barnett468
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Posts posted by barnett468
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ok, as i said, its complicated. you can do what you like, trying it will not hurt but they are WRONG, lol. also the power valve has nothing to do with idle. it basically only opens when your foot is on the floor. if you have a vacuum gauge in your car you can watch exactly when it opens and possibly feel what it does.I don't WANT to run a leaner one, just would like to have them just in case so I dont have to make another trip to the store HAHa.I was under the same impression you take your vac and divide in half and that is the PV u use...If I recall that is what it even says in my carb tuning video.
I have done lots of carbs in my life but aside from Quadrajets I have never tried to use a Vac carb for a performance application.
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Will do.The Carb was brand new but just sat in the box open.
Ill swap the PV and get a 5.0 and 4.5 in case.
I have 2 extra springs that came with the carb as well as the directions and video etc...
Gonna play with it this weekend
why do you want to run a leaner power valve?
also, those carbs are jetted a hair on the lean side. i would think that your jets should be at least around 72 front and 76 rear.
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actually this is not how it should be done and holley actually gives three titally different ways to do it so its easy to understand how people can get confused. 99.9% of the carbs run fine with a 6.5 not matter what the engine vac is. its a bit complicated..How much vacuum are you producing? The guidelines state take vacuum divide by half. So 10' would be a 5.0 PV. Anything above 13' would be 6.5. -
yup, glad it eliminated the worst possible prob and put your mind at ease. now you can drink a few beers because you want to and not because you "need" to, lol.
also, put it in drive and watch the wheels rotate from directly behind each one. if they wobble much, it will also cause probs and is either the rim or a bent axle.
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The 54 on the buck tag is NOT for the interior or body code. It is the DSO.
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Ok put it in neutral, rev'd it up for ten seconds at 15k, 20k, 25k and 30k and the vibration wasn't there, so least it's not the engine or clutch. Will do the tests with the back up at the weekend.thats great news. the other fixes are dirt cheap.
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ok that is fine but if your timing at idle is too low it can have a hesitation off idle. i would run as much idle timing as i can. if it likes more idle timing than just reduce your mechanical advance.My Dist is an MSD Billet Non Vac Advance unit... I think the total timing was 34 degrees and that is where it made the most power at when we ran it on the dyno.
easy deal. buy the optional spring kit and throw the white spring in it. if they open too soon then try heavier ones. if the still open too late with the white spring you are unfortunately sol.Seems like my secondaries open to slow in my opinion when I mash on it hard... -
Barnette The pump shot is nuts on the money so far as timing is concerned, but may need bigger squirters...I believe the 770 comes stock with a 6.5 PVyes the 6.5 is what they come with but you implied it was used so if this is the case it might have been changed or dried up which can cause a hesitation under some conditions. if the valve is old and unknown you should change it before doing anything else.
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i would put a sacraficial anode in it to reduce electrolosis
waterless anti freeze may not cool it very well. but if you don't run hot then it is ok.
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engine is 68 and 69 302 mustang and 68 shelby.
54 might be omaha district delivery
A = no clue
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hello,
what is your timing at idle with the dist vac connected AND disconnected?
are you using ported or manifold vac for adv?
you most likely can not totally eliminate a flat spot because your gears are far to tall. you must have at least 3.73 gears with that engine and 3.91 would be better.
i would run a 6.5 power valve and set the gas level in the carb so it is just below the inspection windows when the engine is running.
look in the carb and open the throttle just a tiny hair. if you do nit see a stream of gas squirt out your accelerator pump is dried out or the pump screw needs to be turned clockwise a little.
reduce and plug the dist vac advance and advance the timing until the rpm quits increasing by large amounts or until the engine stumbles. leave the vacuum off.
if need be put the stiffest spring inn the secondaries.
tell us the results.
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I may have a vac leak as wellok, that makes more sense.
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that's bizarre, but hey, it was a cheap fix.So I took the Holley 600 off and put the factory autolite4v back on. Now it doesn't overheat
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ok well your car should run a least a little hot with that rad if its over 75 degreees outside . look thru the fill hole at the top of the tubes as suggested . . if there is rust sticking out of any it is plugged. . either way its too smal . i would get a 3 row 24 inch high effeciency rad and the bypass . . if it still runs a little warm get a lincoln fan and fan controller . and the 192 t stat i mentioned but a 180 should work and i prefer those. . . fr
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well you can try going up 2 sizees on the main jets . flor it from a dead stop before and after to see if there is a change.
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can you drive all day on the freeway without it boikinh over? , the bypass drops in under the t stat housing .m they work but you need more than just that . 30 degree temp drop is very good . your timing is good . your prob is strange . . how wide is your rad? . . . .m
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Yeah it sounds like the vibration is originating below me when I'm driving if that makes sense, like I can hear the source of it 'shaking' whatever it is.I haven't done that no, I'll give that a go to see if I get the vibrations at a standstill.
Thanks again!
ok, cool, let us know.
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hello;
the overheating started only after you changed the parts?
what about your water pump?
is that 13 degrees with the dist vac disconnected?
whaT IS THE TOTAL TIMING WITH THE DIST VAC DISCONNECTED?
it is not because it is too lean. if it was too lean it would have big flat spots when you hit the gas pedal. it might also ping.
you can get your rad water tested to see if the heads are leaking.
if everything is mechanically good, you need the bypass below.
you need at least a 3 row us made wide radiator or bigger chinese one. US Radiator sells them the us made ones.
if it still tuns hot in traffic you need a bigger fan. there is no way that fan puts put 3000 cfm. i am extremely familiar with electric fans.
a lincoln mark VIII is one of the best fans and can be had for only 150.00 the dual ford contour is also good.
if you run 50% anti freeze, it will run cooler with 10% but should be increased in the winter.
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.r
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I'll order the spacer...looks like it comes with the gaskets.I have a 351 cam in a 302 with gt40 heads. I am running right at 12deg.
ok as long as that 12 degrees is with the dist vac disconnected that is ok.
if it is getting gas when hot then maybe lower your float level around 3/16 - 1/4 inch as a test.
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Didn't know the clutch pressure plate could be off balance, absolutely loathe to drop the tranny so will be my last check :)It's pretty consistent at all speeds when hitting the same revs. Doesn't sound like it's the engine to me seems more like coming from under the driver seat around that area so I'm assuming it's around the tranny/drive shaft. Some good advice to test out will give that a go.
i find vibrations that way all the time.
when on the jackstands, brake slowly so the sudden stop of the wheel doesn't jerk the car. i have never had a prob.
you can straighten a coat hangar, put an 8" loop in it so it will sit on the ground then put then other end next to the driveshaft and turn it and see if the gap gets bigger then smaller etc.. if it dies your shaft us off center or the yoke in the diff is bent. if the u joint does not fut tight in the rear yoke, it is the wrong one and can cause probs.
you also hear something?
if you have not done this then try it. in your driveway, put the car in neutral, hold the rpm at 1500 for 10 seconds, then 2000 for ten then 2500 for ten then 3 for ten. if it makes the same vibration it is the engine or flywheel or pressure plate.
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hello;
what was your idle timing before the changes?
what us is now?
are you using ported or manifold vac?
try advancing it around 6 degrees as a test and see if it runs cooler at idle.
you should run a stant premium thermostat a 192 might be best.
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also if you have exhaust cross overs i would plug them.
when you come back to the car after it gets hot, look in the front venturis and open the throttle at a moderate speed. you should see two strong streams of gas. if not then your bowl might be going low on gas.
what is your ignition timing?
if it is stock or has a small cam then it should be at least 8 deg btdc.
if it has a big cam the 12 - 14 btdc.
connect the dist vac ad to ported vac, not manifold vac.
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just swaping the intake won't affect the afr much. if it runs fine i would leave it. i would hope for slightly tan plugs not gray ones though. i wouldn't live by the afr on a carb car either because you can not get a perfect afr with one.
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hello;
does it get worse the faster you go.
if it is not in the engine, put the rear on jack stands
block the front wheels,
put it in gear and rev it to 1500 for a few seconds then 2000, then 2500. if it does not vibrate it is likely your tires having flat spots or bubbles.
if it does vibrate, remove the rear wheels then put nuts on the hubs to secure them then do the test again.
if the vibration stops your wheels are bent and/or out of balance.
if it continues, it is your driveshsaft or you have a bent yoke in the pumpkin.
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Street Avenger 770 and 408W
in 1969-70 Technical Forum
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