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#1
12-01-2005, 03:27 PM
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400 intake w/exhaust crossover mods?
I have a stock 68 400 intake with the exhaust crossovers. My problem was that the heads and block in the area of the crossover got so hot that it turned the oil into a 2" thick crust that obviously was/would interfere with normal operation of the lifters.
Is there a way, short of cutting the crossover off which I've seen done in at least one book, to block the crossover off on each side so I can keep the intake stock without having the oil/crust problem?
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Barry |
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#2
12-01-2005, 05:06 PM
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check the heat riser valve in the exhaust manifold it may be stuck closed causing the problem
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Its ok to giggle and snicker, Dont laugh and point |
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#3
12-01-2005, 06:17 PM
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It was.
What I want to do is prevent this from being a possibility again. Would just using a different exhaust manifold, like an RA III, work better? Or does someone make intake gaskets that could cover those exhaust ports?
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Barry |
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#4
12-01-2005, 07:23 PM
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mr gasket has a set of intake gaskets with the small plates to cover the crossovers, i think there 502 or something like late, also fel pro also them too
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#5
12-01-2005, 09:15 PM
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Thanks for the info, I'll check those out.
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Barry |
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#6
12-02-2005, 04:29 AM
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The problem was caused by the stuck heat riser, as mentioned. If you don't have a stuck heat riser, your engine is in good tune and you change your oil regularly this will not be an issue regardless of what intake you use or whether the exhaust crossovers are blocked or not.
That said, blocking the exhaust crossover does keep the intake manifold cooler which helps build power and combats detonation. The engine won't warm up as fast on cold mornings, but that's a small price to pay, especially if it's a summer only toy.
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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#7
12-02-2005, 10:55 AM
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I live in SoCal. Warming up is rarely, if ever, an issue.
The heat riser valve on the manifold was so stuck it took a soaking overnight, and a couple of taps with a hammer to loosen the rust. I don't plan on letting the car get into the state of disrepair that the previous owner did. I thought that the exhaust crossover had to be a bad idea for keeping the intake air cool. I think I'll change the exhaust manifolds and use the blocking plates. Thanks for the help.
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Barry |
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