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#1
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Big Block Intake Gaskets
Ok, lets try this again. I tried posting this yesterday, & something went wrong. So... Are the paper intake gaskets that work in conjunction with the "bathtub" valley pan worth using? I'm using an aluminum intake on stock heads.
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#2
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I used just the batyh tub gasket with RTV. No problems.
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#3
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Use the Felpro valley pan #1215 (because it already has the crossover passages blocked) without the paper gaskets. I spread some coppercoat around the intake passages (both sides of the valley pan) and use rtv to seal the ends. Have never had a problem this way. I tried using the paper gaskets once or twice and found that it was too much - I had problems getting the bolts started!!
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#4
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the paper gaskets are good if your mill tend to leak / seep oil at the intake ports.
if all your surfaces are flat and parallel, you shouldn't need anything more than the bathtub and some good sealer. the factory iron intakes were so heavy and rigid, they sealed fine with just the bathtub. if you get seepage problems (sounds like a bizarre medical condition), there are a few options you can try to help fix the issue. good luck |
#5
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Thats whats happening. I've been noticing some oil in the pan, very little but its there. Usually after running the engine hard. Intake is new, and engine is fresh. Oil doesnt appear to be coming from the end seals.
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#6
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You can REuse the valley pan IF you use the paper gaskets.
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#7
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Well it just so happens that I have a couple of new valley pans in the garage, so I'll try some different sealer when I change it.
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#8
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I had machining done on my heads and intake, so to prevent leakage of oil into the intake runners (which is a problem I initially had), I had to go with a gasket above and below the valley pan in order to get things to seal. So, no problem using a gasket in addition to the valley pan. Just also use RTV as a backup for sealing purposes.
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#9
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It's pretty rare but it can happen, I had a hairline crack appear in the reinforcing stamped bead pretty much directly in the middle of the pan gasket, I guess from vibration over time, kept getting a faceful of oil in my old altered, couldn't figure out where it was coming from until I pulled the manifold and was wiping the pan out and pushed down a little hard and the crack opened up. Worth a look.
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#10
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i got tired of oil seepage at one point (likely a hairline crack like 23T mentions).
i also have some minor intake / head parallel issues making things worse. so broke out the tin snips, trimmed away all the beaded port material, and ran a nice quality intake gasket (don't remember brand) just like you would on a small block. no more seepage, and clean intake ports, t |
#11
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That's the way I've been doing it for years, that way the bathtub only serves as a valley cover and the paper gaskets do the intake/head sealing.
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#12
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I hadn't thought of doing it that way before. Sure would make intake swaps cheaper.
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#13
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Cheaper than using RTV? I have had the valley plate crack a couple of times too, it's thin and resonates, which causes cracks. The factory tried to prevent this by putting an "insulator" between the pan and intake under the plenum.
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#14
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Trimming the valley pan and just using paper gaskets is an excellent idea. I see that on Hughes Engines website, he sells paper gaskets for big blocks that have a silicone sealing bead around each port. Those might work nice.
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#15
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If oil is seeping out onto the valley pan, doesn't this mean its seeping into the intake port? My 440 is smoking (new rebuild) and the valley pan is seeping. I'm thinking they are related. There in one plug on each side near the "seep" that is oil fouled.
Thanks, Wayne. |
#16
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Not necessarily, but if you have less than a good seal on the bottom side of the port underneath the pan gasket, vacuum on the intake stroke will draw oil in, even if its a very small gap.
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#17
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I had a thought, but nevermind I didnt pay close enough attention to the question.... but
anyway Theres been a few mentioning rtv...My general rule has been never ever use sealant on intake gaskets because it does the opposite of sealing and "wicks" or draws the fuel into the sealing area which then acts as a solvent and destroys the sealant which results in leaks. I could be wrong, but its just what I was taught. |
#18
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I pulled the intake and confirmed that the valley pan is leaking. Oil had wicked up and around all the manifold/valley/head/block joints.
The order of installation of the intake manifold assembly was head, sealant, paper gasket, valley pan, manifold. The oil was sucked into the intake runners between the paper gasket and valley pan. Once there it wicked everywhere. It there had been sealant between the paper gasket and valley pan it probably would have been OK. ChargerDan - did you use only one gasket? no sealant? As a separate question. I'm using a RPM Performer. Any downside to using the crossover or is it better to leave it blocked? Thanks, Wayne. |
#19
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if memory serves, i used a little sealant where the trimmed
bathtub laid against the head. other than that, just used a good gasket. those silicone bead gaskets on hughes' website should work excellent. |
#20
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I finally solved the problem. I could not get the standard valley cover to seal so I bought Hughes #3271MA 2-piece valley cover. It can be installed with the heads on. It came with the silicon gaskets so everything sealed up nice.
The only issue was the heat crossover on my intake (Performer RPM) hit it. Since I wasn't using the crossover I cut off the bottom of the crossover and its all sealed up. That valley cover is a nice piece and resonably priced. |
#21
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Don't forget, that in addtion to "weak" sealing surfaces, you might have a crankcase pressure/ ventilation problem
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#22
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Weiand makes a full skirt intake for a B/RB (cant remember which one) but it loesnt require a bathtub gasket, only the "fel-pro" style gasket. Dont know if it is worth a flip, but it does exist. I too cut the gasket area out of a bathtub and ran Fel-pro's. Havent run it yet, but I hope there is no weeping.
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#23
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I never needed the paper gaskets. Just a thin bead of silicone around the ports with the valley pan and your'e good to go. Also, put a fairly good size bead on the block facing areas and let it set up a while before you put the sealer around the ports then just bolt in on a go!
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#24
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I've only put rtv on the corners where the heads meet the block & installed the valley pan. Worked every time before, but was wondering if the paper facing gaskets worked any better with the aluminum intake w/ iron heads. Probably not a big deal.
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#25
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alum heads
i am doing a 69 440-6bbl MP alum heads with stock alum intake street highway engine and was wondering about the paper gaskets.never had problem with alum intake and 906 heads . don't know about alum to alum.
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#26
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Shouldn't have any problems with the regular valley pan.
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