Intake Manifold Removal & Install

[Ryan5O]

I was going to remove my intake manifold this weekend so that I could clean it up and paint it. I've never done it before, but it seems pretty straight forward. Are there any foreseen problems that anyone can advise me of? Ive got a new gasket, silicone and a torque wrench. The manifold is on the original 350. Thanks in advance.

[68gmsee]

About the only thing I can think of at the moment is the distributor removal and replacement. Read up on the how to's first if you're not familiar with doing it.

I always take the cap off, set my engine at TDC with the #1 piston on the compression stroke and then mark the location of the rotor. Note how the rotor will turn slightly when you remove the dis. You will have to rotate it the exact amount when reinserting it so that it will rotate back to the original position.
Be sure and not move the crank otherwise you will lose the positioning.

[PanelDeland]

^ what he said^ plus make sure the dist goes all the way back to the bottom on the flange.It drives the oil pump.Put rags in the intake ports to keep "junk"(old gaskets and such) out while cleaning mounting surfaces.Don't use the end gaskets,run a good bead of sealer on the surface of the block and use the gaskets between the mani and heads,I have never been able to get the end gaskets to seal.There are some threads and better discriptions on here but I don't have links.

[domeier]

You can use your digital camera to take a photo of the rotor position before you pull the distributor.

[sean1969c10]

I know it might sound silly but, remember to drain the Anti-freeze. I have seen people skip this and make a mess!!!

[Ryan5O]

Ive never understood the importance of setting the engine TDC in ref to removing and installing the original distributor. Shouldnt I just be able to mark the location of the distributor housing and the rotor, remove it, then install it in the same position assuming the motor hasnt been cranked over?

[MacGyver72]

Yes you can. You obviously know to mark the rotor position since you specifically referred to that and therefore have wrenched pretty deep on motors before. When I removed my first intake, I failed to buy valve cover gaskets not realizing that there was a lip on the valve covers preventing the intake from coming off. Lessons learned.........and I always seem to get the timing 180 degrees off on a new build. You should have no issues but do drain the antifreeze and plug the intake ports. As for the end gaskets, if you have a block with locator holes for them, I would use them with a very small amount of gasket sealer. I've never had issues with that kind. Also be sure to follow the torque specs and the correct tightening pattern for the intake bolts. One final thing. Be sure to remember any brackets or wire hold downs that go on the intake bolts. I've tightened many an intake only to loosen it again to put some bracket back on the bolts I forgot.

[68gmsee]

Originally Posted by Ryan5O

Ive never understood the importance of setting the engine TDC in ref to removing and installing the original distributor. Shouldnt I just be able to mark the location of the distributor housing and the rotor, remove it, then install it in the same position assuming the motor hasnt been cranked over?

As Macgyver said, yes.

It's not an "importance" issue but a habit with me. You can mark it anyway you want as long as you remember the position before and after. I've done it both ways but usually when I taken the intake off, it's because I'm doing some other major work on the engine like valve job or engine rebuild. Marks tend to disappear.

[Ackattack]

Throw away the end gasket and run silicone. The first time I did an intake manifold gasket (many years ago) I didn't do that......and got to re-do the gasket a second time.


I get to replace the intake manifold gasket today on my 91 TBI donor engine too...fun times!

[OJ1988]

Only put enough silicone on the gaskets to hold them in place.

[yuccales]

ALL of the above. I have allways started with a brush and a shop vac held close, make that engine spotless before yanking that intake. Great time to clean out the carbon build up in the crossover port also. Also put some silicone on the shanks of the center intake bolts, to stop that peskey oil seepage.

[Ryan5O]

Cool guys. Thanks again for the input.

[Stricklinator]

Originally Posted by yuccales

ALL of the above. I have allways started with a brush and a shop vac held close, make that engine spotless before yanking that intake. Great time to clean out the carbon build up in the crossover port also. Also put some silicone on the shanks of the center intake bolts, to stop that peskey oil seepage.

X2 on putting silicone on the center bolt shanks. I forgot to do that and now have oil seeping up on the driver's side center bolt.
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[leddzepp]

Originally Posted by Stricklinator

X2 on putting silicone on the center bolt shanks.

X 3 on that.

[stomper]

Careful not to overtighten the intake bolts. You may tend to want to but the way the geometry all works one side pulls against the other and they want to pull the intake apart as much as pull the intake down tighter.
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[wilbilt]

When using silicone sealant in place of a gasket - as on the ends of the intake manifold - be sure to follow the instructions. You want to lay down a small bead (not smear it all over), and then let that bead set up for a few minutes before setting the manifold on it.

[Lippyp]

I did my first one this year with help from the guys on here and it went spot on thanks to the helpful hints and tips. Hardest part for me has been getting it timed right afterwards but thats probably more down to me than the engine!

[D.PASSMORE]

Intresting, this my project for the day. I used the wrong gasket on the intake manifold. I grabbed a generic one out of a old engine gasket set that I had laying around. Wrong! It leaks! So I had to reserch and found that a FEL-PRO 1256 is the right one - ie: port size dimensions and recommended by World products and Wieand for my heads/manifold.
So the process: ** Disconnect Battery**
1. Drain Antifreeze/ remove manifold heater hose / top radiator hose
2. Clean motor - top
3. remove plugs (tag wires) / distrib cap (tag wires) / valve covers - set to TDC (tag your wires!). Use timing tab and balancer mark. Distributor rotor should point to #2 or #4 plug.
4. Remove carb / coil / brackets / distributor / wiring
5. Unbolt intake / remove
6. Stuff clean rags in all openings that leads to the bottom of motor
7. Clean/scrape all gasket material off heads and manifold / lifter valley / intake ports (shop vac - good tool)
8. Match gaskets with heads and intake to ensure correct fitment.
9. Use skim coat of silicone (RTV - Blue) around ports - intake and heads and BOLTS.
10. Install intake manifold / install bolts / tighten in sequence / then tourqe in sequence.
11. Install carb / coil / brackets / distributor - distributor rotor should point to #2 or #4 plug. If it will not seat correctly you might have to slightly turn the oil pump shaft CW or CCW. PIA - use large screw driver, flashlight and small mirror. When reinstalling your plug wires you should have marked them to the corresponding cylinders. No problems then. Wiring: ensure pos wire is on positive side of coil post and negative wire is on neg side. Do not over tighten little nuts.
12. Reinstall valve covers - these will leak sometimes / you will need new gaskets or ensure they are solid. Do not over tighten the screws.
13. Look everything over one time - have a adult beverage - get your timing light out / Set it up.
14. Account for all your tools
15. Refill Radiator / Reconnect the battery / timing light / turn the motor over / might have to play with distrbutor - turn CCW a little. Should fire up!
16. Set timing to 8 to 12 dergree BTC.
17. Test drive....

Have fun!

[Ryan5O]

When I pulled my distributor, I noticed that it didnt have a seal. Are they necessary?

[D.PASSMORE]

Yeah or you will get a small oil leak there. Can't really use RTV, as the distributer will have to rotate.

[treveiger]

All the above. Make sure you clean the bolts properly to ensure proper torque, I also use a little non hardening thread sealer to ensure no leaks! I hate leaks an any bolt hole that had no bottom to it got thread sealer an haven't had a leak yet first time ever doing this kinda stuff too.
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[yuccales]

Originally Posted by Ryan5O

When I pulled my distributor, I noticed that it didnt have a seal. Are they necessary?

Yep. You should have a thin gasket kinda about as thick as a thermostat housing gasket. Good luck on the project.

[Ryan5O]

Well, Ive done it now. Got everything back together, but cant get it to run It will start and idle like crap. When I put it in gear, the engine dies. Not getting any pinging or backfires. Its hard to start; have to put the pedal to the floor. Kinda seams like its not getting any fuel. Any ideas?

[Ryan5O]

By the way, Ive got a friend cover over with a timing light this evening. Im hoping thats all it is.

[yuccales]

Check for vaccum leaks, firing order & timing.