HELP!!! Cracked Air Intake - The 1947 - Present Chevrolet & GMC Truck Message Board Network

2B32 · 02-25-2017, 09:32 PM

-Ok, so to preface, I am not a mechanic but I'm trying to learn. As a result I am making a lot of mistakes.

Today I was switching out my carb for a Sniper EFI unit. While doing so I tried to seat the vacuum port on the intake (the line that runs from the brake booster to the port behind the carb) a little lower to gain some clearance. In doing so I cracked my intake (stupid, I know).

Realizing my intake was now garbage I pulled it, and found oil on all the intake bolts, and oil puddled under the intake. This is a project that I'm learning was jimmy-rigged a lot by the previous owners. I found liquid sealant all over the thermostat, and it looked like some sort of silicone sealant was used for the intake.

I've read a bad intake seal will allow oil to leak. Is the oil on the intake bolts, and puddled oil under the intake from the crappy gasket that was used, or am I looking at a bigger problem here?

davepl · 02-25-2017, 09:40 PM

Just to be totally pedantic and accurate, the valley is always full of oil, so the underside of the intake will always be covered in oil. I'm not sure if you thought that was a problem or not, but that part's OK.

Generally the bolts should be dry, but that doesn't necessarily mean oil was getting anywhere bad (like into the intake ports). But if it's been ingesting oil, you might foul plugs and use oil and so on.

Other than you having a cracked intake and needing new gaskets, I don't see any problem at all, unless I'm missing something...

2B32 · 02-25-2017, 10:01 PM

Quote:

Originally Posted by davepl

Other than you having a cracked intake and needing new gaskets, I don't see any problem at all, unless I'm missing something...

Like I said, I'm no mechanic, so I wasn't sure. Thanks for the clarification!

**HO455** · 02-25-2017, 11:35 PM

Let's see a photo of the crack maybe it can be fixed.

custom10nut · 02-26-2017, 10:36 AM

Are you asking about the little bit of oil that appears on the intake manifold?
If so, that's a normal issue, if you don't put thread seal on those four bolts.
The oil swaps p the threads and it pools there.
More of an annoyance than a real problem.

**Jcfcamaro** · 02-26-2017, 11:03 AM

You could have just put some really good silicone over the crack . You would be surprised how long it would have lasted.

2B32 · 02-26-2017, 11:30 AM

Quote:

Originally Posted by HO455

Let's see a photo of the crack maybe it can be fixed.

There are actually two cracks. One is very fine, the other is more pronounced.
Posted via Mobile Device

**HO455** · 02-26-2017, 11:59 AM

It's hard to tell from the photo, is the intake aluminum? If so then it can be TIG welded and the threads cleaned up with a tap. If it is cast iron it can be brazed or welded but it is getting harder to find people these days who can do cast iron. It may be easier to find a cheap factory manifold. If your still looking for the fitting to sit just tap the hole deeper. Pipe threads are tapered so they fit tighter the more you tighten them. That's why the hole spilt on you. If you need to have a fitting sit deeper you have to run a tap down and cut it deeper. Just don't get carried away. Do a little at a time, like one turn and check it with your fitting. Don't forget to use oil on your tap.

02-25-2017, 09:32 PM	#1
2B32 Registered User Join Date: Jun 2015 Location: Northeast Missouri Posts: 71	HELP!!! Cracked Air Intake -Ok, so to preface, I am not a mechanic but I'm trying to learn. As a result I am making a lot of mistakes. Today I was switching out my carb for a Sniper EFI unit. While doing so I tried to seat the vacuum port on the intake (the line that runs from the brake booster to the port behind the carb) a little lower to gain some clearance. In doing so I cracked my intake (stupid, I know). Realizing my intake was now garbage I pulled it, and found oil on all the intake bolts, and oil puddled under the intake. This is a project that I'm learning was jimmy-rigged a lot by the previous owners. I found liquid sealant all over the thermostat, and it looked like some sort of silicone sealant was used for the intake. I've read a bad intake seal will allow oil to leak. Is the oil on the intake bolts, and puddled oil under the intake from the crappy gasket that was used, or am I looking at a bigger problem here? Attached Images

02-25-2017, 09:40 PM	#2
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: HELP!!! Cracked Air Intake Just to be totally pedantic and accurate, the valley is always full of oil, so the underside of the intake will always be covered in oil. I'm not sure if you thought that was a problem or not, but that part's OK. Generally the bolts should be dry, but that doesn't necessarily mean oil was getting anywhere bad (like into the intake ports). But if it's been ingesting oil, you might foul plugs and use oil and so on. Other than you having a cracked intake and needing new gaskets, I don't see any problem at all, unless I'm missing something... __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible Last edited by davepl; 02-25-2017 at 09:47 PM.

02-25-2017, 11:35 PM	#4
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,024	Re: HELP!!! Cracked Air Intake Let's see a photo of the crack maybe it can be fixed. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

02-26-2017, 10:36 AM	#5
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,864	Re: HELP!!! Cracked Air Intake Are you asking about the little bit of oil that appears on the intake manifold? If so, that's a normal issue, if you don't put thread seal on those four bolts. The oil swaps p the threads and it pools there. More of an annoyance than a real problem.

02-26-2017, 11:03 AM	#6
Jcfcamaro Senior Member Join Date: Jul 2015 Location: Fairfax, Missouri Posts: 1,049	Re: HELP!!! Cracked Air Intake You could have just put some really good silicone over the crack . You would be surprised how long it would have lasted.

02-26-2017, 11:59 AM	#8
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,024	Re: HELP!!! Cracked Air Intake It's hard to tell from the photo, is the intake aluminum? If so then it can be TIG welded and the threads cleaned up with a tap. If it is cast iron it can be brazed or welded but it is getting harder to find people these days who can do cast iron. It may be easier to find a cheap factory manifold. If your still looking for the fitting to sit just tap the hole deeper. Pipe threads are tapered so they fit tighter the more you tighten them. That's why the hole spilt on you. If you need to have a fitting sit deeper you have to run a tap down and cut it deeper. Just don't get carried away. Do a little at a time, like one turn and check it with your fitting. Don't forget to use oil on your tap. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377



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