Leak down test

[bcjjones]

Where did you get your leak down tester and how much did you pay?

Harbor freight has one for cheap but have read bad reviews. Anyone on here have that one?

Also while doing the leak down check, I do have to remove the cams? And if I do, do I still need to find tdc on each cylinder?

Appreciate any help fellas

 

[Str8_Crazy]

I dont have one but i use my friends. His is from snap-on I believe and i dont know how much he paid sorry. Well i havent done a leak down test on a dsm but i dont think you should have to take the cams off. And ya you have to have it at TDC.

 

[95eclipser]

I dont have one but i use my friends. His is from snap-on I believe and i dont know how much he paid sorry. Well i havent done a leak down test on a dsm but i dont think you should have to take the cams off. And ya you have to have it at TDC.

I dont know of any leak down test that requires you to take the cams out of a car.

Evo, sti, civic, dsm, 350z ect ect. none have had the cams removed. you are right about the TDC part tho.

snap on, autozone, champs all sell them.

 

[bcjjones]

Tried autozone they said they only have a compression tester. Don't wanna pay an arm and a leg for a snap on.

Okay so I don't even have to remove valve cover then? Was told it had to be removed the to get all the valves closes but I guess finding TDC would put them closed for that cylinder anyways.

 

[Str8_Crazy]

Tried autozone they said they only have a compression tester. Don't wanna pay an arm and a leg for a snap on.

Okay so I don't even have to remove valve cover then? Was told it had to be removed the to get all the valves closes but I guess finding TDC would put them closed for that cylinder anyways.

When you really think about it snap on is worth it because u have lifetime warranty on all their tools i believe.

No you shouldnt have to remove the valve cover because if i remember right ## just pushing air in through the spark plug holes. Having the engine at TCD should have the valves closed aslong as your on a compression stroke.

 

[bcjjones]

How would yall get the the piston to TDC? Easiest way i guess is a better question. I guess a wrench on the crankshaft pulley?

Okay and say i did remove the cams, and the valves were all closed due to that. Would I still need to find TDC?

 

[jgore1989]

. yes you would still have to set it to tdc if you pulled the cams. because you would have to retime it. why do all that work when all you have to do is take a 1/2 inch ratchet and set the crank puuley to tdc on your timing cover. look in your chiltons or a little searching or vfaq on how to set it to tdc. it only takes about a min if that and is really simple. its alot easer just to set it to tdc then do your boost leak test. no point in doing all that extra work for no reason.

 

[Str8_Crazy]

Just use a 1/2 inch ratchet and turn it. I wouldnt even bother taking of the cams. Makes more of a hassle with retiming it. Usually if u put ## hand over the spark plug hole u can feel wen its on a compression stroke because you feel the air coming up. Once it stops you know its at TDC

 

[jgore1989]

or better yet and to tell more accurately take the spark plug out of the number one cylinder and put a long srewdriver or wooden dowell in it and turn the crank until the screwdriver reaches its highest point. that will tell you tdc

 

[Str8_Crazy]

or better yet and to tell more accurately take the spark plug out of the number one cylinder and put a long srewdriver or wooden dowell in it and turn the crank until the screwdriver reaches its highest point. that will tell you tdc

Thats a good way too but you gotta make sure your not at tdc at the start of an intake stroke because then one valve will be open. Best way i would say is to do both of our ways put ## hand over the spark plug hole and once u start feeling air then put the screw driver in the hole.

 

[bcjjones]

Yea i understand all that. But wouldnt i need to find TDC for each cylinder?

 

[Calan]

Yea i understand all that. But wouldnt i need to find TDC for each cylinder?

You could just read this:

http://www.dsmtuners.com/forums/articles-engine-fuel/338152-compression-leak-down-testing.html

 

[Str8_Crazy]

Well once you get it at TDC on the first cylinder, turning the crankshaft half a turn would get you TDC on the next firing cylinder according to firing order.

 

[bcjjones]

I actually found that link on another post. Thanks though its very helpful.

How the heck do yall get a wrench down on the crankshaft pulley? Seems almost impossible to me.

 

[bryanwheat]

I actually found that link on another post. Thanks though its very helpful.

How the heck do yall get a wrench down on the crankshaft pulley? Seems almost impossible to me.

From the bottom. A breaker bar and socket works way better also.

 

[bcjjones]

And also how the heck do yall turn the crankshaft while also still being able to see the top of the engine? Im guessin and extension or cheater bar, or am I looking that the wrong pulley here?

I could do it easily on my truck, have done compression test before on it, but the crankshaft pulley was in the front of the engine. Much easier done

 

[91-talon-tsi]

You'll have to get someone to watch the cam timing marks while you turn the crank, or turn the crank in small increments and keep checking the cam timing marks.

 

[bryanwheat]

You'll have to get someone to watch the cam timing marks while you turn the crank, or turn the crank in small increments and keep checking the cam timing marks.

I just pressurize it and turn the crank until the valves are sealed. IF you do the test at tdc than you will have to wedge the breaker bar in on the suspension because the air pressure that you are inserting will be pushing down on the piston. You will have about 400 lbs of pressure pushing down on the piston with just 50 psi of air pressure in there.

 

[nickk90]

OTC makes a leakdown tester that goes for about $55 or so. I got mine from tooltopia they got the best prices on tools.

 

[bcjjones]

Just used the harbor freight tool. It does suck as bad as the reviews. Doesnt work as intended at all. Leak percentage never read correctly. Figured out that three of the cylinders were leaking out of the exhaust pretty heavily. The fourth was fine. So i tore into it and it only took me two hours to take the head off!! Much easier then my dodge. Filled the exhaust ports up with wd-40 and sure enough most of them were leaking. Then filled up the intake ports and all those valves were holding perfectly. The previous owner said he had a valve job done about 6 months before i bought the car. Didnt beleive him after the compression test but all the valves look pretty new. I just think the exhaust vavles werent seated at all, or someone did a very poor job. Ill have my buddy who owns a shop re seat them for little to no cost at all.

Thanks for all the help fellas!!!!

 

[pboglio]

Any leakdown tester I'm sure will be fine. Just pressurize the cylinder(s) to maybe 40 psi, then start manually rotating the crank shaft clockwise until everything seals up tight, then kick the regulator up to 100 psi, you can hold the crank with a long breaker bar or long ratchet handle wedged against the ground.

Regarding compression tests, they are also quite useful as they can test at a much higher pressure than the leakdown tester and they are also dynamic. The problem with leakdown testers is that they test leakage at TDC, but not any other piston positions. This is why I use both compression and leakage tests in conjunction.

If you are within 14 psi cylinder to cylinder on the compression tests you are fine. As far as leakdown tests, some say 10% leakage is the threshold, others say 15%.

I've had in the past problems with pushing coolant under boost. I was literally stretching the head bolts and pushing coolant past the headgasket. No compression or leakdown test can simulate 2000 psi in the cylinders.