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I Hate Auto Shops


Onion

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what carb?

Holley 390, single pumper.

 

I've been drooling over a set of triple Webers, though (45DCOE side drafts). Holleys aren't ideal for L6 engines, you have to either run rich on the inner cylinders or run lean on the outers.

Edited by Onion

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Know what you mean by bad shops.My past experience has been that most car dealers have serious problems keeping good mechanics as they continuoudly cut their commissions. The last rate schedule I saw showed them to be about $90/hr - way too high. One shop wanted $250 just to replace my differential gasket. I thought that was total BS.

 

I was lucky to find a mechanic who is semi-retired and runs a one man shop. I recently had a water leak I could not find so I made an appointment. Took him all of 15 minutes to find the problem - rotten freeze plug. He had to pull a lot of stuff to get to it and it was still a bear to replace - no roon to work. Also, he found a bad idler bearing pulley. Total cost - $60. I was amazed considering the amount of work he put in. And, because he found a bad pulley, my SUV runs much better.

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what carb?

Holley 390, single pumper.

 

I've been drooling over a set of triple Webers, though (45DCOE side drafts). Holleys aren't ideal for L6 engines, you have to either run rich on the inner cylinders or run lean on the outers.

 

Depends on the intake!

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what carb?

Holley 390, single pumper.

 

I've been drooling over a set of triple Webers, though (45DCOE side drafts). Holleys aren't ideal for L6 engines, you have to either run rich on the inner cylinders or run lean on the outers.

 

Depends on the intake!

 

 

Not with an L6. All intakes have that problem with a single carb. The outer two cylinders are always lean, or the inner two are always rich. Nothing can be done about it. Its why people hate Holleys on Datsuns. 

Edited by Onion

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Like ccokeman says... it depends on the intake design.... there are ways to make sure the mixture for each cylinder is correct with a single carb... its all about the intake characteristics and how you use tools to your advantage...

 

First you have to understand Fuel Atomization and what causes the fuel to drop out before it gets to the outer cylinders. you can also use Turtles and Diverters to help control that... there are many who do it but you need a dyno to test it...or at the very least EGT probes on each cylinder...

 

Holleys are the easiest to tune...if the float level is right to the bottom of the sight plug loosening the float adjustment will many times start puking fuel... Idle Air bleed adjustment screws are normally set 1.5 turns OUT from dead seat.... that number is usually spot on if the Correct jets are used and the Power Valve isnt blown...

 

you wont ever get a Day/Night difference just on a carb tune unless its flooding and blowing the plugs or dead lean... once it is working correctly you will only see minor improvements... But in most peoples defense most people dont understand a carb nor can they tune one. Lucky for me the guy I work with is probably the best carb tuner in the world bar none and has been a carb tuner 20+ years and has been all over the world for it... 

 

Easiest way to cure your problem is find a Split manifold and run dual carbs ;) or Fuel Injection

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Like ccokeman says... it depends on the intake design.... there are ways to make sure the mixture for each cylinder is correct with a single carb... its all about the intake characteristics and how you use tools to your advantage...

 

First you have to understand Fuel Atomization and what causes the fuel to drop out before it gets to the outer cylinders. you can also use Turtles and Diverters to help control that... there are many who do it but you need a dyno to test it...or at the very least EGT probes on each cylinder...

 

Holleys are the easiest to tune...if the float level is right to the bottom of the sight plug loosening the float adjustment will many times start puking fuel... Idle Air bleed adjustment screws are normally set 1.5 turns OUT from dead seat.... that number is usually spot on if the Correct jets are used and the Power Valve isnt blown...

 

you wont ever get a Day/Night difference just on a carb tune unless its flooding and blowing the plugs or dead lean... once it is working correctly you will only see minor improvements... But in most peoples defense most people dont understand a carb nor can they tune one. Lucky for me the guy I work with is probably the best carb tuner in the world bar none and has been a carb tuner 20+ years and has been all over the world for it... 

 

Easiest way to cure your problem is find a Split manifold and run dual carbs ;) or Fuel Injection

 

A couple different companies have made different intake manifolds to try and cure the rich inner and lean outer problem. None of them have really succeeded. I have the Arizona Z Car manifold, the best one for a Holley 4 barrel. Unfortunately, it still isn't perfect. 

 

That's what happened to me. I unscrewed the sight plug screw, rocked the car a bit, and fuel slowly dripped out. When I unscrewed the float adjustment screw (while holding the nut in place), it started puking fuel until the system lost pressure. I'm having a huge issue where I can't get it to stop squirting fuel, even with the screw tightened all the way. 

 

When I did the idle mixture, I started off with 1.5 turns out, which was pretty much spot on. I did some more fine tuning, got from 15 to 18 in/Hg of pressure, and the car ran better than before. I'm not sure about a night and day improvement as I haven't driven it yet. I don't want to drive a car leaking fuel onto headers...

 

I don't want to go to dual carbs as the dual SUs are stock. If I do go to a different carb, I'm going to do triple Webers. This is really unlikely, as it'll run me over $1700. I want a SBC swap, but that is also very unlikely. I'm pretty sure I'm going to end up with a L28ET swap. Fuel injection, turbo, megasquirt, and stock engine, so it fits with the same wiring harness and gauges and no issues. 

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Like ccokeman says... it depends on the intake design.... there are ways to make sure the mixture for each cylinder is correct with a single carb... its all about the intake characteristics and how you use tools to your advantage...

 

First you have to understand Fuel Atomization and what causes the fuel to drop out before it gets to the outer cylinders. you can also use Turtles and Diverters to help control that... there are many who do it but you need a dyno to test it...or at the very least EGT probes on each cylinder...

 

Holleys are the easiest to tune...if the float level is right to the bottom of the sight plug loosening the float adjustment will many times start puking fuel... Idle Air bleed adjustment screws are normally set 1.5 turns OUT from dead seat.... that number is usually spot on if the Correct jets are used and the Power Valve isnt blown...

 

you wont ever get a Day/Night difference just on a carb tune unless its flooding and blowing the plugs or dead lean... once it is working correctly you will only see minor improvements... But in most peoples defense most people dont understand a carb nor can they tune one. Lucky for me the guy I work with is probably the best carb tuner in the world bar none and has been a carb tuner 20+ years and has been all over the world for it... 

 

Easiest way to cure your problem is find a Split manifold and run dual carbs ;) or Fuel Injection

 

A couple different companies have made different intake manifolds to try and cure the rich inner and lean outer problem. None of them have really succeeded. I have the Arizona Z Car manifold, the best one for a Holley 4 barrel. Unfortunately, it still isn't perfect. 

 

That's what happened to me. I unscrewed the sight plug screw, rocked the car a bit, and fuel slowly dripped out. When I unscrewed the float adjustment screw (while holding the nut in place), it started puking fuel until the system lost pressure. I'm having a huge issue where I can't get it to stop squirting fuel, even with the screw tightened all the way. 

 

When I did the idle mixture, I started off with 1.5 turns out, which was pretty much spot on. I did some more fine tuning, got from 15 to 18 in/Hg of pressure, and the car ran better than before. I'm not sure about a night and day improvement as I haven't driven it yet. I don't want to drive a car leaking fuel onto headers...

 

I don't want to go to dual carbs as the dual SUs are stock. If I do go to a different carb, I'm going to do triple Webers. This is really unlikely, as it'll run me over $1700. I want a SBC swap, but that is also very unlikely. I'm pretty sure I'm going to end up with a L28ET swap. Fuel injection, turbo, megasquirt, and stock engine, so it fits with the same wiring harness and gauges and no issues. 

 

This sounds like the best idea

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watch this 20 minute episode of Horsepower TV's dirt track engine episode and it shows how some companies "Tune" intakes to fix the issue....

 

http://www.powerblocktv.com/episodes/HP2012-16/building-a-competitive-dirt-track-engine

 

That was a great video! I'm definitely going to keep watching those. That guy's skill level with the baffle is incredible. 

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there are some good videos but it just goes to show that with the issues known to engines people like this person have figured out how to overcome them by artificially creating Reversion in the intake... whether you realize it or not the issue can be fixed still using carbs...

 

just think how bad the issue was with straight 8 engines and thats why they quit making them... no one at that time could fix the lean issue with the outer cylinders without using Mechanical Injection.... which was very finicky back then...

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there are some good videos but it just goes to show that with the issues known to engines people like this person have figured out how to overcome them by artificially creating Reversion in the intake... whether you realize it or not the issue can be fixed still using carbs...

 

just think how bad the issue was with straight 8 engines and thats why they quit making them... no one at that time could fix the lean issue with the outer cylinders without using Mechanical Injection.... which was very finicky back then...

 

What about a twin carb for the straight 8 setup? That'd be four cylinders per carb, and a simple linkage, is there a reason why that wouldn't work, or is that one of the ways they fixed the issue?

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