Help Re: Lower Intake manifold gasket question - 91 Exp. 4.0

[cmayna]

Per everyone's encouragement I'm replacing the intake manifold on my '91 Exp 4.0 along with valve cover gaskets, thermostat, etc.

Here's my delima. The local Ford dealership sold me a lower manifold gasket which is a little different that the original. The original is of the same hard substance throughout and the bottom of the valley portion of the gasket is solid. Where as the replacement, bottom of it's valley has large openings and most importantly the front and back of the gasket where it goes around the smaller water ports (where it typically cracks and leaks) is now made of black rubber.

My questin is regarding the usage of RTV on black rubber. Do I still use RTV ? I would think not since it's now rubber but need some opinions before tomrrow when I start to re assemble

I'll enclosed a link showing the new one on the left and old one on the right. What should I do?




Dead Link Removed

 

[Iggy flywheel]

rtv

I would say that you dont want to put rtv on the rubber gasket part. Most people dont use rtv sealant correctly anyways. It makes a gasket. I would say that if you want to put anything on there is to use peratex gasket sealant. It is yellow and acts like a glue to hold the gaskets in place. If you have the time I would call ford where u got it and see what they say for sure..

 

[slow-demon]

Just use some slicone rubber where the cyl head and block meets. There is 4 corners. I would also put some silicone at the same areas above the gasket where the intake,block, and cyl head will meet.

 

[cmayna]

Cmon people. I would like more replies. Does the
new gasket in my attached link look correct ?

:frustrate

 

[bandlow]

Your timing is good! I threw my old intake manifold gasket ('95 4.0L) away yesterday. I fished it out of the trash and compared it to your photo. It is identical to the replacement you have and appears to be an improved version of your original.

I opted for the cheap AutoZone replacement gasket since I expect to have it apart again within a year. I used sensor safe Ultra Black RTV as specified below and haven't had any problems.

From a usually reliable source:

Apply Silicone Gasket and Sealant F7AZ-19554-EA or equivalent meeting Ford specifications WSE-M2G323-A4 to the block and cylinder head mating surfaces at the four corners. Install the intake manifold gasket (9439) and again apply sealer to the four corner locations. Install the lower intake manifold. Tighten the bolts in three stages. Stage 1: 8 N-m (71 lb-in). Stage 2: 12 N-m (9 lb-ft). Stage 3: 16 N-m (12 lb-ft).

I think the idea is to put just enough to cover the crack at the head to block joint.

 

[cmayna]

Bandlow,
Thanks for the reply. What do you mean regarding the different stages ? I'm confused regarding
8 N-m, 12 N-m & 16 N-m ??????

 

[bandlow]

N-m stands for Newton-meters which is metric unit for torque. You can disregard it unless your wrench is calibrated that way. Also, most people say ft-lbs and inch-lbs.

The stages mean that you tighten each bolt more than once; in this case three times. The first time tighten in the proper sequence to 71 lb-in (Note: lb-in not lb-ft!) After that you go around and tighten in the same sequence to a torque of 9 lb-ft (this time it _is_ lb-ft. After that tightening you go around a third time and final tighten to 12 lb-ft. (BTW Chilton's recommends four stages to 18 lb-ft but I think the first procedure is adequate.)

Looking at the manifold from the front, the sequence for the eight bolts is:

1 3

6 5

8 7

4 2

Basically a criss-cross pattern from the outside-in.

The whole idea is to tighten the manifold so that you squeeze the gasket evenly in stages.



Rich