hi I have been using the Holley street dominator dual plane manifold and the thing just will not seal to the head properly. It lets alot of oil into the combustion chambers. I have re sealed it about 5 times and connot cure it even using a bit of master gasket sealer. Has anyone else used these manifolds?what are your results and does anyone have any advice as to why its not sealing properly.
SBC intake manifold
Started by
_75LH_
, Jul 02 2006 08:39 AM
6 replies to this topic
#2
_Toranamuk_
_Toranamuk_
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Posted 02 July 2006 - 09:43 AM
You'll need to ceck the angle of your manifold against the angle of the heads.
There's several ways to check it, simplest on the car is remove the manifold & clean up all the surfaces properly, using a new gasket (felpro 1205 or 1206) sit the gaskets in place with NO sealer, place the manifold in position & line up the bolt holes & lightly screw in some bolts by hand just to "settle" the manifold in position.
Loosen the bolts again. Use your bolt holes as a quick reference as to whether or not the manifold needs some taken off the faces just to align the ports properly, & check the ends against the block, you need approx .080" clearance here.
Using feeler gauges check the gap between the manifold & the gasket. Any more than .005" gap & difference from top to bottom & end to end you will need to get the manifold machined.
This is a simple way to check all manifolds.
PS, your problem may not be the manifold. If the oil is in all the ports i suggest you have a look at the position of the PCV valve in your rocker covers.
It must have a good baffle to stop the oil splashing out of the rocker gear straight into the PCV valve.
Good luck.
Craig
There's several ways to check it, simplest on the car is remove the manifold & clean up all the surfaces properly, using a new gasket (felpro 1205 or 1206) sit the gaskets in place with NO sealer, place the manifold in position & line up the bolt holes & lightly screw in some bolts by hand just to "settle" the manifold in position.
Loosen the bolts again. Use your bolt holes as a quick reference as to whether or not the manifold needs some taken off the faces just to align the ports properly, & check the ends against the block, you need approx .080" clearance here.
Using feeler gauges check the gap between the manifold & the gasket. Any more than .005" gap & difference from top to bottom & end to end you will need to get the manifold machined.
This is a simple way to check all manifolds.
PS, your problem may not be the manifold. If the oil is in all the ports i suggest you have a look at the position of the PCV valve in your rocker covers.
It must have a good baffle to stop the oil splashing out of the rocker gear straight into the PCV valve.
Good luck.
Craig
#3
_75LH_
_75LH_
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Posted 02 July 2006 - 03:44 PM
cheers mate il check the angles when i get the heads back, But i don't use a pcv valve.
#4
_azureblueslr_
_azureblueslr_
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Posted 02 July 2006 - 04:13 PM
hi 75 lh ive had that problem on a 351 cleveland before it was caused by
the heads being shaved and the block being decked when i got it machined. this caused a slight difference in the way the heads sit on the block eg the width from head to head and the angle of the intake port in relation to the manifold which causes sealing problems. the only way to fix it is to get your manifold machined to suit . another way of telling where the leak is coming from is to check the gaskets when you take off the manifold and you will be able to see where the leak is coming from .mine only caused a vacume leak when it happened though so yours could be different also check the manifold with a srtraight edge to be sure its not warped cheers
the heads being shaved and the block being decked when i got it machined. this caused a slight difference in the way the heads sit on the block eg the width from head to head and the angle of the intake port in relation to the manifold which causes sealing problems. the only way to fix it is to get your manifold machined to suit . another way of telling where the leak is coming from is to check the gaskets when you take off the manifold and you will be able to see where the leak is coming from .mine only caused a vacume leak when it happened though so yours could be different also check the manifold with a srtraight edge to be sure its not warped cheers
#5
makka
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Posted 02 July 2006 - 06:29 PM
does your manifold have an egr port?
Edited by makka, 02 July 2006 - 06:29 PM.
#6
_75LH_
_75LH_
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Posted 04 July 2006 - 07:01 AM
it has provision for an egr but im not using it.
#7
makka
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Posted 04 July 2006 - 11:39 AM
ahh k, i just know of a bloke who fitted a aftermarket manifold (with egr) to non egr heads. he left the egr on and connected it up, when ever the egr opened up it let oil not exhaust gasses in to the intake
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