car undrivbeable after cam swap
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Joined: Jul 2001
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From: walla walla, wa
Car: 1990 Eagle Talon TSi AWD
Engine: 4G63T
Transmission: 5 speed
car undrivbeable after cam swap
I just swapped out my stock cam for a summit 1103 hydraulic cam, now my headers and y-pipe get extremely hot, and during the break in, the headers actually started to glow red. If I try to drive it, it wil make them bright red. Also I saw virtually no performance increase. Stock cam was a crappy smogger w/ .380 .400 lift
My engine is a 350 with crappy 8.5:1 compression because I still have the stock 76CC heads. summit camshaft 214/224 .442/.465
edelbrock performer intake and 600 cfm carb and 1 5/8 hooker shorty headers and a dynomax super turbo, only 2.5 inch pipe, and my y-pipe is super crappy.
I've managed to come up with 3 ideas so far
1. my Y-pipe and stock exhaust pipe are too restrictive.
2. I don't have enough compression for a cam this big, but it sounds fine, no popping or backfires.
3. I am somehow going lean, i changed to some richer rods, but that didn't help at all.
My engine is a 350 with crappy 8.5:1 compression because I still have the stock 76CC heads. summit camshaft 214/224 .442/.465
edelbrock performer intake and 600 cfm carb and 1 5/8 hooker shorty headers and a dynomax super turbo, only 2.5 inch pipe, and my y-pipe is super crappy.
I've managed to come up with 3 ideas so far
1. my Y-pipe and stock exhaust pipe are too restrictive.
2. I don't have enough compression for a cam this big, but it sounds fine, no popping or backfires.
3. I am somehow going lean, i changed to some richer rods, but that didn't help at all.
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Here's a stupid question: Did you disconnect the vacuum advance when you set the timing?
you might want to make sure all your vacuum lines are hooked up, especially those big ones like the one on front for the pcv system and the one in back for brakes and stuff. Also might wanna make sure you didn't overtighten the rocker arms when setting lash.
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Joined: Sep 2001
Posts: 6,111
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From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
More than likely a ignition timing issue.
Did you change the timing cover?
Did you check the timing with the vacuum advance hooked up
as 57 said?
IS the distributor advance mechanism working?
Did you change the timing cover?
Did you check the timing with the vacuum advance hooked up
as 57 said?
IS the distributor advance mechanism working?
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Joined: Jul 2001
Posts: 151
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From: walla walla, wa
Car: 1990 Eagle Talon TSi AWD
Engine: 4G63T
Transmission: 5 speed
I have a new timing cover and a new pointer, the 2 'o clock style, and I have one of those proform dampener covers so I know all of my marks are good, and base timing is set to 12 degrees w/o the vac advance hooked up. the mecanical works also.
what's a normal temp for your exhaust to be? I took my snap on laser pyrometer to my collectors and they were 600-650 at idle, but when i revved it up some it went out of range. + 800 or so
I'm looking around to see if anyone I know has a degree kit, so far no luck.
So nobody thinks it's a compression Vs cam issue?
Or too small of exhaust pipe?
I ran it a little bit last night so I could see where it got hot and it was mostly the collectors, the tubes themselves didn't get too hot. Tempted to try running open headers to see if that makes any difference, but i dunno if that's a good idea or not.
I'm going to try hooking up my shops exhaust analyzer to see if i'm leaning out as well.
thanks to all of the ideas so far.
Keep 'em coming, I really need to get this working.
what's a normal temp for your exhaust to be? I took my snap on laser pyrometer to my collectors and they were 600-650 at idle, but when i revved it up some it went out of range. + 800 or so
I'm looking around to see if anyone I know has a degree kit, so far no luck.
So nobody thinks it's a compression Vs cam issue?
Or too small of exhaust pipe?
I ran it a little bit last night so I could see where it got hot and it was mostly the collectors, the tubes themselves didn't get too hot. Tempted to try running open headers to see if that makes any difference, but i dunno if that's a good idea or not.
I'm going to try hooking up my shops exhaust analyzer to see if i'm leaning out as well.
thanks to all of the ideas so far.
Keep 'em coming, I really need to get this working.
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From: Hillsborough, NJ, USA
Car: 1996 Jeep Cherokee
Engine: 4.0
Transmission: 5 speed
It is probably a timing issue. Although, the whole glowing hot exhaust thing is usually a running lean trait, but since you changed the rods, I guess its not that. I would think it would be fuel related, but I guess not.
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Joined: Sep 2001
Posts: 6,111
Likes: 53
From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
Advance the timing and see the effect. Bet the combination of those new parts ( timing cover, tab, balancer cover) has a lot to do with it. Just cause their new don't assume they are right.
You could put a potato in the exhaust and it still would not glow
so don't think that your problem.
A vacuum leak is a possability.
Run the motor at a high idle and get the exhaust to glow.
then get a propane torch and shoot some gas ( propane) down the carb while its running and observe the exhaust system.
If it cools off there's your problem.
HardCore Hot Rods
You could put a potato in the exhaust and it still would not glow
so don't think that your problem.
A vacuum leak is a possability.
Run the motor at a high idle and get the exhaust to glow.
then get a propane torch and shoot some gas ( propane) down the carb while its running and observe the exhaust system.
If it cools off there's your problem.
HardCore Hot Rods
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From: heartland
Car: 89rs (previous 2.8)
Engine: 406
Transmission: 700r4 (for now)
Originally posted by F-BIRD'88
Run the motor at a high idle and get the exhaust to glow.
then get a propane torch and shoot some gas ( propane) down the carb while its running and observe the exhaust system.
If it cools off there's your problem.
HardCore Hot Rods
Run the motor at a high idle and get the exhaust to glow.
then get a propane torch and shoot some gas ( propane) down the carb while its running and observe the exhaust system.
If it cools off there's your problem.
HardCore Hot Rods
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Joined: Jul 2001
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From: walla walla, wa
Car: 1990 Eagle Talon TSi AWD
Engine: 4G63T
Transmission: 5 speed
sorry, I didn't clarify, the tab, cover etc, is new, but I ran it for a while with my old cam and it ran great.
so the propane thing will tell me if I have a vacuum leak?
I'll have to try that.
how far off would my cam timing have to be to get these symptoms.
so the propane thing will tell me if I have a vacuum leak?
I'll have to try that.
how far off would my cam timing have to be to get these symptoms.
Supreme Member
Joined: Sep 2001
Posts: 6,111
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From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
Originally posted by Riley's35089rs+
I'm lost with that reply f-bird could you clarify that for me...what would "The problem" be..
I'm lost with that reply f-bird could you clarify that for me...what would "The problem" be..
Supreme Member
Joined: Sep 2001
Posts: 6,111
Likes: 53
From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
Originally posted by Purple Monkey
sorry, I didn't clarify, the tab, cover etc, is new, but I ran it for a while with my old cam and it ran great.
so the propane thing will tell me if I have a vacuum leak?
I'll have to try that.
how far off would my cam timing have to be to get these symptoms.
sorry, I didn't clarify, the tab, cover etc, is new, but I ran it for a while with my old cam and it ran great.
so the propane thing will tell me if I have a vacuum leak?
I'll have to try that.
how far off would my cam timing have to be to get these symptoms.
Try advanceing the timing, Then look for a vacuum leak,
Then I'd be ripping the timing cover off. Ya goofed somewhere.
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From: Pueblo Co
Car: 1989 C4
Engine: L98
Transmission: 700r4
Axle/Gears: 307
Originally posted by F-BIRD'88
I don't know ..... How far off did you set it? LOL
Try advanceing the timing, Then look for a vacuum leak,
Then I'd be ripping the timing cover off. Ya goofed somewhere.
I don't know ..... How far off did you set it? LOL
Try advanceing the timing, Then look for a vacuum leak,
Then I'd be ripping the timing cover off. Ya goofed somewhere.
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Joined: Jul 2001
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From: walla walla, wa
Car: 1990 Eagle Talon TSi AWD
Engine: 4G63T
Transmission: 5 speed
Hmmm, that's what I thought.
I checked my plugs and they look good, not burned or anything.
Think it could be caused by just a weak-sauce ignition system. I'm sure my advance curve isn't near as good as it could be. and my vacuum advance probably doesn't work that great.
it's weird, the motor just feels like it hits a wall somewhere, then feels like it's trying too hard.
I checked my plugs and they look good, not burned or anything.
Think it could be caused by just a weak-sauce ignition system. I'm sure my advance curve isn't near as good as it could be. and my vacuum advance probably doesn't work that great.
it's weird, the motor just feels like it hits a wall somewhere, then feels like it's trying too hard.
Supreme Member
Joined: Sep 2001
Posts: 6,111
Likes: 53
From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
This cam is not radical and need no special tuning.
Ya F***cked up somewhere.
Once ya get it sorted out you're a prime candiate for some
budget high compression hi flow home ported 305 big valve heads.
This will get the airflow and compression up to allow the new cam to really boogy.
I run 13.0 ets with this same cam. You can too.
Ya F***cked up somewhere.
Once ya get it sorted out you're a prime candiate for some
budget high compression hi flow home ported 305 big valve heads.
This will get the airflow and compression up to allow the new cam to really boogy.
I run 13.0 ets with this same cam. You can too.
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Joined: Jul 2001
Posts: 151
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From: walla walla, wa
Car: 1990 Eagle Talon TSi AWD
Engine: 4G63T
Transmission: 5 speed
I was thinkin about pickin up some 855 vortecs, local junkyard has em for $100 a pop.
thanks for all of the ideas, should keep me busy for a while.
I'll just have to be less cool and drive my V6 firebird till I get this sorted out.
thanks for all of the ideas, should keep me busy for a while.
I'll just have to be less cool and drive my V6 firebird till I get this sorted out.
SO,,,
Did you check the exhaust gasses for HC or extra O²? (Are you rich/lean?)
If the mixture is correct, you're left with timing - either ignition or valve.
To answer your question, "How far off would my cam timing have to be to get these symptoms?", about 17.75° - or one tooth on the cam sprocket.
Did you check the exhaust gasses for HC or extra O²? (Are you rich/lean?)
If the mixture is correct, you're left with timing - either ignition or valve.
To answer your question, "How far off would my cam timing have to be to get these symptoms?", about 17.75° - or one tooth on the cam sprocket.
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Joined: Jul 2001
Posts: 151
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From: walla walla, wa
Car: 1990 Eagle Talon TSi AWD
Engine: 4G63T
Transmission: 5 speed
I won't be able to get my car on a gas analyzer till monday. I'm just gonna mess with my carb and my timing till then.
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