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My L36 LIM Porting (with pics)...NOW WITH DATA!

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Old 02-16-2007, 01:25 PM
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Originally Posted by TJ'sblackbonne
So pretty much all that is happening is you are gasket matching the gaskets to the ports on the LIM.
No. Hes matching the ports to the head ports. The LIM gasket is larger than the head port.
If you were to port all the way, there would be a shelf at the head.
After the UIM, the LIM is only held on by the LIM to head bolts, the p/* coolant elbow, coolant hose, and the EGR.
Old 02-16-2007, 01:25 PM
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yea that makes sense. Willwren, if you get the chance throw me a pm or (you can type it in here). Educate me on this. I am ready to drop some more money and i plan on doing the HV3, so i figure.... since i am in there. Thank you
Old 02-16-2007, 01:26 PM
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I'm not going to gasket-match, as that would make the LIM ports bigger than the head ports, and my understanding is that exhaust reversion could result. I intend to "come short" of the gasket hole by about 1/16" all the way around, so as to leave a "ledge" relative to the gasket hole around the lower LIM port. I measure the gasket hole at exactly 1" wide by 2" high, so I'm shooting for LIM ports 7/8" wide by 1-7/8" high.

If that explanation didn't make sense, hopefully future pictures will!

(I see lash beat me to the reversion explanation)

AFAIK, the only "tough" part about removing the LIM (once the UIM is off) is removing the alternator so that you can get at one certain LIM bolt.

Believe me, I am not the expert on LIM porting...I'm going mostly off of advice I garnered from the more knowlegdable and experienced folks on this site. The best advice I can pass along is this: buy a junkyard LIM and do your porting on that, so there'* no chance of accidentally disabling your car.

As to the HV3...I also got me a junkyard UIM with runner insert to experiment with, to try to replicate a "poor-man'*" HV insert
Old 02-16-2007, 01:34 PM
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Yea, the alternator isnt too bad, i had that off when i did my rockers. I am starting to understand what you are saying about the porting. Also maybe somebody should do a write up on removing the UIM and LIM. Cough Cough. I enjoyed following a step by step on my rockers and that would be nice when doing this. I figure around the middle to end of march i would like to do this. So there is plenty of time for reading and practicing and what not. Keep the info coming
Old 02-16-2007, 01:38 PM
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Agrazela, the Gtech'* inconsistency from run to run and from day to day in hp and tq numbers is so bad it'* laughable. It'* far worse than the error they advertise on their site. I've even gone through hot and cold calibrations in a labratory environment on two Gtech'* trying to improve it, then proving that even a 10° change in temperature will affect your readings.

The Gtech has it'* good points, but what you intend to do with it is it'* greatest weakness.

I've been playing with them for over 4 years, and those people that I know that are familiar with them, know how they work, try to get them to work, and have analytical or scientific minds all come to the same conclusions I do.

The people that believe the hp and tq numbers from a Gtech are those that WANT to believe them, and fail to question the data.
Old 02-16-2007, 01:41 PM
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While you are testing on that scrap. Try the drum sanders..both large and small. 1993 SLE, Sandrock, Jr's3800 and Black94SSEi all have experience with me present with carbide bits and drum sanding. By far the drum will give you a cleaner straighter area with much less experience behind a dremel.

We've proven on this club before that some people have been able to easily dremel certain items where others have difficulty. The last thing you want to do is hurt performance or not have a replacement/spare ready if needed.
Old 02-16-2007, 02:20 PM
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Here'* the step-by-step I put together for myself. The torque specs are from the 1998 FSM (where torque specs were given!), but the nut and bolt sizes are from memory (so some still need to be filled in).

I estimate 8-12 hours if you've never done it before, half that if you have.

(Edit: this procedure was performed on a 1998 Olds 98 L36 engine)

---------------------------------
PROCEDURE TO REMOVE UIM AND LIM TO REPLACE LIM AND UIM GASKETS

Jack up
-Place front of vehicle on jack stands; chock rear wheels (Jack, stands, chocks)

Drain coolant
-Remove air dam (10mm socket)
-Remove rad cap
-Detach lower coolant hose; catch drainage in bucket; rock car to get more (Lg flat, bucket)
-Remove engine cover
-Remove thermostat housing and thermostat (10mm)
-Flush block with hose until water runs clear
-Remove harness, heat shield and front Knock Sensor; catch drainage (??mm, bucket)
-Replace Knock Sensor (??mm, 14 ft lb) and shield (??mm, ??? ft lb), and reattch knock sensor harness
-Reattach lower coolant hose (Lg flat)
-Replace air dam (10mm socket, ??? ft lb)

Drain oil
-Remove drain bolt and drain oil pan; catch oil in bucket (14mm, bucket)
-Remove filter and catch oil (bucket)
-Replace filter (AC Delco PF47)
-Replace drain bolt (14mm, 22 ft lb)

Jack down
-Put vehicle down off jack stands (jack)

Prep for UIM/LIM removal
-Remove battery (8mm and 1/2")
-Remove spark plug wires and boot heat shields from rear cylinders (2,4,6)
-Remove serpentine belt from alternator by rotating breaker c-cwise to remove tension (15mm socket, breaker)
-Remove alternator support brace (??mm)
-Remove alternator mounting bolts (??mm)
-Remove alternator output nut and electrical connector (??mm)
-Remove alternator
-Disconnect MAP sensor harness from UIM
-Disconnect IAT sensor harness from bellows
-Remove airbox and bellows (Flat and phillips)
-Disconnect MAF, TPS and IAC sensor harnesses from TB
-Disconnect coolant temperature sensor from LIM
-Disconnect EGR harness from EGR valve
-Remove vacuum lines from TB and FPR
-Remove EVAP solenoid from bracket; move solenoid assembly out of the way (Flat)
-Remove accessory and brake booster vacuum lines from UIM
-Remove fuel rail nuts (10mm)
-Remove injector wire connectors from injectors
-Remove fuel rail and tie up out of the way (Strap)
-Remove exhaust crossover--optional if have 8/10mm ratchet wrench to reach TB support bracket (??mm)
-Remove CC and throttle cables from TB and bracket
-Remove TB support bracket (10mm)
-Remove TB (10mm)

Remove UIM
-Remove EGR heat shield (??mm)
-Move bundled harness(es) (IAT/MAF/TPS/IAC/EGR/injectors) out of the way
-Remove UIM bolts; remove UIM (8mm)

Remove LIM
-Remove remaining alternator bracketing from rear part of LIM (??mm)
-Remove EVAP solenoid bracket from front part of LIM (??mm)
-Remove EGR tube from LIM (10mm)
-Remove LIM bolts; remove LIM…coolant bypass elbow will break off (10mm)

Clean and prep block
-Stuff rags into all head ports, and place rag over lifter valley
-Pick broken coolant elbow bit out of tensioner (Flat)
-Remove old LIM gaskets and side seals from block; scrape area, clean with solvent, and buff (use your favorite method)

(Now is a good time to inspect belt, hoses, and wiring harnesses)
(Also a good time to change plugs)
(Also a good time to change injector o-rings)
(Also a good time to inspect the valve cover gaskets for leakage)
(Also a good time to degrease the "hard-to-reach" parts of the block and tranny cover)


Clean and prep LIM
-Soak LIM bolts in solvent and wirebush threads
-Remove ECT sensor from LIM, being careful not to break plastic fitting (??mm)
-Pick broken coolant elbow bit out of LIM (flat)
-Remove stovepipe if replacing with Buttermore pipe or other aftermarket pipe (socket to fit inside, vise grips)
-Remove front coolant cap from LIM (10mm)
-Scrape away gunk from sealing surfaces, clean LIM with degreaser/solvent, and buff (again, use your favorite method)
-Examine LIM carefully for cracks, bad pitting and warpage (straightedge, magnifying glass)
-Replace front coolant cap with new gasket (10mm, 15 ft lb)
-Replace ECT sensor with thread sealer (??, 18 ft lb)
-Install stovepipe if replacing (hammer, woodblock)

Clean and prep UIM
-Soak UIM bolts in solvent and wirebrush threads
-Remove MAP sensor and PCV valve housing cover
-Remove vacuum fitting
-Clean inside LIM and runners with generous amounts of solvent/degreaser---it will be nasty
-Remove runner insert; inspect for cracks/damage
-Examine UIM carefully for cracks/breakage, especially in EGR area (small pick, magnifying glass)
-Remove and discard main gasket, TB gasket, PCV o-ring, PCV valve, and vacuum fitting o-ring/seal

Clean and prep TB
-Remove MAF sensor from TB (?? torx or SMALL vise grips)
-Clean out TB and MAF screen with carb cleaner and a toothbrush
-Clean MAF filament with a q-tip and rubbing alcohol
-Replace MAF in TB (?? torx or SMALL vise grips, ?? in lb)

Replace LIM
-Remove rags from valley and head ports
-Place coolant bypass elbow into tensioner hole until seated (lube with anti-freeze if needed)
-Lay new LIM gaskets and new end seals in place; dab RTV in corners
-Lay down LIM, ensuring that bypass elbow seats fully in LIM and bolt holes and gaskets line up
-Place bolts and hand tighten (use blue threadlocker)
-Torque bolts, crosswise pattern, center to ends (10mm, 11 ft lb)
-Replace EGR tube into LIM (use blue threadlocker) (10mm, 21 ft lb)
-Replace EVAP solenoid bracket (use blue threadlocker) (??mm, 22 ft lb)
-Replace alternator bracketing (use blue threadlocker), ensuring fat wire harness goes under the armature (??mm, 22 ft lb)

Replace UIM
-Install new PCV valve and PCV housing o-ring
-Replace PCV housing cover and MAP sensor
-Replace vacuum fitting, using new o-ring/seal
-Install new TB gasket
-Insert runners into UIM
-Install new main gasket, ensuring J-tube hooked end points away from TB inlet
-Lay down UIM, ensuring EGR tube goes through hole in UIM and bolt holes line up
-Place bolts and hand tighten (use blue threadlocker)
-Torque bolts, crosswise pattern center to ends (8mm sock, 89 in lb)
-Reattach EGR heat shield (??mm, 12 ft lb)

Replace TB
-Replace TB on studs (use blue threadlocker on nuts; use red on rear nuts if studs are loose)
-Replace TB support bracket (use blue threadlocker, 10mm, 89 in lb)
-Reattach CC and throttle cables to TB and bracket

Replace other items
-Install new plugs, if changing (use anti-sieze compound, 20 ft lb)
-Reattach exhaust crossover, if removed (use anti-sieze compound, ??mm, 15 ft lb)
-Bring fuel rail down and attach harness connectors
-Install fuel rail, ensuring injectors are well-seated in LIM
-Replace fuel rail nuts and torque (use blue threadlocker, 10mm, 89 in lb)
-Reattach accessory and brake booster vacuum lines on UIM
-Reattach EVAP solenoid on bracket
-Reattach vacuum lines to TB and FPR
-Reattach EGR harness to EGR valve
-Reconnect temperature sensor on LIM
-Reconnect MAF, TPS and IAC sensor harnesses on TB
-Replace airbox and bellows (flat and phillips)
-Reconnect IAT sensor harness on bellows
-Reconnect MAP sensor harness on UIM
-Make sure all harness wiring is properly re-loomed and re-anchored
-Reattach alternator bolts (use anti-sieze, ??mm, 37 ft lb)
-Reattach alternator contact (??mm, 15 ft lb)
-Reattach alternator bracket (use blue threadlocker, ??mm, 15 ft lb)
-Replace serpentine belt onto alternator pulley (15mm socket, breaker)
-Replace spark plug wires (use anti-moisture compound) with boot heat shields (use vaseline)
-Replace battery (use anti-moisture compound, 8mm , 1/2")
-Refill coolant (see Techinfo)
-Install new thermostat with new seal and new gasket (use blue threadlocker, 10mm, 20 ft lb)
-Install new radiator cap
-Refill oil

Checks
Start engine and allow to warm up; meanwhile:
-Check for coolant leaks at hoses, rad cap, bypass elbow, t-stat housing, LIM endcap, LIM gaskets, UIM gasket, TB gasket
-Check for oil leaks at filter and drain plug, LIM gaskets and LIM endcaps
-Test for vacuum leaks at all vacuum hoses and connections, PCV housing, TB-UIM, UIM-LIM and LIM-head interfaces
-Look for exhaust leaks at both ends of crossover pipe
-Watch for CEL codes

Replace engine cover

Test drive, then check everything again
Old 02-16-2007, 02:29 PM
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Just my thoughts.... Why remove the air dam? Doesn't it have a hole to drain through?

And maybe I've been doing this backwards, but I always leave the oil in the engine until everything is back together, THEN drain to remove any particles that may have fallen in, then refill.

Also, why remove the front knock sensor? To drain the block perhaps? Just curious is all.
Old 02-16-2007, 02:33 PM
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Originally Posted by MyLittleBlackBird
Just my thoughts.... Why remove the air dam? Doesn't it have a hole to drain through?

And maybe I've been doing this backwards, but I always leave the oil in the engine until everything is back together, THEN drain to remove any particles that may have fallen in, then refill.

Also, why remove the front knock sensor? To drain the block perhaps? Just curious is all.
Maybe on the Bonnies, the air dam has a drain hole...not so on the Olds 88 or my LeSabre.
I think you're right about the oil change order...I'll do that on my LeSabre.
Front knock sensor is to drain the block. I got over a gallon more out that way.
Old 02-16-2007, 02:40 PM
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Thanks for the tip on the knock sensor. I never thought to do that


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