Fel-Pro #1250 intake gasket for a GT 40 intake with AFR 165's heads lower intake leaks coolant and I used rtv around the water jackets twice what other gasket or trick can I use? the 1250 just aint doing the trick!
I've been noticing there are starting to be a lot of threads like this one lately regarding the 1250 gaskets. I really don't know what advice to offer honestly because they work flawlessly on my car, even using no RTV around the water jackets. I put a couple dabs of RTV just to hold the gasket in place and used 4 studs to guide the intake down. What are your torque settings on the intake bolts?
1250's are junk, they have leaked on 2 of my mustangs ! i had this problem on trick flow twisted wedge heads and recently on my 289 heads but my 289 heads use smaller water ports, i used felpro gaskets for the 66 289 mustang ands the intake ports on the gasket were bigger, you might could trim the water ports .
I don't know that I'd call them junk. Pretty much every manufacturer recommends using them and unless you follow the directions to a T when installing them, you open yourself up to the possibilities of leaks. The 1250s come with a coating around the water passages which negates the need for additional sealant around the ports. They should work great if the heads aren't milled, throwing off the alignment with the lower intake to the heads.
i've just never had problems with gaskets untill i started using the 1250's and no extra rtv here just leaks, the water was crossing the water port into the front cylinders and it was sucking oil from the lifter valley and on my other car it leak from the water ports and yes they were both torqued in sequence !
i had the exact same problem with my 1262's, i tried the mister gasket brand but the coolant passage was WAY to big so i stuck with the 1262 and got some .030 wire out of my mig and made four "o" rings that i rtv'd to the head then rtv'd the gasket over the "o"rings and torqued everything down, seems to be working fine, went thru 4 sets to get this far, every time mine went they washed down the number 1 and 5 cylinder with water, even pulled the heads and intake and had ALL of the surfaces "cleaned up" milled and the problem still persisted, might be a problem of thermal expansion loosening the fasteners and coolant pressure builds enough to lift the intake, make sure to retourqe the intake regularly, i do mine once every two months
Well all the methods mentioned above should work and seal just fine. As an engine builder I can tell you I out a thin coating of Permatex around the water jacket ports, I use gaska-cinch from Edelbrock to hold them to the head, put a bead of Permatex across the front and rear and then use 4 studs to lower the intake down. Proper TQ sequence is very important to prevent any leaks. I also started putting a very small amount of liquid teflon on the intake bolts to help prevent them from backing out as easily since 50% of the bolts are hard to see or get to with the upper on.
I find it usually takes 4-5 passes of the TQ sequence to reach proper tq, I also prefer to use a beam style wrench with the lower TQ settings. I tq to 22ftlbs....