MonteCarloSS.com
MonteCarloSS.com

CELEBRATING 20 YEARS!

Previous Thread
Next Thread
Print Thread
#1072285 - 10/22/21 02:06 AM Intake manifold warpage  
Joined: May 2007
Posts: 5,043
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 5,043
Dharma station 1 the Hydra
After fighting stubborn vacuum leaks, I determined that the intake manifold gaskets were leaking on both banks, especially bad by cylinders 6 and 8. Pulled the intake which is a used GM ZZ4 intake manifold and took a straight edge to it. The passenger side is pretty straight but the driver side has a .015 warpage at the 6/8 cylinder ports. Next step I guess is to measure the old intake gaskets tosee how crushed they are in various spots.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1072289 - 10/24/21 04:24 AM Re: Intake manifold warpage [Re: Buick Runner]  
Joined: May 2007
Posts: 5,043
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 5,043
Dharma station 1 the Hydra
Researching online about this issue I found that for V8s, the intake manifold should not be more than .004 out of flat from end to end. This means the .015 warpage I have is more than triple the max deviation.

I still have the original L69 intake in the barn. Checked it out with the straght edge and its flat. However, the rear coolant ports have pretty bad erosion and likely also requires repairs. Sigh.

Last edited by Buick Runner; 10/24/21 04:28 AM.

SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1072294 - 10/25/21 04:20 PM Re: Intake manifold warpage [Re: Buick Runner]  
Joined: Apr 2011
Posts: 1,200
Hunter79764 Offline
10+ Year
Hunter79764  Offline
10+ Year
Member

Joined: Apr 2011
Posts: 1,200
Grand Prairie, Tx
It's always something... Glad you got the problem diagnosed at least. Seems that is more than half the battle sometimes.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1072295 - 10/25/21 06:26 PM Re: Intake manifold warpage [Re: Buick Runner]  
Joined: Feb 2020
Posts: 561
88ssBrent Online content
Member
88ssBrent  Online Content
Member

Joined: Feb 2020
Posts: 561
Friendsville
Vacuum leaks are never fun but as Shawn said atleast you have it narrowed down.

#1072317 - 10/27/21 04:19 PM Re: Intake manifold warpage [Re: Buick Runner]  
Joined: May 2007
Posts: 5,043
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 5,043
Dharma station 1 the Hydra
The leak didn't show up with the smoke test. Through I performed it while the engine was cold so maybe they were sealed enough when cold not to leak? Once the engine heated up the leaks became worse. Unlit torch test sure found the leaks.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1072416 - 11/06/21 04:06 AM Re: Intake manifold warpage [Re: Buick Runner]  
Joined: May 2007
Posts: 5,043
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 5,043
Dharma station 1 the Hydra
Finally got a replacement used ZZ4 intake. Good news is that its nice and flat. Bad news is that the bottom isn't drilled for a heat shield like my old ZZ4 intake. The replacement has the bosses for the rivet holes but they aren't drilled. Probably GM cost cutting.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1072421 - 11/07/21 01:00 AM Re: Intake manifold warpage [Re: Buick Runner]  
Joined: May 2000
Posts: 1,871
BadSS Offline
20+ Year
BadSS  Offline
20+ Year
Member

Joined: May 2000
Posts: 1,871
Pearl, MS, 39208
Glad you found a replacement - drilling and tapping holes for a machine screw with lock washer (dab of loctite to boot) isn't that bad a deal. I know you'll be happy to get rid of the vacuum leak!

#1072437 - 11/09/21 01:42 AM Re: Intake manifold warpage [Re: Buick Runner]  
Joined: May 2007
Posts: 5,043
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 5,043
Dharma station 1 the Hydra
Bolted the intake on today, hopefully it will seal and remain sealed this time. Bought a new set of GM metal shim style intake gaskets but using RTV on the china walls. Used my old beam type torque wench as I trust it more than the clicker types. The space for the middle bolts are so tight I have to use a 9/16 U joint style socket. Not enough room for a regular socket and a separate U joint. I can see why GM changed the intake manifold bolt angle in 87.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.

Random Images
548/thumbs/DSC004871.JPG
by 84supersport
500/thumbs/10-13-06_4_.JPG
by Monte83
500/thumbs/DSC_0024.JPG
by wanadrv
500/thumbs/DCFN0004.JPG
by madmax74
500/thumbs/Resized_Choice_1.jpg
by s10bowrider
Help MonteCarloSS.com


Recent Contributors
86BlackSuperSport
dns87ss
Authorized Vendors
Tell them you saw it
on MonteCarloSS.com!


CustomMonteSSParts.com
Dixie Monte Carlo Depot
GSI Interiors
HRpartsNstuff
Mikes Montes
Savitske Classic & Custom
Powered by UBB.threads™ PHP Forum Software 7.6.0