Wrenching Tips: How Not to Install an Intake Manifold

intake manifold installationI regularly refer to myself as a “professional automotive amateur”; the reasoning behind that contradiction in terms should be readily apparent by the end of this article. What follows is the tale of my first time doing a straightforward, but relatively involved job: swapping in a new intake manifold and four-barrel carburetor onto my Falcon. Of course I also complicated the issue by replacing the water pump, points, coil and adjusting the valves while I was at it. That, and a pile of rookie mistakes.

Read on and learn from my mistakes, so that you might feel even dumber when you inevitably not repeat them… 

Leaking ford carburetor

If You Give a Mouse a Cookie was actually inspired by a gear head. My finances regularly fall victim to the problem of a $40 part triggering $400 in upgrades. In this case, the Falcon’s two-barrel carb was leaking gas. Easily solvable for under $50, but why drop $50 into a carb that you’ve been wanting to replace anyway? The 2bbl gave incredible throttle response from idle-3000rpm, but after that it was obviously holding things back. A reconditioned 500cfm Edelbrock AVS 4bbl from Summit ($310) and eBay special Edelbrock dual-plane manifold ($101 + $15 gasket) would solve that nicely. While I was at it, I hit up falconparts.com and grabbed a Pertronix electronic ignition ($100) and coil ($40) to liven things up a bit. The water pump was getting swapped because I thought I heard some noises coming out of it…in retrospect I think that was just my flex fan. We’ll ignore the water pump and ignition for now, as they went without issue. 

The basic steps to swap a manifold and carb are as follows:

  • Drain coolant
  • Remove carb and all the stuff connected to it
  • Remove all the stuff connected to manifold
  • Remove distributor (semi-optional)
  • Unbolt, then pry up and lift out manifold

Things went smoothly enough, aside from some minor gas spillage while disconnecting the fuel line and pulling the carb (it does, after all have bowls of gas in it…). In an effort to be clever, I decided to leave the distributor in place and avoid having to re-set my timing. Aside from a little extra gyration yanking the manifold out, it seemed like a great idea.

ford intake manifoldFord V8 lifter valley

One should never miss an opportunity to contemplate the innards of any complicated assembly.

 ford pushrodsFord liftersford pushrods

Now for cleaning. I scraped off the old gasket material and did my best to keep it from dropping down into the lifter valley. Rags laid down and stuffed into ports do a pretty good job of catching most scraped-off gunk, but at one point I managed to dump the contents of one right into the lifter valley. That’s what shop vacs are for. I used a combination of peeling, paint scrapers and a razor blade to get the job done. This took a long time and was kinda frustrating.

 intake gasket scrape offvacuum out lifter valley

Next up: mounting and sealing, but not without stripping a thread on the thermostat housing first. Store-brand helicoil for the…close enough.

 stripped threadshelicoil inserthelicoil intake manifold

Ok, now, let’s slap that baby in. Red RTV along the mating surfaces and gaskets…man, there sure are a lot of surfaces and this slant-y geometry makes it tricky to line things up. Oh well, here we go…[fade out to noises of grunting and cursing, and not in the fun way]…there, it’s in.

intake manifold seal

Install is not the reverse of assembly in this case. Obviously, I’ve got a new carb, but also the heater hookups, coolant temp sensor, and PCV setup are all different. Parts store for a best guess at a PCV valve and some hosing, hardware store for the pipe-thread adapter for the temp sender. Heater goes back to the rear coolant crossover, which actually cleans up the engine bay some.

 intake manifold comparisonintake manifold comparison

Now for the carb. Bolts on and hooks up just fine…except the throttle linkage. ’64 was long enough ago that a rigid bell-crank rod was the norm, not a throttle cable. The rod linkage doesn’t produce enough movement to allow full-throttle with the pedal on the floor. After checking around online, it seems the V6 Granada has a pedal and cable that works correctly. Junkyard run it is. After returning, it dawned on me that I could just increase the length of the bell-crank rod to get more motion (anyone need a spare Granada pedal and linkage?). Time to break out the tools of persuasion…

 intake manifold comparisonbroken weld

Going great until it snapped on what looked a lot like someone else’s weld. Haha, but I have a nifty MIG welder!…and no shield gas. Time to dig out the old stick welder buzz-box and swap the plug. Crappy welds follow, but it’s not like this linkage sees a lot of load. Advice: pick up a craigslist (or Harbor Freight) cheap arc welder for situations just like this.

old arc welderwelding toolsweld preparationcomplete weld

I complemented my newly lengthened rod with a length of double-threaded aluminum rod from McMaster Carr (worth a whole WT article themselves) and a couple of spherical rod ends that I refused to let a roommate throw away eight years ago.

cheap heim jointsthreaded rodthrottle linkage

IT’S ALIVE!!! …and the air cleaner doesn’t fit past linkage. Edelbrock crappy triangle air cleaner for the win!  

Yay, driving! Hmmm…smoke…quite a bit of smoke…Turns out oil’s leaking down on the exhaust, but from where? Remember the silicone sealant along the block-to-manifold surfaces? Remember the gyrating around the distributor to get it in? Turns out those two combine to create a leak off the back of the motor. Time to pull it all back off, scrape the gaskets again and reinstall using proper gaskasinch and serious business sealant. Sidebar: if you lose a cap, use a deck screw.

intake manifold installationintake manifold scrapereplacement cap

Except in my frustrated hurry I didn’t double-check that the coolant had drained all the way…resulting in a horrible gurgling noise as I cracked the manifold loose. Coolant had now drained into the lifter valley, onto the cam, past the crank and into the sump. Needless to say, there was much cursing. Also, not many pictures past this point as I was in scramble mode to get it fixed. I soaked up what I could with rags, then doused everything with WD-40 (trivia: WD stands for “water displacing”), then drained the oil. I finished reassembling, replaced the fluids and fired it up. Three oil changes later (I used the cheapest store brand stuff) and the characteristic oil + water = milkshake was gone.

A year later, everything’s working great, except for a minor oil leak off the front of the intake (that then re-drains through the timing cover) and some extra oil seepage past the newfangled PCV valve assembly. I managed to get a straightforward, but involved job done with only two screwups and one minor engineering project. Between the oil, gaskets, coolant and unnecessary pedal assembly, I probably added $100-150 in extra cost and roughly doubled the timeline of a $500, “two-weekends and some week-nights”  job.

Morals of the story? First off, the bigger the job, the more parts you’re changing, the more likely some unforeseen issue may arise. Deadlines beware. Second, when dropping something big and heavy and fluid-sealing into place, get the right sealants and clear the whole landing zone for easy access. Lastly, don’t be afraid to have a learning experience like this. You’ll come out the other end wiser for it.


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