408 rediculiously simple question - MustangForums.com



Reply
 
 
 
Thread Tools Search this Thread
Old 11-29-2007, 06:34 PM   #1
psuhillbilly150
2nd Gear Member
Thread Starter
 
Join Date: Jul 2006
Location: Pennsylvania
Posts: 186
Default 408 rediculiously simple question

Ok this seems extreamly stupid of a question to ask but i am gonna throw it out there incase anyone has some slick tricks up their sleeves.

Built my 408 used gray RVT silicone to seal the gap between the intake manifold and the block. LEAKS LIKE HELL. The silicone had set for 3+days untill the motor was run. All serfaces were cleaned with gum cutter 2+2 the nastiest solvent I know of. What else is there to do. Is there a cork gasket that can seal that? I am running a 1986 block with a victor jr intake with vitor jr port matchedheads.

HELP
psuhillbilly150 is offline   Reply With Quote
Old 11-29-2007, 07:17 PM   #2
r.barn
6th Gear Member
 
Join Date: Feb 2006
Location:
Posts: 5,263
Default RE: 408 rediculiously simple question

I would just try again with Black RTV.
Might have just been some bad luck on the leak.
r.barn is offline   Reply With Quote
Old 11-29-2007, 07:20 PM   #3
Mustangkiler
5th Gear Member
 
Join Date: Dec 2005
Location:
Posts: 2,005
Default RE: 408 rediculiously simple question

ultra black or ultra blue, only way to go.
Mustangkiler is offline   Reply With Quote
Old 11-29-2007, 08:20 PM   #4
Indy
1st Gear Member
 
Join Date: Apr 2006
Location:
Posts: 138
Default RE: 408 rediculiously simple question

Don't use the cork stuff! It'll just pop out. I had the same problem, but I use the Blue RTV. I found that I did not have enough PCV (positive crankcase ventilation)! I had 2 breathers on my valve covers and just plugged the PCV port on the carb (you know, just like the showy looking engines in the mags). I pulled the intake back off and re-sealed the lifter valley-intake gap with the RTV. Reconnected the PCV hose to from the carb (could be intake) port to a valve cover with a new PCV valve...and it never happened again.

Now you might already be running the "regular" PCV system and still have this problem. So, you might not have enough vaccum to evacuate the built up pressure in the crankcase, lifter valley etc... you could need an auxillary vaccum pump to evacuate that pressure. IMO.

Indy
Indy is offline   Reply With Quote
Old 11-30-2007, 02:38 AM   #5
Ford1158
 
Join Date: Sep 2007
Posts: 32
Default RE: 408 rediculiously simple question

Look for the semi-squishy rubber gasket that wraps around both sides of the bottom (like an upside down U) and has waffle texture on top and bottom contact areas that hold RTV and squeeze as needed. I don't know which engines or gasket makers have that but my '91 5.8 and '85 5.0HO did. Dealer might be able to help locate it. Used ultra black RTV.
Ford1158 is offline   Reply With Quote
Old 12-03-2007, 03:55 PM   #6
86_Notch
 
Join Date: Dec 2007
Location: Delaware
Posts: 24
Default RE: 408 rediculiously simple question

try with rtv black, put a really thick bead along the block surface and in the corners where the heads meet, and let it set up for a few mins before bolting the intake on. i've made the mistake of putting the intake on too soon and had leaks, hope this helps
86_Notch is offline   Reply With Quote
Old 12-03-2007, 04:35 PM   #7
aode08
5th Gear Member
 
Join Date: Oct 2005
Location: Ohio USA
Posts: 4,616
Default RE: 408 rediculiously simple question

You cant rtv that area with great results, you will need the cork pieces, although I prefer the felpro blue rubber, then rtv the corners considerably



aode08 is offline   Reply With Quote
Old 12-03-2007, 04:53 PM   #8
aode08
5th Gear Member
 
Join Date: Oct 2005
Location: Ohio USA
Posts: 4,616
Default RE: 408 rediculiously simple question

also on your carb gasket to manifold, give him a smear of rtv on both sides all around and let dry overnight before install.


Your gonna have one sick engine
aode08 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
window tint issues? chrisdbassplayer 2010-current S197 Appearance Section 4 10-13-2015 07:53 PM
Hello, new user with an older Mustang and a question treesloth New Member Area 4 09-28-2015 08:03 AM
Question about Valve Cover Breather Ipaman 5.0L (1979-1995) Mustang 12 09-22-2015 08:01 AM
revolutionary new diet 2015 99GTvert Off Topic 5 09-21-2015 10:34 AM
New 5.0 carb build bogs at hit of throttle Daddys Girls GTs 5.0L (1979-1995) Mustang 3 09-14-2015 09:46 PM


Tags
50, crankcase, evacuate, rediculiously

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Advertising
Featured Sponsors
Vendor Directory

All times are GMT -5. The time now is 11:53 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.