upgrade not working
April 25th, 2012, 03:32 PM
#1
upgrade not working
Hi all.
I just spent a few dollars trying to upgrade my '66 Cutlass convertible 330ci - - an upgraded cam (nothing radical), new valves, springs, timing belt and headers...
but I am not seeing a noticeable difference. The car feels heavy - as if the brakes are engaged and it slowly lumbers for a while before it starts to pick up...totally NOT why one invests in an upgrade.
Someone suggested to me that it sounds like I need a torque converter - others have suggested that my timing is off, and some others have suggested that my carb needs to be adjusted.
Has anyone else experienced this? From the sounds of my explanation, does any of that make sense? Or are there other ideas for what might be causing the problem?
Thank you,
DO
I just spent a few dollars trying to upgrade my '66 Cutlass convertible 330ci - - an upgraded cam (nothing radical), new valves, springs, timing belt and headers...
but I am not seeing a noticeable difference. The car feels heavy - as if the brakes are engaged and it slowly lumbers for a while before it starts to pick up...totally NOT why one invests in an upgrade.
Someone suggested to me that it sounds like I need a torque converter - others have suggested that my timing is off, and some others have suggested that my carb needs to be adjusted.
Has anyone else experienced this? From the sounds of my explanation, does any of that make sense? Or are there other ideas for what might be causing the problem?
Thank you,
DO
April 25th, 2012, 06:08 PM
#4
Registered User
Join Date: Jun 2010
Location: Rogues Island, USA
Posts: 3,613
Since you have an automatic that means you have the two speed Jetaway transmission. That is a variable pitch converter meaning you have a high and low stall. If your throttle assembly is working correctly it would be in high stall at idle and for approximately a 1/4 throttle more then go back to low stall and at full throttle back to high stall. Whoever suggested a torque converter doesn't understand what you have and is unfamiliar with your set up so you should not need a converter.
It does sound like the cam is retarded or the timing is severely off. It's a timing chain not a belt btw. Is the vacuum advance working properly or do you have some sort of vacuum leak?
66 Quadrajets are notorious for leaking internally and that could make it lazy if it were too rich or entering the engine other than through the jets and boosters. Since it's internal you'll never know other than somehow determining if it's rich (read the plugs, exhaust gas analyzer, etc)
That's all I can think of off the top of my head.
It does sound like the cam is retarded or the timing is severely off. It's a timing chain not a belt btw. Is the vacuum advance working properly or do you have some sort of vacuum leak?
66 Quadrajets are notorious for leaking internally and that could make it lazy if it were too rich or entering the engine other than through the jets and boosters. Since it's internal you'll never know other than somehow determining if it's rich (read the plugs, exhaust gas analyzer, etc)
That's all I can think of off the top of my head.
Last edited by TripDeuces; April 25th, 2012 at 06:11 PM.
April 26th, 2012, 06:09 AM
#5
Administrator
Join Date: Oct 2009
Location: Poteau, Ok
Posts: 41,079
I agree with trip! Whats your timing set to and is your switch pitch working properly. Is you passing gear engaging when its floored.
In addition to the vacuum advance, how is your mechanical advance working?
Are your secondaries opening all the way on your carb?
In addition to the vacuum advance, how is your mechanical advance working?
Are your secondaries opening all the way on your carb?
April 26th, 2012, 06:13 AM
#6
XCELERATIONRULES!
Join Date: Mar 2012
Location: Orwell,Ohio
Posts: 323
Lazy acceleration usually involves a rich condition,but since the headers were installed the engine could be running lean.
I would try to borrow an air fuel meter and see what the tail pipe tells you.
It will quickly give you an indication of the A/F mixture.
I would try to borrow an air fuel meter and see what the tail pipe tells you.
It will quickly give you an indication of the A/F mixture.
April 26th, 2012, 07:18 PM
#7
Registered User
Join Date: Jul 2006
Location: Richfield, Oh
Posts: 1,767
cam
What are the cam specs.
You say not radical...But you only have a 300Ci so what might not seem rad may cause this small cube motor issue in the low torque band area.
Distributor ingition advance will also cause this slow to accel condition. You have to start with the simple least expensive checks first. DO the basics before going BIG like transmissions and convertor swaps.
Tune that carb after you get your timing in. What is your initial timing (idle on the balancer) What is your full advance Throttle up to about 3000 rpm should give you full all in timing advance. and WHEN does FULL advance come in. The quicker you get the advance to come in the quicker the engine can get spinning...
Jim JD
You say not radical...But you only have a 300Ci so what might not seem rad may cause this small cube motor issue in the low torque band area.
Distributor ingition advance will also cause this slow to accel condition. You have to start with the simple least expensive checks first. DO the basics before going BIG like transmissions and convertor swaps.
Tune that carb after you get your timing in. What is your initial timing (idle on the balancer) What is your full advance Throttle up to about 3000 rpm should give you full all in timing advance. and WHEN does FULL advance come in. The quicker you get the advance to come in the quicker the engine can get spinning...
Jim JD
April 29th, 2012, 09:21 AM
#8
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 48,269
Kinda hard to provide any useful information without knowing more about your car and what you did. What cam specs? What carb and intake? What valve sizes? What rear gears and tire diameter (outside diameter, not wheel size)? What cam? What timing?
April 30th, 2012, 08:27 AM
#9
Wow. Thanks for all the feedback. Sorry I haven't logged on for a while so I didn't realize that so many of you had responded.
I have to admit that although I enjoy these cars, I don't know much at all about fixing them.. I'm learning as I go along, primarily from my mechanic. So for some of your more technical questions, I'm afraid I don't have the answers off the top of my head.
That said, I got a "tow-package" cam from CompCam. They had to custom grind the cam, based on specs from some of their other "off the shelf" models for different years. When replacing the cam, I replaced lifters, springs and timing chain - all supplied by CompCam. The only other upgrade was the headers.
Everything else on the car is still original, including the 330ci engine and transmission. I have not upgraded the carb or the intake manifold, so it still has the quadrajet carb on it. There is some question as to whether it's opening fully, but I didn't think that mattered with resepct to accellerating from a stopped position.
Since I last posted, they adjusted my timing and it got a little better, but still not what it should be. They also ruled out torq converter as well. They are now re-adjusting the valves and carb...hopefully these smaller adjustments will do the trick.
I wish I was as sophisticated in my understadning of cars as you all are...but your thoughts are still helpful. I'm taking all of it to my mechanic so he knows what the other experts think of what the problem may be. I will keep you all posted.
I have to admit that although I enjoy these cars, I don't know much at all about fixing them.. I'm learning as I go along, primarily from my mechanic. So for some of your more technical questions, I'm afraid I don't have the answers off the top of my head.
That said, I got a "tow-package" cam from CompCam. They had to custom grind the cam, based on specs from some of their other "off the shelf" models for different years. When replacing the cam, I replaced lifters, springs and timing chain - all supplied by CompCam. The only other upgrade was the headers.
Everything else on the car is still original, including the 330ci engine and transmission. I have not upgraded the carb or the intake manifold, so it still has the quadrajet carb on it. There is some question as to whether it's opening fully, but I didn't think that mattered with resepct to accellerating from a stopped position.
Since I last posted, they adjusted my timing and it got a little better, but still not what it should be. They also ruled out torq converter as well. They are now re-adjusting the valves and carb...hopefully these smaller adjustments will do the trick.
I wish I was as sophisticated in my understadning of cars as you all are...but your thoughts are still helpful. I'm taking all of it to my mechanic so he knows what the other experts think of what the problem may be. I will keep you all posted.
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