My cam/carb difficulty
09-30-2017, 10:13 AM
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Car: '85 Camaro
Engine: LG4
Transmission: 4L80E
Axle/Gears: 3.42:1
My cam/carb difficulty
Ok, please think of this as a mini-blog, to learn from or laugh at.
I love all 67-02 V8 Camaros, I love the part-throttle torque of a mild 350, but I don't have a tenth as much experience as I wish, with aftermarket cams.
I helped a friend put a Summit 1103 in an L31, with long-tube headers and a Q-Jet. The idle was good, about 16.5", and power was decent through 5500.
So when I got this Camaro I have now, it had a 1406 on a Performer EGR, the CCC distributor, and everything else stock LG4/700R-4/2.73:1. Or so I thought.
I tried a Q-Jet on it, but couldn't get it rich enough to idle, even after removing the idle screws and drilling the idle discharge holes larger. The richer the idle, the less the MPG will be. And a V8 Camaro is no fun if you can't afford to drive it. So back to the 1406, which can idle rich enough.
It had low vacuum, about 14.5", and idled poorly, even after trying a bunch of different spark advance settings. I've confirmed it hasn't hurt a lifter or wiped a lobe, and while I had the dial indicator, I checked the lift. I got a few thousandths variation from lobe to lobe, but it was around .442/.465, so I was thinking it might be Comp's DualEnergy 265, since it doesn't idle as well as Summit's 1103. I know the Comp has less advertised duration, but I've come to believe that that really doesn't mean anything.
Yesterday I was finally able to put a degree wheel on it, it seems to be the 1103 or equivalent. So I returned the degree wheel to the machine shop, and the owner asked what I found. Then he asked about the Q-Jet on my friend's 350, which he decided was probably leaking.
So I've chosen a milder cam, a 206/214 on a 112, it's a Melling retrofit hydraulic roller with a reduced base circle. I haven't bought it yet, so IDK if it includes info on which lifters, which pushrods, and which distributor gear, but I have the valvetrain from an LO3 on hand, and if those lifters are too tall, I'll try a HR lifter from a '94 3.1L V6/60. This is an early '86 block without the provisions, so I will need a thrust button, but $300 retrofit linked lifters really aren't necessary, and are relatively heavy.
I love all 67-02 V8 Camaros, I love the part-throttle torque of a mild 350, but I don't have a tenth as much experience as I wish, with aftermarket cams.
I helped a friend put a Summit 1103 in an L31, with long-tube headers and a Q-Jet. The idle was good, about 16.5", and power was decent through 5500.
So when I got this Camaro I have now, it had a 1406 on a Performer EGR, the CCC distributor, and everything else stock LG4/700R-4/2.73:1. Or so I thought.
I tried a Q-Jet on it, but couldn't get it rich enough to idle, even after removing the idle screws and drilling the idle discharge holes larger. The richer the idle, the less the MPG will be. And a V8 Camaro is no fun if you can't afford to drive it. So back to the 1406, which can idle rich enough.
It had low vacuum, about 14.5", and idled poorly, even after trying a bunch of different spark advance settings. I've confirmed it hasn't hurt a lifter or wiped a lobe, and while I had the dial indicator, I checked the lift. I got a few thousandths variation from lobe to lobe, but it was around .442/.465, so I was thinking it might be Comp's DualEnergy 265, since it doesn't idle as well as Summit's 1103. I know the Comp has less advertised duration, but I've come to believe that that really doesn't mean anything.
Yesterday I was finally able to put a degree wheel on it, it seems to be the 1103 or equivalent. So I returned the degree wheel to the machine shop, and the owner asked what I found. Then he asked about the Q-Jet on my friend's 350, which he decided was probably leaking.
So I've chosen a milder cam, a 206/214 on a 112, it's a Melling retrofit hydraulic roller with a reduced base circle. I haven't bought it yet, so IDK if it includes info on which lifters, which pushrods, and which distributor gear, but I have the valvetrain from an LO3 on hand, and if those lifters are too tall, I'll try a HR lifter from a '94 3.1L V6/60. This is an early '86 block without the provisions, so I will need a thrust button, but $300 retrofit linked lifters really aren't necessary, and are relatively heavy.
Last edited by Jeremy85; 09-30-2017 at 10:17 AM.
09-30-2017, 10:23 PM
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Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: My cam/carb difficulty
That melling cam is basically same as stock tpi cam. 89 tpi cams had 207 213 duration on a 117 Bet you could find one much cheaper. Ive got one put back myself I think I got for $65. 049 gm can also came in some c4 vettes also iirc