cam swap help
Thread Starter
Junior Member
Joined: Oct 2007
Posts: 96
Likes: 0
From: Astoria, N.Y.
Car: 1986 Z28 Camaro, 2002 Audi A4 (DD)
Engine: 350 .30 over w/bang for buck combo
Transmission: 700r4
Axle/Gears: stock for now
cam swap help
I just installed this cam http://store.summitracing.com/partde...4&autoview=sku
into my engine its a rebuilt 70-80 350 Small block with 4 bolt mains i'm reusing the stock pushrods and rockers but changed the lifters..
the problem i am having is when i'm adjusting the rockers at tdc i can't seem to get no lash on the rockers with the valves still closed... any help i need the motor in the car by xmas as a gift 2 my dad
John
into my engine its a rebuilt 70-80 350 Small block with 4 bolt mains i'm reusing the stock pushrods and rockers but changed the lifters..
the problem i am having is when i'm adjusting the rockers at tdc i can't seem to get no lash on the rockers with the valves still closed... any help i need the motor in the car by xmas as a gift 2 my dad
John
Joined: Sep 2005
Posts: 28,025
Likes: 2,496
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: cam swap help
I'm not at all sure what you're saying, or what you're asking. But I'll tell you how to adjust the valves, instead of that.
Look at a lifter. Notice that it has a little plunger, that the push rod sits down in. Notice that it has a little spring, with VERY LIGHT tension. Play with it. Notice how easy it is to push that plunger down.
"Lash" exists when the valve is closed, and the lifter descends down into the bore far enough that the plunger is pushed all the way to the top of its possible travel (against the little retaining clip thing inside the lifter), but the push rod still has "slop" between its tip and the rocker arm. Remember carefully how little pressure that is, and how easy it is to depress it, and don't forget that as you follow the rest of the procedure.
Use the "EOIC" mthod for adjusting the rockers. Which is, when the exhaust for a particular cyl is just opening (exhaust opening, or "EO"), you adjust THAT CYLINDER'S intake valve, and that cyl's ONLY; and when a cyl's intake is just closing (intake closing, "IC"), you adjust THAT CYLINDER'S exhaust valve, and that cyl's ONLY.
So: put your crank socket (since like any good engine builder, you're certainly not using the damper bolt) on the crank, and turn the motor, and observe the valves. Notice that as you turn it, some exhaust valve or other just begins to open. Pick one, and make a note of which cyl it is. (let's say, just as a guess, that it's #4.... doesn't matter which) When you see the #4 exh valve JUST BEGIN to open, adjust #4 intake, such that you just barely take up all the vertical play in the push rod between the lifter and the rocker, but WITHOUT depressing the plunger in the lifter. Once you get it to that point, tighten it ¾ turn farther. Then rotate the crank exactly 90°; at that point, you will observe that the exhaust on the next cyl in the firing order (18436572), which in the above situation would be the #3, will be just opening. Adjust the #3 intake valve as described above. Keep going all the way through the firing order. Once a rocker has been adjusted, DO NOT TOUCH IT AGAIN.
Once you get all 8 intakes adjusted, continue to rotate the crank by hand, and watch intake valves, until you observe one of them just reach the point at which it closes. At that point, adjust that cyl's exhaust valve exactly the same way you just adjusted the intakes. Rotate the crank exactly 90°, and do the next one in the firing order. Carry on through all 8.
That's all there is to it.
Look at a lifter. Notice that it has a little plunger, that the push rod sits down in. Notice that it has a little spring, with VERY LIGHT tension. Play with it. Notice how easy it is to push that plunger down.
"Lash" exists when the valve is closed, and the lifter descends down into the bore far enough that the plunger is pushed all the way to the top of its possible travel (against the little retaining clip thing inside the lifter), but the push rod still has "slop" between its tip and the rocker arm. Remember carefully how little pressure that is, and how easy it is to depress it, and don't forget that as you follow the rest of the procedure.
Use the "EOIC" mthod for adjusting the rockers. Which is, when the exhaust for a particular cyl is just opening (exhaust opening, or "EO"), you adjust THAT CYLINDER'S intake valve, and that cyl's ONLY; and when a cyl's intake is just closing (intake closing, "IC"), you adjust THAT CYLINDER'S exhaust valve, and that cyl's ONLY.
So: put your crank socket (since like any good engine builder, you're certainly not using the damper bolt) on the crank, and turn the motor, and observe the valves. Notice that as you turn it, some exhaust valve or other just begins to open. Pick one, and make a note of which cyl it is. (let's say, just as a guess, that it's #4.... doesn't matter which) When you see the #4 exh valve JUST BEGIN to open, adjust #4 intake, such that you just barely take up all the vertical play in the push rod between the lifter and the rocker, but WITHOUT depressing the plunger in the lifter. Once you get it to that point, tighten it ¾ turn farther. Then rotate the crank exactly 90°; at that point, you will observe that the exhaust on the next cyl in the firing order (18436572), which in the above situation would be the #3, will be just opening. Adjust the #3 intake valve as described above. Keep going all the way through the firing order. Once a rocker has been adjusted, DO NOT TOUCH IT AGAIN.
Once you get all 8 intakes adjusted, continue to rotate the crank by hand, and watch intake valves, until you observe one of them just reach the point at which it closes. At that point, adjust that cyl's exhaust valve exactly the same way you just adjusted the intakes. Rotate the crank exactly 90°, and do the next one in the firing order. Carry on through all 8.
That's all there is to it.
Thread
Thread Starter
Forum
Replies
Last Post