Anyone else run into this problem with later (TBI-era?) intake gaskets?

[dyeager535]

Buddy has a 1990 Suburban. Intake has the heater outlet at the rear, meaning it is fed from the passenger side coolant port from the head.

He purchased a Fel-Pro gasket set (complete engine or top end kit, not just the intake gaskets) that were supposedly for his truck.

Turns out the rear ports on both gaskets are stamped (steel insert with fiber covers) closed, with maybe an 1/8" hole. Since they are stamped as part of the core of the entire gasket, we both felt drilling was risky, since it would be possible the bit would grab and deform the metal. Cutoff wheel would be another option, but he says the fel-pro gasket metal is covered in a sealant, which if penetrated would then allow corrosion potentially throughout the gasket.

Obviously that gasket is incorrect. I pulled out a set of OEM (GM) gaskets I have for a Camaro/Firebird SBC of late 80's vintage, and they are correct, fully open at both ends of both intake gaskets.

Looks to me like Fel-Pro 1205 is the right intake gasket kit for an engine setup like his Suburban, according to the pictures anyway.

I suppose this is just a warning for anyone buying gasket kits for an engine that uses the rear heater port on the intake....make sure the intake gaskets are correct!

Not his exact gasket, but same idea. Proper on top, incorrect on bottom (can't hotlink the image apparently):

https://ww2-secure.justanswer.com/uploads/ggrote1/2012-07-08_121216_intake.jpg

 

[nvrenuf]

Do his gaskets have the part number stamped in them (most Fel Pro intake gaskets do)? Just wondering if by getting a engine set, instead of intake only, could the gaskets be more generic?

It's been a while but I remember doing intake gaskets on my 91 V3500, everyone warned me about a heater hose fitting that was notorious for being rotten and breaking off but the fitting on my truck was different than suggested, more "typical" with a fitting screwed in to the intake. Iirc, the difference ended up being that the problematic fitting was on C/K trucks but not the R/V series, perhaps there's a different intake between the 2 body style trucks.

 

[dyeager535]

I'll ask about part number.

He's worried about that metal line/fitting, and would have liked to replace it, but apparently they are unobtanium, or ridiculously pricey. I haven't looked at the setup, but he said the curves and bends essentially require a metal tube, rubber hose would kink.

 

[soonertodd]

Did my intake last summer,you gan get a nice metal fitting that will screw into the intake for the heater hose and if you route the hose correctly it will not kink. I got my fitting at ACE hardware

 

[dyeager535]

Did you use an elbow, straight barb, or...?

 

[soonertodd]

It was straight

 

[1-ton]

When I did the intake manifold on my 1991 TBI I replaced the heater hose intake manifold fitting with a straight one. I then got a hold of a heater hose that had a molded 45 degree bend in it to go over the valve cover like it did from the factory. From what I have heard the intake manifold rear coolant ports on the TBI engine are restricted, in order to allow the coolant to flow in the correct direction through the block for counter clockwise rotation water pumps.

 

[dyeager535]

I need to run the GM part numbers for the intake gaskets used on those engines and see if I can find a pic of one of the "proper" gaskets. An 1/8" hole I think could lead to noise and lack of heat considering the fitting is ~1/2" ID, and the hose is 3/4".

I've never really considered the reverse rotation pumps operation. Only real difference is which way the impeller is designed to push coolant, I don't believe these are a reverse flow setup like the LT1's. Coolant still goes in the front of the block via the lower hose/pump, up through the heads, and out the intake, just like all previous SBC's, correct?

 

[dyeager535]

Figured out the aftermarket (at least Fel-Pro) is mis-making/labeling their gaskets. Fel-Pro 93317 and 93318 is what came in my buddies kit.

The GM part numbers for the intake gasket kits are as follows, for selected engines/years out of the C/K/R/V parts manual:

1986 305 14071744
87-89 305 10054520
90-91 350 10159409

87-89 305 is the one that uses blocked off rear ports. GM gaskets are still out there to visually verify this.
90-91 350 does NOT use blocked off rear ports. GM parts verify that these come with knockout plates, unlike the Fel-Pro 93317/18 that is all one piece.

Unfortunately, places like rockauto list both the 305 and 350 gasket GM part numbers as interchangeable with the 93317/93318 Fel-Pro. They are wrong, that's why GM had different part numbers.

I *believe* Fel-Pro 1204 will be fine if purchasing just gaskets, since the coolant ports are wide open.