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After weeks of chasing a rough engine problem I find some leaks around my new heads where the manifold mates up. Should I double the gasket or use gasket sealant on both sides of the new gasket?
If they were cheap cardboard gaskets I would try the better ones with the silicon bead. If that doesn't work, you may have to goop it up with sealer or pay the machine shop to mill the manifold. That often causes mismatched ports but every case is different.
I dry fit gaskets 1st to check fitment and clearances.
I use Gaskacinch around the intake ports, a little rtv around the water ports and a thck bead on the china walls.
Drop that sucker straight!
Easy money...
If they were cheap cardboard gaskets I would try the better ones with the silicon bead. If that doesn't work, you may have to goop it up with sealer or pay the machine shop to mill the manifold. That often causes mismatched ports but every case is different.
They were Fel Pro - top line. I think sealant around the ports is the answer - thanks for the response
I dry fit gaskets 1st to check fitment and clearances.
I use Gaskacinch around the intake ports, a little rtv around the water ports and a thck bead on the china walls.
Drop that sucker straight!
Easy money...
It goes without saying that all surfaces must be squeaky clean...
And invest in a good torque wrench.
Chevys are easy as compared to Oldsmobiles.
I have very original 65 4-4-2; Oldsey V8 engines have a very wide "V".
The stock cast iron intake weighs a ton!
The manifold drop has to be straight and true the 1st time.
Moving the manifold to line up bolts will result in leaks.
I love my Oldsey; it just might be the most original copy in existence.
96K miles; always garaged.
Check for flatness of the surfaces. I had a similar problem with an aluminum manifold and had it honed. About $30.
You wonder about quality control. Top name guys are putting out some manifolds that need machining out of the box. Have a machine shop check the machined intake surfaces and correct if needed.
Last edited by Street Rat; Jan 5, 2015 at 08:09 AM.
I learned something from my Shop partner John on intake gaskets. He uses the blue Felpro gaskets, but most importantly, he 'glues' the gasket in place with sealer and lets it dry before he puts the intake manifold on! He'll position it through the holes with a couple of the intake manifold bolts, one on each side and makes sure it is aligned perfectly with the ports on the heads.
Often, when you put it on 'wet' the intake manifold will push down the gaskets on both sides, down into the center valley, exposing the lower edge to leakage from there.
See how little room there is on the bottom of the gasket and how easily it could slip down?
After weeks of chasing a rough engine problem I find some leaks around my new heads where the manifold mates up. Should I double the gasket or use gasket sealant on both sides of the new gasket?
Felpro makes a double thick gasket with the printo seal that might help solve your problem.
I learned something from my Shop partner John on intake gaskets. He uses the blue Felpro gaskets, but most importantly, he 'glues' the gasket in place with sealer and lets it dry before he puts the intake manifold on! He'll position it through the holes with a couple of the intake manifold bolts, one on each side and makes sure it is aligned perfectly with the ports on the heads.
Often, when you put it on 'wet' the intake manifold will push down the gaskets on both sides, down into the center valley, exposing the lower edge to leakage from there.
See how little room there is on the bottom of the gasket and how easily it could slip down?
That's exactly what I ended up doing. Leaking at edges and between ports. Installed gaskets with sealer first, trimmed edges at ports because they overlapped and then set the manifold on. what a differrence
intake manifold leaks
