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By TheWitz - 3 Years Ago
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This car was running smoothly but it lacked power. We found low compression on some cyls. The engine was pulled and a local shop rebuild it. The engine has much better power now, but the issue is this: At idle, the engine is running smoothly, but shift into drive and the car starts shaking. It wasn't shaking before the engine was removed. The transmission and torque converter were not removed when the engine was pulled. When stepping on the gas, applying power, the shaking is not noticeable. It's just at idle that it is really noticeable. A whole lot of shakin' goin' on. The transmission is the 3 speed automatic that starts out in 2nd and has no overdrive.
Any thoughts on what could be causing the shaking?
We're trying to figure out if it's the engine, once it is under a load when shifting into drive, that needs an adjustment, or is it the transmission or torque converter.
Thanks.
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By Cliff - 3 Years Ago
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Check valve adjustment, dial in the carb.
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By MoonShadow - 3 Years Ago
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Double check the firing order.
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By 55blacktie - 3 Years Ago
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Was it rebuilt to OEM specs?
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By TheWitz - 3 Years Ago
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As far as I know, the engine was rebuilt to specs, however the pistons are now 30 thousandths oversized. I pointed the shop that did the rebuild to website ford-y-blocks.com where they ordered what they needed to do the work.
As far as firing order, I'll check, but the engine is running strong at idle and on acceleration. I would think if the firing order were off, it would be shaking all the time and lack power.
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By PF Arcand - 3 Years Ago
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Idle speed to low when in gear?.. A vacuum leak?
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By TheWitz - 3 Years Ago
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Idle speed was on the high side when it was first put in gear. Lowered the idle a little with no change to the shaking.
As far as vacuum leaks, that is a possibility I will look into. Thanks.
One other item as it pertains to vacuum. The power brake booster was not removed when the engine was pulled. The brake line was disconnected and the four bolts holding the brake booster were removed and the unit was held to the fender well so it was out of the way. Now that it's all back together, the brake pedal is hard and there is no power braking. Vacuum was present at the booster and past the check valve on the booster. I believe there's a diaphragm inside the booster. If it's damaged that could explain the hard pedal and a vacuum leak. I'll try capping that line as a test to see if the shaking goes away when I shift into gear..
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By Ted - 3 Years Ago
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Assuming the engine is in good condition and there are no vacuum leaks, this sounds like a tuning issue. I’ll suggest revisiting the ignition timing and idle fuel mixture settings. If necessary, block off all the external vacuum sources to eliminate that as the source of the rough idle. This could be as simple as being too lean when putting the transmission into gear.
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By junkyardjeff - 3 Years Ago
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Make sure its running on all 8 and look for vacumn leaks.
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By oldcarmark - 3 Years Ago
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What Carburetor are You using?
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By panel driver - 3 Years Ago
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If there are no vacuum leaks and engine runs smoothly on all 8 cylinders, is there maybe a engine and or transmission mount
that has shifted or broken. Just a thought.
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By TheWitz - 3 Years Ago
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The carb is the Carter WCFB. The shop that did the rebuild, readjusted the valves and timing and it is much better now. Still a little off, can hear one tappet. Thanks to all for the help.
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By DryLakesRacer - 3 Years Ago
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I start everything with a vacuum gauge. I bought a large face one from HF. In neutral my stocker is 19 steady and in drive 17.5 and also steady.
If it seems like it has no power or sluggish I would look to the distributor next. If it’s still the loadmatic you need to see if it is acting correctly with a timing light and a vacuum gauge teed into the line.
Tough in the old days but if you could get on a chassis dyno; drive and accelerate as norm as someone watched the timing going thru the gears you can learn a lot...
Additionally is there a PCV system on the engine? It is a controlled vacuum leak and can be tested with your palm over the oil fill tube and a good seal on the oil dip stick. I had to make one out of leather.. The Carter WCFB is a little different than the standard ones if you have the loadmatic dist also. If the dist was up graded the original carb will not work properly. These are all suggestions of things I’ve found out myself or read about to fix mine to be smooth and perform as designed. Good luck.
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