Intermittent Stalling ONLY IN 4TH!
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From: Vacaville, CA
Intermittent Stalling ONLY IN 4TH!
Hello all,
I finally got my ‘71 on the road! Driving around town is fine for what it is (270s @.050 cam and 365cc heads). It certainly isn’t a daily but it’s what i expected/wanted with these specs. The problem comes ONLY in 4th gear. It seems like the engine completely gives up. I’ve gone as far as going full throttle in 4th, and get NO response. Yet again, I’m at a complete loss. It’s carbureted, so fuel isn’t the issue. Spark is there, too. The weirdest thing is that it’s an intermittent issue. It’s an M23 from Autogear. Any ideas? Thanks!
-Sam
I finally got my ‘71 on the road! Driving around town is fine for what it is (270s @.050 cam and 365cc heads). It certainly isn’t a daily but it’s what i expected/wanted with these specs. The problem comes ONLY in 4th gear. It seems like the engine completely gives up. I’ve gone as far as going full throttle in 4th, and get NO response. Yet again, I’m at a complete loss. It’s carbureted, so fuel isn’t the issue. Spark is there, too. The weirdest thing is that it’s an intermittent issue. It’s an M23 from Autogear. Any ideas? Thanks!
-Sam
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not a ton of information there. Rear gear?
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Well, your cam doesn't sound that big. Many of us on here run more cam without issues. Your heads I can only assume are factory heads. not 365cc's But rather 365 iron heads.
I am not riding along with you. but something isn't working under load.
Timing curve? Vac can Timing? When does it start to tip? When is it all in? What is your idle vacuum?
What do your plugs look like? White? Tan ? or pitch black?
Like I said, you haven't given us much information to go on.
Your rear gear sounds fine.
I am not riding along with you. but something isn't working under load.
Timing curve? Vac can Timing? When does it start to tip? When is it all in? What is your idle vacuum?
What do your plugs look like? White? Tan ? or pitch black?
Like I said, you haven't given us much information to go on.
Your rear gear sounds fine.
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Joined: Nov 2020
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From: Vacaville, CA
Well, your cam doesn't sound that big. Many of us on here run more cam without issues. Your heads I can only assume are factory heads. not 365cc's But rather 365 iron heads.
I am not riding along with you. but something isn't working under load.
Timing curve? Vac can Timing? When does it start to tip? When is it all in? What is your idle vacuum?
What do your plugs look like? White? Tan ? or pitch black?
Like I said, you haven't given us much information to go on.
Your rear gear sounds fine.
I am not riding along with you. but something isn't working under load.
Timing curve? Vac can Timing? When does it start to tip? When is it all in? What is your idle vacuum?
What do your plugs look like? White? Tan ? or pitch black?
Like I said, you haven't given us much information to go on.
Your rear gear sounds fine.
. And the heads are true 365cc intake runners, Brodix Dragonslayers. I built this to START making power at high RPM’s, 5,500+.
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From: Vacaville, CA
All ignition wiring was redone from scratch. 6AL goes straight from the battery and aftermarket switch. It’s a 489 but will rev to 7k+ haha!
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OK. Now where getting somewhere. At least we have some information on your engine.
Can't see why 4th gear makes any difference other than load.
maybe 3.36 is a bit tall for this engine.
Still, is it really Fat?? rich.
Not clear on exactly what it is doing in forth gear.
Can't see why 4th gear makes any difference other than load.
maybe 3.36 is a bit tall for this engine.
Still, is it really Fat?? rich.
Not clear on exactly what it is doing in forth gear.
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Joined: Nov 2020
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From: Vacaville, CA
OK. Now where getting somewhere. At least we have some information on your engine.
Can't see why 4th gear makes any difference other than load.
maybe 3.36 is a bit tall for this engine.
Still, is it really Fat?? rich.
Not clear on exactly what it is doing in forth gear.
Can't see why 4th gear makes any difference other than load.
maybe 3.36 is a bit tall for this engine.
Still, is it really Fat?? rich.
Not clear on exactly what it is doing in forth gear.
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Certainly there is a vacuum port on that carb.
None the less adjusting the idle mixture screws does just that. Adjusts the mixture at idle.
There is a whole lot more to setting up that carb than just adjusting idle mixture.
Perhaps the best thing you can do if you have limited experience with jetting up a carb for a performance engine. Would be to find a dyno tuner with experience with your carburetor.
Get it dialed on a dyno. Then you'll be good to go.
None the less adjusting the idle mixture screws does just that. Adjusts the mixture at idle.
There is a whole lot more to setting up that carb than just adjusting idle mixture.
Perhaps the best thing you can do if you have limited experience with jetting up a carb for a performance engine. Would be to find a dyno tuner with experience with your carburetor.
Get it dialed on a dyno. Then you'll be good to go.
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From: Vacaville, CA
I’ll take it to someone who knows more than me, I’m not too familiar with carb tuning so that sounds like a plan. Thanks for all the insight. I’ll let you know what ends up happening!
Is my vette stock?? HAHA
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THat a lot of intake volume. What is your engine 383, 454, bigger? Whats your compression. You may not be getting enough draw through those ports at its like trying to pull a vacuum on a fire hose versus needing a garden hose. High rpm sucks harder than just above idle. You may have it spec'd for a nice race engine that you are trying to drive on the street and your carb just isnt seeing enough signal.
Take it out again, get it to bog, down shift or put it in nuetral and pop the throttle . If it isnt reving bring it up slowly to you get response then pop the throttle. If it revs then you have too much volume for your driving situation
Take it out again, get it to bog, down shift or put it in nuetral and pop the throttle . If it isnt reving bring it up slowly to you get response then pop the throttle. If it revs then you have too much volume for your driving situation
Is my vette stock?? HAHA
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From: Im not allowed to tell you
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If he changes the heads he may be able to get some use out of it
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FINALLY! something so stupid of me to even do, but I was driving around with no air filter… AND no hood. I dont have the clearance for the stock hood, and my foolishness is to blame for no filter anyway, after putting a filter on, it ran great! It mustve been the surrounding air making some sort of turbulence, or resistance and not getting air into the carburetor! The filter prevents this (along with preventing the engine from being a dust vacuum!) Im really a clown yall
anyway, after putting a filter on, it ran great! It mustve been the surrounding air making some sort of turbulence, or resistance and not getting air into the carburetor! The filter prevents this (along with preventing the engine from being a dust vacuum!) Im really a clown yall
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Well, At least you found the issue! Happy Motoring!