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Any one running a Holley?
I'm running a Holley 600CFM on a 13B 4 port with a street port. Having trouble with it breaking up mid range 4000 up. Pulls great up till then and will sit and idle at 800 all day long. In the Holley I currently am running jets, 68 primary, 63 secondary with a white spring in the vacum secondary and an orange cam on the accelerator pump.
Tell me what some of you are running in your Holley's?
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google .. jetting 13b holley .... could be a few things ...Accelerator Pump Discharge Nozzle... timing...too much to guess with out the car in front of me..search button is your friend
what fuel pressure u running at and float levels set right? could be just running it out of gas. RB recommends 6 psi for the holley. and shouldn't the secondary jets be larger than the primary?
Running 5 lbs with a Holley blue pump. Floats are set correctly. Your probably correct on the jets. It's running so well lower RPM I guess the thing to do is up the secondaries and see what happens. Just bought a Fuel Air gauge so going to get that on today and see where I am at.
Op does not state whether the Holley carb he's got is a RB unit or not. The #1850 cfm Holley vacuum secondary does not have separate replaceable secondary jets,they have a calibrated metering plate mounted on metering block for secondaries.
The primary jet size of 68 sounds about right but am confused about OPs statement of rear JETS being size 63.
Where op states engine begins to break up is right about where secondary circuit should be flowing 100%. While rear jet plate size may not be optimal for his engine mods/needs,the fact OP states 4k is the ceiling where engine revs no more indicates to me the secondary section of carb is not flowing any fuel at all.
While correct fuel pressure feeding any carb is crucial,fuel pressure to Holley carbs is everything. 1st thing to check is is float bowl level in both bowls,should be right at threads in bowl. Used on musclecars,engine had to be running to set floats properly as engines were fed by mechanical fuel pump. OP has to have electric pump of some sort(should have pressure regulator in circuit) regulated to 5-6 psi that can be actuated by turning ig switch on without starting engine.
2nd thing to check is diaphragm that controls secondaries,remove diaphragm body from carb complete and note there is a small gasket between it and carb body. Operate linkage protruding from bottom of diaphragm to be certain it is not bound up some how internally. While linkage is pushed in as far as possible,while holding in this position and covering vacuum hole on diaphragm housing that mates to carb with your finger should keep linkage in retracted position. If not,diaphragm should be removed and inspected for pinholes/tears. A large enough hole will prevent secondary operation,a smaller pinhole/tear will cause late and lowered secondary function. A hand vacuum pump can also be used to check secondary diaphragm. Next to check is with engine running,open throttle fully for a short amount of time and feel for vacuum with your finger placed over diaphragm vacuum supply port in carb body,alternately use a vacuum gauge on this port to test for available vacuum. If satisfactory vacuum is found,this should prove actuation system for secondary linkage to be sound.
Engine off,manually open/close secondary throttle plates to be certain they operate without binding thru full range. Air cleaner off,start engine and rev to more than half throttle,manually open secondaries,watch for fuel to flow from boosters into secondary venturies. The engine will also accelerate quickly if they're functional so be fast to close secondaries and release throttle so you don't overrev engine.
By this point,if you've done your testing in order as described... if you have working secondaries by manually opening them,source of problem will be no vacuum signal to secondary diaphragm. If testing of diaphragm and vacuum source proved good,but manually working secondary linkage with engine running produced no fuel into secondaries,it's time to remove and disassemble carb. Op doesn't state whether a new carb or used. If used,no telling if prior owner had carb apart for possibly some other problem and assembled incorrectly,particularly with incorrect gaskets installed OR correct gaskets oriented incorrectly. This is very easy to do and have come across this more times than i have fingers to count on.Try to save all gaskets removed for comparison with new gaskets from carb kit.
Op,look at # stamped on right front side of airhorn and get a Holley overhaul kit for this model and go thru the carb thoroughly cleaning everything. Use a carb bath or spray carb cleaner followed with compressed air to verify all passages in carb body,metering blocks,jets and throttle plate are clear. Lay out all the parts and gasket match to be certain needed passages are not blocked with wrong or incorrectly oriented gaskets. Compressed air can be used to verify all sub assembled carb circuits are open.
You can test vacuum signal for secondary diaphragm by using compressed air for vacuum signal that comes from throttle plate is good by directing compressed air into passage in carb body that corresponds with hole in throttle plate that feeds it(without diaphragm body installed)and feeling for air pressure at vacuum hole in right side of carb body that corresponds to vacuum source for diaphragm. Initially set floats(new needles/seats)front and rear to just under 1/2 way up in bowl(viewed right side up) to allow you to make fine adjustments on car with key turned on to fill bowls before starting engine.
Post back findings,results so future readers of your thread can benefit from your experience. Happy hunting!
OK! Finally got the 13 B running well. Here again it is an early 13B with a strong street port completed by Tri-Point back in the 80"s.
I installed a Holley 1850-2 600CFM with vacum secondaries, metering blocks primary and secondaries. After sitting car would start and idle but would break up around 3,000 RPM. Checked timing and everything looked good there.
Cleaned and rebuilt still had problems.
Thought it was running lean so played with jets, accelerator cams, secondary springs, etc.
Finally got it running great with the following combination.
Orange accelerator cam. (no others worked near as well).
Yellow vacum springs. (tried white and orange both worked but with minor issues).
Removed vacum unit check ball. ( both recommendations came from Racing Beat). Thanks for your help Racing Beat
Plugged the power valve
61 jets in primaries (tried everything from 57 to 68).
63 secondaries jets
Holley blue pump set at 5 lbs of pressure
Car now idles at 900 RPM all day long. Runs up through RPM's with no hesitation.
Recommendations!
Make sure no vacum leaks.
Check float levels
Set idle adjustments at 1 1/2 turns out to start with. ( I ended up set at approximately 1 turn for each)
Make sure butterflies are closing all the way to begin with. Then adjust idle speed as needed with idle screw.
I realize everyone's engine can or will be different. But for mine this is the combination that worked well for me after hours of playing with it.
Hope this helps!
Very clean setup! Glad you got it sorted. VW chassis?
Just noticed your location,whereabouts in Pa? Likely not too far from me.Love to see that in person. Do you take it out much or for show?
I'm up near Reading Pa.Haven't had it out much recently. Matter of fat I recently bought some WWII military vehicles and need some room. Thinking about selling it.
03-08-19, 12:25 PM
