Intake trouble
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Intake trouble
I have a '68 F250 Highboy with a 390 with Edelbrock heads, intake and carb with about 5,000 miles on a rebuild. It had a oil leak at the rear main which we just fixed and when we did a HUGE leak showed up in the front of the intake. So I had the garage re-seat the intake. The mechanic said that the intake didn't quite seat all the way down - it hits the heads before it seats on the block. He went ahead and put it in and the rear blew a leak in the first 20 miles but the real problem is that this leak is so bad that apparently I know have a vaccum leak as well - the truck stranded me yesterday. I thought it was a bad fuel pump or clogged fuel filter but eventually I added 2+2+2 and figured it out.
Is it common to have to shave either the intake or the heads when installing Edelbrock intake and heads?
This truck is going to diesel in a few weeks - is there any way to cheaply keep it running until then. I can keep putting oil in, but I got to have a good seal on the vaccum.
Any help would be appreciated.
Peter
Is it common to have to shave either the intake or the heads when installing Edelbrock intake and heads?
This truck is going to diesel in a few weeks - is there any way to cheaply keep it running until then. I can keep putting oil in, but I got to have a good seal on the vaccum.
Any help would be appreciated.
Peter
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The intake does not "meet" the block. There is supposed to be a gap in there.
There are cork end-gaskets in the intake manifold kit. Sometimes, if the heads were shaved, they no longer fit. Either way, a thick bead (not too thick) of RTV is probably the best thing, aside from the 24 hour cure time.
There are cork end-gaskets in the intake manifold kit. Sometimes, if the heads were shaved, they no longer fit. Either way, a thick bead (not too thick) of RTV is probably the best thing, aside from the 24 hour cure time.
Posting Guru
Joined: Jul 2003
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From: Colville, Washington
Peter, there is no oil pressure anywhere that the intake seals. I would guess your mechanic rubbed the RTV while seating that 80 lb intake and wiped it off the mating surfaces. RTV will span at least 1/8" with ease, if you can't get it to seal with the RTV, try Permatex Right Stuff sealant.
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If there's a thick enough bead of RTV, and the surfaces are TOTALLY CLEAN of oil/grease, it should span a good 1/4" at least.
The only reason cured RTV comes off of a surface is if it wasn't totally clean of oil/grease.
Period. In my experience. I think
The only reason cured RTV comes off of a surface is if it wasn't totally clean of oil/grease.
Period. In my experience. I think
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Cargo Master
Joined: Feb 2004
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From: Central Texas
If you are "blowing" the end seals...sounds like you might have too much block pressure. Do you have a correctly working PCV system or other block venting options?
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From: Long Island USA
Originally Posted by PROSTOCK
If you are "blowing" the end seals...sounds like you might have too much block pressure. Do you have a correctly working PCV system or other block venting options?
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I need to understand more about why I might have excessive block pressure - I do think that is the issue as the first bead of RTV was put on at the machine shop by a very meticulous guy and the second bead was put no by a mechanic that was specifically trying to stop an intake leak. The second mechanic indicated that he saw a lot of blow-by when the engine was cold.
I have a working PCV valve on one valve cover and a vent on the other.
New felpro gaskets arrived today and I want this to be the last time I take this da** intake on and off.
Any help would be appreciated.
Peter
I have a working PCV valve on one valve cover and a vent on the other.
New felpro gaskets arrived today and I want this to be the last time I take this da** intake on and off.
Any help would be appreciated.
Peter
Hotshot
Joined: May 2003
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From: south louisiana
If there was trouble twice using a bead of RTV in place of the end seals, I'd skip the RTV and use the seals. Just make sure they're glued down beforehand. And check the end gap under the intake, it could be too wide.
Needsmorecoffee.
Joined: Oct 2004
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From: CT
You might want to check that Edelbrock intake to be sure it's square. There have been a few guys that have found their Edelbrock intakes have been machined wrong and are having the same issues. Just because they are new does not always mean they are good. And a few have slipped past QC. If you still have the old stocker place it on and compare it to the fit of the Edelbrock. If your having problems seating the intake I bet that's it. good luck!
G.
G.
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Unfortunately I don't have the original intake, I wish I did. I may have to run down to the junkyard and find one. I only need this truck to run for about 20 more miles and then the engine is coming out and then a diesel is going in. A stock intake would be a lot easier.
Peter
Peter
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Originally Posted by workingdog
Unfortunately I don't have the original intake, I wish I did. I may have to run down to the junkyard and find one. I only need this truck to run for about 20 more miles and then the engine is coming out and then a diesel is going in. A stock intake would be a lot easier.
Peter
Peter
