New Intake Manifold - Ready for Fluids

This evenings project was to reinstall all the various items I removed so I can add fluids and then start up the Mustang.  I installed everything except the coolant just to provide one more night of drying time for the RTV.

I installed the distributor, heater hoses, radiator hoses, carburetor, throttle linkage, fuel lines, and then replaced all the spark plugs (NGK FR5 7373).  The old plugs looked worse than they did when I checked back in November.  Several were so fouled I just threw them in the trash.  I held on to the best four to place in my spare parts bin in the truck on the car.

Tomorrow night, I will all coolant, start up the Mustang, check timing, and then start the process of tuning over again in hopes of reaching a good air-fuel ratio.

New Intake Manifold - Intake Installed

This evening after work I installed the new intake manifold.  I started by cleaning all the mating surfaces several times with paint thinner to ensure everything was completely clean.  I then installed four 4" bolts with the heads cut off to help in aligning the intake for install.

I used Permatex Gasket Sealant around a few bolt holes on the head itself and then on the mating surface of the intake gasket.  While it started drying, I put some Permatex Ultra Grey Gasket RTV around the water ports below and on top of the intake gasket. I then installed the gaskets and test fit the intake to see the amount of RTV which would be needed at the edges.

The intake came back off at that point and I put a bead of the Ultra Grey in the corners of the intake followed by a bead across the front and back.  I then put the intake on one last time and installed all the bolts finger tight.  I let the intake set for 45 minutes like this and then torqued all the intake bolts down in the proper sequence to 20 ft-lbs.

I waited to install the intake as I decided last minute to switch to a Fel-Pro 1250S-3 intake gasket because it has a steal core.  Sounds like overkill but I don't want this thing cracking and coming apart like the last one did.  I'll just sell the 1250 gasket I purchased along with the old intake manifold.

New Intake Manifold - Painting and Clean-Up

Today I spent a little time cleaning up and preparing to install the intake manifold.  I'd go ahead and install it but I decided to use a Fel-Pro 1250S gaseket which is metal lined instead.  It will take a few days to get here but it is added insurance so that I don't have the same problem with the gasket as last time.

I painted the timing cover and water pump were the leaky thermostat housing discolored it over the past couple of years.  This took some time as I had to remove quite a bit and then use some strips of tape to cover bolts and pieces of plastic to protect everything from overspray.  The job took a bit but the engine looks good again.  

New Intake Manifold - Installation Discovery

I'm working a small amount on the intake installation in the evenings.  I work for a bit and then take a break for the evening as it is rather hot in the garage and I'm in no hurry to get the job done.  

While working on the car last night, I took a picture if the engine before removing the intake.  I've become familiar with seeing the blue intake on top from when I painted it years ago.  I expect it will look quite a bit better with the bare aluminum intake.  

Once I removed the intake, I found the gasket was in horrible condition.  There are two cylinders (#6 and #2) where the intake gasket cracked and caused very clear leaks to the top side of the motor.  There are several cylinders (#3, 5, 6, and 7) with leaks to the interior of the engine.  The intake slid over so that it actually blocked the ports on cylinder 6 and 7 to a degree. 

I'm quite shocked at the condition of the intake manifold.  The front two bolts felt a little lose when removing them but the rest did not seem too loose.  The center bolts were tight but they did not feel over torqued.  I'm not sure what caused this to occur and how long it has been this bad.

I'm a bit concerned about the situation as I purchased the same FelPro 1250 gasket for the new intake.  I remember installing the intake last time and I was incredibly meticulous about every task of installing the components as I wanted it perfect.  The following picture is from the install and shows the gasket adhesive, rtv around the intake ports, and everything looks perfect.  I can only assume bolts came loose over time or were not torqued properly and slowly the gasket deformed.

This explains the difficulty I have experienced when trying to tune the carburetor.  I would reject the carburetor and it would seem better but then be lean again over time.  This is concerning as I was likely making certain cylinders incredibly rich so the O2 reading averaged out properly while certain cylinders were very lean.

The second item this explains is the burning of oil.  I thought the engine was picking it up through the PCV valve.  I did not expect a leak between the lifter valley and intake to be the cause.  It is most certainly the main cause of the problem.

Lastly, I noticed before when performing a compression check that cylinder 3 and 7 had strange looking spark plugs.  I think those two were lean from breaks in the intake manifold.  Looking back at the pictures, cylinder 5 was also darker than the rest and that is likely from oil entering that cylinder because the gasket is all deformed. 

I'll be happy to get this job done and see how the engine runs.  I'm curious if I will notice any improvement in the performance.

New Intake Manifold - Edlebrock RPM Air Gap

There are numerous items which still need work on the Mustang.  One would think I would continue to work on untouched areas to finish up the restoration.  Instead, I replace gears I installed a short time ago and am now going to replace a perfectly good intake.

The existing intake is a Weiand Stealth (#8020WND) which I installed in 2009 with my Holley Street Avenger carburetor.  While there are no issues with the intake, I'd like to switch over to an Edelbrock RPM Air Gap intake.  I don't expect much if any improvement in performance but want to switch for appearance reasons and to have the carburetor run a little cooler.

On Sunday evening, I purchased an Edelbrock RPM Air Gap intake (#7521), Scott Drake aluminum thermostat housing (#SDK-C5OE-8592-A), a set of FelPro intake gaskets (#1250), and a FelPro 35067 thermostat gasket.  In normal fashion, Summit sent them to me in record time.

I drove the car this evening to take a picture with my son and the 2006 Mustang he just purchased.  I've been wanting to take the picture with him since we purchased it about three weeks ago and just now found the opportunity.  Now I can pull the intake and swap it without worrying about taking the car out of commission for a few days or longer if I choose.