289 Intake torque specs

[Jbrooks]

Bought a new set of intake bolts for the 289. Is the attached torque spec sheet correct?  Since the car is 54 years old, should the torque be de-rated at all for the rebuilt 289 and aluminum intake?  Thanks in advance for any help.

[shelbydoug]

Use a box wrench of normal 6" length or so and just snug the bolts up with that. The end bolts are the ones in danger of being over torqued and cracking the manifold but that seems to be associated with years of corrosion and structural deterioration internally near those water passages.

Do not let the gorilla tighten these bolts up. They really only need to be snugged up.

Do not use the cork end gaskets under the manifold. Use silicone caulk/gasket maker.

[Skidado]

Do you use silicon around the intake ports or just the dry gasket?

David

[shelbydoug]

289's are not particularly susceptable to vacuum leaks around the intake ports. Using a bead around the water ports is a good idea but you have to do it in a manor not to have the excess wind up in the engine.

Take a "carpenter's square" and hold it on the edges of both the head and the intake. Look to see if there are any noticeable gaps. Those are the spots to consider A LITTLE SILICONE.

Lots of original COBRA aluminum intakes are showing considerable corrosion damage where the rear water ports are blocked. That was caused really by using straight water in the engine. Check to see how the intake gaskets fit around those ports in the back.

The gaskets really should not be cut for rear water passages since the manifold does not use them and the manifold itself needs protection in that area.
I don't think those gaskets exist though? They all seem to be cut for rear water passages.

[roddster]

  A suggestion: retorque the next day.  The gaskets settle.

   The cork end gaskets: for a more original look, cut the gaskets in half, a little glue to hold them, then fill-in behind them with silicone.

[pbf777]

  should the torque be de-rated at all for the .................aluminum intake? 

     As compared to an iron intake?    YES!

     15-18 ft-lbs max. with several re-torquings and minimal use of silicone sealers as excess displaces the gasket and makes a mess, and only about the water ports; and don't use "lock-washers as they chew-up the aluminum, squirm out of shape, and provide an open path enhancing leakage.  If possible pull to only 10 ft-lbs. let set overnight then complete process following day (or so)   

     Scott.

   

[Skidado]

Thanks for the advice on silicone around the water ports only. Also I wasn't aware of the de rated torque values! 😳. I have been struggling to get mine to seal resulting in vacuum leaks all along the visible top edge of the gasket between the head and intake manifold. If I run a bead of water along the joint at idle much of the water immediately disappears.

I have checked the mating surfaces for flatness and tried 3 different FelPro gaskets but no improvement.

I've been recommended Victor Reinz gaskets and they look better for my situation. They have much more 'meat' around the water passage cutouts, and they seem a little thicker and more pliable.

I won't get to fit them until the weather breaks but I'm hopeful...

David

[pbf777]

I have been struggling to get mine to seal resulting in vacuum leaks all along the visible top edge of the gasket between the head and intake manifold. If I run a bead of water along the joint at idle much of the water immediately disappears.

I have checked the mating surfaces for flatness and tried 3 different FelPro gaskets but no improvement.

      After three gasket attempts, assuming your selection of gasket application is reasonable (not really referring to brand as Fel-Pro is probably sufficient) your either a slow learner, or you have a problem in the relationship of the two supposed mating surfaces.  Not only checking for flatness in the length of both surfaces (intake & cylinder head) but also establish that the angle from the opposing faces mate reasonably.  On the next R & R with the to be gasketed surfaces clean and bare lay the intake in its' responsible position, now if pushing on one side or the other, does it "rock", next probe with a feeler gauge strip, say .002" or .003", if so where is it able to pass?     

      Now I have even seen instances where the two surfaces present themselves as flat and with minimal rocking clearance, but upon closer inspection the two surfaces prove to be divergent; this is generally caused by improperly machined intake surfaces, not generally the cylinder head intake face as this is rarely addressed post the O.E.M. but can be caused by very badly angling in the milling or surfacing process of the cylinder head deck faces; though this has also been encountered when upon the last installment of the cylinder heads someone left out one or more of the head alignment dowels!       

     Scott.

[shelbydoug]

Yes to all of that BUT the cork gasket is the culprit in many cases simply because it is too thick and raises the manifold away from seating the manifold snugly to the cylinder head.

DO NOT UNDER ANY CIRCUMSTANCES ATTEMPT TO USE THEM. Throw them away immediately to protect the innocent.

[Skidado]

"...slow learner..."!!! 😮  A bit rude! 😂

I am not using the cork valley gaskets, and I will try some of the other suggestions.

Thanks for everyone's help.

David

[Jbrooks]

Thank you everyone for the input and the knowledge sharing that goes on with this group. I didn't go concourse with the gasket kit on this car. Except for the head gaskets, I went with the Fel-Pro gaskets for my rebuild. I'll make sure that I don't "gorilla" the intake bolts (which I've been guilty of before .