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Post by chris05 on Jan 8, 2008 21:02:33 GMT -5
I'm having some trouble figuring out my small block..... well first of all it is a small block 350 Bord 40 over it has a 462 to 480 lift comp cam and a new 650 holly and a new distributer but the truck sounds great and idles good but when i stomp the gas it stumbles hardcore and almost dies and i was looking for some advise with what it could be its starting to frustrate me i don't know what i could do to fix it it has electric fuel system regulated to 7.5 psi and also could it be the valves out of adjustment?
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Post by Pontiac1976 on Jan 9, 2008 16:15:28 GMT -5
What style 650 Holley is it a Vac secondaries or double pumper. The carb is it right out of the box or has some had this on a motor be for yours.
Does your truck smell like unburned gas , If in park and you stomp it down quick let off does it still stumble does it rev up smooth. try to keep the rpm under 4500.
Have you adjusted bowls fuel level ?
The fuel pressure you could try 6.0 or 6.5 And your valves should be set and tighten down to the proper specks be for you start to work on any thing else.!
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Post by chris05 on Jan 13, 2008 0:44:19 GMT -5
yea it has a vacume sec.. and i think i may have found the problume the jets were to small i think oh i found out it was a 750 it had the jet size of 50 so i thin ima try 62s out of a older 650 carb could that be whats wrong?? it makes like a muffle sound when i stomp on it like it is runnig out of gas what about the accalater pump think i should get a new one
when i stomp it quick it falls on its face and one it gets to a lil higher rpm could it be spark plugs ther bran new but could it be a bad one
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Post by Pontiac1976 on Jan 13, 2008 10:32:14 GMT -5
Sound like that might be it, if it is a 750 with the cam you have. You might be-able to go up to 72's , but the # you going with will be a good start. I would try that then go up two # try that again un-till seams to loose power then drop back two #'s that should be close to right. As for the I think if it was new it should be OK but if it looks old and wet I would get a new one. I would make sure that the floats are set at the right level get new needles seats for the bowls.
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Post by chris05 on Jan 13, 2008 22:26:19 GMT -5
dammit that didn't fix it what size of power valve should i use and should i get a lighter spring for the secondaries so they open sooner??
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Post by Pontiac1976 on Jan 14, 2008 18:47:57 GMT -5
The first thing is this is a 750 now you say is this a 3310 Holley center hung floats dull feed or single feed tube to both bowls.
most stock power valves are 6.5 most used and should be OK since the jets where so small I would think un-less it's blow-en. I guessing the carb was set up on the conservative side for a smaller cam. The floats have to be set so the fuel is just even with the sight plug hole. set up all to basic setting get it running well then start to fine tune from there.
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Post by chris05 on Jan 14, 2008 19:29:17 GMT -5
its a duel feed center hung
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Post by Pontiac1976 on Jan 15, 2008 16:29:12 GMT -5
Was looking at you motor pic I see a few things I would add to the motor a PVC on the right valve cover. Attach hose to the big tube coming out of the bottom of the carb at the back you may need a Tee in line if your using it for something else too. I would put one of the in line brake booster filter from the 81-up trucks it helps prolong the Vac booster bladder side. The rubber gas line near the carb,I would try to keep it as short as you can and I would cover it with some kinda heat barrier just to be on the safe side and help keep fuel line cooler just in case vapor lock. Does your 4 bbl linkage work free and do you get full open @ 3/4 to floored peddle. I found that if there air in the fuel line you can have look like not getting enough fuel . Do you have electric fuel pump or Mech, ( if mech pump un-do the fuel line at the carb. Start truck up let idle make sure you have a bucket as soon as it fuel on air stop the truck gently pinch the rubber line so air does not go back in the line hook it up the carb as fast as you can. same for a electric pump just you do not have to run the truck turn the key on un till the air out and just steady fuel come out.) Re start motor let it warm up to running temp Jets should be 2-1/2 turn out as a basic start point, The bowls should be set so fuel just at the threads of the sight plugs . Now a Vac gauge hooked up intake vac port try to get the highest reading steadiest vac you can when adjusting the jets when motor is running. then take it for a test run see what happens. Then you might want to jets or check the see if it getting fuel on the secondaries. Try this . You do know how to do rough set up of the holly carb right.
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Post by chris05 on Jan 15, 2008 18:25:17 GMT -5
hey thanks for the help im new to carburaters and i know nothing about them just a couple things but rough set up?? whats that i just checked the level in the fuel bowels and it was even with the botom of the sight hole is that good or should i adjust it and yes i do have electric fuel pump and i herd they suck and thats the first thing i need to change i do u think that is a good idea? and the fuel pump free flow 140 gph pump...... and also i was thinking aout putting braided heater house and rad. house vacume lines and kinda making the engin compartment all nice and shine
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Post by Pontiac1976 on Jan 16, 2008 8:18:11 GMT -5
Basic is something that wil get to work on most motor's . So you taylor it to the motor and set up of that car or truck. Oh yes it sound like you have the floats set ok . I would try to pick up a holley tune up book .I try to put down some tips to try help you there .
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Post by chris05 on Jan 19, 2008 19:07:17 GMT -5
ok so it has the two idle needle adjust ments on the meeting plate so say if i tightin it all the way up what is basic from there !!? is it 1 and a half or 2 turns out?? could that be out of adjustment that is the only other thing i could think of
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Post by Pontiac1976 on Jan 20, 2008 8:48:02 GMT -5
Well yes that the one that you will have to adjust 2-1/2 turns out. you do it like you said just gently turn them all the way in just snug do not over tighten them.
Tip: "trick tool" : this tol has three type of main uses. A Vacuum Gauge really help you fine tune a carb like a pro,
if you can do it by sound & smell that good but in most cases if you have a Vacuum gauge you will be better then the pro that tunes the idle, for the low and high idle needles on the sides. So after you get the 2-1/2 turns out then you use the Vacuum gauge to fine tune so you have the highest vacuum reading but a good response. If you buy a Vacuum gauge it will tell you how to hook it up to the motor then you just do the reg tune up set up as most carb you would do. So you may have less or more then the 2-1/2 turns in or out. The side park idle and in linkage once set should be set to the motor specks for best fuel setting or if you like you motor rev a little more could be @ 800 or 1000 RPM but most stock setting would be around 550, 600, 650, 700 there a few motor set up that had as high as 750, or 800 RPM. This is for mostly to help charging or if the car had a more then stock TQ convert. So you should use the stock setting to get started adjust to your motor or what idle the motor likes or you feel better with.If your try to safe gas then higher idle will eat a little more gas so try to find a that happy med between them, or go on the low side if you did mod to the motor keep the stock setting for stock motor .Oh the two best tools you can have for a tune up Timing Gun & Vacuum Gauge Pontiac1976 hope this helpsby
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Post by chris05 on Feb 14, 2008 23:03:02 GMT -5
ok i fixed that problum now im having a oil pressure problme the oil is full but yet the oil pressure is perfict when im driving its like 45 to 55 pounds but at idle it is like 30 pounds should it be a bad baring i checked the oil and cut the filter its clean no meddle shavings so could it be a bad gage or is it cuz its a freshly bult engine and its finaly all breaking in and wearing could that be it?? and i have only changed the oil twice and it has like 1,000 miles on it
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Post by Pontiac1976 on Feb 16, 2008 8:38:36 GMT -5
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