Intake Manifold Gasket Failure: Cracked/Split
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Intake Manifold Gasket Failure: Cracked/Split
Took the '80 in to solve valve train noise and bad idle once and for all.
Valvetrain noise turned out to be a result of the cruise control bracket forcing the driver's valve cover slightly forward causing a valve spring to rub on the oil baffle. Mechanic made a small dent in the baffle and recommended I either adjust the cruise bracket or clearance the valve cover ever so slightly... I'm in the process of doing both. This is the notorious 'ticking' noise I have chased since I installed the DART heads. My guess is there is a slight fitment issue with the cruise bracket against the DARTs; never an issue with the 624's or 882's as they were both OEM GM.
Vacuum issue (rough idle) turned out to be a failed pair of intake gaskets. Gasket had literally 'squirmed' up the face of the pasenger cyl head face on #2/#4 resulting in the two intake ports actually being exposed. Also, both intake gasket pieces that mount on the cyl heads had cracks/splits in multiple places. The gaskets are 1256's and I had used Edelbrock's gaskacinch AND had overtorqued to 30lbs; Edelbrock says max 25lbs. Not sure if it was the glue not sticking in some places and sticking in others that caused the gaskets to crack or also the overtorque but, this time, I installed 'dry' with just black permatex at the corners and a dab around each coolant passage (both sides of the two gaskets) @ 25lbs. Haven't fired it yet as I ran out of time but I intend to do so once I return late Friday (once the sun is up on Saturday morning).
Will advise.
Valvetrain noise turned out to be a result of the cruise control bracket forcing the driver's valve cover slightly forward causing a valve spring to rub on the oil baffle. Mechanic made a small dent in the baffle and recommended I either adjust the cruise bracket or clearance the valve cover ever so slightly... I'm in the process of doing both. This is the notorious 'ticking' noise I have chased since I installed the DART heads. My guess is there is a slight fitment issue with the cruise bracket against the DARTs; never an issue with the 624's or 882's as they were both OEM GM.
Vacuum issue (rough idle) turned out to be a failed pair of intake gaskets. Gasket had literally 'squirmed' up the face of the pasenger cyl head face on #2/#4 resulting in the two intake ports actually being exposed. Also, both intake gasket pieces that mount on the cyl heads had cracks/splits in multiple places. The gaskets are 1256's and I had used Edelbrock's gaskacinch AND had overtorqued to 30lbs; Edelbrock says max 25lbs. Not sure if it was the glue not sticking in some places and sticking in others that caused the gaskets to crack or also the overtorque but, this time, I installed 'dry' with just black permatex at the corners and a dab around each coolant passage (both sides of the two gaskets) @ 25lbs. Haven't fired it yet as I ran out of time but I intend to do so once I return late Friday (once the sun is up on Saturday morning).
Will advise.
Last edited by TedH; Apr 20, 2006 at 05:34 PM.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Have clearanced the cruise bracket with my 'FORD tool' (hammer) and a drift. Also replaced the valve covers with a spare set that had a twist on/off oil filler cap to ease oil filling.
Vacuum: Resolved with the fresh gaskets (FelPro 1256) installed dry except for black RTV around the coolant passages (both sides of gasket); torqued to 25ft lbs.
Vacuum: Resolved with the fresh gaskets (FelPro 1256) installed dry except for black RTV around the coolant passages (both sides of gasket); torqued to 25ft lbs.
