Holley kaasarispesialisteja Turun suunnalla ?

Olisiko Turun suunnassa kavereita/pajoja, joilla olisi Holleyn säätäminen/virittäminen hanskassa ? En nyt tarkoita mitään tyhjäkäynnin säätämisiä yms., vaan tahoja, jotka tuntevat Holleyn niksit läpikotaisin (tai ainakin melkein :smile. Tarkemmin tuo kaasari olisi 4779-5, eli 4150 -sarjalainen 750 cfm tuplapumppari 351C:tä ruokkimassa ja suht. normaalissa katukäytössä. Itse en kyseistä murikkaa juuri tunne, joten tarkoitus olisi tsekata onko kaikki niin kuin pitää, saada säädöt viimeisen päälle kohdalleen ja mahdollisesti tehdä pikku modikset samalla, nämä kun eivät käsittääkseni tehtaalta lähtiessään mitenkään optimissaan ole.

Ei myöskään ollenkaan haittaisi, jos samalla kaverilla olisi sytysasioiden tietämyskin kohdallaan...

Jos joku tunnistaa yltä itsensä, laitapa privaattia/ soita 040-5897 348, niin katsotaanpa asiaa eteenpäin ! Tietenniin tänne palstalle kannattaa heitellä vinkkkejä muittenkin tarvitsijoiden iloksi näistä kaasari/yleisimminkin V8-pajoista tällä alueella.

Toivottavasti sitten nämä Nimettömät säästävät itseltään näppäilemisen vaivat ja jättävät nämä "Heitä se Holley hevon per******n" -kommentit kirjoittelematta.

 

Väännä seos ruuvveja kiinni päin ja kun kone ökähtää niin puol kierrosta auki.... Aika karkea nyrkkisäätö, mutta toimiva..

 

Nimetön pässi iski..nyt iskee toinen uudelleen!!! juuri äskeinen kaveri kertoi että tarviisi hieman muutakin kuin tyhjäkäynnin seoksen säätöä, joten onko luki vaikeuksia vai ????

 

Nostetaanpa, kun tiedän jonkun säätöpajan Turussa olevan. En vaan perkula muista itsekään nimeä!

Holleyn säätämisen opettelin joskus ihan ite. Tosin omani olivat tavallisia alipaine toisiolla varustettuja. Bensanpinnan korkeuden säätö, kiihdystyspumpun nokan vaihto, toisiokurkkujen alipainekalvon jousen vaihto ja suuttimien vaihto on aika helppoa.

Nyt on omassa autossa Cartteri ja tekisi mieli viedä se asiantuntevaan paikkaan, että sais kunnolla säätöihin! Kiitos etukäteen munkin puolesta jos joku tämän säätöfirman muistaa/tietää.

 

Kai nyt joku osaa hommelit/ tietää alan pajat ?

 

osaa joo.mutta kun kaasari tehään kunnolla ja säädetään ja optimoidaan se vie aikaa ja vaivaa.mitä oot valmis maksamaan?ite oon puljannu 15 vuotta noiden kans eikä ikinä oo tullu ongelmaa joka ei olis ratkennu.holley 4150 mallit o yksinkertasia ja hieeman karkeita mut kyllä ne toimimaan saa.voisin suositella yhtä hemmoa mut ku en tunne niin hyvin.yleensä race ukot hallittee noi kaasarit suht hyvin.

 

Kaarinasa oli ainakin tämän dragster haapasen korjaamo joskus,oli erikoistunut jenkkeihin.Nykypäivän tilanteesta en tiedä.
Auto-haapanen oli nimenä.

 

Tässä on artikkeli vakuumi-Holleyn säätämiseen. Valitettavasti en löytänyt vastaavaa artikkelia tupla-pumppu -Holleysta, mutta ehkäpä tällä pääsee alkuun :smile:

Liitän myös oheen artikkelin sytytyksen säätämisestä, toivottavasti siitä on iloa.

Edit: tämäkin koskee GM-moottoreita, Fordeista minulla ei ole tietoa :sad:


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How to Tune a Holley
(basic)

by Lars Grimsrud
Colorado Corvette Crazies (CCC)
The Ultimate Corvette Tuning & Beer Drinking Fraternity
Lafayette, CO Rev. A 2-6-02


This tech paper will discuss basic set-up and tuning of Holley vacuum secondary carbs for optimum street performance and drivability.


Overview
Holley carbs have been used by hot rodders for many decades now. Holley offers a very tuneable, modular carb design, yet it’s surprising how few people understand the basic tuning principles and procedures for these carbs. This tech paper will discuss some basic tuning procedures and techniques to help you get your setup optimized a little better.

Holley carbs have several operating systems, all of which can be tuned independently. Often, an improper setup of one system will give false indications of a problem in another system. Attempting to cure Holley problems by tuning the wrong system results in a really messed up carb, and a lot of frustration for tuners and car owners.

Holleys have the following basic operating systems:

Idle System
Accelerator System
Main Metering System
Power System
Secondary System

These systems at times overlap in their operation. Not only does each system need to be properly tuned, but its timing and “overlap” with other systems is critical to proper performance.


Tech Tip #1
Before you go trying to fix all the errors of the previous carb tuner, set your carb up to the stock Holley spec for your carb List Number (stamped into the front of the air horn). Holley does a pretty decent job of supplying a ready-to-run carb, so the jetting, pump cam, shooter sizing, and spring rates are usually pretty close. This will give you a good baseline starting point for your tuning process. You can either call your local Holley distributor for the stock specs on your List Number carb, or go to this website to check out the baseline configuration:
http://www.mortec.com/carbs.htm

Tech Tip #2
When buying tuning parts for your Holley you have two choices:
Obviously, Holley offers original parts at the Holley price. I highly recommend original Holley rebuild kits, gaskets, and power valves. BG, or Barry Grant, also makes parts for Holleys, and offers them at a fraction of the Holley price. BG is a great source for items such as the accelerator pump cam kits.

Tech Tip #3
Virtually all musclecars (with a only a few notable exceptions) came from the factory with a dual plane intake manifold, also known as a “180-degree” manifold. A dual plane intake is characterized by having two separate sides (right and left) which feed two different “levels” inside the manifold. Half of the cylinders are “fed” from the one level, and the other half are “fed” from the second level. A dual plane manifold promotes higher intake velocity at lower rpm, improving low-end torque and low-end throttle response. A dual plane manifold also promotes very good vacuum at idle and at low speed.

At very high rpm, a dual plane manifold will loose some efficiency. For this reason, there are single plane manifolds available. Known also as “360-degree” manifolds, the single plane manifolds typically have large intake runners and a large, open plenum under the carb. Very good for high-rpm use, these manifolds can be a real challenge to tune for low-end, street rpm use. A single plane manifold will typically significantly reduce vacuum, and this causes several problems.

Intake vacuum is used by the carb as a “signal” for many different events to occur. As vacuum is reduced, caused by large plenum intakes and large overlap cams, the vacuum “range” becomes much more narrow. The carb tuner must make the various events occur within this narrow tuning range, while hitting a much more narrow “tolerance” for overlapping events to occur. Typically, a large-plenum intake will require richer main jetting and a richer pump shot to avoid a lean stumble hesitation upon initial acceleration. The idle transition may even require extensive recalibration of the idle restrictors – not an operation for the do-it-yourselfer.

My recommendation: don’t use a single plane intake on a street driven car unless you have a lot of cubic inches and you’re willing to put in a lot of time tuning the idle transition. If you’re experiencing an off-idle stumble on a car with a single plane manifold, your problem may be in the manifold and not with the carb. Consider spending the $$ for a dual plane intake and saving yourself some frustration.

Tech Tip #4
Which way to tune the accelerator pump – richer or leaner?
Hesitation, stumble, or backfire is usually indicative of a lean condition.
“Lazy throttle” is usually indicative of a rich condition.
A rich condition may also be accompanied by a small puff of black smoke upon initial acceleration.

Tech Tip #5
When removing the float bowl, pull one of the lower float bolt screws first. Place a small container, such as the plastic cap off of a spray paint can, under the float bowl, and catch the fuel as it drains out. When you put it all back together, you can use a small kitchen funnel (just don’t tell your wife about it) to pour the drained fuel back into the bowl by dumping the fuel down the bowl vent tube (the tube sticking up right at the choke).

Tech Tip #6
When using a Holley on a car with a bumpy cam, it is often necessary to screw the idle speed screw in far enough that the ported vacuum slot in the throttle bore is uncovered, producing significant ported vacuum to the distributor vacuum advance at idle. When the engine is rev’ed up, the vacuum source advances the timing, as it should. When the throttle is closed, the rpm will very gradually bleed down as vacuum advance gradually fades: the engine will not settle down immediately to the correct idle speed. To eliminate this problem, you can adjust the secondary opening screw to allow the secondary throttle plates to be cracked open a little more than the spec requirement. This will bleed a little air through the secondaries at idle, increasing idle speed and allowing the primaries to be closed down to correct the ported vacuum problem.

Tools and Equipment Required
As a minimum, you will need the following tools:

1. Vacuum Gauge
2. Small cup to drain fuel into
3. Screwdrivers
4. Box end wrenches
5. Spark plug removal tools
6. Rags


Procedure
Here is my recommended sequence and procedure for doing a basic Holley set-up:

1. Set the float level.
You’ll be amazed how many people try tuning a Holley without ever checking the float level. An incorrect float level can give you all kinds of symptoms and problems, so get this one set right off the bat. Most Holleys have a sight plug on the side of the float bowls, and have externally adjustable floats. With the engine HOT and running (float level will change with engine temperature – make sure you’re completely warmed up before setting this), put a rag under the sight plug area and pull the plug. Adjust the float level until fuel just barely starts to dribble out of the plug, then lower it until the dribble barely stops. The slotted screw in the center of the adjustment is the locking feature – loosen it and turn the hex nut CW to lower the float level, CCW to raise it.

2. Make sure your Power Valve is in the ballpark.
Most “stock” Holleys come with a power valve in the 6.5” range. This means that the power valve will open and start dumping fuel into the discharge when manifold vacuum hits 6.5” Hg (Mercury) of vacuum. A lot of cars with big overlap cams, single plane manifolds, or operating at high altitude will not pull 6.5” vacuum with the transmission in “drive.” This means that the power valve is flooding the engine with fuel on very light acceleration right off idle, and you’ll never get the tuning right unless you fix it.

Hook up a vacuum gauge to the intake manifold or to one of the vacuum ports at the base of the carb. With the transmission in “drive” (or in neutral on a manual car), note the vacuum reading. Your power valve should be rated at about 2” below the actual vacuum reading. On a car running at 11” of vacuum in drive, you will need about an 8.5” power valve.

3. Now get the main metering circuit in the ballpark.
Now that your power valve is not flooding you out, you can get the main metering jets tuned in. If your main metering circuit is either too lean or too rich, you will not be able to properly set up the accelerator pump circuit. Trying to fix a bog on acceleration with pump cams and discharge nozzles when the main metering is off is like chasing your tail. The main metering system also affect the idle circuit, so you need to get the main jets in line before going on to the other tuning parameters.

Pop a new set of spark plugs in the engine (don’t use the new Platinum or other exotic metal plugs- they won’t read right). Now take the car out for a drive around a few blocks. Get it up to steady-state cruise rpm, and make a few moderate accelerations. Pull the car back into the garage, allowing it to idle as little as possible. Shut it down and pull a few of the plugs. The plugs should have a very light, off-white or tan color around the nose of the insulator. If you’re pure white (completely clean), you’re probably running too lean. If you’re picking up black soot, you’re too rich. Raise or lower primary jet sizes by 2 sizes at a time and repeat this test until your plugs are showing the correct color.

4. Tweak your idle screws.
Screw both of the screws in until they gently bottom out, and turn them both out 1-1/4 turns. This is a good starting point. With a tach on the engine to monitor rpm, start the engine and turn the screws ½ turn at a time, turning both screws the same amount, until the best rpm reading is observed. Then turn them in 1/8 to ¼ turn to lean it out just a tad. Once set, I like to shut the engine off and turn both of the screws all the way in, counting the turns, until they gently bottom out again. Just to make sure they’re both set the same. Then back them out to the setting you had.

5. You’re finally ready to fine-tune the accelerator pump circuit.
Many people start by tuning this, and can never get the stumble tuned out of the car. By making sure that the other systems are approximately right, you can now set this system up so that it’s not trying to compensate for other deficiencies.

There are two tuning parameters to the accelerator pump circuit: Pump Cam and Discharge Nozzle.

The pump cam, a little plastic, color-coded part located on the throttle shaft with a single screw, will determine the total volume of the pump shot.

The discharge nozzle, or “shooter,” is available in different sizes, and determines the rate of discharge. In other words, it is possible to install a large-volume pump cam, and have a small-diameter “shooter” which “bleeds” the total volume in over a longer duration. Or you can install a big “shooter” which allows the entire pump shot to be dumped in almost immediately.

There is no real scientific way of coming up with the exact correct combination for these parts. As a rule, of the car stumbles, backfires, or hesitates on initial throttle opening, try a larger shooter (the size is stamped on the body, and they’re available in .001” increments). If the car has a “lazy throttle,” indicative of a rich condition, try a smaller pump cam at first.

6. The last step in the initial tuning process is to set the secondary opening rate.
The secondary opening rate is determined by the spring in the secondary diaphragm. A soft spring will allow the secondaries to open sooner. Install softer springs until the car develops a slight stumble from the opening rate, then go back one spring level. This will allow the secondaries to open as quick as possible while avoiding a stumble.

A common mistake made by “performance” tuners is to remove the secondary diaphragm check ball. The check ball is installed in the secondary diaphragm housing, and helps to control the secondary opening rate. Removal of the ball will result in immediate opening of the secondaries with very little mass air flow through the primaries, with a resultant massive stumble upon acceleration.

You cannot normally get the vacuum secondaries to open by flicking the throttle and rev’ing the rpm with the car in neutral. This is not a valid test of the functionality of the secondaries.

7. Now, if you want to fine-tune the primary jetting, you can do one of three things:
For maximum horsepower, you will need to run the car through a measured distance and note its speed at the end of the distance. Using one of the available performance computers, or running the car at a track, is best for this. The correct size jets are the jets which give the car the highest mph at the end of the measured distance (not the shortest elapsed time). Again, change jet sizes 2 sizes at a time to see if the speed increases or decreases.

For maximum economy, drop the jet size until the car develops a slight stumble upon acceleration, then go up two sizes.

For a really good, scientific way of setting up the jetting, check out this website:
http://www.bob2000.com/carb.htm


Questions, Comments & Technical Assistance
If you have questions or comments regarding this article, or if you notice any errors that need to be corrected (which is quite possible since I’m writing this from memory…), please feel free to drop me an e-mail. Also, if you need any technical assistance or advice regarding this process, or other maintenance issues, feel free to contact me:

V8FastCars@msn.com

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How to Set Your Timing for Peak Performance
(Non-HEI)

by Lars Grimsrud
Colorado Corvette Crazies (CCC)
The Ultimate Corvette Tuning & Beer Drinking Fraternity
Lafayette, CO Rev. B 4-18-01


This tech paper will discuss setting the timing on a Chevy V8. This procedure also applies to other GM V8s.

The procedure outlined here differs from the Service Manual, and is based on my years of experience doing this work in the quickest, least painful, most economical way while keeping the level of quality high. It is recognized that other people will have different methods of doing things, and may disagree with specific methods and procedures that I use.

How to Set the Timing
When you think about it, setting the timing at idle speed makes no sense at all: You don’t operate your car at idle, and timing changes as the rpm changes. Fact is, the timing spec at idle speed is provided as a simple way for most people to set the timing, and is not a good procedure for optimum performance.
Small block Chevys (and most other GM performance V8 engines) perform best when the total timing (full centrifugal advance plus the initial timing setting with vacuum advance disconnected) is all in by 2,500 – 2,800 rpm and is set to 36 – 38 degrees. If you have an adjustable timing light, this is very easy to check. If you don’t, you need to scribe a 36-degree mark on your harmonic balancer. Here’s how:
Measure the circumference of your harmonic balancer using a sewing tape measure (or other flexible tape measure). Get it as accurate as you can. Take this measurement and divide by 10. The number you get is the distance to 36 degrees. Measure this distance CLOCKWISE from your existing harmonic balancer timing mark and place a clear mark on the balancer.
Remove your distributor cap and rotor. Remove the 2 centrifugal advance springs. Install the rotor and the cap (without the springs). Disconnect the vacuum advance.

NOTE: This procedure cannot be used on the HEI ignition systems. Removal of the springs will cause an artificially over-advanced condition that will never be achieved with the springs in place. You can use the basic technique described in this paper with the HEI units (setting timing up to 36 degrees), but to check total timing, you must install a set of soft springs. You cannot remove the springs altogether. With the soft springs in place, rev the engine until the centrifugal advance is pegged out. Adjust for 36 degrees total. Then re-install your original springs.

Start the engine. It may kick back a little due to the advance coming in immediately without the springs. If you’re using an adjustable timing light, set the light to 36 degrees advanced. Now rev the engine just a little while observing the timing marks with the light. It shouldn’t take much rpm to peg out the advance without the springs installed. With an adjustable light set at 36 degrees, align the stock timing marks with “0” when the timing is “pegged out.” With the non-adjustable light, align your new 36-degree mark with “0.” Rev the engine a little to make sure the timing will not advance any further. Shut it down.
Pop the cap and rotor and re-install the springs. Put everything back together, but leave the vacuum disconnected. Start it up. For future reference, make a note of the timing setting at idle. This is your new curb idle timing spec. Now give the engine a few quick rev’s past 3,000 rpm and verify that the full timing (36 degrees) is coming in. If it’s not, you need to change to a softer set of springs until you get full 36-degree advance before 3000 rpm. (NOTE: A stock set of springs will usually not allow full centrifugal advance to come in before redline rpm. If you have stock springs installed, don’t rev the engine beyond its limits to try to force full advance in.)
Shut it down and hook up the vacuum. Now do a road test.
The 36-degree 2500 rpm advance curve is optimum for performance, but may require premium fuel. Lug the car around, and punch the throttle at low rpm while listening for detonation (“engine knock”). If you’re getting any audible knock, you MUST retard the timing. Retard the timing in 2-degree increments until engine knock stops. Engine knock will seriously damage engine components if not corrected. If you get no knock, you may see slightly improved performance at 38 degrees total timing. This is particularly true if you’re running at high altitude.
If you have no engine knock under acceleration, but the car “chugs” or “jerks” at cruising speed (light throttle application), you are getting too much vacuum advance on top of the mechanical advance. You may need to change out the vacuum advance diaphragm with an adjustable unit available from aftermarket sources. Adjust these units so that you get the most vacuum advance possible without any “chugging” or “jerking” at cruise speed.
Your timing is now set for best possible performance. Make note of the new setting, and use this for your future tune-up work.

Questions, Comments & Technical Assistance
If you have questions or comments regarding this article, or if you notice any errors that need to be corrected (which is quite possible since I’m writing this from memory…), please feel free to drop me an e-mail. Also, if you need any technical assistance or advice regarding this process, or other maintenance issues, feel free to contact me:

V8FastCars@msn.com



<font size=-1>[ Tätä viestiä muokkasi: tapio 2004-06-28 11:14 ]</font>