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1G Boost leak check

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I forgot where I read that you want it TDC so the valves are closed or something like that.

No matter where you put it, some will be open and some will be closed. They can’t all be closed at the same time
 
No matter where you put it, some will be open and some will be closed. They can’t all be closed at the same time
True, but you can position the valvetrain to a point where no more than one set of valves is open in each cylinder. TDC is not one of those positions, think about it.
 
True, but you can position the valvetrain to a point where no more than one set of valves is open in each cylinder. TDC is not one of those positions, think about it.

Yeah but what about the other two cylinders? Are you saying you have to be at tdc to blt? The throttle body is closed

I see this Steve.

https://www.dsmtuners.com/threads/does-the-motor-need-to-be-tdc-to-do-a-boost-leak-test.307590/

I've done about 10 blts and never rotated the crank, and I've seen leaks from a T fitting for boost gauge and afpr hoses that's post tb. Also, it always held pressure for a long time. Enough time to spray down all the areas and inspect them for leaks. Never had an issue after fixing all the boost leaks this way.:idontknow:
 
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Are you saying you have to be at tdc to blt?

No I'm not saying that! What I keep saying is that TDC is the worst time. I know cylinder 4 has got all it's valves open then and the air should rush right through the engine.

Check my math. The only time both the intake valves and the exhaust valves are open is during overlap at the end of the exhaust stroke and beginning of the intake stroke. That happens once every 720 crank degrees in each cylinder or every 180 degrees for all four. If you look at the cam specs you'll see for how long after 0* the exhaust valves are open and you need to advance past that point to make sure it's closed but not so far are to have the intake open on the next cylinder.

The quick answer was 30* ATDC is easy to find on the crank and not close to either event that if you miss being exactly at 30 it won't trip you up.
 
No I'm not saying that! What I keep saying is that TDC is the worst time. I know cylinder 4 has got all it's valves open then and the air should rush right through the engine.

Check my math. The only time both the intake valves and the exhaust valves are open is during overlap at the end of the exhaust stroke and beginning of the intake stroke. That happens once every 720 crank degrees in each cylinder or every 180 degrees for all four. If you look at the cam specs you'll see for how long after 0* the exhaust valves are open and you need to advance past that point to make sure it's closed but not so far are to have the intake open on the next cylinder.

The quick answer was 30* ATDC is easy to find on the crank and not close to either event that if you miss being exactly at 30 it won't trip you up.

I see what you’re saying and don’t ask me to repeat it.
 
Ok. So I can just hook my tester up to my turbo. And slowly add a Max of 15psi since that's what my car is at.

That should be fine. You can test higher also. I run 28psi and test at 40psi. Just be careful and make sure your tool is tight as it can become a projectile.
 
Ok so we I'm at my car doing the BLT and I found it leaking really bad on the outer throttle body gasket and on the bottom where I have the fiav block off plate. Thery're both new gaskets. Idk why they're leaking.

Should I put gasket maker on it?

The only leak I'm seeing and I bet that's my problem why my idle is surging..
 

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