Here are the induction system...
Here are the induction system parts we'll be replacing in this job. Shown are thenew intake manifold and runners, throttle body (and box), mass air flow (MAF) sensor,EGR insulation, and manifold gaskets that we had to purchase separately asthey were, surprisingly, not included with the manifold.
LAST time, our "Got Fuel?"(August 2007) story detailed the proceduresfor upgrading fuel injectors andthe fuel-pressure regulator. This month,we will explain air-managementupgrades to take the best advantage ofthe improved fuel delivery.
More fuel is usually better. But only ifmore air is available to make most efficientuse of the enhanced fuel/air mixture.After all, if properly managed,more air/fuel mixture translates intomore ponies to the pavement. Havingupgraded our fuel injectors and fuelpressureregulator, we decided now wasthe time to install a high-performancethrottle body, runners, and intake manifoldin our project '87.
Once again we turned to the folks atMid America Motorworks to see whichpieces they recommended to complementthe modifications made previously. Theyrecommended Accel's trio of throttlebody, intake runners, and intake manifold,so we ordered up these parts andwent back to re-read the previous storyon fuel-system upgrades because all ofthose pieces would have to come backoff for this job. Certainly it makes senseto do both jobs at the same time if yourcheckbook can withstand the shock. Butif not, we think doing the fuel upgradesfirst is both more affordable and lessintimidating, so when you're ready totackle the manifold and runner job, you'llbe more confident.
01 We removed the metal PCV...
01 We removed the metal PCV tube from the throttle body at the front and thevalve cover vent at the rear.
02 In removing the insulated...
02 In removing the insulated EGR tube, we observed that the insulated wrappingwas coming apart, so we'll be installing new wrapping during reassembly. While theexisting insulation was adequate, we're replacing it primarily for cosmetic reasonswith a nice piece from Mid America Motorworks.
03 After the MAF sensor is...
03 After the MAF sensor is off, removingfour bolts allowed us to lift off thethrottle body. Note the plugs that wehad installed when we previouslybypassed the passage of coolantthrough the throttle body. While thiscoolant flow pre-heats the air for bettercold engine performance, it's not anasset during quarter-mile runs whenthe engine is fully warmed up.
We'll say right up front that this jobdid not go as well as previous jobs for anumber of reasons. Access to bolts andparts was, in some cases, difficult. Andwe learned the hard way that manypieces had to come off and go back on ina very specific order, so trial fitting duringreassembly is critical. Further, althoughthe instructions with the manifold advisethat some modifications might be necessaryfor everything to fit right, we weresurprised and disappointed at the sometimesobvious interference points that wefelt should have been engineered betterbefore the final design was released.
And, finally, there were areas like theport size in the new runners that weremuch larger than the ports in the originalplenum, leaving what we felt was a tooabruptchange in diameter. We addressedthat matter by milling the ports in theplenum to match those of the new runners.And the passage for the cold startenrichment injector (the so-called ninthinjector) was simply machined in thewrong place and in the wrong shape. Asa result, we ended up spending time onour machinist's Bridgeport making modificationsthat shouldn't have been necessary.Finally, we found that the new intakemanifold did not come with manifold-tocylinderhead gaskets, so they had to bepurchased separately.
04 The plenum can be lifted...
04 The plenum can be lifted off afterthe runner-to-plenum bolts have beenremoved. You can lift off the plenumwith one runner still in place, which willmake it easier to remove the oneremaining runner bolt on either sidethat points from the centerline of theengine out toward the side.
05 With all the intake manifold...
05 With all the intake manifold boltsremoved, you can now lift off the manifold.It may be necessary to pryslightly to break loose the gasket surfaces.Be very gentle, and choose yourlocation carefully to avoid damaginganything.
06 It is necessary to transfer...
06 It is necessary to transfer thisshield from the original intake manifoldto the new Accel manifold. This splashshield prevents build-up of oil residueon the underside of the manifold.
07 We chose to use thread...
07 We chose to use thread locking compoundon these shield bolts in order toprevent the catastrophic results of oneof these bolts dropping into internalareas of the engine.
08 We installed the new manifold,...
08 We installed the new manifold, beingcareful not to dislodge the new gaskets.Accel's instructions are very specificin directing you to use O2-friendlyRTV sealer and not preformed manifoldend gaskets. They also specify usingthis RTV on both sides of the intakemanifold side gaskets as well, which iscontrary to what most gasket manufacturersrecommend. We took the instructionof the gasket makers on this one.
09 It's important that intake...
09 It's important that intake manifoldbolts be torqued to the proper value, inthe proper sequence.