Detaching GM 454 lower intake manifold

[rationull]

I finally got down to the bolts on my 454 Suburban's lower intake manifold. I've removed 6 bolts from the passenger side and 5 from the driver's side -- the Chilton's manual makes it look like there should be 6 on both sides but I can't find any more, and the "extra" one on the passenger side seems to be there so that there can be a bolt on each side of a heater fitting.

Either I'm missing a bolt that's still in there, or the existing gasket + RTV is just really holding the manifold on there. Any tips for pulling the manifold off these engines? I don't see anything I'd really like to pry against...

 

[Trav]

what year is this 454?

 

[rationull]

Heh, yeah sorry that would be a key piece of information. It's a 1999 Vortec 7400 (GMT400 platform Suburban).

 

[Trav]

Does this help?

Edit: Look for a Torx or Allen head bolt they may have used one and it may be recessed.

 

[rationull]

Hmm, perhaps. That rear-most driver side bolt is pretty close to the corner of the manifold. There's a fuel line bracket at that corner and it's possible it's covering up another bolt. I will have to take it off - hopefully it will move out of the way without disconnecting the injectors and removing the rail.

 

[Trav]

Is the fuel rail on a stud? Normally the rail is real easy to remove.

 

[rationull]

There sure was another bolt down there, because we all know the best place for a bolt is directly under a bracket! Thanks for posting the diagram, that bolt was pretty hard to see without looking specifically for it.

The fuel rail is (was) attached with three bolts which were not bad. Pulling the rail off was kind of a bear -- the injectors were stuck in their holes pretty tight. After straining my hands pretty good and gingerly applying some leverage with a screwdriver I managed to unstick them all and pull the rail off.

I've now removed the last bolt, but am still unable to pull the manifold off. I'm pretty sure it's not attached by anything anymore, other than its gasket, RTV, and years of gunk buildup.

Not sure how hard it's supposed to be to pull off. My arms are pretty sore right now from unrelated work yesterday (I am a weakling computer programmer by day) so it could just be that I'm not pulling hard enough.

 

[yonyon]

Should you find yourself removing another fuel rail in the future, try using a bit of silicone spray lube and rocking the injectors around in a circular motion so the o-rings get wet. Then, you can twist the injectors back and forth while gently pulling up. This pretty much always gets them out easily and without damaging the o-ring. A scuffed lower o-ring becomes a vacuum leak if you don't notice it and put a new one on.

 

[Trav]

They can be a real bear to remove even with all the bolts out, i usually find some place to pry it carefully or yank it by the thermostat housing using a wooden hammer handle for a little extra leverage.

 

[rationull]

Originally Posted By: yonyon
Should you find yourself removing another fuel rail in the future, try using a bit of silicone spray lube and rocking the injectors around in a circular motion so the o-rings get wet. Then, you can twist the injectors back and forth while gently pulling up. This pretty much always gets them out easily and without damaging the o-ring. A scuffed lower o-ring becomes a vacuum leak if you don't notice it and put a new one on.


That would've been a good idea. This V8 has a single fuel rail with injectors coming out in two planes for the two banks, which limited the motion available for rocking them loose.

I was figuring on replacing the o-rings regardless.


Originally Posted By: Trav
They can be a real bear to remove even with all the bolts out, i usually find some place to pry it carefully or yank it by the thermostat housing using a wooden hammer handle for a little extra leverage.


Hmm.. I removed the t-stat housing so I didn't think of that, but maybe it'd be a good idea to put it back on for a spot to pull. I've been kneeling on the upper brace in front of the radiator and trying to pull up through the pass-through air passages in the manifold.

 

[rationull]

Got it off, finally, a few hours ago. I was able to pry at a few spots against a lip on the top of the heads. Sucker was glued on tight with RTV. Was relieved when it finally broke free.

Thanks for the help, guys!

 

[rationull]

Looks like the FelProp MS95826 replacement gasket set is available locally without drama from any auto parts stores, which is nice. I'm hoping/assuming this is the one I've read good things about, and it looks like it's got rubber pieces to seal the front and back where the manifold holds against the block - glad I won't have to use RTV to fill that hole area.

 

[JasonC]

How heavy was that intake?

 

[Trav]

Grab that Fel Pro set through AA and use a coupon code.

$50 off $150 Coupon Code: VISA
35 of $85+ with Coupon Code: RAF7JA1102
$10 off $30, $20 off $50, $30 off $100 Coupon Code: A123
$30 Off $75+ with Coupon Code: BIG30

 

[rationull]

Originally Posted By: JasonC
How heavy was that intake?


I'm probably not that great a weight estimator, but if I had to guess the lower half is maybe 15 pounds, no more than 20, and probably about the same for the upper half.

Trav, thanks for posting the deals. Gotta figure out what else makes sense to buy right now and pick up a batch of parts!

 

[JasonC]

I would have thought that BBC intake would have been at least 50lbs.

 

[rationull]

By my estimate above both halves together could be 40 lbs, and I could be off a bit. All I know was it seems a little heavy to me but not too heavy, and I'm just a weakling.

Keep in mind it's cast aluminum.