intake gasket which one?
Thread Starter
Pro
Joined: Jan 2003
Posts: 567
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From: Oswego Illinois
intake gasket which one?
Just one quick? guys as I dont have a micrometer could tell me what size ports I should order for my intake manifold gasket and if I know there is diff kinds I read on the forum that someone had somthing blocked on their gasket and some left it open/
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: intake gasket which one? (vetteguy216)
If your heads and base are stock AutoZone has the FelPro upper/lower intake gasket sets (usually) in stock.
I use FelPro gasket set P/N MS-93318; the package says that this set is for Chevy 350 V8, 1986-'93. The intake base-to-heads gaskets have the blocked off (with only a steam vent hole) water passage on the rear of each gasket. These gaskets are listed as FelPro P/N 93317/93318=left/right side.
These are the style gaskets that came OEM on the car and I've used them for replacements with no problems.
I use FelPro gasket set P/N MS-93318; the package says that this set is for Chevy 350 V8, 1986-'93. The intake base-to-heads gaskets have the blocked off (with only a steam vent hole) water passage on the rear of each gasket. These gaskets are listed as FelPro P/N 93317/93318=left/right side.
These are the style gaskets that came OEM on the car and I've used them for replacements with no problems.
Le Mans Master
Joined: Apr 2000
Posts: 6,341
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From: Shelton CT
Re: intake gasket which one? (65Z01)
WHy is that rear coolant port blocked off?
The gaskets for my '85 have that always open.. The car runs damn cool too.. always under 200 even under racing..I barely use my fans now in town..(I went to a 160degree thermostat from the previous 185.
The gaskets for my '85 have that always open.. The car runs damn cool too.. always under 200 even under racing..I barely use my fans now in town..(I went to a 160degree thermostat from the previous 185.
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
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Re: intake gasket which one? (MrNuke)
I'm not sure why it's blocked off, except for the small steam hole, but it started with the '86 L98 so may be related to design of coolant flow in the Al heads.
Also my intake base has a small hose running to a heater hose, which I believe wasn't present with the earlier iron heads. So, something differs there with coolant flow.
Also my intake base has a small hose running to a heater hose, which I believe wasn't present with the earlier iron heads. So, something differs there with coolant flow.
Race Director
Joined: Aug 2000
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Re: intake gasket which one? (MrNuke)
Ive used the Fel Pro gaskets and love the fit and finish.Ive too wondered why the rear water ports were blocked off,but with a small hole.Ive heard reasons such as to stop a water/air pocket bubbling noise that was a complaint on earlier TPI cars.Another was to increase warm up temps faster in the back of the block.
Oh well.
Btw,be sure the fel pros are for your year car.I know the 84 and 85 cars had a heat riser passage in the intake and the later 86 and up did not for egr so the gaskets may have the heat riser blocked off on the later years.I cant remember if my fel pro gasket had the heat risers blocked off on them or not but something to check when buying the correct gaskets.
Oh well.
Btw,be sure the fel pros are for your year car.I know the 84 and 85 cars had a heat riser passage in the intake and the later 86 and up did not for egr so the gaskets may have the heat riser blocked off on the later years.I cant remember if my fel pro gasket had the heat risers blocked off on them or not but something to check when buying the correct gaskets.
Team Owner
Joined: May 2002
Posts: 24,337
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: intake gasket which one? (MrNuke)
WHy is that rear coolant port blocked off?
The gaskets for my '85 have that always open.. The car runs damn cool too.. always under 200 even under racing..I barely use my fans now in town..(I went to a 160degree thermostat from the previous 185.
The gaskets for my '85 have that always open.. The car runs damn cool too.. always under 200 even under racing..I barely use my fans now in town..(I went to a 160degree thermostat from the previous 185.
Only the two ports at the front of the engine flow coolant into the intake base, and it stays up front too.. it only goes to the temp sensors, tb heater line, and thermostat. The pass side center port is egr and the drivers side center port dead ends.
Note: This all applies to 85 intake base.
[Modified by CentralCoaster, 1:47 AM 4/26/2003]
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: intake gasket which one? (vetteguy216)
Stock or 'small port' is 1.23" x 1.99" and uses a Felpro 1204. Then there are the 'medium race' and 'large race' ports that use Felpro 1205 / 1206 respectively.
The rear coolant crossover doesn't "go" anywhere; it just connects the coolant passages of the two heads, presumable to balance pressure. To get out of the block the coolant has to flow to the front of the heads, into the front manifold x-over, then out the water outlet. Folk who need to cool the rear of the heads better tap a NPT fitting into the rear and run aeroquip lines to a space under the water outlet. Then coolant exits the heads at all 4 corners.
The exhaust heat riser does nothing more than heat up your intake air and worsen performance. It's an emissions thing. I think on the earlier models it might feed the EGR; but later alum head models get EGR via a pipe from the R exhaust manifold.
The rear coolant crossover doesn't "go" anywhere; it just connects the coolant passages of the two heads, presumable to balance pressure. To get out of the block the coolant has to flow to the front of the heads, into the front manifold x-over, then out the water outlet. Folk who need to cool the rear of the heads better tap a NPT fitting into the rear and run aeroquip lines to a space under the water outlet. Then coolant exits the heads at all 4 corners.
The exhaust heat riser does nothing more than heat up your intake air and worsen performance. It's an emissions thing. I think on the earlier models it might feed the EGR; but later alum head models get EGR via a pipe from the R exhaust manifold.
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