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Discussion Starter #1 (Edited)
Since I installed this motor I was pulling 12" of vaccum. During the week I went to start is one day and it took alot of turnovers for it to start, almost like it was flooded. This is not like this motor. It started and that never happened again. I then noticed it had a small mis? I checked all the vac lines(disconnected and plugged), checked my timing again, replaced all the plugs with the same brand and gap, even re adjusted the valves! The Vac is now around 8" and jumps around a little also. I don't hear any noises. I'll check the manifold gasket tonight with some carb cleaner or something. I hope nothing major happened. It was kind of weird because it happened in the middle of my tach install !!??? Yes I disconnected the tach lead and it's the same.

Any Ideas?
 

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Discussion Starter #3

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I didn't read the link but agree that a valve problem could be at fault. zdld17 has a good suggestion - leak down test. A compression check might be the simplest, but a leak down would give a better result. A vacuum leak can cause the problem also depending on the size of the leak and where it is located. When you checked the timing, was it close to where you had it, or did it change? If the damper slipped it could throw off your timing and cause the vacuum to drop when readjusted.
 

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Discussion Starter #6
I didn't read the link but agree that a valve problem could be at fault. zdld17 has a good suggestion - leak down test. A compression check might be the simplest, but a leak down would give a better result. A vacuum leak can cause the problem also depending on the size of the leak and where it is located. When you checked the timing, was it close to where you had it, or did it change? If the damper slipped it could throw off your timing and cause the vacuum to drop when readjusted.
I don't have any tools for a leak down test but I'm going to do a compression test right now. The timing is where it was before, it never moved. I did a better test with the engine fully warm and the gauge reads 10" now and jumps around 1" each way. I know it's not alot but there is a miss that wasn't there before. I'll let you know how the compression test came out. I hope good. Pray for me......
 

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Discussion Starter #9
are any of the plug wires close to the headers? If so, check em close for lil black dots, or worse signs of burning thru.

Its not hard to start, It starts right up. It was only that one time.

Jim I looked at all the wires. The #5 plug thats close to the header I put a heat boot on. I took it off and the boot looks perfect. I have the 8.8 MSD wires that are only 8 months old. I'm running out of ideas and wondering if I should buy a cheap set of wires and try it. The cap doesn't look bad also. I'll tell you my eyes were burning before when it was running in the garage with the door open. Seems real rich???? I re adjusted the timing just to make sure at 15* initial and 36* total. Also adjusted the idle air with a vac gauge again. Seems the same. If I slowly bring up the throtle above 2000 it smooths out. I wonder if it's my carb? It's the only thing on the engine I didn't buy when I built the motor. Here are my compression tests.
#1 = 160
#3 = 162
#5 = 162
#7 = 162
#2 = 157
#4 = 160
#6 = 160
#8 = 157
I know they seem a little low but there all within specs, thank god.

Any ideas?
 

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Compression is good. Are you running a Holley? Is motor trying to load up ? My thought was the PV.

If you are running red msd wires, I would run an ohm test , check with the MSD site and they will give you a baseline ohm reading for the red wire. I think the whole wire will read under 100. I got many years out of my msd blue and for guilt, went to red.
 

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Discussion Starter #11 (Edited)
Compression is good. Are you running a Holley? Is motor trying to load up ? My thought was the PV.

If you are running red msd wires, I would run an ohm test , check with the MSD site and they will give you a baseline ohm reading for the red wire. I think the whole wire will read under 100. I got many years out of my msd blue and for guilt, went to red.
Yes it's a Holley 600cfm, Its and older one. It doesn't seem like it's loading up and the throttle response feels good. It's mainly at idle and slowly reving it up to 2000 rpm that it feels like a mis. And Yes they are the Red MSD wires. I'll go on MSDs sight and look up the reading. Thanks. Still think it could be the PV?

Update... Just checked the wires. The most I have is 127 Ohms on the longest wire. MSD says 40-50 ohms per foot. My wires are good.....????
 

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unless they're arcing thru a hole, they are good.

It's dark now, at least here, fire her up in the dark and look for a light show.

A miss is gonna be ignition. It could be a lean missfire but that doesn't go aloing with the stinky idle too well. Ignition.

Hook up your timing light to each cylinder in turn and see if one doesn't have a steady flash.

Is your vac advance hooked to manifold vacaum or ported vac?
Putting it on manifold can give you a better idle (unless your cam is very radical)

On the "stinky idle". The mixture screws on that holley control fuel, not air. Typically they will be 1/2-1 turn out. Bottoming both screws should kill the engine. If it doesn't, you have too much throttle opening at idle, or possibly a blown power valve.

Bottom the idle mix screws, then preset to 1 1/2 turns. With motor warm, bring them both in together, 1/8 turn at a time, while listening and watching the vac guage. wait 30 seconds before giving them another 1/8 turn in. Repeat untill you get the highest vac reading, come out a 1/8 turn from there and you're set.

Hot rods can have stinky idles, mine does.
 

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Discussion Starter #14
unless they're arcing thru a hole, they are good.

It's dark now, at least here, fire her up in the dark and look for a light show.

A miss is gonna be ignition. It could be a lean missfire but that doesn't go aloing with the stinky idle too well. Ignition.

Hook up your timing light to each cylinder in turn and see if one doesn't have a steady flash.

Is your vac advance hooked to manifold vacaum or ported vac?
Putting it on manifold can give you a better idle (unless your cam is very radical)

On the "stinky idle". The mixture screws on that holley control fuel, not air. Typically they will be 1/2-1 turn out. Bottoming both screws should kill the engine. If it doesn't, you have too much throttle opening at idle, or possibly a blown power valve.

Bottom the idle mix screws, then preset to 1 1/2 turns. With motor warm, bring them both in together, 1/8 turn at a time, while listening and watching the vac guage. wait 30 seconds before giving them another 1/8 turn in. Repeat untill you get the highest vac reading, come out a 1/8 turn from there and you're set.

Hot rods can have stinky idles, mine does.
I'll try the timing light thing today. The vac is on manifold, it always worked good that way. The idle screws are around 1 1/8 out and I did adjust then the way you said. I could close one all the way and it still runs but if I do both it stalls. I'll keep checking...
 

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Discussion Starter #15

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Discussion Starter #17
possible causes can be a sticking lifter or binding valve spring.
intake manifold leak (inside leak) check oil for a gassy smell.
PCV plugged or not working (or no breather)
best bet is to pull the intake and reinstall after checking
When I readjusted the rockers everything look good.
I was thinking about the manifold leak, but I want to try everything else before I pull it. The PVC is making a fast rattleing sound, but when I take is off and hold my finger on the vac the idle goes down but still has the same mis. I have a breather.

Just checked all the wires with the timing light and all is good. Also readjusted the idle screws to as much vac I could get 10". I used to have 11-12".

Could the carb be doing this? I could turn down the pass idle screw all the way without stalling but if I turn down the drivers screw(putting back the pass) it stalls instantly. A power valve was metioned.
 

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rattling pcv is an indication of an interior intake leak.
and im betting your oil has a strong gassy smell.
were the heads milled correctly?
an old mechanic trick is to lightly coat both sides of the intake gasket with sealer or RTV to lessen the chances of the intake leak.
seems like one or more of your intake runners are leaking into the lifter valley.
 

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Discussion Starter #19
rattling pcv is an indication of an interior intake leak.
and im betting your oil has a strong gassy smell.
were the heads milled correctly?
an old mechanic trick is to lightly coat both sides of the intake gasket with sealer or RTV to lessen the chances of the intake leak.
seems like one or more of your intake runners are leaking into the lifter valley.

When I installed the manifold I did run a 1/16th bead around every port on the gasket top and bottom. I'll go check the oil.
 

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Discussion Starter #20 (Edited)
The oil smells different than new oil, maybe some gas smell but I'm no expert.

A couple of things... When I pull the vac off the maniflod port it makes a F,F,F,F like a steady flutter sound not a constent swish sound. Ideas?

Also I read on another thread this...try this old shade tree mechanic trick.

with the engine running at idle, place your hand over the top of the carb. slooowly close off the top, basically you're starving it of air. now this should do 2 things, 1st, it should create this really cool sucking feeling on your hand...
2nd, your rpms should raise slightly because you just richened up your fuel mixture.

now, if your rpms don't raise up this means you have a vacuum leak inside, i.e. probably an intake/runner not sealing from the lifter valley side. i've seen this trick done before and the carb was completly shut off from on top and the motor still ran.


Here was another thread try....
try the 2 hands over the carb smother test ....If you can choke out the car with both hand covering carb, chances of vacuum leak are small ... If the car continue to run smooth even though you have virtually covered the carb, then you probably have a vacuum leak ... Also, timing can affect idle ... advancing the timing will bump the idle



I checked it again and the idle didn't go up just stalled.
 
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