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Topic Review (Newest First)
09-26-2012 05:46 AM
foodstamp
small update after MIA

well i know its been a while since i last posted, ended up putting truck in the shop. carb issue never got fixed, but found out what cam was in it... it had a 292 comp cam... with 2 lobes completely wore off, 2 lobes thatrounded smoothly... so i had a howards cam and lifters installed. cam specs are

Strong Low & Mid-Range Torque
.447/.447 lift
280/280 in/out
208/208 in/out @050
111 lobe seperation

lifters came with the cam, says they are matched, but i think its more snake oil than anything...

a few more details about engine/trans: 3970010 block punched 30 over, the new cam/lifters,1.6 rollers,small camel hump heads and a 700r4 trans.

hope this helps
02-21-2012 03:34 PM
F-BIRD'88 The idle quality of the Weiand 7546 manifold is not that great in general.
Of al the different SBC intakes I have used this was by far the worst for idle quality, in general. Good power on a racey motor thou.
A really bad choice for a truck.
02-21-2012 03:01 PM
F-BIRD'88 If it has a long duration cam you will never get it right untill you address the distributor advance curve. A low stall converter will not allow an engine to idle correctly in gear if the cam is big.

fix the distributor

Cam or converter swap, pick one.
02-21-2012 02:57 PM
F-BIRD'88
Quote:
Originally Posted by foodstamp
UPDATE!!!!


WELL got my carb on but it still wont run, changed plugs cuz they was black and wet, still nothing... so a friend says check for spark... no spark now...

so i had ignition module checked and turns out it was bad, so i replaced it and still nothing, so its either the coil or the pickup.... so im to the point of just buyin a new dizzy as if i replace both the coil and the pickup, i could have a new one.... anyone ever got one them clear cap 65k hei's off ebay?
run a ground wire from the engine to the fire wall, or any-all HEI distributors will misfire.
02-21-2012 02:51 PM
foodstamp UPDATE!!!!


WELL got my carb on but it still wont run, changed plugs cuz they was black and wet, still nothing... so a friend says check for spark... no spark now...

so i had ignition module checked and turns out it was bad, so i replaced it and still nothing, so its either the coil or the pickup.... so im to the point of just buyin a new dizzy as if i replace both the coil and the pickup, i could have a new one.... anyone ever got one them clear cap 65k hei's off ebay?
02-17-2012 05:02 PM
foodstamp well made a lil progress today... rebuilt carb last nite just for satisfaction of knowing its done right (watched a guy rebuild his on youtube and followed step by step) and started to stick it on manifold.... thats where i ran into a small glitch. pass. rear bolt hole is stripped out, figure thats where i was getting my vacuum leak. so currently put some red locktite in it and screwed it till it started to get tite b4 it was gonna jump threads again and left it be, will go out in morning and torque carb down after it has set up.

so as i had extra time to kill since i couldnt work on carb, i set in to change out my valve cover gaskets as the passenger side was leaking like a sift. and then i got a neat lil suprize... 1.6 roller rockers on double hump heads... WOOT WOOT!!

now i can do most of my own mechanicing, but iv never messed w/ roller rockers, so how to i tell if its solid or hyd. roller rockers and how do i adjust them accordingly??
02-09-2012 02:47 PM
foodstamp Then you don;t want a big honkin cam in it.
Get a cam that suites matches what you are trying to do there.

im not swapping cams... its what came in the truck when i traded for it...

This is especially true if:
Your truck was an early tbi design which has too much fuel pressure for a carb;
or
if you saw signs of flooding on the old 1405, like fuel dripping down the throttle bore at idle or fuel weeping, dripping from the gaskets at the fuel bowl.

truck is a 81 chevy swb scottsdale. when took off the carb,my original 1405, the inside of the manifold was suprizingly clean, no discolored spots where fuel been pooling.
tho the actual mouth where the carb mounts had some brown discoloration, so i took one them sponges with the scrubbing side and cleaned it all up nice and shiny again b4 i swapped gaskets. so i would assume, someone took the carb off another motor and didnt bother tuning for the truck, but as the case may be im gonna get it rebuilt to factory specs by local rebuilder as soon as i have the funds....


the carb i borrowed off my friend, was older than mine, it had crude and all kinds of gunk built up on it, bowls was black where he filled it with 2 stroke oil b4 he put it up to keep it from drying out.
02-09-2012 01:55 PM
starnest I just saw Fbird's post, he is right about checking the fuel pressure.

The 1405 doesn't like too much pressure, I've been successful at about 7 psi, but I've also had problems at about 7 psi.

This is especially true if:
Your truck was an early tbi design which has too much fuel pressure for a carb;
or
if you saw signs of flooding on the old 1405, like fuel dripping down the throttle bore at idle or fuel weeping, dripping from the gaskets at the fuel bowl.

If your fuel pressure is just a little high then the reason your friends carb worked was because the needle/seat was probably a little newer (stronger) and able to hold off the flooding.
02-09-2012 01:49 PM
starnest After I read through the whole thread I was amazed that no one said to look at the carb. Which is the problem; you and your friend figured that out with the one you borrowed.

It's not the cam, and its not timing; the idle circuit on your 1405 carb has a problem, either not enough fuel or too much fuel. When you adjust the idle screw all the way in you tip in the butterflies and start running (idling) on the part throttle circuit, which with enough throttle opening overcomes the idle circuit fuel (too much/too little) problem.

The good news is the 1405 is an easy rebuild, get the kit and a (big) can of gunk. Disassemble the carb, put only metal parts in the gunk and soak overnight (up to about 24 hours).
After soaking I like to spray out the carb and pieces with gumout carb cleaner. Then reassemble the carb using the gaskets and other items from the kit.

I do agree that you should get a timing light and verify your timing is set correctly. It's been a while, but I thought the 1405 carb had connections for both ported and unported vacuum. The vacuum advance should use the unported (manifold) vacuum.

If the vacuum advance is working properly, and the distributer is stock, don't worry about the advance curve springs, just set the static advance, and check the total advance. The curve setting is for high performance, but you wouldn't notice much difference on a daily driver.

Good luck.
02-09-2012 01:44 PM
F-BIRD'88
Quote:
Originally Posted by foodstamp
well a friend cme by tody to try to help me sort out some problems... i have very lil adjustment on my edelbrock 1405, so he had a 1405 on an old ford truck, so we went and got it and slapped it on. fired right up and idled like a dream... until the pump gave out on it, so im gonna get mine rebuilt by someone who knows these carbs in and out. so when i get carb back, i found a friend of a friend of a friend that has a timing light, but he dont trust ppl with his tools, so he gonna come set the time on it (which i dont care as long as it gets set) ... but im not fmiliar with the springs/weights in the distributor as i dont have a clue to what to do there, its more of a daily driver than a playtoy, i just want it to run good.

they a guy supposed to be coming later today to possibly buy my towncar, if he does, iv have money to buy the parts i need, if not, ill scrape by until i can fix it.

Edelbrock carb:

Make sure the idle fuel pressure is 5.5PSI or less.
Get a fuel pressure regulator if nessessary.

its more of a daily driver than a playtoy

Then you don;t want a big honkin cam in it.
Get a cam that suites matches what you are trying to do there.

Much cheaper than new torque converters etc.

Lokk for a vacuum leak.
02-09-2012 01:26 PM
foodstamp well a friend cme by tody to try to help me sort out some problems... i have very lil adjustment on my edelbrock 1405, so he had a 1405 on an old ford truck, so we went and got it and slapped it on. fired right up and idled like a dream... until the pump gave out on it, so im gonna get mine rebuilt by someone who knows these carbs in and out. so when i get carb back, i found a friend of a friend of a friend that has a timing light, but he dont trust ppl with his tools, so he gonna come set the time on it (which i dont care as long as it gets set) ... but im not fmiliar with the springs/weights in the distributor as i dont have a clue to what to do there, its more of a daily driver than a playtoy, i just want it to run good.

they a guy supposed to be coming later today to possibly buy my towncar, if he does, iv have money to buy the parts i need, if not, ill scrape by until i can fix it.
02-09-2012 12:05 PM
oldbogie
Quote:
Originally Posted by foodstamp
ok, new to the forum, so dont flame me anyway, iv search and read and tried many diff things from what iv read on the board and still end up with same problem. i just traded for the truck so i dont know the cam specs but it has a nice overlap. with that bein said, i cant hold an idle less idle screw is turned almost all way in then it idles really high but when i drop in gear, it wont hold an idle if im not feathering the gas. i know it isnt good cuz im getting the drive line "snap" where its churping the tires when it goes into gear. as far as the idle, iv twisted dizzy back and forth, set it by ear at highest rpm that it doesnt climb anymore and starts w/ a bump of key. but idle is still alot less than desired as it has to idle up ruffly 1200-1400 rpm to stay running. i dont know if my vac. advance is working. plugging carb and vac line makes no differance, but if i put vac. line back on carb and lift it slightly... idle climbes, but as soon as i drop it idle drops back to bein really choppy. as far as trans, im hoping and praying i dont have to get a bigger stall as i cant afford one right now, much less payin someone to put it in.
I'd say you need to get info on the cam, it might need 1200 to idle depending on its timing characteristics. If you can't get published data then you'll have to go through the drill with a degree wheel, piston stop, a good dial gauge, and friend who will wrench the engine around for beer.

The wilder the cam the harder it will be to tune, as someone said you need a timing light if price is a problem look at Harbor Freight, it's Chinese but at least you pay for made in China unlike so many American brands that are also made in China but charge you made in America prices.

Bogie
02-09-2012 09:37 AM
F-BIRD'88 you need to recurve the distributor.
The stock out of the box curve will not work.


Get a timing light and find out how much inital timing the motor needs to idle in gear. WITHOUT any vacuum advance.

if it needs say 26deg BTDC base timing at idle to idle in gear than recurve the distributor mehcanial advance system to allow this yet not over advance at max rpm . Limit the distributor advance travel stop to around 10deg.

This allows 26deg at idle and 36deg at max advance and allows the camed motor to idle correctly while in gear and not flair up in neutral and not require excessive throttle opening at idle.

Then reconnect the vacuum advance.
If the idle flairs up when going to neutral, when using vacuum advance then use the ported vacuum source. (and or recurve the vacuum advance so its not all in at idle)

You may still need a high stall converter to get it right.
( or change the cam)

check the timing tab location. For true accurate TDC.
02-08-2012 07:20 PM
DoubleVision Then your asking for engine failure which is going to put you further in the poor house. If you have a advance or auto zone in your town you can get a timing light by renting it. All you do is make a deposit to rent it. When you return it you get your full deposit back.
02-08-2012 06:51 PM
foodstamp
Quote:
Originally Posted by whyholdback
Vacuum advance: Are you running ported vacuum, from the carb, or are you running manifold vacuum? It should be manifold vacuum. If not, there's a problem.
Are the throttle blades drilled? If not, then start small. If so, open them up a little. Either way, you have to remove the carb. This will get you some adjustment back, but you'll have to re-adjust your idle mixture screws.
Does your intake manifold have a divided plenum? If so, are you using a 4-hole carb gasket? If not, get one.
Also, FYI, any cam that has any idle noticeable as not being stock is a wild cam, not a mild cam.



ok, im running ported vacuum as the local parts store here doesnt have a "T" valve i can run into my intake to split my brake/vac. id rather not have to drill my butterflies as its a fairly new edelbrock 1405, and i dont have another carb to swap on if it dont solve problems. intake is a wieland 7546 open plentium, no spacer (tho i have a spcer, but its open also) i dont understand what u mean as its a wild cam.... i say mild cam cause its a lil hotter than a rv cam, but nothing like a full blown race car.


[/QUOTE]I'm not flaming you here, but I say this quite often and the same thing applies to you and everybody else that is guilty of the same crime.
You cannot time it "by ear" It's the same thing as shooting in the dark. Get a timing light and find out where the timing is otherwise your wasting your time and your asking for parks breakage when detonation sets in and ruins your engine. Once you get the timing where it should be if it still won't idle it will need a stall converter.
When you get a timing light, with vacuum advance disconnected and plugged, set it to 12 degrees before top dead center. Lock down distributor. Now plug in vacuum advance to a full time manifold vacuum source. This is a source that pulls vacuum at idle. When you connect it right away it's going to idle up. If it does not the vacuum canister is ruptured. Now recheck the timing. It should be 18 to 24 degrees before top dead center. Now idle it down to 700 to 650 RPM and reset the idle mixture screws. Now put it in gear and see if it idles, if not then more than likely it needs a stall converter.
[/QUOTE]

currently i dont have access to a timing light and/or a vacuum gauge as i dont know anyone here who has one or able to buy one. so guess im shooting in the dark till money gets better.
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