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I'm stumped, please give me some ideas...
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disturbthepeace1
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Joined: 14 Jun 2003
Posts: 303
Location: Stanton, CA
10195.60 points


1965 Volkswagen Beetle

PostPosted: Wed Mar 02, 2011 4:39 am    Post subject: I'm stumped, please give me some ideas... Reply with quote

hey, I'm in need of some help Confused I have a customer that brought me a 74 vette that some previous mechanic had hacked all up. I have been repairing the repairs that have been done but I cant seem to get this motor to idle correctly. Vac bounces between 10-12 and the quality reminds me of the lope a 230@050 old style grind would have but not consistent. It performs great in all other driving conditions. It has great power, starts easy, and cruises smooth. The motor is a very fresh rebuilt 383 that was done by a local machine shop that does quality work.


what it has and whats been done:

center bolt 383, pro comp dual plane manifold, 3310 holley new, MSD hei dist new, wires NEW, plugs NEW

cam specs .428 lift 212@050

it has 170 cold cranking psi dead even on all cylinders

verified lift on 4 valves, cam is good IMO. No metal found in oil or in the head.

swapped out carb with another 3310 that I had, no change

all plug connections, wire, voltage is good

all vacuum lines that run the head lights are plugged off. motor is only running brakes, trans, and vac advance.

Sprayed the motor with carb cleaner, no vac leaks

timing is set, plug gap @.045

No choke on carb

what am I missing Question

The only clue I have is that it idles best when the mixer screws are backed out about 4 turns each side Shocked If this were a weber I would throw some larger idle jets at it but since it's a holley the idle circuit is petty much set in stone...

Plugs look good when they were pulled, jets up front are @73

any ideas?

Joe

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SMOKEmUP
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Joined: 30 May 2002
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65097.54 points


1979 Chevrolet Camaro

PostPosted: Wed Mar 02, 2011 10:54 am    Post subject: Reply with quote

Maybe the hydraulic lifters are too tight?

What about the alignment between the intake manifold and the heads? Sometimes the aftermarket intakes and/or heads have been milled leaving a small gap allowing air to pull from the valley area.

How do the plugs look? Any oil?

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squeeezer
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1991 Chevrolet Camaro

PostPosted: Wed Mar 02, 2011 1:14 pm    Post subject: Reply with quote

do compression check on all cylinders or dont do it at all
how does the needle jump when advancing the timing?


pull the valve covers how are the springs? other than new!!!

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disturbthepeace1
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Joined: 14 Jun 2003
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Location: Stanton, CA
10195.60 points


1965 Volkswagen Beetle

PostPosted: Wed Mar 02, 2011 2:12 pm    Post subject: Reply with quote

squeeezer wrote:
do compression check on all cylinders or dont do it at all
how does the needle jump when advancing the timing?


pull the valve covers how are the springs? other than new!!!



Quote:
it has 170 cold cranking psi dead even on all cylinders


Springs are good and I watched the valve train while I did the comp check and they are all looked good.

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disturbthepeace1
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Joined: 14 Jun 2003
Posts: 303
Location: Stanton, CA
10195.60 points


1965 Volkswagen Beetle

PostPosted: Wed Mar 02, 2011 2:15 pm    Post subject: Reply with quote

SMOKEmUP wrote:
Maybe the hydraulic lifters are too tight?

What about the alignment between the intake manifold and the heads? Sometimes the aftermarket intakes and/or heads have been milled leaving a small gap allowing air to pull from the valley area.

How do the plugs look? Any oil?


Plugs are very clean and show a solid mixture. Tight Hyd valves may be it. It's the only thing left(I think). Maybe a warm cranking compression check will show me some thing?

Joe

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disturbthepeace1
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Joined: 14 Jun 2003
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Location: Stanton, CA
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1965 Volkswagen Beetle

PostPosted: Wed Mar 02, 2011 3:49 pm    Post subject: Reply with quote

Just re adjusted the valves to 1/2 turn after 0 lash. No change Mad

Joe

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Paul P
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1971 Chevrolet Chevelle

PostPosted: Wed Mar 02, 2011 4:24 pm    Post subject: Reply with quote

Needle steady on the vacuum gauge?

How much is the throttle open? sounds like there is air getting in somewhere. You never said what the idle speed was when the mixture screws were 4 turns out.

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2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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disturbthepeace1
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Joined: 14 Jun 2003
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Location: Stanton, CA
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1965 Volkswagen Beetle

PostPosted: Wed Mar 02, 2011 4:51 pm    Post subject: Reply with quote

needle flutters, and it idles about 700 rpm in drive. any lower and it sounds like it wants to die


throttle isnt open much, the throttle blade is just barely into the transistion port.....


shoot me

Joe

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Paul P
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1971 Chevrolet Chevelle

PostPosted: Wed Mar 02, 2011 8:05 pm    Post subject: Reply with quote

fluttering is not good sort of points to valve issues but lets step back for a minute.

Is this thing running points or HEI?

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2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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disturbthepeace1
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Joined: 14 Jun 2003
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Location: Stanton, CA
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1965 Volkswagen Beetle

PostPosted: Wed Mar 02, 2011 8:52 pm    Post subject: Reply with quote

New MSD hei dizzy.
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Paul P
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1971 Chevrolet Chevelle

PostPosted: Wed Mar 02, 2011 9:09 pm    Post subject: Reply with quote

sorry did not see that one. Make sure it has a fat #10 wire feeding the HEI not the standard points power wire that came with the vette in 74. You will find that the wire is large at the harness inside and goes to a reduced size out to the distributor. I had to do this on the Chevelle. This might make all the difference.
_________________
2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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disturbthepeace1
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Joined: 14 Jun 2003
Posts: 303
Location: Stanton, CA
10195.60 points


1965 Volkswagen Beetle

PostPosted: Wed Mar 02, 2011 9:13 pm    Post subject: Reply with quote

Ya it's got the original light wire hooked up. might just make a quick jumper from the alt to see if there is a diff

If that doesn't work I'm gonna swap the dizzy out

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Paul P
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1971 Chevrolet Chevelle

PostPosted: Wed Mar 02, 2011 10:43 pm    Post subject: Reply with quote

I'd bet that is most if not all of your problem that wire can't deliver nearly enough current to the HEI. This is a basic that can't be overlooked with the older chassis electrical systems. You will find that at the other end of that wire it is connected to a large 10 gauge wire. All you need to do is extend it back up to the distributor.
_________________
2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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disturbthepeace1
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Joined: 14 Jun 2003
Posts: 303
Location: Stanton, CA
10195.60 points


1965 Volkswagen Beetle

PostPosted: Thu Mar 03, 2011 1:40 am    Post subject: Reply with quote

Jumped the hei with a large gauge wire, no change Mad

I have to rebuild the original dizzy because the last guy who worked on it replaced it with this hei and didnt realize that he needed the tac drive to make the gauge work Rolling Eyes

I plan on installing a pertonix unit and swapping it out but the car has a apointment with the exhaust shop for a new set off mufflers so if I can't figure it out by tomorrow, I probaly won't get another crack at it for a week or two.

Thanks for the help but I'm still stumped. It's been awhile since a car got the best if me, I guess I had it coming.

Joe

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Knarley Darley
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PostPosted: Thu Mar 03, 2011 2:05 am    Post subject: Reply with quote

Try taking a paper clip, bend it in a U shape and put the ends in the primary idle air bleed holes to partially restrict them. This should richen the idle so the mixture screws can be turned in to 1 turn out or so. Is the carb base matching the manifold flange, and gasket combo? Smoke brings up another good point with the under side of the manifold. A easy way to check this is to pull the PCV and temporarily seal all other breathers/ openings (I just put the palms of my hands or tape over the valve cover holes) If the manifold is leaking it will quickly build vacuum in the crank case and your idle will get better. When you pull your hand off one of the covers you will hear a big woosh of air suck into the motor. If it builds pressure, then the mani is probably sealed pretty good. This test is done with the engine running of course. good luck and keep us posted
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