Edelbrock 2959 intake gasket

[tracyracin]

hey guys I have a question. I was trying to install the intake on my engine last night and the gap on the front and back of the intake to the block seem to be quite large. The gasket set (felpro 1282) came with cork front and back gaskets, but it seems that no one uses them, just black rtv. When i tried to use rtv I dont think i can create a good enough seal. Do you use the cork gasket and the rtv?

[427dart]

Did you actually measure the gap? How is the vertical port and bolt hole alignment?

[tracyracin]

I didnt measure it last night but I will today. All of the ports and the holes for the intake bolts seemed to be right on the money. I guess it just seems like it will take alot of rtv. I know the gap is greater than 1/4"

[cv67]

Wondering if it wont lessen once its torqued down. Started using the cork again with some brown permatex no leaks, ever.
Wonder if it was a lazy mechanic thing that started that trend yrs ago?

[427dart]

I use the Right Stuff for the intake end gaps and never a problem.

[groberts101]

prep is the key to making that rtv stick well over the long term. Protect the valley from debri, preclean with acetone, sand the china walls and manifold ends with 120 grit and then scrub and wipe once more with acetone. prep is done.

Then another important step is to pre-apply a small amount of rtv by finger to BOTH intake and china wall surfaces first. Then immediately apply just thick enough bead to squish out and slightly bulge after final torque. Have to work very quickly since you need to avoid skinning.

Otherwise, with the typical apply bead and install scenario you can potentially end up with some areas not fully penetrating and bonding with all surfaces 100% over the long term. Especially true if it's hot out and/or you get delayed during the install process after the rtv has been applied for more than a few minutes and starts to skin over. Another trick is to install and torque the manifold 1 step from final torque number(no closer than about 10 lbs off), let dry overnight and finish the final torque the next day. Helps load the rtv a bit better after it's in solid dryed form. Good luck getting it off later on though. LOL

PS. forgot to say.. scrap the end seals completely. Many and myself have tried to use them in conjunction with rtv and all you end up with is more failure points over the long term. Cork eventually absorbs the oil and then breaks away from the rtv's bond. I tried coating the entire cork end seal once, helped but was a hell of a mess and still goes away over time. But the pure rtv end seal will probably last longer than the motor itself!

[tracyracin]

Thank you so much to everyone that replied. I measured the gap to be about .45 when the manifold was just resting on the heads with the gaskets in place. I tried to install last night and got all but 2 bolts threaded in and they gave me so much trouble that i didnt get it done in time for the rtv. I took it off and cleaned it up, trying again tonight.

[hondo383]

Not sure what your combo is but that may need some spacers bolted to the China wall or manifold rails....450 is a big gap to fill

[tracyracin]

They are a set of hvh pbm 15 degree heads, edelbrock castings I believe. The intake is a 2959 match ported by hvh pbm to mach the heads. I bought the combo off a engine and it came with everything, so unless they didnt tell me about the spacers, they didnt run them.

[427dart]

Right off something isn't right with that manifold/ shortblock. Have the heads been milled a bunch?
That's a much larger than a normal china wall gap!

[groberts101]

Unless you're running a big vac pump?, I wouldn't sweat it at all. Done far worse than that with long lasting results. If you really are concerned here's another tip.

Also prep in similar fashion about 1/8" up onto exterior manifold face and down onto blocks china wall face. The tape off to protect the rest of painted or aluminum surfaces before applying rtv. Once applied and torqued down you can use a putty knife, piece of plastic(bondo spreaders work good when cut down) to flatten that front seal out a bit. Then pull tape immediately and use good old fashioned spit on the finger to finalize the seal and lay it out till it's nice and rounded on the edges. This will enlarge the sealing surface area and prevent issues with higher vacuum applications.

As you found out already.. get all your ducks in a row with tools handy and work really fast. Can also put the rtv in the fridge to delay the skinning a bit more. The cooler the manifold and block the better too but too cold will cause sweating so no fridge tricks allowed there! lol Good luck with it!

[tracyracin]

No vac pump, circle track engine. I will give it a go tonight and see if it works. Thank you all

[BOOT]

Thank you so much to everyone that replied. I measured the gap to be about .45 when the manifold was just resting on the heads with the gaskets in place. I tried to install last night and got all but 2 bolts threaded in and they gave me so much trouble that i didnt get it done in time for the rtv. I took it off and cleaned it up, trying again tonight.

I now test fit with the gaskets that all the intake all bolts go in good before I RTV ends. Had two eddy intakes that the same rear bolts were off and had to be corrected. If they are tight it can shift the intake when you tighten them down and it might leak. As others mentioned clean clean clean n Let he RTV cure overnight. I've had times where I set the intake on, then when checking noticed I didn't get the bead thick enough in a spot and just added some with my finger, while still wet & clean of course.

edit: Those small extending mirrors are handy for checking the rear of the intake.

[user-30257]

Unless you're running a big vac pump?, I wouldn't sweat it at all. Done far worse than that with long lasting results. If you really are concerned here's another tip.

Also prep in similar fashion about 1/8" up onto exterior manifold face and down onto blocks china wall face. The tape off to protect the rest of painted or aluminum surfaces before applying rtv. Once applied and torqued down you can use a putty knife, piece of plastic(bondo spreaders work good when cut down) to flatten that front seal out a bit. Then pull tape immediately and use good old fashioned spit on the finger to finalize the seal and lay it out till it's nice and rounded on the edges. This will enlarge the sealing surface area and prevent issues with higher vacuum applications.

As you found out already.. get all your ducks in a row with tools handy and work really fast. Can also put the rtv in the fridge to delay the skinning a bit more. The cooler the manifold and block the better too but too cold will cause sweating so no fridge tricks allowed there! lol Good luck with it!

Wtf. . You would send something like that.
Or you could fix it right.
If the ports align properly, you can machine some aluminum China wall spacers. drill and tap, countersink them with Allen head bolts. And use less than .5 inch of silicone

[MadBill]

Or you could use the cork seals plus silicone beads...