You may recall that I'm trying to build up an LG4 on the cheap using L69 goodies: exhaust manifolds, y and intermediate pipes, secondary metering rods and hanger, etc). RB83L69, I've noted in the Camaro White Book and in one of your posts that the L69 had pullies that were underdrive compared to the LG4. Can you or any the L69ers provide more info and/or part numbers?

JamesC

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The parts man at my local GM dealership says there's no difference.

JamesC

 

No difference between what parts? I hope he doesn't mean the engine as a whole. L69 and LG4 are like night & day, as far as power output goes.
You've got the basics already-the exhaust manifolds have 2.5" collectors, and the downpipes and intermediate are both 2.5" as well. The cat converter was also larger and has a 4-bolt flange.
Don't quote me but I 'think' the rods are DR and the hanger G, i'm still looking for an affirmative on that seeing as my L69 didn't have it's original carb when I got it. It's also been said that the carb itself had a slightly different casting. The PROM chip was also different.
The L69 has a better cam also, there's a little more lift to it (sorry, don't have the spec here in front of me). I believe the intake manifold flows a bit better too.
On the Camaros you'd find the dual snorkel aircleaner, on the T/A's there's a hood louver.
The L69 cars usually have 3.73 gears in the diff too.
That's all I can think of, if it's any help to you. If any of this is inaccurate someone let me know or elaborate on it.



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D.R. Stevens
1984 Trans Am 305HO L69
all the usual external/free mods, original engine
1991 Firebird 305 L03
bone-dead-slow-stock

 

eightTfourTA,

I'm aware of the differences you suggest, thanks. The 'no difference' I was refering to was the pullies.

JamesC

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James —

The replacement part may very well be the same whether the actual original one was or not. However, on all the LG4 motors I've worked on that I can remember about, the pulley for water pump and alternator belt was larger than the other 2 grooves for the PS & A/C. On the L69 motor the 3 grooves are the same size, so the WP and alt are driven more slowly. I don't know if this applies to [i[every[/i] LG4 or not, in every year etc.

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"So many Mustangs, so little time..."
ICON Motorsports

 

RB and Guys,

Thanks for your responses. Another question. I was messing with the dual snorkel yesterday and discovered the neither flap in the snorkels closes on start up, thus not allowing the heat stove to function properly. I checked the snorkel's vac hoses but all were clear and unpinched. Believing that both vac motors are non-functioning is difficult to believe. Perhaps, the sensor? By the way, when I was poking around in there with the vac lines, the idle kicked up big time. One other thing, would the L69 chip do me any good (I've already bumped the timing up).

JamesC

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[This message has been edited by JamesC (edited September 17, 2001).]

[This message has been edited by JamesC (edited September 17, 2001).]

 

The thing that closes them is a temp sensor, I'm not sure what the temp it's supposed to operate at is. I guess you could unplug the lines to the diaphragms and hook vacuum straight up to them and make sure they work, and put the breather in the fridge or something and see if the system works...

OBTW on my prior post, I forgot to mention, it was the crank pulley I was talking about.

On the chip, some years it would make a difference; at least up to 84, the LG4 didn't have a knock sensor but the L69 did. THe L69 also seems to have a generally more aggressive timing curve, judging by swapping one into a LG4 once.

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"So many Mustangs, so little time..."
ICON Motorsports

 

RB and Guys,

No vac at either motor, although there is vac at the carb. As you suggest, RB, I need to check the motors, but providing they function, is my next best guess, the sensor?

JamesC

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I'd put my bet on the sensor, i've had about three of those screw up on me. I did get one to work once by cleaning all the junk off/out from it but it didn't last long. (After getting fed up with it I did away with my Thermac system completely and I never noticed any difference, it's always warm down here anyway and there's no E-checks)

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D.R. Stevens
1984 Trans Am 305HO L69
all the usual external/free mods, original engine
1991 Firebird 305 L03
2 free mods and a K&N,
otherwise stock

 

The driver's side vac motor was bleeding air, so I'll need to replace it, then we'll see if anything else is awry.

JamesC

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