Engine Vacuum Leak In Crankcase?

if you used the fel-pro 1250 lower intake gaskets, i would count that as suspect #1. they have a tendency to squirm/distort/tear, especially around the water ports.

pull a valve cover and see if air is coming out the pushrod holes. Chances are the intake gaskets distorted. You could be running rich due to the vacuum leak and the computer is adding more fuel to compensate.

the ms93334 is probably the best quality (steel cored rubber) there is, but its sized for the e7 heads. the 95952 is usually halfway decent if installed correctly (no rtv except the end rails), and after that its the steel-cored 1250-s3.

use the 1250s3, not the regular 1250 print o seals. The S3 are steel core and do not distort like the paper gasket. Also, I am not a fan of the cork end pieces. Use either the rubber end pieces dry with some Tuff Stuff on the corners or lay a nice bead of Tuff Stuff down and let it cure, then lay down the intake.

chuzie said:

I am pretty sure I used RTV on the whole gasket. Guess that could be what screwed. Gotta research the porting differences between the D7 and E7 heads.

So no RTV (except water jackets) on the 95952?
What is the RTV consensus on the 1250-s3?

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NO RTV on the intake gasket. That is what caused your leak. Intake gaskets go on dry. Put some Tuff Stuff in the corners where the intake and end gaskets meet.

Intake manifold installation tips:

Whatever you do, don't skimp on cleaning the gasket surfaces. New gaskets need to seat against bare metal and not the residue left from the old gaskets in order to seal leak free. This is the most time consuming and tiresome part of the job. Put a piece of cardboard in the lifter valley to cover it up. It will reduce the amount that falls down into the valley and hydraulic lifters. I suggest that you make good use of a shop vac while you are scraping and cleaning to avoid getting the old gasket material lost inside the engine. Look for little things that need to be replaced like the short hose from the thermostat hosing to the water pump, damaged vacuum lines and hose clamps that are rusted or broken.

Plan on cutting the thermostat to water pump hose, or removing the thermostat housing. Also plan on removing the distributor to get clearance to remove the intake manifold. Remove #1 spark plug, stick your finger in the spark plug hole and crank. When your finger gets air moving past it, stop cranking. Turn the engine until the timing marks line up with the pointer. Now you can pull the distributor out.

My favorite trick that saves time and effort is the stay in place gasket. Be sure that you scrape (don't use a wire brush) all the old gasket material off, then clean all the surfaces with acetone or MEK.

When the surfaces are clean, use weather strip adhesive on the head to manifold surface. Also use the weather strip adhesive on the side of the gasket that mates to the head. When you are done, the head surface and the gasket surface that mate together will have weather strip adhesive on them. Follow the instructions on the tube or can and when it gets tacky, press the gasket down on the head.

Clean the area where the rubber rails mount to the block in front and in the rear with more acetone or MEK and do the same trick with the weather strip adhesive that you did to the heads.

Coat the rubber seals and the gasket area around the water passages with lots of Blue Silicone gasket sealer and put it together. Bingo! no leaks, and no gaskets that shifted out of place.

If you reuse the injectors from your old setup, a repair kit is available from most auto parts stores if needed. Coat the injector body "O" rings with oil before you use them and everything will slide back together.

Fuel injector seal kits with 2 O rings and a pintle cap (Borg-Warner P/N 274081) are available at Pep Boys auto parts. Cost is about $3.50 - $4.00 per kit. The following are listed at the Borg-Warner site ( http://www.borg-warner.com ) as being resellers of Borg-Warner parts:

http://www.partsplus.com/ or http://www.autovalue.com/ or http://www.pepboys.com/ or http://www.federatedautoparts.com/

Most of the links above have store locators for find a store in your area.

Use motor oil on the O rings when you re-assemble them & everything will slide into place. The gasoline will wash away any excess oil that gets in the wrong places and it will burn up in the combustion chamber.


Intake manifold to head bolts
--Step 1 96 in/lbs
--Step 2 16ft/lbs
--Step 3 23-25 ft/lbs

Wire brush can score up the surface, the gaskets need a nice, flat, smooth surface to be able to seal.

use some 00 steel wool or emery cloth. Iron heads are harder than aluminum so you can be a LITTLE more aggressive. No whiz wheel or wire brushes. A sharp razor and some throttle body cleaner can get rid of most of the residue. Err on the side of caution. Lay a straight edge on the intake port side and see how flat the surface is. The intake gasket will compress and fill in irregularites up to a point. If the pitting is substantial you may need to mill the heads and intake the SAME small amount to avoid misalignment. NO RTV on the head surface. That causes the intake gasket to distort.

Cracked lower intake?

There shouldn't be any hole in the ports on the intake side, my bet is that is the source of youre leak.

Factory e7 heads will have a cross-drilled hole on the exhaust side for the air injection system (emissions). Its for putting extra o2 into the exhaust to make the cats work better at cold start.