new crate engine won't idle below 1000 RPM - Team Camaro Tech
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post #1 of 9 (permalink) Old Jul 21st, 02, 04:46 PM Thread Starter
 
Join Date: Jul 2002
Location: Troy, MI USA
Posts: 5
Hi folks,
In a word, HELP !!! I don't know what to try next and I am about ready to pull my hair out. My wife has a gorgous yellow/black striped 69 RS. We just put a new Jon Barrett 370 horse 350 crate motor in it. Fairly mild, dart iron eagle heads, 480 lift/230 duration cam, edlebrock dual plane intake, msd distibutor (not hei).

The problem is I can't keep it running below 1000 RPM. When it is dropped into gear, it hits 300 RPM and dies. The car runs really rich too. Everything on the engine is new, including the Holley 750 dual feed single pump. We have jetted it down to 63's from 72's and have the one of the lowest power valves (3.5). Fuel pressure stays constant at 7 to 8 pounds. We have tried all sorts of timing and advance spring combinations. We have set valves hot too. All of this seam to make no change either good or bad.

There do not seam to be any intake leaks, but I will double check tomorrow. Baring that, what else do I try or look for? I have heard about a resistor wire in the harness, what color(s) do I look for. If it is there, what is the best method to replace it?

I am open to all and any sugesstions. Please resond to either my wife's e-mail ([email protected]) or mine ([email protected]). Either is fine.

Thanks in advance !!!

Rick and Kristi Langley
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post #2 of 9 (permalink) Old Jul 21st, 02, 05:09 PM
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Jody
 
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Did Barrett say anything about needing a higher stall converter? Is yours stock?

That cam is a little large for a stock torque converter. Will it idle below 1000 rpm in Park?

I would also say you don't need anywhere near a #63 primary jet. Have you checked the float levels? The fuel pressure shouldn't be 8 psi as that's pretty much the limit that the Holley needle and seats can handle without flooding; 7 psi is fine.

I'd run at least 12-14 degrees of initial advance. Make sure the idle mixture screws are adjusted correctly, floats adjust correctly, and the idle speed is low enough that you're on the idle circuit. This cam should definitely idle at 750-800 rpm or so in Park or neutral.

Jody
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post #3 of 9 (permalink) Old Jul 21st, 02, 05:11 PM
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Start off by rechecking the float levels. If it's dribbling fuel down the carb you can readjust til you're blue in the face. Next turn your idle mixture screws all the way in and then back them out 1-1/2 turns as a starting point. Start the car and turn the idle speed down as far as you can without stalling. Using a tach or vacuum gauge adjust the mixture screws in or out a 1/8-1/4 turn at a time until you get the highest reading. If turning the mixture screws has no affect check for vacuum leaks and if you have vacuum advance hook it up to manifold vacuum port at the base of the carb instead of the ported vacuum on the side of the carb. This will usually allow you to back the idle speed screw out farther and get back down into the idle circuit. Let us know how you make out.

------------------
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post #4 of 9 (permalink) Old Jul 22nd, 02, 05:30 AM
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Scott
 
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Sure sounds like a vacuum leak. Hook up a vacuum gauge and start plugging everything off one-by-one and see if you can find the culprit.
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post #5 of 9 (permalink) Old Jul 23rd, 02, 06:31 AM
 
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I would check the timing. That may be the problem. Make sure you time it properly with the advance disconnected and the hose to the carb plugged. The timing sounds slightly retarded.

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post #6 of 9 (permalink) Old Jul 23rd, 02, 04:01 PM Thread Starter
 
Join Date: Jul 2002
Location: Troy, MI USA
Posts: 5
Jody,
Thanks for the reply. We have checked the float level several times. I tore the intake off tonight and couldn't believe what I found. The runners in the intake are 1/4 inch shorter than the openings on the heads. Basically, the very top outside edge of the intake runner's flange lines uo with the opening of the heads. No wonder they all leaked so bad. I think the heads are 180 cc runners will the intake runners are 165cc. this explains why squirting WD 40 didn't show up the problem, but 40 weight oil did,

Needless to say, I'll be on the phone to the builder, dart heads and edlebrock manifolds tomorrow !!!

Thanks for the help !!!

Rick and Kris

<BLOCKQUOTE>quote:</font><HR>Originally posted by 1 2RUN:
Start off by rechecking the float levels. If it's dribbling fuel down the carb you can readjust til you're blue in the face. Next turn your idle mixture screws all the way in and then back them out 1-1/2 turns as a starting point. Start the car and turn the idle speed down as far as you can without stalling. Using a tach or vacuum gauge adjust the mixture screws in or out a 1/8-1/4 turn at a time until you get the highest reading. If turning the mixture screws has no affect check for vacuum leaks and if you have vacuum advance hook it up to manifold vacuum port at the base of the carb instead of the ported vacuum on the side of the carb. This will usually allow you to back the idle speed screw out farther and get back down into the idle circuit. Let us know how you make out.

<HR></BLOCKQUOTE>

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post #7 of 9 (permalink) Old Jul 23rd, 02, 04:05 PM Thread Starter
 
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Location: Troy, MI USA
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Hello,
We check vacuum several times and it was between 16 to 22 inch pounds dependineg on rpm. I tore the intake off tonight and couldn't believe what I found. The runners in the intake are 1/4 inch shorter than the openings on the heads. Basically, the very top outside edge of the intake runner's flange lines uo with the opening of the heads. No wonder they all leaked so bad. I think the heads are 180 cc runners will the intake runners are 165cc. This explains why squirting WD 40 didn't show up the problem, but 40 weight oil did. Needless to say, I'll be on the phone to the builder, dart heads and edlebrock manifolds tomorrow.
Thanks for the help !!!
Rick and Kris

QUOTE]Originally posted by bonecrusher67conv:
Sure sounds like a vacuum leak. Hook up a vacuum gauge and start plugging everything off one-by-one and see if you can find the culprit.[/QUOTE]

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post #8 of 9 (permalink) Old Jul 23rd, 02, 04:07 PM Thread Starter
 
Join Date: Jul 2002
Location: Troy, MI USA
Posts: 5
Hello,
We have check all these things several times. Vacuum was between 16 and 22 inch pound depending on RPM. I tore the intake off tonight and couldn't believe what I found. The runners in the intake are 1/4 inch shorter than the openings on the heads. Basically, the very top outside edge of the intake runner's flange lines uo with the opening of the heads. No wonder they all leaked so bad. I think the heads are 180 cc runners will the intake runners are 165cc. This explains why squirting WD 40 didn't show up the problem, but 40 weight oil did.
Needless to say, I'll be on the phone to the builder, dart heads and edlebrock manifolds tomorrow !!!
Thanks for the help !!!
Rick and Kris

QUOTE]Originally posted by bonecrusher67conv:
Sure sounds like a vacuum leak. Hook up a vacuum gauge and start plugging everything off one-by-one and see if you can find the culprit.[/QUOTE]

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post #9 of 9 (permalink) Old Jul 23rd, 02, 04:13 PM Thread Starter
 
Join Date: Jul 2002
Location: Troy, MI USA
Posts: 5
Hello,
The car has a 2200 stall in it now. The car would not idle beloww 1000 rpm, even in park. We checked float levels, vacuum, several timing settings, different springs in the distributer, etc.
I tore the intake off tonight and couldn't believe what I found. The runners in the intake are 1/4 inch shorter than the openings on the heads. Basically, the very top outside edge of the intake runner's flange lines up with the opening of the heads. No wonder they all leaked so bad. I think the heads are 180 cc runners will the intake runners are 165cc. This explains why squirting WD 40 didn't show up the problem, but 40 weight oil did.

Needless to say, I'll be on the phone to the builder, dart heads and edlebrock manifolds tomorrow !!!
Thanks for the help !!!
Rick and Kris

QUOTE]Originally posted by Camcojb:
Did Barrett say anything about needing a higher stall converter? Is yours stock?

That cam is a little large for a stock torque converter. Will it idle below 1000 rpm in Park?

I would also say you don't need anywhere near a #63 primary jet. Have you checked the float levels? The fuel pressure shouldn't be 8 psi as that's pretty much the limit that the Holley needle and seats can handle without flooding; 7 psi is fine.

I'd run at least 12-14 degrees of initial advance. Make sure the idle mixture screws are adjusted correctly, floats adjust correctly, and the idle speed is low enough that you're on the idle circuit. This cam should definitely idle at 750-800 rpm or so in Park or neutral.

Jody
[/QUOTE]

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