Project: 97 6-speed, SC400 supercharged 4.7L V8
#137
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Here is the problem with the rear water bridge. With the coolant lines for the water cooler it wont fit anymore.
So here is my solution. New Water bridge adaptors. These were no five minute job, You have to make a Y someplace to feed the factory heater line too.
So here is my solution. New Water bridge adaptors. These were no five minute job, You have to make a Y someplace to feed the factory heater line too.
#138
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Here they are installed. AN-16 line connects them.
Last, I had some small lift lugs laser cut to get rid of the big ugly hooks.
Last, I had some small lift lugs laser cut to get rid of the big ugly hooks.
#140
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Well John Cribb on Lextreme really got me thinking about my TB choice. I now have bought two different GM TB's to look at as well as my Nissan. Between them all I am sure I will find the magic combo. The more I thought this all out the more I like the IACV built in the TB. I am most likely going to use the ported and polished GM LS1 TB that I just bought. It not only is ported and polished on the in inside but the outside is pretty too. It has a built in IACV so I wont need to find a home for the stock one. Thanks for all your help on this John.
Next up, I got back to the cams and valves today. First I got to say, it is a bit of a trick getting a Dial indicator on the lifters but after some time I finally was able to do it. I first set the degrees on the intake cams, once I got them set I checked Valve to piston clearance. I was pleased to find the minimum during the rotation cycle is .110"! Kelford says .080" minimum so I can now breathe a sigh of relief. I didn’t get time today to check the exhaust in relation to the intake but I hope to find good news there as well.
Next up, I got back to the cams and valves today. First I got to say, it is a bit of a trick getting a Dial indicator on the lifters but after some time I finally was able to do it. I first set the degrees on the intake cams, once I got them set I checked Valve to piston clearance. I was pleased to find the minimum during the rotation cycle is .110"! Kelford says .080" minimum so I can now breathe a sigh of relief. I didn’t get time today to check the exhaust in relation to the intake but I hope to find good news there as well.
Last edited by ScottURnot; 03-16-09 at 11:03 AM.
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Scott are you still going to check clearances of valve to piston using the clay method. Sometimes one valve might be a little different from others and make contact. Clay and a dry turn of the crank really shows your clearances
#143
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Well I was not planning on do the clay method, I did Checked 3 different pistons with the same result so I should be good.
Last edited by ScottURnot; 03-16-09 at 11:20 AM.
#144
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The "Clay method" is actually less scientific than taking actuall measurements in the rotation cycle. For those that dont know the method I used here it is.
CHECKING PISTON TO VALVE CLEARANCE
When you install a high performance cam, it is possible that there may not be sufficient clearance between valves and pistons when near TDC on overlap. Even if they don't touch when you rotate the crankshaft slowly by hand, they may hit and damage the engine at high revs due to slight "Floating" of the valves, stretch in the rods, deflection in the valve train, and other causes.
We recommend at least .080" clearance between intake valves and pistons at all times, and at least .100" for exhaust valves, which expand more with heat. Add .030" to these figures if you have aluminum rods in the engine to allow for their expansion and stretch.
If you are using aftermarket heads, many of them have modified valve positions and/or valve angles. This may cause valve to piston valve relief alignment problems. If your engine is equipped with an aftermarket head of this type, we recommend checking piston to valve over a broader range. The easiest way of checking piston to valve clearance in an engine, with the cylinder heads installed, is to install a pair of light checking springs in place of the valve springs. These light checking springs will allow you to depress the valve easily at any time during the entire rotation of the engine, enabling you to measure the piston to valve clearance.
If you are going to use rocker arms with a higher than stock rocker ratio now or in the future, you will need to check piston to valve clearance with the higher ratio rocker at this time. (Higher ratio rockers increase gross valve lift). After the light checking springs are installed in place of the standard valve springs, install the rocker arms and then adjust valve lash to zero, zero lash will work best to give you flexibility if at any time you want to tighten or loosen lash to change performance characteristics, and you'll know that you have sufficient clearance.
Be absolutely certain that you use the correct type of lifter for the camshaft that is being checked. This means a flat tappet for a mechanical or hydraulic cam (do not use a hydraulic lifter, as the plunger can move), or a mechanical roller tappet for a roller camshaft. Remember; always use a flat tappet lifter on a flat tappet cam and a roller lifter on a roller cam. As a general rule, the closest point of piston to valve clearance during the rotation of an engine is between 15 degrees and 5 degrees before top dead center overlap for the exhaust valve and between 5 degrees and 15 degrees after top dead center overlap for the intake valve. This sequence takes place during the overlap cycle when both valves are open, 360 degrees from the top dead center compression stroke.
1. With your degree wheel still mounted to the engine in correct TDC position, and the valves adjusted to zero lash, turn the engine in its normal direction of rotation until you come to 15 degrees before top dead center overlap on your degree wheel, then set the tip of the dial indicator on the exhaust valve spring retainer, in line with the movement of the valve. (Figure 8) Preload the dial indicator to about the mid-point of travel, and set to zero. Depress the valve with your finger by pressing on the valve end of the rocker arm until the exhaust valve contacts the piston, make a note of the reading on the dial indicator, and record the clearance. Now, continue turning the engine in its normal direction two degrees at a time, checking and recording the clearance every two degrees until you reach top dead center, on your 7 4/00 803 Figure 8. Degree wheel. Remember, since the valve will be moving, the dial indicator will not return to zero. You can either subtract the difference or reset the dial indicator back to zero each time before you make your clearance check.
2. Move the dial indicator to the intake retainer and start checking the intake piston to valve clearance the same way you checked the exhaust, except begin at top dead center and continue to 15 degrees after top dead center, turning the engine in its normal direction of rotation. The actual position of closest piston to valve clearance will depend on how far advanced or retarded your cam is. Remember, as you advance your cam you will lose intake piston to valve clearance and as you retard your cam you will lose exhaust piston to valve clearance.
CHECKING PISTON TO VALVE CLEARANCE
When you install a high performance cam, it is possible that there may not be sufficient clearance between valves and pistons when near TDC on overlap. Even if they don't touch when you rotate the crankshaft slowly by hand, they may hit and damage the engine at high revs due to slight "Floating" of the valves, stretch in the rods, deflection in the valve train, and other causes.
We recommend at least .080" clearance between intake valves and pistons at all times, and at least .100" for exhaust valves, which expand more with heat. Add .030" to these figures if you have aluminum rods in the engine to allow for their expansion and stretch.
If you are using aftermarket heads, many of them have modified valve positions and/or valve angles. This may cause valve to piston valve relief alignment problems. If your engine is equipped with an aftermarket head of this type, we recommend checking piston to valve over a broader range. The easiest way of checking piston to valve clearance in an engine, with the cylinder heads installed, is to install a pair of light checking springs in place of the valve springs. These light checking springs will allow you to depress the valve easily at any time during the entire rotation of the engine, enabling you to measure the piston to valve clearance.
If you are going to use rocker arms with a higher than stock rocker ratio now or in the future, you will need to check piston to valve clearance with the higher ratio rocker at this time. (Higher ratio rockers increase gross valve lift). After the light checking springs are installed in place of the standard valve springs, install the rocker arms and then adjust valve lash to zero, zero lash will work best to give you flexibility if at any time you want to tighten or loosen lash to change performance characteristics, and you'll know that you have sufficient clearance.
Be absolutely certain that you use the correct type of lifter for the camshaft that is being checked. This means a flat tappet for a mechanical or hydraulic cam (do not use a hydraulic lifter, as the plunger can move), or a mechanical roller tappet for a roller camshaft. Remember; always use a flat tappet lifter on a flat tappet cam and a roller lifter on a roller cam. As a general rule, the closest point of piston to valve clearance during the rotation of an engine is between 15 degrees and 5 degrees before top dead center overlap for the exhaust valve and between 5 degrees and 15 degrees after top dead center overlap for the intake valve. This sequence takes place during the overlap cycle when both valves are open, 360 degrees from the top dead center compression stroke.
1. With your degree wheel still mounted to the engine in correct TDC position, and the valves adjusted to zero lash, turn the engine in its normal direction of rotation until you come to 15 degrees before top dead center overlap on your degree wheel, then set the tip of the dial indicator on the exhaust valve spring retainer, in line with the movement of the valve. (Figure 8) Preload the dial indicator to about the mid-point of travel, and set to zero. Depress the valve with your finger by pressing on the valve end of the rocker arm until the exhaust valve contacts the piston, make a note of the reading on the dial indicator, and record the clearance. Now, continue turning the engine in its normal direction two degrees at a time, checking and recording the clearance every two degrees until you reach top dead center, on your 7 4/00 803 Figure 8. Degree wheel. Remember, since the valve will be moving, the dial indicator will not return to zero. You can either subtract the difference or reset the dial indicator back to zero each time before you make your clearance check.
2. Move the dial indicator to the intake retainer and start checking the intake piston to valve clearance the same way you checked the exhaust, except begin at top dead center and continue to 15 degrees after top dead center, turning the engine in its normal direction of rotation. The actual position of closest piston to valve clearance will depend on how far advanced or retarded your cam is. Remember, as you advance your cam you will lose intake piston to valve clearance and as you retard your cam you will lose exhaust piston to valve clearance.
#147
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Almost have all my stuff ready for the powdercoaters! Still cant decide if I should heat coat my beautiful polished headers or leave them stainless.
#149
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Well, I am trying to decide what to do about throttle body selection. Right now I have three choices
Choice #1 is the stock. Stocker is 70mm dia. I dont think this is even a option.
Choice #2 is the Nissan Q45 TB. This unit is 80mm dia. This was my original plan until I realized the GM units had a IACV on them.
Choice #3 is the GM TB. This unit is a 75mm. I have 2 of these, one is stock and I was considering machining it out to around 78mm like John Cribb's is. Is the trouble worth 3mm? The other unit I have is modified. It has the following mods.
Ported and polished throat / interior.
Polished return spring
Shaved / sanded & polished exterior.
Throttle blade is thinned and polished.
Blade screws are cut and reinstalled with thread-lock.
Bump stop modified to ensure fully opened operation.
Shaft cut / halved to reduce air restriction.
IACV and TPS sensors.
IACV polished.
IACV/TPS screws polished.
Here are some pictures
Left to right Stock/GM/Nissan
Now here is a look in the throat of the GM
Side of the GM, it sure is nice and short.
Now a look through it with the butterfly open. Notice the cut shaft, I think removing half the shaft to open it up and help air flow has some nice merit to it. Also the flush screws help and of course the ported polished bore helps. The only thing stopping me on this TB is its 75mm bore.
Nissan opened, Note shaft still there.
Stocker opened
So, What do You guys think? is 75mm going to feed my engine enough?
Choice #1 is the stock. Stocker is 70mm dia. I dont think this is even a option.
Choice #2 is the Nissan Q45 TB. This unit is 80mm dia. This was my original plan until I realized the GM units had a IACV on them.
Choice #3 is the GM TB. This unit is a 75mm. I have 2 of these, one is stock and I was considering machining it out to around 78mm like John Cribb's is. Is the trouble worth 3mm? The other unit I have is modified. It has the following mods.
Ported and polished throat / interior.
Polished return spring
Shaved / sanded & polished exterior.
Throttle blade is thinned and polished.
Blade screws are cut and reinstalled with thread-lock.
Bump stop modified to ensure fully opened operation.
Shaft cut / halved to reduce air restriction.
IACV and TPS sensors.
IACV polished.
IACV/TPS screws polished.
Here are some pictures
Left to right Stock/GM/Nissan
Now here is a look in the throat of the GM
Side of the GM, it sure is nice and short.
Now a look through it with the butterfly open. Notice the cut shaft, I think removing half the shaft to open it up and help air flow has some nice merit to it. Also the flush screws help and of course the ported polished bore helps. The only thing stopping me on this TB is its 75mm bore.
Nissan opened, Note shaft still there.
Stocker opened
So, What do You guys think? is 75mm going to feed my engine enough?
#150
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IDK man Q45 is 86mm or close to that.... Honestly I would go with Nissan. You might not need it at the power level you're going to be at, but you know that if you decide to get really serious with it one day then it's one less thing you have to change and worry about. Just my two cents. The chance of the shaft for the butterfly valve being a factor is extremely minimal when you take into consideration the entire volume of the ID of the TB.