Air leaking from fresh air intake during compression check

[iknowless]

Hey ya'll

So today I blocked the throttle open and pumped air into the #1 (TDC) spark plug hole with an air compressor and adapter @ about 20 psi. I can hear air coming out what seems like the intake side of the engine. I disconnected the fresh air intake hose, and I can definitely feel and hear air coming out.

What symptoms does this indicate? From what I know about compression checks, a little air will blow past the piston ring when they are not oiled and air will hiss out the oil cap, but at TDC all valves are closed, right?

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I checked the rest of the cylinders at TDC, with the same result. Only I also noticed air coming out of the exhaust & the fresh air intake, and at the oil filler cap. When I close the throttle, less air comes out of the intake (to be expected?).

Looking forward to hearing some good reasons!

 

[dented_coffee]

Sounds like your not at the compression stroke. Try turning the crank over again to get it in the compression stroke.

 

[nothingfiction]

+1/ make sure your top dead center compression stroke.

Sounds like piston 1 isn't in compression stroke. try piston # 4 with where your at now.

 

[iknowless]

Thnx for the replies, I have had trouble getting the site to load. :/

The piston was top dead center. I used a plastic straw down the spark plug hole to check. During compression and combustion strokes at TDC, all the valves should be closed? I checked all four cylinders a second time, just to be sure.

Anyways, all of the rocker arms on the intake side POPPED OFF!! The camshaft lobes are all scratched up too!! This is supposed to be a DD, is it possible to repair with the engine in the car, or do I need the head rebuilt?

TY in advance, need advice!!

 

[romeen]

Well, if you're positive that the piston was at TDC of the compression stroke and not TDC of the exhaust stroke (for cylinder #1 this would put the cam dowel pins at 12 o'clock) then you must be leaking air past the intake valves (valve/valve seat).

 

[nuclearr]

Thnx for the replies, I have had trouble getting the site to load. :/

The piston was top dead center. I used a plastic straw down the spark plug hole to check. During compression and combustion strokes at TDC, all the valves should be closed? I checked all four cylinders a second time, just to be sure.

Anyways, all of the rocker arms on the intake side POPPED OFF!! The camshaft lobes are all scratched up too!! This is supposed to be a DD, is it possible to repair with the engine in the car, or do I need the head rebuilt?

TY in advance, need advice!!

Sounds like your valves are bent and your going to need to rebuild the head at least.

 

[iknowless]

Hmm...Yes that makes sense. So not only did the valves bend, when they contacted the piston, but they also shoved the rocker arms into the cam lobes.

I took an engine apart (when 14 years old), but never rebuilt one. I have enough common sense and guts to do it, though. I wouldn't think you can fix the head with the engine in the vehicle.

This sounds like the perfect opportunity to turn my 95 GS into a turbocharged 95 GS hahahaha

OK, if I am serious about this (which I am), I am going to need some help. I have only dreamed about this stuff before. Where do I start?

I imagine the cylinders need to be honed & head resurfaced by a machine shop. Will most machine shops port the head for more air flow?

I am sure the pistons, cam, valve & springs, etc. need to be upgraded...

I know the exhaust will need to be upgraded for higher flow, but what about the intake?

Any advice from wisemen/someone who has done this before?

Wow this is exciting. Looking forward to hearing some d!