88 c4 Intake Manifold question
Thread Starter
Instructor
Joined: Oct 2013
Posts: 121
Likes: 6
88 c4 Intake Manifold question
So I'm breaking down the top of my L98 to swap out the head gaskets. After breaking several T-40 Torx bits (Sears saved me with a T45 hardened bit) I removed the intake and noticed that the drivers side rear port had a metal piece from the manifold gasket...when I swap out a new gasket should I remove that foil to allow the coolant to flow through the back of the intake journals? Also who makes a good intake manifold bolt kit?
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Do yourself a favor and buy Allen head cap screws , more common and generally cheaper than the Torx style , less prone to stripping the head out
From any engineering supply or nut and bolt shop
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
I would suggest getting the intake gaskets with the rear restrictors when you replace the intake manifold.. I asked this same question a few years ago on here about which intake gaskets to get for my 89 and almost everyone said to go with the stock gaskets with the restrictors...There also the ones listed in the Factory Service Manual....WW
Here's the whole kit with the proper intake manifold gaskets and all the runner and plenum gaskets....
http://www.summitracing.com/parts/fe...make/chevrolet
.
.
.
.
Here's the whole kit with the proper intake manifold gaskets and all the runner and plenum gaskets....
http://www.summitracing.com/parts/fe...make/chevrolet
.
.
.
.
Last edited by WW7; Nov 9, 2013 at 08:50 PM.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
Gentlemen, they are not restrictors, because there's no flow across the back of the tpi intake. I think they were more of a plug.
To the OP: using Felpro blue coated gaskets with a thin layer of silicon at the water jacket ports only will reduce the electrolysis GM created with the stock steel gasket. Do not use silicon at intake ports.
To the OP: using Felpro blue coated gaskets with a thin layer of silicon at the water jacket ports only will reduce the electrolysis GM created with the stock steel gasket. Do not use silicon at intake ports.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
Gentlemen, they are not restrictors, because there's no flow across the back of the tpi intake. I think they were more of a plug.
To the OP: using Felpro blue coated gaskets with a thin layer of silicon at the water jacket ports only will reduce the electrolysis GM created with the stock steel gasket. Do not use silicon at intake ports.
To the OP: using Felpro blue coated gaskets with a thin layer of silicon at the water jacket ports only will reduce the electrolysis GM created with the stock steel gasket. Do not use silicon at intake ports.
Last edited by WW7; Nov 9, 2013 at 08:55 PM.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
There is a bleed port (brass plug by the dist in pic ) from the rear coolant crossover that the GM engineers installed because apparently
they thought there might be a problem with air or steam pockets on the new alum heads
The aftermarket didn't agree so most AM intakes have no rear coolant port at all.
Last edited by vetteoz; Nov 9, 2013 at 09:13 PM.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
Sorry but my 89 has coolant in that rear crossover, there's also a small coolant line going from that crossover to a tee in the heater hose on my car....I remember hearing something about the restrictors were to keep the rear of the head from running colder then the front of the head..Those gaskets have a small hole in them to restrict flow...WW
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
No problem Mr ******...
...It looks like the restrictors were only used on the 305 and 350 cars from 86-91, but they were used on SB chevy trucks for a longer period....From what vetteoz says it looks like they really aren't needed at all since most of the aftermarket companys don't use them and they don't have any problems.....WW
.
.
.
.
.
...It looks like the restrictors were only used on the 305 and 350 cars from 86-91, but they were used on SB chevy trucks for a longer period....From what vetteoz says it looks like they really aren't needed at all since most of the aftermarket companys don't use them and they don't have any problems.....WW.
.
.
.
.
Last edited by WW7; Nov 10, 2013 at 09:12 AM.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
No problem Mr ******......It looks like the restrictors were only used on the 305 and 350 cars from 86-91, but they were used on SB chevy trucks for a longer period.. I agree with vetteoz on the after market intakes because my 383 with the Edelbrock intake didn't have coolant in the rear crossover, it was blocked off , only the stock intakes used them...WW
...It looks like the restrictors were only used on the 305 and 350 cars from 86-91, but they were used on SB chevy trucks for a longer period.. I agree with vetteoz on the after market intakes because my 383 with the Edelbrock intake didn't have coolant in the rear crossover, it was blocked off , only the stock intakes used them...WWHonestly, I don't see the purpose. Too me it would seem to be a stagnant flow by design?
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
....WW
Last edited by WW7; Nov 9, 2013 at 09:53 PM.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
I will only add this for the OP. I would avoid using a steel piece between two aluminum items if it were me. I do like the idea of a bleed off as Vettoz mentioned to avoid any air pockets. Too me, adding electrolysis to a coolant system when it can be avoided is nuts. I think GM screwed the pooch on this one unless you do have a way to bleed this off.
I know I'm not the only one to pull off a GM intake with steel gaskets and have to have it welded and milled?
I know I'm not the only one to pull off a GM intake with steel gaskets and have to have it welded and milled?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
My '86 with cast iron heads does have the crossover passage in the rear of the intake manifold. I left the restrictors out. It's been about 10 years and I haven't seen any problems.
I also have a so-called "steam tube" that connects to the place previously shown (post #7) with the brass bleeder that goes to the heater core tubes.
I also have a so-called "steam tube" that connects to the place previously shown (post #7) with the brass bleeder that goes to the heater core tubes.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Many of us have deleted or fitted an aftermarket intake will no ill effect on the heads.
http://forums.corvetteforum.com/1567214670-post3.html
http://forums.corvetteforum.com/1543964236-post18.html
http://forums.corvetteforum.com/1543960976-post14.html
http://forums.corvetteforum.com/1543971416-post19.html
http://forums.corvetteforum.com/c4-t...g-removed.html
Possibly it is like the TB heater , there to cover all possible bases?
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
I would suggest getting the intake gaskets with the rear restrictors when you replace the intake manifold.. I asked this same question a few years ago on here about which intake gaskets to get for my 89 and almost everyone said to go with the stock gaskets with the restrictors...There also the ones listed in the Factory Service Manual....WW
Here's the whole kit with the proper intake manifold gaskets and all the runner and plenum gaskets....
http://www.summitracing.com/parts/fe...make/chevrolet
.
.
.
.
Here's the whole kit with the proper intake manifold gaskets and all the runner and plenum gaskets....
http://www.summitracing.com/parts/fe...make/chevrolet
.
.
.
.