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Lobe separation

Old 02-08-2005, 11:39 PM
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Default Re: Lobe separation

Originally Posted by RichardCranium572
What do the heads flow at .300" lift? Specifically the exhaust? What is the inside diameter of the primary tubes on the headers? What is the max rpm? Carb or EFI?
Intake at .300 244.7 cfm
Exhaust @ .300 202.3 cfm

Primary tubes are 2.25 ID

Carb 1250 dominators Max rpm 6250

Swept down headers to exit under the swim platform on a 32 Fountain.

Wette Vette, Yes I am seeing the pulsing you are dscribing but the boat sits very very low in the water. Although the pipes do not go under water, The swim platform is literally sitting on the water creating a pocket of air underneath. If a wave comes up while idling, the motors will suck up water like vacuum poluting the oil.

Seems when fountain removed the bottom material to create the step, it allows the boat to sit 4 inches lower in the water than a non-step 32, The same amount of the step height.
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Old 02-08-2005, 11:54 PM
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Default Re: Lobe separation

Originally Posted by 2112
They are all just air pumps

Any input on changing the cam specs?
Spread the lobes to 112.Less overlap,reversion, and idle quality will improve.
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Old 02-09-2005, 07:34 AM
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You need to install flappers if your pipes are that low. That applies even with stock power. I ran a 276/284 dur @ .050" solid roller cam in my Baja. The headers had the water injected about 6" from the end of the tailpipe and the tailpipe came through the hull about 4" below the water. Never had an ounce of reversion. If you aren't seeing water residue on your plugs or milky oil after running your motor you aren't getting reversion. Get some flappers!!

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Old 02-09-2005, 08:08 AM
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Default Re: Lobe separation

Originally Posted by dahkem1
Nice welcome. NOT

If you remember seventh grade biology, cranium is skull or head. Richard or dick........Lighten up
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Old 02-09-2005, 08:36 AM
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Can I ask a question not about lobe sep angle on this post what is the operating temp of the engine with this problem ? I just had a problem with a customers engine and found something I had never seen before and might be able to help find the solution. Feel free to give me a call and I might be able to help Sincerely Laz Mesa
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Old 02-09-2005, 01:35 PM
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Most would understand the even if it's not there. You are a newbie as well,,lighten up, it was obviously chosen as a funny name,right?
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Old 02-16-2005, 02:52 PM
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Default Re: Lobe separation

2112, I'm glad to see your heads flow good numbers at .300" lift, alot of head porters get the high lift numbers and don't get the lower lift. Always keep in mind the valve is at .300" twice

As for cam specs for the RPM band you are using, because the exhaust ports are so good, I don't think you need the extra exhaust duration. I would do a single pattern camshaft at ~.750" gross lift and 268 @.050" on a 114 LC. I would also use the 18726543 firing order for better idle quality too. This combination will help reduce pumping losses in your engine. Another plus is you will probably pick up horsepower as well
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