How to Perform a Leak Down Test & Interpret Results

Рет қаралды 67,329

Speedway Motors

2 ай бұрын

Пікірлер: 56

@user-wz4po4rx7p 2 ай бұрын

Just means that engine is ready for about 17psi of boost 😆

@eoghanhennessy443 Ай бұрын

Low compression. We will fix that with 20 psi boost 😂

@Mario-G-Man Ай бұрын

🤣🤣🤣🤣🤣

@gorporpio 2 ай бұрын

Forget the gauges. Do it at night when it's real quiet. Connect the air to the plug hole. Listen to the exhaust port. If you hear air, you needa valve job. Do the same with the intake ports. If you hear air, you need a valve job. Ring gaps always leak. The make a pssstss sound. All cylinders should sound the same. Only a broken ring will effect leakdown.

@MikhailScottKy 2 ай бұрын

LOL. if it sat and the rings got stuck you will get a false bad reading. You need to pressurize the oil system and rotate the motor several times to make the rings reseat after sitting. THEN you test.

@xeromorris 2 ай бұрын

Except you have to put each cyl in position with it valves closed which means the crank will be turned and the pistons will move causing the rings to move.

@budgroweryt9947 2 ай бұрын

@@xeromorrisbut the rings will still be dry

@whitlcj1 2 ай бұрын

I do believe soaking with marvel or chain oil could help as well

@MikhailScottKy 2 ай бұрын

@@budgroweryt9947 The rings will be lubricated by rotating the assembly and pressurizing the oil system. How do you think the rings work? They scrape oil off of the walls of the cylinder.

@budgroweryt9947 2 ай бұрын

@@MikhailScottKy if you are rotating it by hand, the oil pressure will not be high enough to lube anything.

@bige9830 Ай бұрын

Performing a leak down will only tell you part of the story of that motor.

@frankquijano6749 2 ай бұрын

Leack down test calls for engine oil introduced thru de spark plug opening, rotate engine and then test.

@Hedgey119 2 ай бұрын

Great for checking bottom end but could be a burned out valve. Probably worth pulling the heads before binning it!

@MoreBollocks-ui2zs 2 ай бұрын

If they actually knew how to do a differential pressure compression test they would follow through with the standard troubleshooting to identify whether its bottom end, intake or exhaust leak.

@michaelbartholomew1038 2 ай бұрын

Differential test will not tell you if you have bad camshaft.

@mystikalxs3996 2 ай бұрын

Sweet tip. Ty

@BernardBouchard-qq9kq Ай бұрын

Piston will go down. Bore scope it. Hook up starter pull plugs run compression test observe everything.

@whitlcj1 2 ай бұрын

Thank you sir

@oso_nomada 2 ай бұрын

Rule #1: Don’t pick up a used LS without KNOWING it’s good😂

@kiwi8. Ай бұрын

You can do it at the junkyard with a big co2 fire extinguisher with homemade fittings

@ronaldhudson5678 2 ай бұрын

Thanks 😅

@danthurman9076 2 ай бұрын

well what about the valves leaking ? That would also show pressure drop. What about a crack in the head, cracked piston, cracked block.

@reddirtfarm7704 Ай бұрын

These are professionals....😵‍💫 lol

@mikelazcano1310 Ай бұрын

Run it outside car , on stand then check, used always a risk

@gabrielmovers8689 Ай бұрын

The same procedure for a 7.3 powerstroke?

@billybadass9031 2 ай бұрын

That's the rings tested. Now bearings, valvetrain, crank, pushrods, gaskets. Is this a test for a healthy motor? Or a motor healthy enough to spend the money on other parts.

@glennmorgan4197 2 ай бұрын

As long as the block isn't cracked you can still get a little life out of it 😊

@rc846 2 ай бұрын

Why are the spark plug wires so close to the hot exhaust manifold? Bad design if you ask me.

@wb3161 Ай бұрын

Crank it over and you can hear if a cylinder has low compression or not

@CROFTY71 2 ай бұрын

I understand the concept. But I'm guessing with different input pressures you're going to have a percentage difference in the blow by as such. Or would I be wrong by saying that. 🤓🤪🇭🇲

@MrSprintcat Ай бұрын

Good motor if you're just swapping it out. but if you want to Hot Rod it not so friendly ,you need a dyno,I'll stick to my 350 chevy

@turkeyboyjh1 Ай бұрын

You don’t need a dyno😂, you don’t even need efi, I used to be all about sbcs and big blocks until I built my first 6.0l Holley 750 lq9 valve springs cam and msd spark box, it made 550 on a chassis dyno after years of beating on it you can make that power with a small block but not for under 2800$

@MrSprintcat Ай бұрын

@turkeyboyjh1 okay your tempting me 😅

@MichaelCuff-qp3oo 2 ай бұрын

How lomg? An hour? 24 hrs.?

@MrChevelle83 2 ай бұрын

noone does this. we just slam the engine in and fired that mug up. when its got a nasty skip we go from there and sometimes pulling the engine to repair it is part of it. lol.

@himwhom 2 ай бұрын

Junkyard LS is getting torn down anyway 🤷‍♂️ Unless your putting it into your daily... EVEN then you can find a good running ls in a rusty truck for 500$

@BoomerangC10 2 ай бұрын

Why though?

@himwhom 2 ай бұрын

@BoomerangC10 why what brother?

@richardkelley779 2 ай бұрын

the only ls you will find for 500 is one that has already been tore down so it needs rebuilt

@himwhom 2 ай бұрын

@richardkelley779 where you from, bro? Fb marketplace a lm7 5.3 (Lm7 is drive by wire.. better for swap) I've got them complete with 140k or less for 500-400$ EVERYWHERE.. 100 million ls engines were made, and the 5300 is the most common..