cylinder leak test results.

[99 gst spyder]

I finally did a cylinder leak down test today and with bad results on my build.

Air is mostly heard from these places and air may be escaping from other places as well.

Cylinder #1. Leak from throttle body, and air is coming up from the spark plug wells as well.

Cylinder #2. Throttle body, and #4 spark plug well.

Cylinder #3. Oil cap and dipstick.

Cylinder #4. Air escaping from #4 spark plug well, oil cap and dipstick.

I'm wondering why air is escaping through the spark plug well.

None of the cylinder will hold any % on the gauge. When air is pushed in (up to 90psi), meter on the gauge just goes down on the negative side behind the 100% mark.

Anything during the build that I might of messed up on?

I know I f*ck up bad and I know I'm gonna have to tear it apart again.

Thanks.

 

[BogusSVO]

If it is comming back up the spark plug well, the tool is not seated right, allowing the air to leak out.

Before you just rip back in the engine, try running the leak down test again.

Also did you rotate the engine to bring each cylinder to TDC when you tested it?

 

[99 gst spyder]

If it is comming back up the spark plug well, the tool is not seated right, allowing the air to leak out.

Before you just rip back in the engine, try running the leak down test again.

Also did you rotate the engine to bring each cylinder to TDC when you tested it?

Yes, each cylinder was tdc before testing by cranking the crank sprocket clockwise.

The tool is hand tight, I can try it again to tighten it more and see. But otherwise, I can hear hissing sound from the places that I said.

Again, but how can I be testing cylinder #1 and air coming out of cylinder #2 spark plug well? I don't get it. Should all spark plug be out or just one at a time while performing each test at tdc?

 

[BogusSVO]

Have all the plugs out.

You may need to use a long reach adapter to get a good seal.

Also you may have to be a few degrees BTDC to have the valves seal , Remember the cam will start oping the valves a bit before TDC.

So when doing the test, rock the crank and see if the readings work out

If injecting air in cyl#1 and air comes out #2, you have a compression blown HG

 

[99 gst spyder]

Have all the plugs out.

You may need to use a long reach adapter to get a good seal.

Also you may have to be a few degrees BTDC to have the valves seal , Remember the cam will start oping the valves a bit before TDC.

So when doing the test, rock the crank and see if the readings work out

If injecting air in cyl#1 and air comes out #2, you have a compression blown HG

I don't get it, even with a new composite hg?

 

[chadillac2820]

I'm assuming you had the head resurfaced and pressure checked right?

 

[BogusSVO]

What work did you have done to the head?

checked for warp?

http://www.dsmtuners.com/forums/articles-engine-fuel/341627-how-check-head-warp.html

Surfaced? If so How was it done?
http://www.dsmtuners.com/forums/cyl...0613-why-not-let-your-head-belt-surfaced.html

http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html

 

[YZFR1]

I like to take off my valve cover sometimes when doing a leak down test and make sure that both cams for a given cylinder are positioned on a base circle. This way i know that the valves are as closed as they can be. Since, when at TDC some of my valves usually end up being already cracked open.

Another issue that i have seemed to run into when getting air escaping out of an adjacent cylinder is the intake manifold plenum. Since all cylinders share the plenum it is possible for air to travel into a different cylinder. But that doesn't happen very often just something to look into before changing out the head gasket.

If you repeat the leak down test and have air escaping from an adjacent cylinder every time than chances are it is you headgasket. If it did it just once or something it could be the intake manifold plenum.

Hope this helps. Good luck

 

[99 gst spyder]

What work did you have done to the head?

checked for warp?

http://www.dsmtuners.com/forums/articles-engine-fuel/341627-how-check-head-warp.html

Surfaced? If so How was it done?
http://www.dsmtuners.com/forums/cyl...0613-why-not-let-your-head-belt-surfaced.html

http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html

No work done to head, it wasn't pressure check, deck/resurface or anything. I just swapped it from my other working 1g talon that has 85K, but I have change the valve seals on the head.

redid leak down test.

#1 is at 55%. leaking from oil cap and dip stick.
#2 is at 67%. leaking from #2 well and oil cap and dip stick.
#3 is at 65%. leaking from #1 well and throttle body.
#4 is at 70%. leaking from #3 well and throttle body.

One question, I bought my cylinder leak down tester from a local harbor freight store. The gauge is reading this when not hook to compressor. Is the gauge on the right suppose to be all the way down to the red part or the other way. Is it reading correctly when not pressurized?

First I set it to 0/set, then hook it up to see where the % is at. adjust it louder if I need to hear more.

 

[YZFR1]

I have the same HFT leak down tester. Forget about the second gauge, it stoped working for me on the 1st or 2nd time i tried it . Just use your first gauge, note the reading before sticking it in the cylinder than look at the value after you stuck it. Using the difference in readings calculate the leak down %.

It's a cheap tool but works just as good when used properly

 

[99 gst spyder]

I have the same HFT leak down tester. Forget about the second gauge, it stoped working for me on the 1st or 2nd time i tried it . Just use your first gauge, note the reading before sticking it in the cylinder than look at the value after you stuck it. Using the difference in readings calculate the leak down %.

It's a cheap tool but works just as good when used properly

I'll take it back for an exchange. doesn't seem right.