LT1 Intake Manifold - Sigh
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,340
Likes: 1
From: St. Petersburg, Fla.
LT1 Intake Manifold - Sigh
In reality, how hard is it for the moderately skilled mechanic to replace the intake gaskets on a late-model LT1? I've researched and read a ton of write-ups on here today, but decided to ask those who have tackled it already.
I'm having a hard time coming to grips with the fact that I'm going to have to change the gaskets (was hoping and praying it was the valve covers), but when trying to replace my negative battery cable last night I hit another 'oil field' of grime on that end of the block (driver side rear, behind the #7 cylinder). The fact that a lot of grime has built up there combined with everything I've been having to clean on the front of the engine (doing the Opti replacement and hit an oil field of grime that would make the Saudi's take note) point to one thing - a badly leaking intake in areas notorious for leaks, with only 77k on the clock.
I'm just trying not to face the facts right now, but while the front of the engine is disassembled, it may be in my best interests...
...I'm having one of those moments we all talk about where it feels like it's never-ending and I will never get it put back together and on the road again.
I'm having a hard time coming to grips with the fact that I'm going to have to change the gaskets (was hoping and praying it was the valve covers), but when trying to replace my negative battery cable last night I hit another 'oil field' of grime on that end of the block (driver side rear, behind the #7 cylinder). The fact that a lot of grime has built up there combined with everything I've been having to clean on the front of the engine (doing the Opti replacement and hit an oil field of grime that would make the Saudi's take note) point to one thing - a badly leaking intake in areas notorious for leaks, with only 77k on the clock.
I'm just trying not to face the facts right now, but while the front of the engine is disassembled, it may be in my best interests...
...I'm having one of those moments we all talk about where it feels like it's never-ending and I will never get it put back together and on the road again.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
If you're able to replace the Opti, the intake is a cake-walk.
- remove the throttle body
- remove the fuel rail/injectors as an assembly (leave the fuel lines attached) and lay it on a towel on the windshield
- remove other misc electrical connectors and sensors
- unbolt intake
After cleaning the end walls, use "The Right Stuff" vs regular RTV for the end seals. It costs about $10 more, but worth every penny.
After you've done a few, the r&r of an LT1/4 intake takes 90 minutes or less.
- remove the throttle body
- remove the fuel rail/injectors as an assembly (leave the fuel lines attached) and lay it on a towel on the windshield
- remove other misc electrical connectors and sensors
- unbolt intake
After cleaning the end walls, use "The Right Stuff" vs regular RTV for the end seals. It costs about $10 more, but worth every penny.
After you've done a few, the r&r of an LT1/4 intake takes 90 minutes or less.
Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
I've never done it on a LT1, but I've done it many times on a L98 (and I'd say a LT1 is probably easier). It's a fairly straight forward job that I would think almost anyone with a few tools a little know-how could easily do. Take your time, take digital pictures at all stages of dis-assembly, label things (hoses, electrical connectors) and you'll be fine. Also use some ziplock bags to help you organize bolts, parts, etc when they come off. I would say even taking your first time you can do it in a day. At worst, give yourself a weekend.
Racer
Joined: Nov 2005
Posts: 310
Likes: 47
If you're able to replace the Opti, the intake is a cake-walk.
- remove the throttle body
- remove the fuel rail/injectors as an assembly (leave the fuel lines attached) and lay it on a towel on the windshield
- remove other misc electrical connectors and sensors
- unbolt intake
After cleaning the end walls, use "The Right Stuff" vs regular RTV for the end seals. It costs about $10 more, but worth every penny.
After you've done a few, the r&r of an LT1/4 intake takes 90 minutes or less.
- remove the throttle body
- remove the fuel rail/injectors as an assembly (leave the fuel lines attached) and lay it on a towel on the windshield
- remove other misc electrical connectors and sensors
- unbolt intake
After cleaning the end walls, use "The Right Stuff" vs regular RTV for the end seals. It costs about $10 more, but worth every penny.
After you've done a few, the r&r of an LT1/4 intake takes 90 minutes or less.
http://www.amazon.com/Permatex-25224...Permatex+25224
What is a good choice for the intake gaskets (I have a 1990 L98)? Job does not sound too bad. Looks like the valve coves stay put. How tough is it to pull the intake once its unbolted? Is it usually stuck on to the point where you have to break it free and, if so, where is the best place to do that on the intake?
Thanks.
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,340
Likes: 1
From: St. Petersburg, Fla.
Do you have a part number on the Right Stuff. I found this one on Amazon.com (Permatex 25224) and that looks like what you are describing:
http://www.amazon.com/Permatex-25224...Permatex+25224
What is a good choice for the intake gaskets (I have a 1990 L98)? Job does not sound too bad. Looks like the valve coves stay put. How tough is it to pull the intake once its unbolted? Is it usually stuck on to the point where you have to break it free and, if so, where is the best place to do that on the intake?
Thanks.
http://www.amazon.com/Permatex-25224...Permatex+25224
What is a good choice for the intake gaskets (I have a 1990 L98)? Job does not sound too bad. Looks like the valve coves stay put. How tough is it to pull the intake once its unbolted? Is it usually stuck on to the point where you have to break it free and, if so, where is the best place to do that on the intake?
Thanks.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
You have to completely dismantle the intake , plenum , runners , before you can access the intake base
Almost sure to need to pull the covers to get at the bottom runner bolts
LT1 is a cake walk in comparison .
I suspect a intake virgin would take at least double the time to do a L98 over a LT1;
there is three times the number of bolts ( of varying lengths that only go in one location) for starters,
you have to drain the coolant which you don't have to do on a LT1 ,etc........
Have had to put a length of water pipe in the TB hole and lever plenum loose on some stubborn ones.
If intake base can not be lifted from heads, then same applies .
Hit with rubber hammer to crack loose, have also had to use a length of pipe in one of the ports to crack the base loose
Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
Do you have a part number on the Right Stuff. I found this one on Amazon.com (Permatex 25224) and that looks like what you are describing:
http://www.amazon.com/Permatex-25224...Permatex+25224
http://www.amazon.com/Permatex-25224...Permatex+25224
Racer
Joined: Nov 2005
Posts: 310
Likes: 47
Would I be wise to use this same gasket material for the valve covers? Also, does anyone recall seeing a thread (with pictures) of the intake removal and reinstall on an L98? I found this one and it looks pretty thorough and covers just about everything including the various size bolts:
http://www.corvettefever.com/techart...ake/index.html
If anyone has another set of photo step-by-step instructions, that woould be great.
http://www.corvettefever.com/techart...ake/index.html
If anyone has another set of photo step-by-step instructions, that woould be great.
Last edited by summerst; Jun 18, 2012 at 01:46 PM.
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Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
R/R the rocker covers many times on stock and aftermarket heads with no problems or leaks reusing the same gasket
Perimeter bolt heads are completely different; need to glue the gasket in place on the cover otherwise it will lift out of it's seat and allow leaks.Tightening the bolts only squashes gasket out further