valve off the pump a turn open; in the driveway, use the valve feeding the hose to control water flow. it's a single pass cooling system, and the water outlet temp is not indicitive of actual engine temp, like on a car with a closed cooling system. once you're on the water, adjust the valve a little if you like, but don't run it with the valve closed. the engine water outlet is plumbed to the snails and out the exhaust, and there are rubber exhaust hoses which can melt away on you if they get too hot - they need the water to stay in one piece.
also, if you're running it in the driveway, keep the bow of the boat higher than the back like it sits in the water, to prevent any of that water from running backwards up into the heads. if the boat's not level side to side, use a jack to level it.
I'm talking about the engine temp not the temp out of the pump. The sending unit for the guage is in the head. This is close to the top of the water level in the block. By the time water hits the sending unit it has gone through the water logs and the block.

Makes sense what you say about the angle of the boat in the driveway. I will keep that in mind when I run it.
 

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understand exactly what you're talking about; both of my engine's outlet temp sensors are in the intake manifold. don't worry about the outlet temp being in the 120-140 range, that's fine.
the "preheat" from those logs may not be as significant as you might think, with both water entry/exit at the front of the log. i.e, does it really have a divided water passage, forcing water from the lower front all the way back, then out the top of the front of the log? i know my chevy logs don't, but they do have ports at the rear so i can assure flow through the whole log. after you've run it on the water for awhile, feel the front and the rear and see if there is any delta??

regardless, it's a single pass cooling system, taking 50-60 degree water out of a hose (or lake), making one pass through the engine, then out (to the lake or driveway). cutting water flow back to trickle, just to heat water, isn't a good thing, especially with those rubber hoses. crusing on a lake, your oil temp will generally be 75-100 degrees higher than whatever you'll see for water temp.
 

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AKA OhOneWS6
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understand exactly what you're talking about; both of my engine's outlet temp sensors are in the intake manifold. don't worry about the outlet temp being in the 120-140 range, that's fine.
the "preheat" from those logs may not be as significant as you might think, with both water entry/exit at the front of the log. i.e, does it really have a divided water passage, forcing water from the lower front all the way back, then out the top of the front of the log? i know my chevy logs don't, but they do have ports at the rear so i can assure flow through the whole log. after you've run it on the water for awhile, feel the front and the rear and see if there is any delta??

regardless, it's a single pass cooling system, taking 50-60 degree water out of a hose (or lake), making one pass through the engine, then out (to the lake or driveway). cutting water flow back to trickle, just to heat water, isn't a good thing, especially with those rubber hoses. crusing on a lake, your oil temp will generally be 75-100 degrees higher than whatever you'll see for water temp.
Cool. It's just a hard habit to break for a car guy.
 

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E-7 Sheepdog (ret)
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Yep, it's plumbed right, and good advice from bp on all counts.

My outlet temp was 170 or so idling, 140 running cruise for most of my boat's 31 years.

The TT headers (Lightnings) changed the plumbibng a bit, and did away with pre-heat, so I now run about 155/125 with no problems at all.

Worry about adjusting it under actual running conditions, not in the driveway.
 

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My boat didnt come with a gate valve at all. I added one but keep it wide open. It's only there in case I bust a hose and need to shut down the water...
 

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need help with plummbing my logs

Just picked up a new project and need help plumbing the exhaust. It has a spot for four hoses on the plate and the manifold. Do i loop intake to the plat for the second set... I have some threaded hoses that seem to fit perfect for that. But my last jet only had 2 and 2 like this last pic
 

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Just picked up a new project and need help plumbing the exhaust. It has a spot for four hoses on the plate and the manifold. Do i loop intake to the plat for the second set... I have some threaded hoses that seem to fit perfect for that. But my last jet only had 2 and 2 like this last pic
like this?

http://www.rexmar.com/images/page160.jpg

info for you:
Thermostat Kits

depending on where you use your boat, you dont really need and can go back to the standard housing that you have had before.
 
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