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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.

 

Currently there are "36 comments" on this Article:

  1. salguod says:

    Nice write up. Sounds like how I'd do a job, that is try to cut a few harmless corners that end up biting you in the end.

    BTW – Your click-through images are enormous, making them slow to load and they then overwhelm the screen. Maybe scale 'em down a bit. :-D

  2. OA5599 says:

    Now you know why these used to be so common.
    <img src="http://www.justanswer.com/uploads/molurch/2007-05-01_195156_4to2BarrelAdapter.jpg&quot; width=500>

  3. JayP2112 says:

    Last fall I bought a Scott Drake 8.8 rear diff cover to install. Looks way better than the stamped steel part keeping oil in. And it has fill and drain plugs. You'd think this was a simple swap out. Nooo… gotta drop the panhard bar, remove the sway bar, and getting oil 'up in there' is a pain in the tail.

    First time I installed it, I didn't get the seal perfect and it leaked. No matter how I wrenched, it leaked. Dumped $50 of oil and modifier to take it off for attempt #2.

    #2- tried again but didn't use a gasket since there was a few who said sealer would be OK. $50 oil and modifier. Retorqued that pain in the ass and was DONE. A few days later, I can smell that stink! Hell!

    #3- Got a new gasket, drained the oil into a clean pan to reuse. Bought a real bottle pump, and got all my crap together to get this right. I was getting more sealant when I discovered THERE IS SUCH A THING AS DIFF COVER SEALANT.

    So no more leaks.
    Then Ford comes out with the 302 cover that looks more kickass and is $10 cheaper!

  4. CptSevere says:

    Yeah, I hate when the intake manifold leaks from the back. I've had to do it twice myself, and much swearing and bitching ensued. I always have a hard time getting valve covers to not leak. Use sealant, don't use sealant because it's a cork gasket, both either work or don't work. Even if I do the same thing, the results vary. Just one of those things.

  5. Joe_Btfsplk says:

    When you start a job like this, make believe that you are being paid by the hour and remember that short-cuts are usually money out of your pocket. My dad always said: "If you don't have the time to do it right the first time, when are you gonna find time to fix it?"

  6. Van_Sarockin says:

    Nice writeup. It all sounds about right. I'd have given some thought to making up a lowering rig, maybe with a come-along, so you could ease the new manifold down in place without so much wrestling. I remember that getting water pumps to fully seal on For I-6es was always a pain. Nice fix for the throttle linkage, too.

    So, how's the new rig run? I hope it's doing what you hoped.

    • Mad_Science says:

      Actually lost a little sub-2500rpm responsiveness, but the sound and power when the secondaries kick in at about 3800 is worth it.

      Still not actually fast, but better than it was.

  7. Stu_Rock says:

    McMaster-Carr is a lifesaver worth a WT article. I just got a shipment today for my diesel fuel filter replacement/retrofit project on my Peugeot.

    Extra tip: I found out that if I have them ship to my work address, I get next-day shipping for the same cost as slowpoke UPS shipping to home.

    • Thrashy says:

      Surfing the McMaster-Carr site is like being a kid in a candy store, except for that the candy store is the size of a city block and accessed though a glowing rectangle of light. Also, the candy is three times more expensive than it should be, but where else are you going to find a reverse acme-threaded nylon… uhm, chocolate bar? I think I bent this metaphor past the breaking point.

      • P161911 says:

        I remember 15 years ago or so when they just had 6" thick catalogs, that seemed to be hard to come by. I was lucky to get one three or four editions old.

        "Oh look, you can get left-hand threaded whitworth bolts in titanium!"

      • wunno sev says:

        If surfing the website is like being a kid in a candy store, the will call station is like being at the gates of Wonka's factory but not allowed to go in. Or take pictures.

      • Tanshanomi says:

        That's okay. You can weld it.

  8. Tiller188 says:

    As an aspiring gearhead/hoon who really hasn't done much hooning or getting his hands dirty (other than on an FSAE car, which is quite a bit different…), I love the Wrenching Tips series. Thanks for being willing to share your pain…er, knowledge, with us, Mr. _Science.

  9. MattC says:

    Sounds like me trying to replace the blower fan on a 2001 GMC Sonoma. GM in its infinite wisedom decided to place the blower fan on the firewall. That in itself is not the problem. . However, in order to remove it, you must remove the ECM, then the radiator overflow tank, followed by removing 5 5.5mm bolts. The problem lies in that it is next to impossible to get to the lower 2 bolts without removing the inner fenderwell. I wound up breaking 2 bolts in order to remove the blower fan.

  10. Alff says:

    Thanks for the write up. One question … Did Mrs. Science make you spend a few nights alone in that swell looking motel as penance?

  11. buzzboy7 says:

    1) I have always loved your tudor, since I set eyes on it on the Falcon Pages.
    2) Make sure you give the Pertronix 12 volts. I missed that step and fried my Pertronix unit after like 3 months of 8 volts.

    • Mad_Science says:

      Im curious…what source on your car was outputting 8v? Did you just have a bum generator or is there something funky in the original wiring?

      As far as I know the source line Im using is 12V. All this work took place a year ago, with no problems yet.

      • buzzboy7 says:

        I pulled power off of the ignition, because that's how my VW was wired for years. Turns out that the stock ignition uses high resistance wire to bring the voltage down to 8v. Never would have thought that.

        • themagicboltbox says:

          Right – points will burn up if they get constant 12v, so there's either a resistance wire or a ballast resistor to knock it down a bit.

  12. dukeisduke says:

    Good carburetor choice. The Carter AFB Edelbrock is an excellent performance carb. And unlike a Holley, it doesn't leak in 27 different places.

  13. dukeisduke says:

    And as for sealants go, I'm old school – I still use Permatex #2.

  14. jeepjeff says:

    Awesome write up. Unfortunately, that sounds a little too much like my cylinder head swap job… Next time I have to do any surgery in the engine bay, I'm going to a shop to get the A/C depressurized, and then I'm going to yank it and sell it. Bloody useless thing, and the hard lines get in the way of everything. Those were the main obstacle for getting the head out.

    I still haven't admitted to anyone on here what bits of bodging I pulled on the cylinder head job…

  15. HTWHLS says:

    I'm sorry..I didn't see any problem or issues with this job…that's part for the course!

  16. failboat says:

    reminds me of my recently completed timing belt job…….first time doing one and mostly a learning experience. I didnt blow anything up but did have to fuss around with belt tensions because I got the timing belt too tight, the tensioner pretty much required complete disassembly to get to (aka mostly doing the whole job again) then rushing when putting things back together and not tightening a bolt all the way, causing the crank pulley to snag on it, causing me to pull everything apart to fix that (aka mostly doing the whole job again). lol. well at least I can change this damn belt in about an hour now.

    It only took me a month to get things right. (whats that saying about finding time to do the job again?)

  17. LTDScott says:

    Pro-tip for laying the intake down onto the block: Cut down some bolts which use the same threads as the intake manifold to use as locating studs. Most of the time, the reason you'll have a problem sealing the intake to the block/heads is because the intake moves around as you're sitting it down. Using studs eliminates that possibility.

    I have pulled the intake on my LTD more times than I care to think about.

  18. Matt says:

    Yep that 'bout sums up a swap with my and my Pops. I guess that's why they say when you set a budget to double it or worse case triple it and that's how much it'll really cost ya.

  19. gearhead says:

    Being a small-block Ford guy, I've done this job at least two hundred times. You know that Ford mentions special intake manifold alignment pins in their service manuals? My '65 Mustang/Falcon/Fairlane manual gives instructions to make these yourself: I made a set 30 years ago, and it's been one of the best investments I've ever made.

    Also, if you got the correct carburetor for your application (instead of one of those one-size-fits-most fuel flushers) your linkage would have popped right in place with no issues.

    • Mad_Science says:

      Talking about a 4100?

      Thought about it, but when I was searching, I couldn't seem to find one that was reasonably priced and not in need or a rebuild. Also, the Carter/Edelbrock design is the only carb I actually understand the inner workings of.

      Doing a quick search on eBay motors right now, the results actually have me reconsidering my decision…

  20. Big_B says:

    Did this swap years ago on my 289. I couldn't believe how heavy that old manifold was compared to the Al one. Also had problems with the alignment – installed two studs to help with that. For linkage, get two small heim joints with some threaded rod in between them. Cut down a piece of brake line housing that fits over the threaded rod for a smoother look. Cheap cheap and solid.

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