Build engine
06-29-2022, 12:12 PM
#11
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hello SB..if it is engine fed oil will it have oil pressor like the crank...or just sprinkle like the valves...thank you
06-29-2022, 12:21 PM
#13
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06-29-2022, 12:28 PM
#14
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06-29-2022, 12:38 PM
#15
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06-29-2022, 12:55 PM
#17
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..wish you all the best and i'll write back when i have more info..tnx
06-29-2022, 01:44 PM
#18
Charter Member
hey wally....so the engine oil looks fine no water yust the hose that brings back oil from charger to block...i allso thout that prochargers have their own lubrikations but this one came with the oil hose conected to the engine block..it is an m-1 procharger...regarding the vacum i can see -1 bar but not at idle only when i start tu give trotle...could the valves couse that problem(wrong preload)?
But low vac could be lots of different things....manifold gaskets, carb gasket, carb out of adjustment, timing, bad rings, many variables....
here, i copied this off another website but it can give you a place to start looking with your vac gauge:
A vacuum gauge shows the difference between outside atmospheric pressure and the amount of vacuum present in the intake manifold. The pistons in the engine serve as suction pumps and the amount of vacuum they create is affected by the related actions of:
- Pistons rings
- Valve train
- Ignition system
- Fuel control system
- Other parts affecting the combustion process, like emissions devices
Each of these has a characteristic effect on vacuum and you have to judge their performance as compared to what is considered "normal". To do this, it's important to judge engine performance by the general location and action of the vacuum gauge needle, rather than just by a vacuum reading. What follows is a list of the kinds of gauge readings you may find.
Normal Engine Operation
At idling speed, an engine at sea level should show a steady vacuum reading between 14 in. and 22 in. Hg. A quick opening and closing of the throttle should cause the vacuum to drop below 5 in., then rebound to 23 in. or more.
General Ignition Trouble or Sticking Valves
With the engine at idle, the continued fluctuation of 1 to 2 inches may indicate an ignition problem. You should check things like spark-plug gap, primary ignition circuit, high-tension cables, distributor cap or ignition coil. Fluctuations of 3 to 4 inches may point to sticking valves.
Intake System Leakage, Valve Timing or Low Compression
A vacuum reading at idle that is much lower than normal might indicate leakage through the intake manifold gaskets, manifold to carburetor gaskets, vacuum brake booster or the vacuum modulator. Low readings could also be caused by very late valve timing or worn piston rings.
Exhaust Back Pressure
Starting with the engine at idle, slowly increase engine speed to 3,000 rpm. Engine vacuum should be equal to or higher than vacuum at curb idle. If vacuum decreases at higher rpm, an excessive amount of back pressure is probably present due to a restriction in the exhaust system.
Cylinder Head Gasket Leakage
With the engine at idle, the vacuum gauge pointer will drop sharply every time the leak occurs. The drop will be from the steady reading shown by the pointer to a reading of 10 in. to 12 in. Hg. or less. If the leak is between two cylinders, the drop will be much greater. You can determine the location of the leak by doing a compression test.
Remember, engine problems can affect transmission performance. If you suspect an engine problem, connect a vacuum gauge to the intake manifold. Note the location and action of the vacuum gauge needle, and use that information to determine the engine problem. Correct the engine problem before doing extensive calibration work on the transmission.
__________________
-Wally
Money can't buy happiness, but it can buy horsepower. And I've never seen a sad person hauling a$$!
-Wally
Money can't buy happiness, but it can buy horsepower. And I've never seen a sad person hauling a$$!
06-29-2022, 02:20 PM
#19
Registered
Thread Starter
Do a compression test...if you have wrong preload then the cyl wont seal right and compression will be down.
But low vac could be lots of different things....manifold gaskets, carb gasket, carb out of adjustment, timing, bad rings, many variables....
here, i copied this off another website but it can give you a place to start looking with your vac gauge:
A vacuum gauge shows the difference between outside atmospheric pressure and the amount of vacuum present in the intake manifold. The pistons in the engine serve as suction pumps and the amount of vacuum they create is affected by the related actions of:
Each of these has a characteristic effect on vacuum and you have to judge their performance as compared to what is considered "normal". To do this, it's important to judge engine performance by the general location and action of the vacuum gauge needle, rather than just by a vacuum reading. What follows is a list of the kinds of gauge readings you may find.
Normal Engine Operation
At idling speed, an engine at sea level should show a steady vacuum reading between 14 in. and 22 in. Hg. A quick opening and closing of the throttle should cause the vacuum to drop below 5 in., then rebound to 23 in. or more.
General Ignition Trouble or Sticking Valves
With the engine at idle, the continued fluctuation of 1 to 2 inches may indicate an ignition problem. You should check things like spark-plug gap, primary ignition circuit, high-tension cables, distributor cap or ignition coil. Fluctuations of 3 to 4 inches may point to sticking valves.
Intake System Leakage, Valve Timing or Low Compression
A vacuum reading at idle that is much lower than normal might indicate leakage through the intake manifold gaskets, manifold to carburetor gaskets, vacuum brake booster or the vacuum modulator. Low readings could also be caused by very late valve timing or worn piston rings.
Exhaust Back Pressure
Starting with the engine at idle, slowly increase engine speed to 3,000 rpm. Engine vacuum should be equal to or higher than vacuum at curb idle. If vacuum decreases at higher rpm, an excessive amount of back pressure is probably present due to a restriction in the exhaust system.
Cylinder Head Gasket Leakage
With the engine at idle, the vacuum gauge pointer will drop sharply every time the leak occurs. The drop will be from the steady reading shown by the pointer to a reading of 10 in. to 12 in. Hg. or less. If the leak is between two cylinders, the drop will be much greater. You can determine the location of the leak by doing a compression test.
Remember, engine problems can affect transmission performance. If you suspect an engine problem, connect a vacuum gauge to the intake manifold. Note the location and action of the vacuum gauge needle, and use that information to determine the engine problem. Correct the engine problem before doing extensive calibration work on the transmission.
But low vac could be lots of different things....manifold gaskets, carb gasket, carb out of adjustment, timing, bad rings, many variables....
here, i copied this off another website but it can give you a place to start looking with your vac gauge:
A vacuum gauge shows the difference between outside atmospheric pressure and the amount of vacuum present in the intake manifold. The pistons in the engine serve as suction pumps and the amount of vacuum they create is affected by the related actions of:
- Pistons rings
- Valve train
- Ignition system
- Fuel control system
- Other parts affecting the combustion process, like emissions devices
Each of these has a characteristic effect on vacuum and you have to judge their performance as compared to what is considered "normal". To do this, it's important to judge engine performance by the general location and action of the vacuum gauge needle, rather than just by a vacuum reading. What follows is a list of the kinds of gauge readings you may find.
Normal Engine Operation
At idling speed, an engine at sea level should show a steady vacuum reading between 14 in. and 22 in. Hg. A quick opening and closing of the throttle should cause the vacuum to drop below 5 in., then rebound to 23 in. or more.
General Ignition Trouble or Sticking Valves
With the engine at idle, the continued fluctuation of 1 to 2 inches may indicate an ignition problem. You should check things like spark-plug gap, primary ignition circuit, high-tension cables, distributor cap or ignition coil. Fluctuations of 3 to 4 inches may point to sticking valves.
Intake System Leakage, Valve Timing or Low Compression
A vacuum reading at idle that is much lower than normal might indicate leakage through the intake manifold gaskets, manifold to carburetor gaskets, vacuum brake booster or the vacuum modulator. Low readings could also be caused by very late valve timing or worn piston rings.
Exhaust Back Pressure
Starting with the engine at idle, slowly increase engine speed to 3,000 rpm. Engine vacuum should be equal to or higher than vacuum at curb idle. If vacuum decreases at higher rpm, an excessive amount of back pressure is probably present due to a restriction in the exhaust system.
Cylinder Head Gasket Leakage
With the engine at idle, the vacuum gauge pointer will drop sharply every time the leak occurs. The drop will be from the steady reading shown by the pointer to a reading of 10 in. to 12 in. Hg. or less. If the leak is between two cylinders, the drop will be much greater. You can determine the location of the leak by doing a compression test.
Remember, engine problems can affect transmission performance. If you suspect an engine problem, connect a vacuum gauge to the intake manifold. Note the location and action of the vacuum gauge needle, and use that information to determine the engine problem. Correct the engine problem before doing extensive calibration work on the transmission.
06-29-2022, 11:21 PM
#20
Platinum Member
Platinum Member
.8 bar of vacuum = 24" of mercury.
That's a LOT of vacuum. I would think 18-20" of mercury would be all you'd see at a 750-800rpm idle.
10 psi of fuel pressure? What is the box pressure? Usually, you'll have a little positive pressure in the carb box even at idle. If you are running "box pressure" to your fuel pressure regulator (you should be), then you want to see about 7 psi PLUS box pressure. If you have 4 psi of box pressure then you want to see 11 psi of fuel line pressure. If you have 10 psi in the box (at higher speeds of course) then you want to see 17 psi of fuel line pressure. By the way, you can't run a fuel pump that doesn't have a built in regulator (unless it has a boost reference port).
You mention a problem with higher rpm problems. What is your fuel pressure at max speed, and what if your boost pressure at that speed.
That's a LOT of vacuum. I would think 18-20" of mercury would be all you'd see at a 750-800rpm idle.
10 psi of fuel pressure? What is the box pressure? Usually, you'll have a little positive pressure in the carb box even at idle. If you are running "box pressure" to your fuel pressure regulator (you should be), then you want to see about 7 psi PLUS box pressure. If you have 4 psi of box pressure then you want to see 11 psi of fuel line pressure. If you have 10 psi in the box (at higher speeds of course) then you want to see 17 psi of fuel line pressure. By the way, you can't run a fuel pump that doesn't have a built in regulator (unless it has a boost reference port).
You mention a problem with higher rpm problems. What is your fuel pressure at max speed, and what if your boost pressure at that speed.
