On a SB is there a Gasket on the Oil

On a SB at the block where the filter is you have the plate there that has the bolt to
the mount plate for the filter.. my question is.. is there a gasket on the block side at
the mount bolt... I cant remember... I'm in the house and dont have my book with me

no gasket on the center bolt

Mr P , are you talking about the bolt with the 3/8 square in the center to mount the plate on ? if so that bolt don't use a washer.

I didnt think there was but I have a Superformance 90* gasket set and it has the large outer
gasket then 2 for the center bolt.. one is cork and the other is hard gasket... so you guys are
saying no gasket at all on that center bolt

The plate that bolts to the block has no gasket on the bolt, but the OEM 90 degree adapter does take gaskets on the bolt. Like most of the 340's had, your gasket kit I am sure has gaskets for both style oil filter adapters.

This is on a 340 but I dont use a 90* adapter so I will pull the one gasket out thats
behind the plate on the center bolt... thanks guys

I think you will find that the plate will have a gap under the bolt hole when the outter 4 inch gasket is in place. I think the plate will act like a spring. For that reason I always have put a fiber gasket under the bolt hole too if I use a hollow bolt withe a nut head to tighten it down...

Iffylube did an oil change on my 65 Bcuda and pulled my 90 degree adapter sideways and that broke the seal and the center bolt unspun. Made it 5 miles down the road when the back tires spun out in a corner and my IDIOT light came on.

On a side note (for a 90 deg adapter) you want the cork one inside on the center bolt & the hard one under the bolt head outside the adapter

http://www.hughesengines.com/Index/...l1=T2lsaW5nIFN5c3RlbQ==&partid=30912

this is the only plate style cover i would use on a hp small block

Does anyone know the thickness of the large outer gasket.. I think this is the problem point..
the one I have is about 3/16" thick and when I put the plate on I think it can/is bowing the plate
I tried the thin small gasket and it was less of a leak but still leaked.. I will have to check
to see if I have a thinner large gasket more like the superformance one

I like that one but $70 plus Hughes shipping rate.....

I made my own from a stock magnum one. I do use the thicker Felpro large outter gasket with a smeer of RTV and the fiber one under the bolt area. The 6 holes are drilled out to 3/8 inch. The center of the bolt is also drilled to 1/2 inch inside.

Ok.. you are using the felpro large gasket with the fiber gasket...I might try that... thanks guys

It should have to deflect the plate some when the center stud is tightened to ensure pressure on the outer gasket. Stack gaskets under the center and it takes pressure off of the outer ring.

I've never seen a gasket used under the center of the plate - a small leak there is meaningless - and the outer rings are at least .150" thick. A smear of silicone on the center block boss should be adequate to seal that joint if it's a concern.

This block looks to be machine deeper than most(in the filter area) I had to stack up
2 of the outer gaskets and it JUST does have a couple thousands compression on the plate..
I think it should have more compression on it but I will try it

Using a used outter plate gasket, when I put my 4 hole Commando plate on the new Magnum 5.9 block there was about 0.055 gap (stacked feeler gauges) from the plate to the iron thread hump. The Magnum 6 hole plate had about a 0.040 gap. That is a huge gap and I don't think the hollow stud will compress the gasket enough to get the steel to touch iron. I did use a used Magnum plate gasket.
There will not be enough of an internal oil leak due to the threads sealing. I just know if the steel plate is not touching the iron block, then the plate is in compression and the hollow stud may work loose. You want the hollow stud to be 'STRETCH' of torque so it can not come loose.

I just measured the compressed thickness of the large outer gasket that came off an old 340 block with a plate. .075". Laying the filter plate block side down on a flat surface and measuring the distance from the center filter stud surface to the flat is about .110".

Checking the filter area on an old X block, the center attachment boss is approx. .080 higher than the outer gasket surface. Setting the plate on the bare block confirms the center boss is higher than the outer gasket surface.

This is just a few quick checks with some parts I have handy. Stacking any gaskets under center of the plate is asking for the outer gasket to leak based on what I see, Again, a smear of silicone is all I would chance using on the center of the plate.

Your parts may be different, but the fits can be checked with what you are using.


ETA... Just checked a second plate and it is substantially different - maybe .100" more offset center to outer surfaces. So, not all plates are the same. Ultimately the parts you have and how the block is machined will determine how you assemble yours. I would want a good crush on that outer gasket when done.

I finally got my oil leak fixed..it holds at 80 psi.. now just need the push rods